Quiz 1.
Grade Details – All Questions
Question 1. Question :
(TCO 2) The atomic number of an atom is equal to the number of
Student Answer:
CORRECT protons.
Instructor Explanation: See Chapter 3; the atomic number = number of protons.
Points Received: 2 of 2
Comments:
Question 2. Question :
(TCO 2) Consider a neutral atom with 30 protons and 34 neutrons. The number of electrons in this atom is
Student Answer:
CORRECT 30.
Instructor Explanation: See Chapter 3. In a neutral atom, the number of protons equals the number of electrons. Therefore, the number of electrons in this instance is 30.
Points Received: 2 of 2
Comments:
Question 3. Question :
(TCO 2) Heptane is always composed of 84% carbon and 16% hydrogen. This illustrates the law of
Student Answer:
CORRECT definite proportions.
Instructor Explanation: See Chapter 2.
Points Received: 2 of 2
Comments:
Quiz 2.
EXPERIMENT 5: FACTORS AFFECTING REACTION RATE
This experiment shows that these factors affecting reaction rate so as to increase or decrease the speed of reaction?Discribe the rate of a chemical reaction is influenced by a number of factors: the nature of the reactants, temperature of the reaction, concentration of the reactants, the surface area of the reactants, the presence of a catalyst and the pressure the reaction is under. The rate of a chemical reaction is greater, it needs less time for the amount of reactants to form products. The rate of a reaction can be determined by measuring the time it takes, or for the products to be formed.
The order of reaction with respect to iodide ion?.
The order of reaction with respect to peroxydisulfate ion?
3.Effect of a catalyst on the reaction rate
The order of catalyst activity: MnO2
Give the detail presentation
Quiz 3.
Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) On the electromagnetic spectrum, visible light is immediately between two other wavelengths.
Name them.1) _______
A) infrared and ultraviolet
B) microwave and x-ray
C) gamma ray and ultraviolet
D) infrared and x-ray
E) radio and microwave
2) Calculate the wavelength (in nm) of the blue light emitted by a mercury lamp with a frequency
of 6.88 × 1014 Hz.
2) _______
A) 436 nm B) 675 nm C) 229 nm D) 485 nm E) 206 nm
3) Which of the following occur as the energy of a photon increases? 3) _______
A) the wavelength increases
B) the wavelength gets shorter.
C) the frequency decreases.
D) the speed increases.
E) None of the above occur as the energy of a photon increases.
4) Determine the longest wavelength of light required to remove an electron from a sample of
potassium metal, if the binding energy for an electron in K is 1.76 × 103 kJ/mol.
4) _______
A) 147 nm B) 885 nm C) 68.0 nm D) 387 nm E) 113 nm
5) Calculate the wavelength of an electron (m = 9.11 × 10-28 g) moving at 3.66 × 106 m/s. 5) _______
A) 5.52 × 10-9 m
B) 5.03 × 10-10 m
C) 1.81 × 10-10 m
D) 1.99 × 10-10 m
E) 2.76 × 10-9 m
6) For n = 3, what are the possible sublevels? 6) _______
A) 0, 1 B) 0, 1, 2, 3 C) 0, 1, 2 D) 0
7) What are the possible orbitals for n = 3? 7) _______
A) s, p, d, f B) s, p C) s, p, d D) s
8) Which of the following statements is TRUE? 8) _______
A) We can sometimes know the exact location and speed of an electron at the same time.
B) All orbitals in a given atom are roughly the same size.
C) Atoms are roughly spherical because when all of the different shaped orbitals are
overlapped, they take on a spherical shape.
D) Since electrons have mass, we must always consider them to have particle properties and
never wavelike properties.
E) All of the above are true.
9) Which of the following quantum numbers describes the shape of an orbital? 9) _______
A) Schrödinger quantum number
B) angular momentum quantum number
C) principal quantum number
D) spin quantum number
E) magnetic quantum number
10) Which of the following quantum numbers describes the orientation of an orbital? 10) ______
A) spin quantum number
B) Schrödinger quantum number
C) magnetic quantum number
D) principal quantum number
E) angular momentum quantum number
11) Which of the following quantum numbers describes the size and energy of an orbital? 11) ______
A) magnetic quantum number
B) spin quantum number
C) Schrödinger quantum number
D) angular momentum quantum number
E) principal quantum number
12) If two electrons in the same atom have the same value of “l”, they are 12) ______
A) in the same level, but different sublevel.
B) in the same sublevel, but not necessarily in the same level.
C) in different levels and in different shaped orbitals.
D) in the same orbital.
E) none of the above.
13) Describe the shape of a p orbital. 13) ______
A) three balls
B) spherical
C) eight balls
D) dumbbell shaped
E) four balls
14) Give the numbers for ml for an f orbital. 14) ______
A) -3, -2, -1, 0, 1, 2, 3 B) 0, 1, 2, 3
C) 1, 2, 3, 4 D) -2, -1, 0, 1, 2
15) No two electrons can have the same four quantum numbers is known as the 15) ______
A) Heisenberg uncertainty principle B) Pauli exclusion principle
C) Hund’s rule D) Aufbau principle
16) Only two electrons, with opposing spins, are allowed in each orbital is known as the 16) ______
A) Hund’s rule B) Aufbau principle
C) Heisenberg uncertainty principle D) Pauli exclusion principle
17) Choose the orbital diagram that represents the ground state of N. 17) ______
A)
B)
C)
D)
E)
18) What period 3 element having the following ionization energies (all in kJ/mol)?
IE1 = 1012 IE2 = 1900 IE3= 2910 IE4= 4960 IE5= 6270 IE6 = 22,200
18) ______
A) P B) Mg C) Si D) Cl E) S
19) Place the following in order of increasing IE1.
N F As
19) ______
A) As < N < F
B) As < F < N
C) N < As < F
D) F < N < As
E) F < As < N
20) Identify the species that has the smallest radius. 20) ______
A) anion B) neutral
C) cation D) they are all the same size
21) Identify the number of valence electrons in Cl-1. 21) ______
A) 8 B) 4 C) 7 D) 5 E) 6
22) Give the ground state electron configuration for Br⁻. 22) ______
A) [Ar]4s24p6
B) [Ar]4s23d104p5
C) [Ar]4s23d104p6
D) [Ar]4s23d104p4
E) [Ar]4s24d104p6
23) Which of the following represent the Lewis structure for Cl? 23) ______
A) B) C) D) E)
24) Give the complete electronic configuration for Br-. 24) ______
A) 1s22s22p63s23p64s24d104p6
B) 1s22s22p63s23p64s24p6
C) 1s22s22p63s23p64s23d104p5
D) 1s22s2p63s2p64s23d104p6
E) 1s22s22p63s23p64s23d104p6
25) Which of the following statements is TRUE? 25) ______
A) An ionic bond is much stronger than most covalent bonds.
B) Once dissolved in water, ionic compounds rarely conduct electricity.
C) Ionic compounds at room temperature typically conduct electricity.
D) An ionic bond is formed through the sharing of electrons.
E) None of the above are true.
26) Use Lewis theory to determine the chemical formula for the compound formed between Al and
O.
26) ______
A) Al3O2 B) Al2O3 C) AlO D) AlO2 E) Al2O
27) A single covalent bond contains ________ of electrons. 27) ______
A) 1 pair B) 3 pairs C) 0 pairs D) 2 pairs E) 4 pairs
28) Identify the shortest bond. 28) ______
A) triple covalent bond
B) double covalent bond
C) single covalent bond
D) all of the above bonds are the same length
29) Identify the number of bonding pairs and lone pairs of electrons in water. 29) ______
A) 2 bonding pairs and 1 lone pair
B) 2 bonding pairs and 2 lone pairs
C) 3 bonding pairs and 2 lone pairs
D) 1 bonding pair and 1 lone pair
E) 1 bonding pair and 2 lone pairs
30) Identify the compound with the smallest dipole moment in the gas phase. 30) ______
A) HF B) ClF C) LiF D) Cl2
31) Choose the best Lewis structure for OCl2. 31) ______
A)
B)
C)
D)
E)
32) Give the number of valence electrons for XeI2. 32) ______
A) 18 B) 16 C) 20 D) 22 E) 24
33) Choose the best Lewis structure for SO42⁻. 33) ______
A)
B)
C)
D)
E)
34) Draw the Lewis structure for CO32- including any valid resonance structures. Which of the
following statements is TRUE?
34) ______
A) The CO32- ion contains two C—O single bonds and one C O triple bond.
B) The CO32- ion contains one C—O single bond and two C O double bonds.
C) The CO32- ion contains three C—O double bonds.
D) The CO32- ion contains two C—O single bonds and one C O double bond.
E) None of the above are true.
35) Using Lewis structures and formal charge, which of the following ions is most stable?
OCN⁻ ONC⁻ NOC⁻
35) ______
A) ONC⁻
B) NOC⁻
C) OCN⁻
D) None of these ions are stable according to Lewis theory.
E) All of these compounds are equally stable according to Lewis theory.
36) Place the following in order of increasing bond length.
NO2⁻ NO3⁻ NO
36) ______
A) NO3⁻ < NO2⁻ < NO
B) NO < NO2⁻ < NO3⁻
C) NO2⁻ < NO3⁻ < NO
D) NO < NO3⁻ < NO2⁻
E) NO3⁻ < NO < NO2⁻
37) Use the bond energies provided to estimate ΔH°rxn for the reaction below.
PCl3(g) + Cl2(g) → PCl5(l)
Bond Energy (kJ/mol)
243ΔH°rxn = ?Bond
Cl-Cl
P-Cl331
37) ______
A) -662 kJ B) -243 kJ C) -67 kJ D) -905 kJ E) -419 kJ
38) Determine the electron geometry (eg) and molecular geometry(mg) of BCl3. 38) ______
A) eg=trigonal planar, mg=trigonal planar
B) eg=tetrahedral, mg=trigonal planar
C) eg=trigonal planar, mg=bent
D) eg=trigonal bipyramidal, mg= trigonal bipyramidal
E) eg=tetrahedral, mg=trigonal pyramidal
39) Consider the molecule below. Determine the molecular geometry at each of the 3 labeled
atoms.
39) ______
A) 1=trigonal planar, 2=tetrahedral, 3=trigonal pyramidal
B) 1=tetrahedral, 2=tetrahedral, 3=tetrahedral
C) 1=tetrahedral, 2=tetrahedral, 3=trigonal planar
D) 1=trigonal planar, 2=trigonal pyramidal, 3=trigonal pyramidal
E) 1=trigonal planar, 2=tetrahedral, 3=tetrahedral
40) Place the following in order of increasing F-A-F bond angle, where A represents the central
atom in each molecule.
PF3 OF2 PF4⁺
40) ______
A) OF2 < PF4⁺ < PF3
B) PF4⁺ < PF3 < OF2
C) OF2 < PF3 < PF4⁺
D) PF4⁺ < OF2 < PF3
E) PF3 < OF2 < PF4⁺
41) Place the following in order of increasing dipole moment.
I. BCl3 II. BIF2 III. BClF2
41) ______
A) II < I < III
B) I < III < II
C) II < III < I
D) I < II < III
E) I < II = III
42) Identify the number of electron groups around a molecule with sp hybridization. 42) ______
A) 5 B) 3 C) 1 D) 4 E) 2
43) Identify the number of electron groups around a molecule with sp2 hybridization. 43) ______
A) 5 B) 3 C) 4 D) 1 E) 2
44) Give the electron geometry (eg), molecular geometry (mg), and hybridization for H2O. 44) ______
A) eg=trigonal pyramidal, mg=trigonal pyramidal, sp3
B) eg=tetrahedral, mg=bent, sp3
C) eg=trigonal planar, mg=trigonal planar, sp2
D) eg=tetrahedral, mg=trigonal pyramidal, sp3
E) eg=bent, mg=bent, sp2
45) Give the hybridization for the Br in BrO4⁻. 45) ______
A) sp3d2 B) sp C) sp3d D) sp3 E) sp2
46) Give the hybridization for the S in SF6. 46) ______
A) sp B) sp3d C) sp3 D) sp2 E) sp3d2
Quiz 4.
Match each formula to its correct IUPAC name, and vice versa
Tetracarbon nonahydride
Ca(HCO3)2
Iron (II) sulfite
TiO2
Lead (IV) sulfate
Al (OH)3
Cobalt (II) acetate
HNO2
Ammonium chlorate
HC2H3O2
Quiz 5.
Learning Objectives: Name ionic and covalent compounds and derive their chemical formulas Observe absorption spectra of metal ions using flame test Draw Lewis structures of simple covalent compounds In this laboratory exercise, we will learn how to derive formulas of ionic and covalent compounds and name them. We will also flame test for various metal ions and make models of simple covalent molecules. Read the lab before coming to class. The expectation at Chamberlain (CCN/CU) is that you come to class fully prepared for lab. This lab will involve the use of acids and burners. Be careful and mindful of your surroundings as you handle the chemicals and burners. Always check with your instructor regarding proper waste disposal Listen carefully to the professor’s instructions and work safely Always follow the rules outlined in the safety contract If in doubt of how to use a piece of lab equipment, as you instructor. Improper use of lab equipment can be dangerous or could damage lab materials. If you have any safety concerns, see your instructor. Always dress properly for lab. Be sure to wear closed toed shoes and long pants to lab. In lab, ware your safety equipment including goggles, lab coat, and gloves. Use deionized water (DI water) in your experiments. Exploration 1: Explain the following terms (Complete prior to class). Cation Anion Ionic bond Polar covalent bond Nonpolar covalent bond Hydrogen bond Exploration 2: Ionic compounds Part 2A: Cations and their names Metals form cations by donating electrons in their valence shell to satisfy the octet rule. The name of a cation is the same as name of the element. Complete Table 1 by providing names of cations, their chemical symbols and charges. Part 2B: Anions and their Names Non-metals form anions by accepting electrons to complete their valence shell and satisfy the octet rule. The name of an anion is never the same as the name of the element, but rather is named by adding the suffix –ide. Complete Table 2 by providing names of anions, their chemical symbols and charges. Part 2C: Polyatomic ions and their Names As the name suggests, the polyatomic ions are cations or anions that contain more than one element. Complete Table 3 by providing names of polyatomic ions, their chemical symbols and charges. Part 2D: Naming Ionic compounds Derive the names of the ionic compounds based on the rules discussed above and complete Table 4. Part 2E: Deriving chemical formulas of Ionic compounds In the previous section, we learned about naming ionic compounds. In this activity, we will learn to derive the chemical formulas of ionic compounds. In order to derive chemical formulas, we will follow the following steps. Complete the Table 5 by deriving the chemical formulas. Exploration 3: Covalent compounds Part 3A: Naming Covalent compounds and deriving chemical formula Based on the information given here, complete the Table 6. Complete the following table (Table 7) by deriving chemical formulas of covalent compounds based on the name of the compound. Exploration 4: Flames Test- Identifying the Cation Materials: Solids or 1 M solutions of lithium chloride (LiCl), potassium chloride (KCl), copper sulfate (CuSO4), calcium chloride (CaCl2), sodium chloride (NaCl), 1M hydrochloric acid (HCl), DI water, metal loop, burner Method: Questions: What is the color of the flame of the unknown solution? The unknown contains one of the cations in the table above. Based on the color of the flame, what cation is present in the unknown? Exploration 5: Appearance and Solubility of Ionic and Covalent Compounds Materials: weigh plates, CaCl2, NaCl, sucrose, stearic acid, 8 test tubes, test tube holder, spatula, water, ethanol, and parafilm. Method: Questions: Based on the appearance of the compounds, which would you expect to be ionic and which would you expect to be covalent? Based on the results of the solubility study, which compounds do you expect to be ionic and which compounds do you expect to be covalent. Exploration 6: Conductivity of Ionic and covalent compounds Materials: Water soluble compounds from Exploration 5 and a conductivity meter Method: Questions: Do your identifications of the compounds as ionic or covalent from the conductivity study match the results from Exploration 5? If not, which ones do not match? Based on the results of both Explorations 5 and 6, which of your substances are ionic and which are covalent. Exploration 7: Draw Lewis structures of simple ionic and covalent compounds Part 7A: Lewis Symbols for Ionic Compounds Draw the Lewis symbols to show electron transfers for the following compounds: Part 7B: Lewis Symbols for Covalent Compounds Draw Lewis structures of the following molecules and compounds. Then, comment on the VSPER shape these molecules would have. Reflection: Reflect on 4 key concepts that you learned in this lab exercise. Be specific in your answer (this should require 5-10 sentences).
Quiz 6.
Calculate ΔH for the following reaction: (6 points)
CH4 (g) + O2 (g) ⇌ CO2 (g) + H2O (l)
Compound ΔH
CH4 (g) -74.8 kJ/mol
H2O (l) -285.8 kJ/mol
CO2 (g) -393.5 kJ/mol
2.
The enthalpy change of the reaction (∆Hrxn) is based on the amount of heat generated per gram of substance.
Quiz 7.
1.A1.001 sample of a gas as STP has a mass of 0.759g. The molar mass of the gas is
2. The pressure of 8.4L of nitrogen gas is in a flexible container is decreased to one-half
Its original pressure and its absolute temperature is increased to double the original
Temperature .The volume is now?
3. For an ideal gas, which two valuables are directly proportional to each other( if all other
conditions remain constant)
4. A flexible vessel contain 41L of gas where the pressureis1.2atm. What will be the volume
be when the pressure is 0.76atm, the temperature remaining constant
5 .Which condition of P.T and n respectively are most ideal?
6.How many moles of gas are in a gas sample occupying 1.77L at 623mmHg and 298K
7.All of the following are postulates of the kinetic molecular theory of gas except
8. A particular gas exerts a pressure of 6.23mmHg. What is this pressure in units of atmosphere
9. Consider the following thermochemical equation.
N2(g)+2O2(g) 2NO2(g)+H=66.2Kj
10. According to the following thermochemical equation if 471.0g of NO2 is produced ,how much
Heat is released at constant pressure ? 2NO(g)+O2(g) 2NO2(g) =_114.4Kj
11. Given 4NCl3(g)+3O2(g) 2Al2O3(g) =529.0Kj
Determine H for the following thermochemical equation
Cl(g)+Al2O3(s) ACl3(s)+O2(g)
12. If𝞿=31Kj for a certain process , that process
13. Given
Fe2O(s) + 3CO2(g) 2Fe(s)+3CO2(g) H=26.8Kj
FeO(s)+CO2(g) Fe(s)+CO(g) =_16.5Kj
Determine H for the following thermochemical equation
14. Exactly 273.5 J will raise the temperature of 10.0g of a metal from 25.00C TO 60.00C. What
Is the specific heat capacity of the metal?
15. The energy associated with a speeding bullet is called
16.How much heat is gained by nickel when 29.2g of nickel is warmed from 18.30C to 69.60C. The specific heat of nickel is 0.443J (g 0C)
17. What is the frequency of a photon having a wavelength of 602.5 nm
(c=3.00*103m/s, h=6.63*1034Js,1 meter=1*109nm
18. What is the wavelength of a photon having a frequency of 3.00*1015H2
(c=3.00*108ms, h=6.63*10_34Js, 1 meter=1*109nm
19. What is the wavelength of a photon that has an energy of 4.28*10_18J
(c=3.00*103m/s, h=6.63*_34Js, 1 meter=1*109nm)
20. What is the energy of a photon of electromagnetic radiation with a wavelength of 689.8nm
(c=3.00*103m/s, h=6.63*10_34Js, 1 meter=1*109nm)
Quiz 8.
Chapter 15—Complex Ion and Precipitation Equilibria
MULTIPLE CHOICE
1. Which of the following equations represents the formation constant of Ti(NH3)63+?
2. The formation constant for Zn(NH3)42+ is 3.6 ´ 108. What is the ratio of Zn(NH3)42+ to Zn2+ in 0.010 M NH3?
3. The formation constant for Ag(CN)2-(aq) is 2 ´ 1020. At what cyanide ion concentration is [Ag+] = [ Ag(CN)2-]?
4. Ksp stands for
5. What is the chemical equation that describes the dissolution of calcium iodate in water?
6. What is the chemical equation that describes the dissolution of nickel(II) hydroxide in water?
7. What is the chemical equation that describes the dissolution of silver oxalate, Ag2(C2O4), in water?
8. Which of the following equations is the solubility product of Cu(II) hydroxide, Cu(OH)2?
a.
9. What is the equilibrium constant expression for the dissolution of solid lead oxalate, PbC2O4, in water?
10. What is the equilibrium constant expression for the dissolution of solid calcium fluoride in water?
11. Consider the equilibrium of PbCl2(s) in water.
PbCl2(s) Pb2+(aq) + 2Cl-(aq)
What is the effect of adding NaCl(aq) to the equilibrium solution?
12. Consider the equilibrium of Ca(OH)2(s) in water.
Ca(OH)2(s) Ca2+(aq) + 2OH-(aq)
What is the effect of raising the pH of the solution?
13. Consider the equilibrium of lead sulfide, PbS, in water.
PbS(s) Pb2+(aq) + S2-(aq)
What is the effect of adding PbS(s) to the solution?
14. Consider the equilibrium of magnesium fluoride, MgF2(s), in water.
MgF2(s) Mg2+(aq) + 2F-(aq)
What is the effect of adding perchloric acid (i.e. decreasing the pH of solution)?
15. The Ksp of barium chromate is 1.2 ´ 10-10. What is the concentration of Ba2+ in equilibrium with BaCrO4(s) if [CrO42-] = 4.3 ´ 10-3 M?
16. The Ksp of calcium iodate is 7.1 ´ 10-7. What is the concentration of Ca2+ in equilibrium with Ca(IO3)2(s) if [IO3-] = 3.3 ´ 10-2 M?
17. The Ksp of aluminum hydroxide, Al(OH)3, is 2 ´ 10-31. What pH is required to limit the Al3+ concentration to less than or equal to 1 ´ 10-10 M?
18. The Ksp of calcium phosphate is 1 ´ 10-33. What is the concentration of Ca2+ in equilibrium with Ca3(PO4)2(s) if [PO43-] = 1 ´ 10-5 M?
19. The Ksp of Fe(OH)3(s) is 3 ´ 10-39. What concentration of Fe3+ can exist in solution at pH 3.0?
20. The Ksp of BaSO4 is 1.1 ´ 10–10 at 25°C. What mass of BaSO4 (molar mass = 233.4 g/mol) will dissolve in 1.0 L of water at 25°C?
21. For AgCl, Ksp = 1.8 ´ 10-10. What will occur if 250 mL of 1.5 ´ 10-3 M NaCl is mixed with 250 mL of 2.0 ´ 10-7 M AgNO3?
22. For PbCl2, Ksp = 1.7 ´ 10-5. What will occur if 250 mL of 0.12 M Pb(NO3)2 is mixed with 250 mL of 0.070 M NaCl?
23. For Ca(OH)2, Ksp = 4.0 ´ 10-6. What will occur if 1.0 L of 0.100 M Ca(NO3)2 is prepared in a solution that is buffered at pH 12.50?
24. For Mg(OH)2, Ksp = 6 ´ 10-12. What will occur if 1.0 L of 0.010 M Mg(NO3)2 is prepared at pH 10.00?
25. What is the water solubility of AgI (Ksp = 1 ´ 10-16, MM = 234.8 g/mol) in moles per liter?
26. What is the water solubility of PbI2 (Ksp = 8.4 ´ 10-9, MM = 461 g/mol) in moles per liter?
27. What is the water solubility of Hg2Br2 (Ksp = 6 ´ 10-23) in moles per liter?
28. What is the water solubility of AgCl (Ksp = 1.8 ´ 10-10, MM = 143.4 g/mol) in grams per liter?
29. The Ksp of BaSO4 is 1.1 ´ 10–10 at 25°C. What mass of BaSO4 (molar mass = 233.4 g/mol) will dissolve in 1.0 L of water at 25°C?
30. What volume of water is needed to completely dissolve 100 g of AgBr (Ksp = 5 ´ 10-13, 187.8 g/mol)?
31. What volume of water is needed to completely dissolve 1.0 g of Ag2CrO4 (Ksp = 8.0 ´ 10-12, MM = 331.8 g/mol)?
32. The Ksp of Ca(OH)2 is 5.5 ´ 10–5 at 25°C. What is the concentration of OH–(aq) in a saturated solution of Ca(OH)2(aq)?
33. A saturated solution of lead(II) sulfate can be prepared by diluting 0.0101 g of PbSO4 to 250 mL. What is the Ksp of lead(II) sulfate?
34. At pH 10.0, only 0.019 g of MgCl2 will dissolve per 1 L of solution. What is the Ksp of magnesium hydroxide, Mg(OH)2?
35. The solubility of BaCrO4(s) in water is 3.7 milligrams in 1.0 L at 25°C. What is the value of Ksp for BaCrO4?
36. What is the concentration of Ag+ in a saturated solution of Ag2CrO4 if Ksp = 1 ´ 10-12?
37. What is the concentration of Hg22+ in a saturated solution of Hg2Cl2 if Ksp = 1 ´ 10-18?
38. What is the water solubility of AgCl (Ksp = 1.8 ´ 10-10) in 0.25 M NaCl?
39. What is the water solubility of BaCO3 (Ksp = 2.6 ´ 10-9) in a solution containing 0.20 M CO32-(aq)?
40. What is the water solubility of PbI2 (Ksp = 8.4 ´ 10-9) in 0.15 M KI?
41. What is the water solubility of BaF2(s) in 0.033 M KF(aq) at 25°C? The Ksp of BaF2 is 1.8 ´ 10–7 at 25°C.
42. What is the molar solubility of Fe(OH)3(s) in a solution that is buffered at pH 2.50 at 25°C? The Ksp of Fe(OH)3 is 6.3 ´ 10–38 at 25°C.
43. An aqueous solution contains 0.010 M Br– and 0.010 M I–. If Ag+ is added until AgBr(s) just begins to precipitate, what are the concentrations of Ag+ and I–? (Ksp of AgBr = 5.4 ´ 10–13, Ksp of AgI = 8.5 ´ 10–17)
44. A solution contains 0.10 M Ca2+ and 0.10 M Mg2+. The pH of the solution is raised without changing the volume of the solution. What percentage of Mg2+ remains in solution when Ca(OH)2(s) first begins to precipitate? (Ksp of Ca(OH)2 = 4.0 ´ 10-6 and Ksp of Mg(OH)2 = 7.1 ´ 10-12)
45. What is the net ionic equation for the reaction of iron(III) hydroxide with a strong acid?
46. What is the net ionic equation for the reaction of Ca3(PO4)2 with a strong acid?
47. Determine the equilibrium constant, K, for the following reaction,
Mg(OH)2(s) + 2H+(aq) ® Mg2+(aq) + 2H2O(l)
given the Ksp of Mg(OH)2 is 6 ´ 10-12 and Kw is 1.0 ´ 10-14.
48. Determine the equilibrium constant, K, for the following reaction,
Ca(OH)2(s) + 2H+(aq) ® Ca2+(aq) + 2H2O(l)
given the Ksp of Ca(OH)2 is 4.0 ´ 10-6 and Kw is 1.0 ´ 10–14.
49. What is the net ionic equation for the reaction of KCl with a strong base?
50. What is the net ionic equation for the reaction of ZnS with a strong acid?
51. What is the net ionic equation for the reaction of an aqueous solution of AgNO3 and NH3?
52. Given the following reactions,
AgBr(s) Ag+(aq) + Br–(aq) Ksp = 5.4 ´ 10–13
Ag+(aq) + 2 CN–(aq) Ag(CN)2–(aq) Kf = 1.2 ´ 1021
determine the equilibrium constant for the reaction below.
AgBr(s) + 2 CN–(aq) Ag(CN)2–(aq) + Br–(aq)
53. Consider the reaction
Cu(OH)2(s) + 4NH3(aq) Cu(NH3)42+(aq) + 2OH-(aq) K = 4 ´ 10-7
If the Kf for Cu(NH3)42+ is 1 ´ 1012, what is the value of Ksp for Cu(OH)2?
54. A solution containing an unknown metal ion is analyzed by qualitative analysis. Addition of chloride has no effect on the solution. Addition of H2S at pH 0.5 results in a precipitate. What group of cations is present?
55. Which of the following metals will precipitate as chloride salts: Ag+, Pb2+, Ca2+, K+, and Cu2+?
56. In the qualitative analysis scheme, Mg2+ is a group IV cation. What anion is used to precipitate Mg2+?
57. Which of the boxes below represents solid MX2 in equilibrium with M2+ (squares) and X- (circles)?
58. A soluble ionic species, SX, is dissolved in water. An excess of slightly soluble solid, MX, is added to the solution. Which of the boxes below represents MX in equilibrium with M+ (squares) and X- (circles) in the presence of SX?
59. A solution containing an unknown metal ion is analyzed by qualitative analysis. Addition of chloride has no effect on the solution. Addition of H2S at pH 0.5 results in no precipitate. Addition of H2S at pH 9.0 results in no precipitate. What group(s) of cations may be present?
60. The addition of an anion to dissolve one precipitate from a mixture of precipitates is known as _____ .
Quiz 9.
Homework 6
An ammonia water solution is added at a specified rate to a charge of a formaldehyde water solution. The reaction is instantaneous, that is, as soon as the ammonia and formaldehyde mix they react forming HMT and water; the reaction is also highly exothermic. A cooling jacket surrounds the reactor to cool the liquid.
Process Information:
Initial charge of formaldehyde water solution = 1000 kg
Mass fraction of formaldehyde in the original solution = 0.42
Initial temperature of formaldehyde water solution = 50 oC
Feed flow rate: ; Ammonia mass fraction in feed:
Feed temperature:
Heat capacity of reactants and products:
Heat of reaction (assumed constant):
Overall heat transfer coefficient:
By the way, the jacket volume (volume of liquid in the jacket) is 2 m3. Be careful with the units!
The feeding time is 130 minutes.
a) Assume that the cooling water flow rate is so high that its temperature due to heat transfer hardly increases that is, its exit temperature is also. Find the heat transfer area such that the reactor temperature just rises to by the end of the feeding time.
b) Assume now that the utility plant providing the cooling water is limited in its capacity, and we must remove the assumption of very high cooling flow and thus, constant cooling temperature. It is necessary to find out the water flow rate that experiences no more than increase in temperature, that is, the maximum exit water temperature cannot be over, and at the same time does not allow the reactor’s content to exceed by the end of the feeding time. Use the heat transfer area obtained in (a).
Quiz 10.
MIDTERM: MATSE 201 Exam
1. Which is true regarding the seven crystal systems?
A) they completely define a crystal structure
B) they describe the shape of the unit cell.
C) there are 7 shapes that can completely fill 3D space through translational symmetry
D) all of the above.
2. Which of the following is NOT one of the 7 crystal systems?
A) Tetragonal
B) Rhombohedral
C) Trigonal
D) Face centered cubic
3. Elemental metals do not commonly crystallize in which of the following lattices
A) simple cubic
B) facecentered cubic
C) hexagonal close packed
D) body centered cubic.
4. Which direction has the highest linear density in a crystal of Cu that crystallizes in the fcc? A) [100]
B) [110]
C) [111]
D) (110)
5. Which direction has the highest linear density in a crystal of Na that crystallizes in the bcc? A) [110]
B) [100]
C) [111]
D) (111)
6. In a BCC metal, the plane with the highest planer density is: A) (100)
B) (110)
C) (111)
D) (200)
7. The closest packed plane in a metal FCC structure is: A) (100)
B) (110)
C) (111)
D) (200)
8. Which is TRUE about Bragg’s Law?
A) It defines conditions necessary for diffraction in primitive cells
B) It is insufficient to predict diffraction in nonprimitive cells
C) It relates the the path length difference between to diffracted beams to the lattice dspacing
D) All of the above
9. Which plane will show a peak on a diffraction pattern for alphaFe (metal bcc structure)? A) (100)
B) (220)
C) (210)
D) (221)
10. Which of the following statements about vacancies is true?
A) vacancies are always present in materials
B) as temperature increases, the number of vacancies will increase
C) as temperature decreases, the number of vacancies will increase
D) vacancies are considered linear defects
11. The HumeRothery rules give the conditions to be met for
A) Mixing between two elements
B) Assignment of coordination number
C) The existence of an impurity
D) Complete solid solubility
12.
Which of the following describe the defect represented by AlMg•
A) Aluminum vacancy on a magnesium site
B) Magnesium vacancy on an aluminum site
C) Aluminum substitution on a magnesium site
D) Magnesium substitution on an aluminum site
13. Which of the following could be used to maintain electroneutrality for the substitution of an aluminum atom into a magnesium lattice point?
A) For every two aluminum substitutions, create one oxygen vacancy
B) For every two aluminum substitutions, create a magnesium vacancy
C) Electroneutrality is maintained for this substitution
D) For every two aluminum substitutions, create a magnesium interstitial
14. Which is true regarding dislocations in crystals?
A) they are categorized as being twodimensional defects
B) they occur only in metals
C) they can be described quantitatively by their Burger’s vector
D) cannot be readily detected because they are too small.
15. Twin boundaries, grain boundaries, and stacking faults all represent which kind of defect?
A) Types of dislocations
B) Two dimensional defects
C) Linear defects
D) Point defects
16. Which of the following statements describes Fick’s first law?
A) the diffusivity is proportional to the concentration gradient
B) the net mass flux is proportional to the diffusivity
C) the flux is described by the error function
D) the diffusivity is thermally activated
17. Diffusion in a solid
A) is facilitated by point defects such as vacancies
B) is a function of temperature
C) requires a concentration gradient,
D) all of the above.
18. A condition of nonsteady state diffusion (i.e. the net flux is varying with time) can be described by
A) Fick’s Second law,
B) the Avrami equation
C) an Arrhenius relationship
D) none of the above.
19. Diffusivity has units of
A) mass/time2
B) length2/time
C) mass/length2•time
D) masslength/time
20. Which of the following statements about diffusion is TRUE?
A) As the bond strength is increased, the diffusion coefficient increases
B) The smaller the diffusing species the smaller the diffusivity
C) As atomic packing factor increases, diffusivity increases
D) As bond energy increases, the activation energy for diffusion increases
21.
NaCl crystallizes in the Rocksalt structure illustrated above. (the figure shows multiple unit cells together). Its xray diffraction pattern for lamda = 0.154 nm is also shown. The table attached shows relevant data for atoms and ions which you may find useful to answer the questions, 2124, below.
21. Consider NaCl as well as the compounds MgO, MgS, and KBr which also crystal in the same Rocksalt structure. Which shows the ranking order these compounds from lowest to highest melting point?
A) MgS < MgO < KBr < NaCl
B) MgO < MgS < KBr < NaCl
C) NaCl < KBr < MgS < MgO
D) NaCl < KBr < MgO < MgS
22.
Refer to the picture in question 21. The peak for the (220) takes place at a 2theta value of 45 degrees. Calculate the lattice parameter for NaCl. The value of the lattice parameter is
A) 0.201 nm
B) 0.569 nm
C) 0.109 nm
D) 0.308 nm
23. Refer to the figure in question 21. The calculated the theoretical density of NaCl is A) 13.29 g/cm3
B) 1.05 g/cm3
C) 2.11 g/cm3
D) 0.527 g/cm3
24.
Refer to the figure in question 21. For a similar XRD pattern for MgS (with lamda=0.154 nm) at what diffraction angle (2theta) would you expect the first peak to appear?
A) 30.2 degrees
B) 15.1 degrees
C) 17.9 degrees
D) 35.8 degrees
25.
Refer to figures (i) – (ii) to answer questions 25 – 26 about the specific directions and planes depicted below using proper Miller (or MillerBravais) indices.
25. Which choice indicates the three directions shown in Figure i?
A) (101), (111), (010)
B) [101], [111], [010]
C) [110], [010], [011]
D) None of the above
26. Which choice indicates the plane shown in Figure ii, in question 25? A) [101]
B) (110)
C) [110]
D) (101)
27.
Using a MgCl2 crystal as an example, Which of the following choices describes a Frenkel defect reaction in this material?
A) Null → VMg″ + VCl•
B) MgCl2 → VMg″ + 2Cli•
C)
Cl
MgCl2 → VMg″ + Mgi•• +2Cl x
D) Null → VMg″ + 2VCl•
28.
Using a MgCl2 crystal as an example, If the fraction of intrinsically vacant Mg sites in this crystal is 2.3 x1013 at 500°C and the activation energy for this vacancy formation is Ev = 2.3 eV, calculate the fraction of Mg vacancies expected to exist at 800°C.
A) 3.6 x109
B) 1.1 x104
C) 1.4 x1017
D) 4.6 x1022
29.
Using a MgCl2 crystal as an example, If the compound was MgBr2, how would you expect the slope of the curve to change in a plot of ln (fraction of intrinsically vacant Mg sites) as a function of 1/T?
A) Slope of curve would become positive
B) Slope of the curve would decrease
C) Slope of the curve would increase
D) Slope would stay the same
30.
Using a hydrocarbon gas to carburize the surface of a steel, we obtain a surface carbon content of 1.0 wt%. The initial carbon content of the steel is 0.2 wt%. How long would take at 1000˚C to obtain a carbon concentration of 0.6 wt% at a distance 1mm from the surface? Given: Do = 20 x 106 m2/S; Q = 142 kJ/mol
A) 1.52 x105 hours
B) 1.02 x107 hours
C) 15.2 hours
D) 10.2 hours
Quiz 11.
Pennsylvania State University – MATSE 201quiz 1 1. Ethane (CH3CH3) and Fluoromethane (CH3F) have the same number of electrons and are essentially the same size. However, ethane has a boiling point of 184.5C and fluoromethane has a boiling point of 194.7C. Which answer best explains this 10 degree difference in boiling point in terms of the van der Waals forces present. A) It has nothing to do with van der Waals B) Both molecules have both dispersion and orientation forces present, but fluoromethane is a slightly larger molecule C) Both molecules have dispersion forces, but fluoromethane also has orientation forces present D) Both molecules are non-polar, but fluoromethane is a slightly larger molecule Table for Individual Question Feedback Points Earned: 2.0/2.0 2. Covalent interactions are generally long range (i.e., greater than 10 nm). A) True B) False Table for Individual Question Feedback Points Earned: 2.0/2.0 3. Hydrogen bonding is only found between polar molecules. A) True B) False Table for Individual Question Feedback Points Earned: 2.0/2.0 4. Describe all types of bonding that you would expect to exist in each of the following compounds: a silicon carbide crystal A) Predominantly covalent and some ionic B) Predominantly ionic and some covalent C) Equally ionic and covalent D) Ionic only Table for Individual Question Feedback Points Earned: 2.0/2.0 5. Describe all types of bonding that you would expect to exist in each of the following compounds: potassium fluoride (KF) A) predominantly covalent and some ionic B) ionic only C) covalent only D) predominantly ionic and some covalent Table for Individual Question Feedback Points Earned: 2.0/2.0 6. Describe all types of bonding that you would expect to exist in each of the following compounds: an alloy composed of 90%Al, 7%Si, 3%Mg A) ionic, covalent and metallic B) metallic only C) metallic and ionic D) metallic and van der Waals Table for Individual Question Feedback Points Earned: 2.0/2.0 7. Describe all types of bonding that you would expect to exist in each of the following compounds: zirconia (ZrO2) A) predominantly ionic and some covalent B) predominantly covalent and some ionic C) ionic only D) covalent only Table for Individual Question Feedback Points Earned: 2.0/2.0 8. Describe all types of bonding that you would expect to exist in each of the following compounds: ice A) predominantly ionic and some covalent B) van der Waals only C) predominantly covalent, some ionic and van der Waals D) predominantly ionic and some van der Waals Table for Individual Question Feedback Points Earned: 2.0/2.0 9. Covalent bonding occurs as a result of columbic attraction and the transfer of valence electrons. True or False? A) True B) False Table for Individual Question Feedback Points Earned: 2.0/2.0 10. Metallic bonds are different from covalent bonds in that the shared valence electrons are delocalized. True or False? A) True B) False Table for Individual Question Feedback Points Earned: 2.0/2.0
Quiz 12.
Chapter One
Topic: Introduction to Organic Chemistry
1. Chemical reactions occur as a result of:
A) Attraction between opposite charges
B) Nucleus–Nucleus interactions
C) Motion of electrons
D) Like atoms interacting
E) Combining two chemicals
2. Credit for the first synthesis of an organic compound from an inorganic precursor is generally ascribed to:
A) Berzelius
B) Arrhenius
C) Kekulé
D) Wöhler
E) Lewis
3. What was long thought to be the difference between inorganic and organic compounds?
A) The number of atoms
B) The synthesis of organic compounds required a vital force
C) The molecular weight
D) Inorganic compounds exhibited a strong nuclear force
4. Inorganic compounds were composed exclusively of transition metals Constitutional isomers may not differ in what aspects?
A) Physical properties
B) Atomic connectivity
C) Molecular formula
D) Name
E) Constitution
5. What is the relationship between the following compounds?
H O H H H
H C C H H
C C C
H H
H H C C C C H H H C H
H
A) They are isotopes
B) They are constitutional isomers
C) They are the same structure
D) They are composed of different elements
E) There is no relationship
6. What is the relationship between the following compounds?
H H H H H H
H C C O C H H C C C O H
H H H H H H
A) Resonance isomers
B) Constitutional isomers
C) Empirical isomers
D) There is no relationship
7. Carbon generally forms four bonds and is considered:
A) Tetravalent
B) Divalent
C) Trivalent
D) Monovalent
E) Qudravalent
8. Which of the following compounds are constitutional isomers of each other?
H
H H Br
C C
H C C
C C
H C
Cl H
H
C H
H
Br C H
C H
C Cl
C C
C C
C H
H
H
H C C H C C H
C C
Br C H
H Br H H
C C C H H C C H
C C
Br C H
H H H H
I II
A) I & II
III Cl
IV Cl
B) III & IV
C) I, II & III
D) II, III & IV
E) All of these
9. Which of the following compounds are constitutional isomers of each other?
Cl H
H Cl
H Cl
C C Cl H
H C C Cl
H H Cl H H
H Cl
I II III IV
A) I & II
B) III & IV
C) II & III
D) I & IV
E) All of these
Difficulty Level: Medium
10. Which of the following compounds are constitutional isomers of each other?
H
H H H
H C N C O C C H
H
C
H H
N
H C O
H H H
H C C C N C H
H O
H C C
H H H H
H C C
H H H H
H C N H
H C
I
A) I & II
H
II III IV H H
B) III & IV
C) I, II & III
D) I & IV
E) All of these
11. Draw three constitutional isomers that have molecular formula C4H8BrCl Ans:
H H H H H
H H H H
H H H H
H H Cl H
T
12. Draw three constitutional isomers that have molecular formula C4H8O.
Ans: H H
H H H O H H
H C C C C O H
H C C C C H
H C C C O C H
H H H H
H H H
H H H H
There are additional correct answers
13. What force is not taken into account in the formation of a covalent bond?
A) Repulsion between two positively charged nuclei
B) Repulsion between electron clouds on individual atoms
C) Force of attraction between positively charged nuclei and electrons
D) Repulsion of electrons by neutrons
E) All forces listed are involved in forming a covalent bond
14. What is the correct Lewis dot structure for S?
S S S S S
I
A) I
B) II
C) III
D) IV
E) V
II III
IV V
15. What is the correct Lewis dot structure for C?
C C C C C
I
A) I
B) II
C) III
D) IV
E) V
II III
IV V
16. What is the correct Lewis structure for PH3?
H
H P H
H P H H
P H P H
H H P H H
I H II
A) I
B) II
C) III
D) IV
E) V
P III IV P V
17. What is the correct Lewis structure for COCl2?
C C O
Cl C O Cl
Cl C Cl
Cl O Cl
Cl O
Cl Cl C Cl
I
A) I
B) II
C) III
D) IV
E) V
18. What is the correct Lewis structure for CH3CO2H?
H H O H
H C C O O H
C H C O H
H C O O C H
H H
I II
H O H
H
III
A) I
B) II
C) III
D) IV
E) V
19. Which of the following compounds has two lone pairs on the central atom?
A) CO2
B) SCl2
C) NF3
D) CS2
E) SO3
20. What is the formal charge on oxygen in the following structure?
H
H C O H
H H
A) 2-
B) 1-
C) 2+
D) 1+
E) 0
Section: 1.4 Difficulty Level: Easy
21. What is the formal charge on nitrogen in the following structure?
H
H H
H C N
H H
A) 2-
B) 1-
C) 2+
D) 1+
E) 0
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Easy
22. What is the formal charge on oxygen in the following structure?
H
O
H C H
C C
H H H H
A) 0
B) 1+
C) 2+
D) 1-
E) 2-
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Easy
23. What is the formal charge on oxygen in the following structure?
H O H C C
H H H H
A) 2+
B) 2-
C) 1+
D) 1-
E) 0
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Easy
24. Which of the following structures have zero formal charge on carbon atom?
H H H H
H C
H
I
A) I & III
H C
II H
H C H C
H
III IV
B) II & III
C) III & IV
D) I & IV
E) II & IV
Ans: C
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Easy
25. Which of the following structures have 1- formal charge on sulfur atom?
H
H C S H
H
H C S H
H
S
C H O
H
H
O H C S H
IV
O
H H O S O H
O V
A) I
B) II
I II III
C) III
D) IV
E) V
Ans: A
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Easy
26. Which of the following structures have 1+ formal charge on sulfur atom?
H
H C S H
H
H C S H
H
S
C H O
H
H
O H C S H
IV
O
H H O S O H
O V
A) I
B) II
I II III
C) III
D) IV
E) V
Ans: C
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Easy
27. What are the formal charges on boron and fluorine in the following structure?
F H
F B N H
F H
A) B = 1+, N = 1+ B) B = 1+, N = 1- C) B = 1-, N = 1- D) B = 1-, N = 1+ E) B = 1-, N = 0
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Easy
28. What are the formal charges on boron and oxygen in the following structure?
H H
F C H
F B O
F C H
H H
A) B = 1-, O = 1- B) B = 1-, O = 1+ C) B = 1+, O = 1+ D) B = 1+, O = 1- E) B = 1-, O = 0
Topic: Identifying Formal Charges
Section: 1.4
Difficulty Level: Medium
29. Which of the following structures have 1+ formal charge on the central atom?
H H H H
. . . . . . . .
H : Be : H H : B : H H : N : H H : N : H H : O : H
. . . . . . . .
I
A) I
B) II
C) III
H
II III
H
IV V
D) III & V
E) IV & V
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Medium
30. Which of the following structures have formal charge on at least one atom?
H
H N F H O O H
H C F
H O B O H
I II III H
IV O
H
A) I
B) II
C) III
D) IV
E) None of these
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Medium
31. Which of the following structures have 1- formal charge on nitrogen atom?
H
H C N
H H
C H H C N
H
H H C N
H
H H C
N C H H O N H
H H H H
H H H H H V H
A) I
B) II
C) III
D) IV
E) V
I II III IV
Topic: Identifying Formal Charges Section: 1.4
Difficulty Level: Medium
32. The bonding pattern of oxygen with a formal charge of –1 could be described as:
A) One lone pair of electrons and three single bonds
B) Two lone pairs of electrons and two single bonds
C) Three lone pairs of electrons, and one single bond
D) One lone pair of electrons, one single, and one double bond
E) Zero lone pairs, and two single and one double bond
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Medium
33. In ammonium ion, nitrogen has a valence of 4, and zero nonbonding electrons. What is the correct formal charge of nitrogen with 4 covalent bonds?
A) 2-
B) 2+
C) 1-
D) 1+
E) 0
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Medium
34. What is the correct Lewis structure for nitric acid (HNO3) including the formal charges?
O
H O N O
O N O H O
O H N O
O H O N
A) I
B) II
C) III
D) IV
I II III IV
E) None of these
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Medium
35. What is the correct Lewis structure for hydrocyanic acid (HCN) including the formal charges, if any?
H C N H C N H C N H C N
I II III IV
H C N
V
A) I
B) II
C) III
D) IV
E) V
Ans: B
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Hard
36. What is the correct Lewis structure for SCN— including the formal charges, if any?
A) I
B) II
C) III
D) IV
E) V
Ans: A
Topic: Identifying Formal Charges
Section: 1.4, 1.3 Difficulty Level: Hard
37. What is the correct Lewis structure for N2O including the formal charges, if any?
N
A) I
B) II
C) III
D) IV
E) V
O N N O N N O N N O N N O
I II III IV V
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Hard
38. What is the correct Lewis structure for hydrazoic acid (HN3) including the formal charges, if any?
H N H
N N N H
N N N H
N N N H
N N N
A) I
B) II
C) III
D) IV
E) V
I II III IV V
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Medium
39. Draw Lewis structure for NH2CN including formal charges, if any?
Ans:
H
N C N
H
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Medium
40. Draw Lewis structure for –CH2CN including formal charges? Ans:
H C C N
H
Topic: Identifying Formal Charges Section: 1.4, 1.3
Difficulty Level: Medium
41. Draw Lewis structure for ozone (O3,) including formal charges, if any? Ans:
O O O
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
42. The electronegativity of elements on the periodic table tends to increase .
A) From left to right, top to bottom
B) From right to left, bottom to top
C) From left to right, bottom to top
D) From right to left, top to bottom
E) F
Ans: C
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
43. Which of the following is the least electronegative element?
A) B
B) C
C) N
D) O
E) F
Ans: A
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
44. Which of the following is the most electronegative element?
A) B
B) C
C) N
D) O
E) H
Ans: D
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
45. Which of the following is the least electronegative element?
A) P
B) N
C) Mg
D) Si
E) K
Ans: E
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
46. Which of the following is the most electronegative element?
A) P
B) N
C) S
D) O
E) F
Ans: E
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
47. What is the correct order of increasing electronegativity for Rb, F and O?
A) Rb < F < O
B) Rb < O < F
C) O < F < Rb
D) F < Rb < O
E) None of these
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Medium
48. Which of the following series has the correct order of elements in increasing electronegativity?
A) C < N < B < Br
B) P < N < As < F
C) Li < B < N < F
D) Cl < Cs < C < Co
E) Be < B < Ba < Br
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
49. The Cl—Cl bond is best described as _.
A) Nonpolar covalent
B) Polar covalent
C) Ionic
D) Coordinate covalent
E) None of these
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
50. The C—Cl bond is best described as .
A) Nonpolar covalent
B) Polar covalent
C) Ionic
D) Coordinate covalent
E) None of these
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
51. The bond between potassium and oxygen is best described as .
A) Nonpolar covalent
B) Polar covalent
C) Ionic
D) Coordinate covalent
E) None of these
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
52. The bond between carbon and hydrogen is best described as .
A) Nonpolar covalent
B) Polar covalent
C) Ionic
D) Coordinate covalent
E) None of these
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
53. Which of the following is the correct depiction of induction for a C—F bond?
C F C F C F C F
A) I
B) II
C) III
D) IV
I II
III IV
E) None of these
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
54. Which of the following is the correct representation of dipole for P—Cl bond?
d+ d+ d- d+ d+ d- d- d- d d
P Cl
P Cl
P Cl
P Cl
P Cl
A) I
B) II
C) III
I II
III IV V
D) IV
E) V
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Easy
55. Which of the following is the correct representation of partial charges at the indicated atoms?
II
I III
C H
C
H H
H
A) I = d+; II = d+; III = d+ B) I = d–; II = d–; III = d– C) I = d+; II = d+; III = d– D) I = d–; II = d–; III = d+ E) I = d+; II = d–; III = d+
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Medium
56. Which atom has the most d+ in the following compound?
Br
H C N O
Br
A) N
B) O
C) Br
D) H
E) C
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Medium
57. Which of the following statements best describes the C—Cl bond in the following compound?
H H
Cl C H C C
H H
H
A) nonpolar; no dipole
B) polar; d+ at carbon and d– at chlorine
C) polar; d– at carbon and d+ at chlorine
D) ionic
E) None of these
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Medium
58. Which of the following compounds have both polar covalent and ionic bonds?
A) NH4Br
B) H2O2
C) HCN
D) H2S
E) None of these
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Medium
59. For the following compound identify the polar covalent bonds and indicate the direction of dipole moment using d+ and d-.
O
C H
C
H H
Ans:
d-
H
H
O d-
C d+ H
C
H H
H
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Medium
60. For the following compound identify the polar covalent bonds and indicate the direction of dipole moment using d+ and d-.
O
C H
C N
H H H
Ans:
Topic: Induction and Polar Covalent bond Section: 1.5, 1.3, 1.4
Difficulty Level: Medium
61. For NaSCH3, identify each bond as polar covalent, nonpolar covalent or ionic.
Ans:
polar covalent
H
Na S C H nonpolar covalent
H
ionic
Topic: Induction and Polar Covalent bond Section: 1.5
Difficulty Level: Medium
62. For the following compound, identify each bond as polar covalent, nonpolar covalent or ionic and place a d+ on the most electropositive carbon.
O
C F
H C
Ans:
H H
polar covalent
C d+
H C
H H
F
polar covalent
nonpolar covalent
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
63. Orbitals with the same energy are called .
A) Quantum orbitals
B) Atomic orbitals
C) Antibonding orbitals
D) Bonding orbitals
E) Degenerate orbitals
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
64. What is the letter designation for the following atomic orbital?
A) s
B) p
C) d
D) f
E) g
Ans: B
Topic: Atomic Orbitals
Section: 1.6 Difficulty Level: Easy
65. What is the letter designation for the following atomic orbital?
A) s
B) p
C) d
D) f
E) g
Ans: C
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
66. In quantum mechanics a node (nodal surface or plane) is:
A) location where y is negative
B) location where y is positive
C) location where y2 is positive
D) location where y2 is negative
E) location where y is zero
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
67. Which of the following principle states that ―Each orbital can accommodate a maximum of two electrons with opposite spin‖?
A) Aufbau principle
B) Pauli exclusion principle
C) Hund’s Rule
D) Heizenberg Uncertainty principle
E) Le Chatelier principle
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
68. Which of the following principle states ―When orbitals of equal energy are available, every orbital gets one electron before any gets two electrons‖?
A) Aufbau principle
B) Pauli exclusion principle
C) Hund’s Rule
D) Heizenberg Uncertainty principle
E) Le Chatelier principle
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
69. Which of the following represents ground state electron configuration for phosphorous? A) 1s2 2s2 2p6 3s1 3p4
B) 1s2 2s2 2p6 3s2 3p4 C) 1s2 2s2 2p6 3s2 3p3 D) 1s2 2s2 2p6 3s2 3p2 E) 1s2 2s2 2p6 3s2 3p5
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
70. The atomic number for nitrogen is 7. Which of the following represents ground state electron configuration for nitrogen?
A) 1s2 2s1 2p4
B) 1s2 2p5
C) 2s2 2p5
D) 1s2 2s2 2p3 E) 1s2 2s2 3s3
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
71. Which element has the electron configuration 1s2 2s2 2p6 3s2 3p5?
A) oxygen
B) fluorine
C) sulfur
D) chlorine
E) bromine
Ans: D
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Easy
72. Which element has the electron configuration 1s2 2s2 2p6 3s2 3p3?
A) Cl
B) S
C) P
D) Al
E) N
Ans: C
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
73. What is the electronic configuration for the nitride ion? A) 1s2 2s2 2p0
B) 1s2 2s2 2p2 C) 1s2 2s22p3 D) 1s2 2s22p4 E) 1s2 2s2 2p6
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
74. What is the electronic configuration for the magnesium ion? A) 1s2 2s2 2p63s2
B) 1s2 2s2 2p6 C) 1s2 2s22p4
D) 1s2 2s22p63s1
E) 1s2 2s2 2p63s22p2
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
75. What is the electronic configuration for the oxide ion? A) 1s2 2s2 2p6
B) 1s2 2s2 2p2 C) 1s2 2s22p4 D) 1s2 2s02p6
E) 1s2 2s2 2p63s22p2
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
76. Which element has the following electronic configuration?
1s 2s 2p
A) boron
B) carbon
C) silicon
D) nitrogen
E) fluorine
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
77. Which element has the following electronic configuration?
1s 2s 2p
A) boron
B) carbon
C) silicon
D) nitrogen
E) fluorine
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
78. The following ground state electron configuration violates .
1s 2s 2p
A) the Aufbau principle
B) the Pauli Exclusion principle
C) Hund’s Rule
D) Heisenberg’s Uncertainty principle
E) None of these
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
79. The following ground state electron configuration violates .
1s 2s 2p
A) the Aufbau principle
B) the Pauli Exclusion principle
C) Hund’s Rule
D) Heisenberg’s Uncertainty principle
E) None of these
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
80. The following ground state electron configuration violates .
1s 2s 2p
A) the Aufbau principle
B) the Pauli Exclusion principle
C) Hund’s Rule
D) Heisenberg’s Uncertainty principle
E) None of these
Topic: Atomic Orbitals Section: 1.6
Difficulty Level: Medium
81. Ar, K+, and Cl– have equal numbers of electrons, and are considered isoelectronic. Provide the ground state electron configuration for them.
Ans: 1s2 2s2 2p6 3s2 3p6
Topic: Valence Bond Theory Section: 1.7
Difficulty Level: Easy
82. Constructive interference of waves results in .
A) a wave with smaller amplitude
B) a wave with larger amplitude
C) cancellation of both waves
D) formation of a node
E) Both C & D
Topic: Valence Bond Theory Section: 1.7
Difficulty Level: Easy
83. Destructive interference of waves results in .
A) a wave with smaller amplitude
B) a wave with larger amplitude
C) cancellation of both waves
D) formation of a node
E) Both C& D
Topic: Valence Bond Theory Section: 1.7
Difficulty Level: Easy
84. All single bonds can be classified as:
A) nonpolar covalent
B) polar covalent
C) ionic
D) s bonds
E) p bonds
Ans: D
Topic: Valence Bond Theory Section: 1.7
Difficulty Level: Easy
85. Which of the bonding type has circular symmetry with respect to the bond axis?
A) s bond
B) p bond
C) d bond
D) covalent bond
E) ionic bond
Topic: Molecular orbital Theory Section: 1.8
Difficulty Level: Medium
86. The difference between valence bond theory and molecular orbital (MO) theory is:
A) valence bond theory requires the linear combination of atomic orbitals
B) MO theory requires the linear combination of atomic orbitals
C) valence bond theory considers only individual atomic orbitals
D) Both A & B
E) Both B & C
Topic: Molecular orbital Theory Section: 1.8
Difficulty Level: Medium
87. How many molecular orbitals are formed, when the 1s orbitals of two hydrogen atoms combine to form a hydrogen molecule?
A) 1
B) 2
C) 3
D) 4
E) 5
Topic: Molecular orbital Theory Section: 1.8
Difficulty Level: Medium
88. Which molecular orbitals are formed, when the 1s orbitals of two hydrogen atoms combine to form a hydrogen molecule?
A) Two bonding molecular orbitals
B) Only one bonding molecular orbital
C) One bonding and one antibonding molecular orbital
D) Two antibonding molecular orbitals
E) Only one antibonding orbital
Topic: Molecular orbital Theory Section: 1.8
Difficulty Level: Medium
89. How are electrons distributed in the molecular orbitals, when the 1s orbitals of two hydrogen atoms combine to form a hydrogen molecule?
A) 2 electrons in the bonding molecular orbital
B) 1 electron in the bonding molecular orbital, 1 electron in the non–bonding molecular orbital
C) 1 electron in the bonding molecular orbital, 1 electron in the antibonding molecular orbital
D) 2 electrons in the antibonding molecular orbital
E) 2 electrons in the non–bonding molecular orbital
Topic: Molecular orbital Theory Section: 1.8
Difficulty Level: Easy
90. According to molecular orbital theory the highest energy molecular orbital that is occupied with an electron is referred to as:
A) degenerate
B) antibonding
C) the LCAO
D) the LUMO
E) the HOMO
Topic: Molecular orbital Theory Section: 1.8
Difficulty Level: Easy
91. According to molecular orbital theory the lowest energy molecular orbital that is unoccupied with an electron is referred to as:
A)
Quiz 13.
Make a reading outline for those sections in the class slides/notes and your text that discuss biochemical techniques (Section 3.3 and p. 179 in Nelson/Cox or Section 5.2 in Garrett/Grisham). Pay atte ntion to the following techniques: • Purification • Ammonium sulfate precipitation • Chromatography – Gel filtration/size exclusion (same thing, just two different names) – Ion exchange – Hydrophobic interaction – Affinity chromatography • Detection • Absorption spectroscopy • Gel electrophoresis (Determining the MW and number of subunits in a protein). – SDS and native gels – Isoelectric focusing • Protein assays • Immunological methods (These methods use antibodies). – ELISA – Western immunoblotting To get more at home with some of these techniques and how they are displayed and represented in papers you can look at some of the animations available online. GE healthcare has several animations covering different types of chromatography: http://proteins.gelifesciences.com/knowledge-library/video-hub/ or https://www.youtube.com/user/gelifesciences. Assay of Proteins Total (non-specific) Protein Determination These assays are performed to determine or estimate the amount of all protein in a given sample. 1. UV Absorption – Proteins have a characteristic absorption between 275-280 nm due to the presence of tyrosine and tryptophan residues. 2. Colorimetric Reactions – Several reagents have been developed that bind or complex with proteins to form colored products that can be measured spectrophotometrically Specific Protein Determinations For any purification or characterization of a specific protein, some method must be found to quantitatively detect its presence. 1. Enzyme Activity – As we will see, enzymes are proteins with catalytic activity. An assay for an enzyme that catalyzes a reaction with a readily detectable product can be easily developed. 2. Binding Assays – Some proteins, such as receptors, are often assayed because of their ability to bind to specific ligands. 4. Bioassays – Many proteins, like hormones, have specific biological effects. The effects on a standard tissue, cell, or whole organism can be observed and often quantified Purification of Methyl-coenzyme M Reductase from Methanothermobacter marburgensis To put all the theory about the difference purification steps and techniques in context we will examine the purification procedure of methyl-coenzyme M reductase. This is an enzyme found in methanogenic Archaea that catalyzes the reaction: Membranes vs. cytosol When a purification is performed for the first time, the first step will always be to determine in what part of the cell the activity can be found. After the cells are broken the protein solution is ‘spun-down’ at high speed in a centrifuge. This will cause all the membrane fragments to form a pellet at the bottom. After centrifugation the cytosol can be decanted and kept in a new tube. Buffer can be added to the old tube to resuspend the pellet with the membrane fragments. Now both solutions can be tested for the desired activity. In the case of methyl-coenzyme M reductase it was found that the activity is present in the cytosolic fraction. Therefore the cytosol is collected (2: ‘cell extract’) and used in the next purification step. Ion-exchange chromatography Ion-exchange chromatography is based on the attraction of charged proteins to oppositely charged beads present in a chromatography column Why In order to understand biomolecules, biochemists often need to isolate these molecules from the biological medium and, once isolated, to characterize them chemically. Many techniques are available to accomplish these tasks. In addition, biochemists have found ways to chemically synthesize some biomolecules. In understanding these techniques and procedures you will gain a better understanding of the nature of biomolecules, their functions, and how biochemists manipulate them to gain additional understanding of them. Outcomes 1. Describe the molecular basis for some techniques used to isolate and characterize biomolecules in general, and proteins and amino acids specifically. 2. Select proper techniques or sequence of techniques to accomplish a given isolation or biomolecular characterization. 3. Use critical thinking and problem solving skills to identify necessary tools to elucidate aspects of protein structure. Critical Thinking Questions 1. Which technique(s) could you utilize to separate two proteins that (a) differ greatly by size, (b) differ by pl, and (c) that have similar physical characteristics (e.g. size and pl), but have very different functional characteristics? In each case briefly describe how the separation would be accomplished. 2. On the computer go to the link https://www.youtube.com/watch?v=IWZN_G_pC8U and watch the animation. In this example both protein samples contain 3 bands. Does that mean that we have 3 different proteins in each fraction or are there other possibilities? Discuss the different options (if any). 3. Imagine protein with subunits. This 100 kDa protein has two subunits (70 kDa and 30 kDa) joined by two disulfide bonds. Draw the gel electrophoresis pattern for SDS-PAGE with a lane that includes 2-mercaptoethanol (2-ME) and one lane without 2-ME. Be sure to include a molecular weight (MW) marker lane. Note: 2-ME is one of two commonly used reducing agents. The other is DTT (dithiothreitol). Explain your drawing. Are subunits always kept together with disulfide bonds? 4. Both SDS-PAGE and gel filtration chromatography are used to separate proteins based on size. On the computer go to the link https://www.youtube.com/watch?v=oV5VB5kO3tQ and watch the animation. Imagine you have a mixture of proteins: (b) If your experimental goal is to collect each intact protein for further analysis, would gel filtration or SDS-PAGE be preferable? Why? 5. Watch the animation on ion exchange chromatography on the GE healthcare site: http://proteins.gelifesciences.com/knowledge-library/video-hub/ or https://www.youtube.com/user/gelifesciences. A graph is generated during the purification procedure, the so-called elution profile. Redraw the graph and label all the axes. Explain how such a graph is obtained in the lab. Refer to the labels of the x- and y-axes to help determine what data were collected. What is being detected in the broad gray peak? What is being detected in the colored peaks? How would a scientist wishing to isolate a particular protein use the information given in the plot? 6. What techniques can be used to determine the amount of a specific protein in a sample? What characteristic(s) of the protein does each technique take advantage of? 7 An isoelectric focusing experiment with a protein sample shows that there are 3 protein present with a pI of 3 (protein A), 7 (protein B) and 9 (protein C). Since the focusing experiment can only be done with very small amounts of protein an ion exchange column purification step is designed to separate the three proteins. Describe how you would design this experiment: What column will you use (cation or anion exchange)? What will be the pH of the buffer used in the procedure? Draw the expected elution profile for your column. 8. A biochemist discovers and purifies a new enzyme, generating the purification table below. This is another example of a more realistic set of steps when trying to purify an enzyme for the first time. This includes a lot of trial-and-error. A good examination of the purification table will help to remove unnecessary steps for future purifications. (a) From the information given in the table, calculate the specific activity of the enzyme after each purification procedure. Why do we calculate this? (b) Which of the purification procedures used for this enzyme is most effective (i.e., gives the greatest relative increase in purity)? (c) Which of the purification procedures is least effective? (d) Is there any indication based on the results shown in the table that the enzyme after step 6 is now pure? What else could be done to estimate the purity of the enzyme preparation? (e) Would you advice the biochemist to perform the purification the same way the next time he performs this or would you recommend any changes in the procedure. If any, what changes would you recommend? 9. Refer to the purification table for methyl-coenzyme M reductase. Describe and discuss the different trends in the different columns of the table. For example, the total amount of protein is going down. Is that a good thing or a bad thing? 10. Shown in this document is a very polished purification procedure for methyl-coenzyme M reductase. The first time this enzyme was purified, however, the information provided would not have been enough to decide it was pure at this stage. Discuss, why that is and what other purification steps and or procedures would have been performed to conclude that the enzyme was pure after the Q-sepharose step. After you did this, the professor will provide you with data for an additional purification step. Discuss this new data. Does it confirm your proposal?
Quiz 14.
Three energy barriers Form ES Convert substrate to product release product Rate limiting step Step with highest activation barrier Enzyme substrate binding models lock and key enzyme complime ntary induced fit hypothesis Lock and key Favors ES complex Barrier between ES and EP Enzyme complimentary Substrate changes to fit enzyme Induced fit hypothesis Enzyme and substrate change after initial fit preferred model Types of enzyme catalyzed reactions General acid base catalysis covalent catalysis Metal ion catalysis electrostatic catalysis catalysis through transition state binding Covalent catalysis Forming covalent intermediate with enzyme Covalent Catalysis • Side chains of AAs provide nucleophilic centers for attack on electrophilic centers of substrates. • Form covalent intermediate which can be changed by water or a second substrate for desired product • Ping-pong kinetic mechanisms Glycogen Carbohydrate storage in animal liver Structural polysaccharides Aspartate Asp,D pKa: 3.63 Glutamate Glu,E pKa: 4.25 Serine Ser,S Threonine Thr,T Cysteine Cys,C pKa:8.18 Selenocysteine Sec,U pKa: 5.7 Asparagine Asn,N Glutamine Hyaluronate Proteoglycan Phospho-fructokinase Three steps for dissolving water Important interactions involving water (4) How do polar compounds interact with water? When crystalline substances dissolve in water their is an _ in entropy How is water involved in reaction with non-polar substances?How does water interact with amphipathic compounds? Two examples of water as a reactant Water’s important interactions among biomolecules Effective Concentration Uncommon AA due to modification Uncommon AA due to different side group crystal structure:ribbon model of protein What does the ribbon model represent? What does the ribbon model represent? A separate amino acid chain of a protein, several identical or different chains can make up a protein. Combination of certain secondary structures like a helices and B sheets that can be found in several proteins, forming a protein family. Protein fold How does ammonium sulfate precipitation work? Describe how salting out works Size-Exclusion Chromatography Define hydrophobic chromotography. affinity chromatography: specific interactions What does the purification table describe? The ratio of enzyme activity relative to total protein is called absorbance spectroscopy What does absorbance spectroscopy identify? SDS-PAGE Isoelectric focusing Four steps of protein sequencing Trypsin What can amino acid sequencing tell us? What proteins are associated with the membrane through electrostatic interactions and H bonding with the hydrophilic domainsof integral proteins and the polar head groups of membrane lipids ? Membrane proteins How can peripheral proteins be removed from the membrane What are firmly associated with the membrane, removed only by agents that interfere with hydrophobic interactions, such as detergents, organic solvents, or denaturants. Covalently attached proteins can be removed from the membrane how? fibrous proteins BLOSUM scoring matrices How does BLOSUM scoring matrices work? What amino acids/sequences are most likely to be conserved? Evolutionary relationships Changes at C-terminus Addition of fatty acyl groups Changes in individual AAs Attachment of lipids to individual AAs Denaturation is a loss of _ and _ structure. The _ structure stays intact. What four things denature proteins? How do high temperatures denature a protein? Circular dichroism spectroscopy How is circular dichroism spectroscopy used? How do chaperons DnaJ and DnaK function in protein folding? Prevent folding of parts of the chain until the whole chain has been synthesized Role of ubiquitin in breakdown of cellular proteins What methods are available to detect the folding/unfolding of a protein/enzyme? The binding of a ligand is often coupled to a conformational change in the protein that makes the binding site more complementary to the ligand Why do we need proteins to transport oxygen? Why does oxygen bind to heme C and not a single Fe ion? Amino acids are not capable of binding to oxygen, so this capability is provided by In a multi-subunit protein, a conformational change in one subunit often affects the conformation of other subunits How do different pHs affect hemoglobin? Why are enzymes such good catalysts? What are the benefits of measuring the initial rate of a reaction V0? What does the steady state assumption, as applied to enzyme kinetics, imply? Inhibitors that bind covalently with or destroy a functional group that is essential for the enzymes activity Catalysis Mechanisms: Metal Ion Catalysis Sequential/Single Displacement Reaction leads to the formation of a Double displacement reactions proceed via the formation of _. Three steps of glycolytic pathway that differ from gluconeogenesis Why is gluconeogenesis catalyzed by different enzymes? Steps of glycolysis/gluconeogenesis that differ Main reactive oxygen species What role does the pentose phosphate pathway play in removal of reactive oxygen species? Structural role of sugar What about sugars makes it them good structural features of fibers? 1st 3 steps of enzyme hydrolase Hydrolysis of ATP:Resonance Hydrolysis of ATP:Ionization Hydrolysis of ATP:Standard Conditions Hydrolysis of ATP: Solvation What does the pentose phosphate pathway create How does the pentose phosphate only create NADPH or ribose? How does bifunctional enzyme phosphofructokinase-2/fructose- 2,6-bisphosphatase and product fructose-2,6-bisphosphate regulate glycolysis and gluconeogenesis What happens if a muscle preparation containing glycogen phosphorylase is treated with: phosphorylase kinase and ATP What happens if a muscle preparation containing glycogen phosphorylase is treated with: PP1 What happens if a muscle preparation containing glycogen phosphorylase is treated with: epinephrine How is glycolysis regulated by levels of ATP/AMP How is gluconeogenesis regulated by levels of ATP/AMP? What activates or inhibits phosphofructokinase How is NADH recycled under anaerobic conditions? How is NADh recycled in aerobic conditions?
Quiz 15.
1. Give the general Henderson-Hasselbalch equation and sketch the plot it describes (Ph against amount of NaOH added to a weak acid). On your curve label the pKa for the weak acid, and indicate the region in which the buffering capacity of the system is greatest.
2. Name and briefly define four types of noncovalent interactions that occur between biological molecules.
3. Draw the structure of alanine, leucine, isoleucine, tyrosine, lysine and histidine (At pH 7.0). Give also the three-letter and the one-letter codes. Indicate the pKa of the side groups. (Draw 1 amino acid completely, draw only the R group for the other amino acids).
4. Explain the differences between common and uncommon amino acids
5. Given below is the structure of the polypeptide Glu-Gly-Leu-Ser-Leu-Ser-Lys.
6. What is the charge of the peptide at pH 3.0, pH 8.0, and pH 12?
7. What is the pI of the peptide?
8. A student has purified a protein. The table below describes the followed procedure: The student also prepared an SDS-PAGE gel:
9. Explain the SDS-PAGE technique
10. Can you use this information to tell whether the purification was successful? Note that there are different answers possible. What would be the next logical step to discern between these possibilities?
11. Describe the principle of ion-exchange chromatography
12. Explain in detail the different steps of sequencing a peptide/protein and their purpose
13. What can we learn from sequence alignments
14. A biochemist purified a polypeptide containing 8 amino acids Amino acid analysis showed the following composition:
15. Ala, Glu, Leu, (Lys)2, Met, Tyr, Val The native peptide was incubated with 1-fluoro-2,4-dinitrobenzene (FDNB) and then hydrolyzed; 2,4-dinitrophenylglutamate was identified by HPLC. Incubation of the native peptide with trypsin gave a tripeptide, a tetrapeptide and a single Ala. Incubation with FDNB found a Glu residue for the tripeptide, a Met residue for the tetra peptide. When the native peptide was exposed to cyanogen bromide (CNBr), two tetrapeptides were obtained. Incubation with FDNB found both 2,4-dinitrophenylglutamate and 2,4 dinitrophenyltyrosine. The amino acid composition of one of the pentapeptides was Ala, Lys, Tyr, Val. What is the sequence of the polypeptide?
16. The picture on the right shows the ribbon model of a protein.
17. Explain what the ribbon represents. The ribbon represents the position of the six-atom that lye in the same plane as the peptide bond:
18. What do you see? What is the main type of secondary structure present in this figure? The long stretches of ribbon indicate that the main type of secondary structure is of the b-sheet type. (The sheets are organized as a b-barrel). The remaining structure has a ”random” structure. No α-helices are present.
19. Explain what properties give this type of secondary structure its stability.
20. Can you tell if this is a globular, fibrous or membrane protein? Explain your answer.
21. Why are glycine and proline often found within a β turn?
22. Explain the differences between subunit, domain and fold. Explain the difference between protein families and protein super families
Quiz 16.
BCHE 5180/6180: Spring Final
1. Based on what you have learned about the functioning of enzymes and proteins explain why the pH in the cell has to be buffered.
2. In addition to the pH, also the redox potential needs to stay constant in the cells.
(a) What species are formed that can higher the redox potential of the cytosol?
(b) What species are involved in buffering the potential and remove these species?
(c) What role does the pentose phosphate pathway play in the removal of these
species?
3. For a peptide with the sequence shown below determine the pI. Glu–His–Trp–Ser–Gly–Leu–Arg–Pro–Gly (Hint: If you cannot do that directly, first calculate the charge at different pH values and use those to find the pI region.).
4. The cyanobacterium Nostoc punctiforme can live in symbiosis with plants. The signal peptide nostopeptolide A1 plays an important role in the symbiosis. Some of the amino acids have been modified, like the methyl-proline (mPro), the acetylated Leucine (LeuAc) and there is also a butyrate group attached. Can you assign the remaining amino acids (circled with a solid line).
5. Explain the principle of hydrophobic interaction chromatography. For each of these purifications provide a detailed explanation whether you think the protein is pure or not and whether additional steps are needed to confirm purity. Note that the total activity is indicated, not the specific activity.
6. For each of these purifications provide a detailed explanation whether you think the protein is pure or not and whether additional steps are needed to confirm purity. Note that the total activity is indicated, not the specific activity.
7. In question 6, only the total activity was indicated and not the specific activity.
(a) Explain how these are different.
(b) Would your answers have been different if the specific activity would have been given for each step?
8. Describe/draw in detail the ‘catalytic cycle’ of the folding of proteins by the GroEL/GroES complex. Explain in detail the different steps.
(b) Why does this process require ATP? A folded protein has a much lower potential energy than the unfolded proteins and therefore the folding process should in principle produce energy not require energy.
9. What is the effect of O2, H+, CO2, and 2,3-bisphosphoglycerol (BPG) on Hemoglobin
10. Explain how the effects of sickle cell disease demonstrate that hemoglobin undergoes a conformational change upon releasing oxygen.
11. Write out the Michaelis-Menten equation and the reaction equation that describes the mechanism for enzyme action used as a model by Michaelis and Menten. Under what assumptions and conditions can we use this equation? (List all 5).
12. Describe in details the difference between competitive, noncompetitive and uncompetitive inhibitors. (b) Give a shortly description on how the identity of an unknown inhibitor can be established through simple activity measurements.
13. What does a large KI value for a competitive inhibitor indicate about the potency of the inhibition? Note that the equation that relates KI to values from the graphs is shown below.
14. Describe the basic differences between second order reaction types: Sequential/single displacement reactions vs. double-displacement (ping-pong) reactions.
15. Describe in detail how the sugar code is used to direct white blood cells to sites of inflammation
16. List and explain the five reasons why the hydrolysis of ATP has a large negative ΔG°’ value.
17. Draw the glycolysis pathway from glucose to glyceraldehyd-3-phosphate (include all the structures of the intermediates in the pathway, the names of these compounds, other small molecules, and the names of the enzymes catalyzing the respective reactions).
18. The cofactor thiamine pyrophosphate (TPP) is used by pyruvate decarboxylase
(a) Draw the complete structure of this cofactor
(b) Draw part of the mechanism to explain the important role of this cofactor in the reaction mechanism. Provide an explanation with the drawing.
19. (a) In class we learned that typical metabolic pathways contain some reactions that are close to equilibrium and a few reactions that are for from equilibrium. This has important consequences for how the flux of metabolites through a pathway is regulated. Explain why that is.
(b) Explain how this method of regulation translates into the specific way glycolysis and gluconeogenesis are regulated
20. There are three forms (isozymes) of glycogen phosphorylase: brain (bGP), liver (lGP) and muscle (mGP).
(a) What is the function of this enzyme and how is the activity of mGP and lGP regulated? Indicate the effect of the different types of regulatory compounds on the activity of GP by drawing additional curve in the plot below.
(b) Brain glycogen phosphorylase is also regulated by H2O2. Explain what how that works and what the positive and possible negative effects are of this type of regulation.
Quiz 17.
Matching Choose the correct answer from the list. Not all the answers will be used. A) HDL B) propionyl-CoA C) LDL D) Dihydroxyacetone phosphate E) malonyl-CoA F) ACP G) chylomicrons H) pho sphopantetheine I) flavin J) albumin K) ketone bodies L) cholesterol 1. Lipoproteins formed in the intestinal mucosal cells are called . Section: 20.1.B Level of Difficulty: Easy Learning Objective: Lipid Digestion, Absorption, and Transport 2. Cholesterol and other lipids are transported from tissues to the liver by . Section: 20.1.B Level of Difficulty: Easy Learning Objective: Lipid Digestion, Absorption, and Transport 3. The glycerol backbone of triacylglycerols is catabolized to . Section: 20.1.B Level of Difficulty: Easy Learning Objective: Lipid Digestion, Absorption, and Transport 4. Free fatty acids bind to for circulation in the bloodstream. Section: 20.2 Level of Difficulty: Easy Learning Objective: Fatty Acid Oxidation 5. Cells take up by receptor mediated endocytosis. Section: 20.1.B Level of Difficulty: Easy Learning Objective: Fatty Acid Oxidation 6. The b oxidation of odd-numbered fatty acids results in as a final product. Section: 20.2.E Level of Difficulty: Easy Learning Objective: Fatty Acid Oxidation 7. The molecules acetoacetate, acetone, and D-b-hydroxybutyrate are metabolic fuels termed . Section: 20.3 Level of Difficulty: Easy Learning Objective: Ketone Bodies 8. Acyl carrier protein (ACP) contains a prosthetic group. Section: 20.4.C Level of Difficulty: Easy Learning Objective: Fatty Acid Biosynthesis 9. Fatty acid synthesis requires both acetyl-CoA and as initiator molecules. Section: 20.4.B Level of Difficulty: Easy Learning Objective: Fatty Acid Biosynthesis 10. is formed from ordered sequence of condensation of isoprene units. Section: 20.7.A Level of Difficulty: Easy Learning Objective: Cholesterol Metabolism Multiple Choice 11. Digestion of triacylglycerols is aided by the cholesterol derivatives synthesized by the liver known as A) bile acids. B) lipoproteins. C) lanosterols. D) chylomicrons. E) colipases. Section: 20.1.A Level of Difficulty: Moderate Learning Objective: Lipid Digestion, Absorption, and Transport 12. Which of the following would result in a net increase in uptake of LDL by the liver? A) increased availability of LDL receptors B) high levels of cholesterol synthesis C) increased availability of clathrin triskelions D) all of the above E) none of the above Section: 20.1.B Level of Difficulty: Difficult Learning Objective: Lipid Digestion, Absorption, and Transport 13. Which of the following is required for entry of fatty acids into the oxidation pathway? I. priming via the enzyme acyl CoA synthetase II. conservation of free energy from ATP hydrolysis by use of a thioester linkage III. transport to the cytosol for oxidation via a carnitine carrier protein IV. hydrolysis of carnitine palmitoyl transfer protein A) I, II B) I, II, III C) I, II, III, IV D) III, IV E) I, III Section: 20.2.A Level of Difficulty: Difficult Learning Objective: Fatty Acid Oxidation 14. Which of the following vitamins is part of the prosthetic group 5¢-deoxyadenosylcobalamin? A) B1 B) B2 C) B6 D) B12 E) none of the above Section: 20.2.E Level of Difficulty: Easy Learning Objective: Fatty Acid Oxidation 15. , a condition in which acetoacetate production exceeds it metabolism and results in a sweet breath odor due to nonenyzmatic of acetoacetate to . A) ketosis; decarboxylation; hydroxylbutryate B) ketosis; carboxylation; hydroxylbutryate C) ketosis; carboxylation; acetone D) glyceroneogenesis; decarboxylation; hydroxylbutryate E) glyceroneogenesis; decarboxylation; acetone Section: 20.3 Level of Difficulty: Moderate Learning Objective: Ketone Bodies 16. Triacylglycerols are synthesized by during times of starvation via a process known as . A) Dihydroxyacetone phosphate; ketosis B) Dihydroxyacetone phosphate; glyceroneogenesis C) acetyl CoA; ketosis D) acetyl CoA; glyceroneogenesis E) ketone bodies; ketosis Section: 20.4.E Level of Difficulty: Moderate Learning Objective: Fatty Acid Biosynthesis 17. Two phosphatidylglycerol molecules condense to form the molecule , and glycerol is eliminated as the side product. A) phosphatidic acid B) cardiolipin C) plasmalogen D) sphingomyelin E) squalene Section: 20.6.B Level of Difficulty: Easy Learning Objective: Synthesis of Other Lipids 18. The activity of lipases is controlled in part by a process known as which functions effectively due to the where lipases are active. A) interfacial activation; lipid-water interface B) lipase activation; lipid-water interface C) lipase activation; bile salt-water interface D) micelle activation; water-salt interface E) none of the above Section: 20.1.A Level of Difficulty: Moderate Learning Objective: Lipid Digestion, Absorption, and Transport 19. Which of the following accurately ranks lipoproteins from highest to lowest density? A) chylomicrons > HDL > LDL > IDL > VLDL B) HDL > IDL > LDL > VLDL > chylomicrons C) HDL > LDL > IDL > VLDL > chylomicrons D) chylomicrons > VLDL > IDL > LDL > HDL E) VLDL > IDL > LDL > HDL > chylomicrons Section: 20.1.B Level of Difficulty: Moderate Learning Objective: Lipid Digestion, Absorption, and Transport 20. Which of the following statements about apolipoproteins (with the possible exception of apoB-100) is TRUE? I. The apolipoproteins are water-soluble and loosely associate with the lipoproteins. II. The apolipoproteins contain helices with hydrophobic and hydrophilic groups on opposite sides of the helical cylinder. III. The apolipoproteins are synthesized in the intestinal tissues. IV. The apolipoproteins appear to float on the surface of phospholipids. A) I only B) I and II C) III, IV D) I, II, III E) I, II, IV Section: 20.1.B Level of Difficulty: Moderate Learning Objective: Lipid Digestion, Absorption, and Transport 21. Knoop’s experiments with fatty acids A) involved the novel use of chemical labels to elucidate metabolic mechanisms. B) demonstrated that fatty acids are broken down by two carbons at a time by oxidation at the ω carbon. C) demonstrated a distinct difference in the mechanism of odd chain versus. even chain fatty acid oxidation. D) A and B E) A, B, and C Section: 20.2 Level of Difficulty: Difficult Learning Objective: Fatty Acid Oxidation 22. Which of the following statements about peroxisomes is FALSE? A) b oxidation in peroxisomes can shorten very long fatty acids. B) Mammalian peroxisomes can synthesize some lipids, including bile salts. C) In plants, peroxisomes and glyoxysomes serve as the site of b oxidation. D) Long chain fatty acids are transported into the peroxisome via a carnitine carrier protein where they are activated for oxidation. E) b oxidation in peroxisomes varies slightly from the mitochondrial process. Section: 20.2.F Level of Difficulty: Difficult Learning Objective: Fatty Acid Oxidation 23. An important structural lipid found in nerve cell membranes, , is a type of . A) sphingomyelin, phospholipid B) phosphatidylcholine, phospholipid C) palmitate, glycerophospholipid D) glucagon, hormone E) none of the above Section: 20.6.B Level of Difficulty: Moderate Learning Objective: Synthesis of Other Lipids 24. Pain and inflammation are triggered by which are synthesized by an enzyme inhibited by . A) cardiolipins; aspirin B) prostaglandins; aspirin C) analgesics; statins D) prostaglandins; COX-1 E) cyclooxygen; NSAIDS Section: 20.6.C Level of Difficulty: Moderate Learning Objective: Synthesis of Other Lipids 25. Cholesterol is a precursor to I. prostaglandins II. vitamin K III. steroid hormones such as androgens 164 IV. bile acids A) I, III, IV B) I, II, III, IV C) III only D) IV only E) III, IV Section: 20.7 Level of Difficulty: Easy Learning Objective: Cholesterol Metabolism 26. Which of the following best describes arachidonic acid? A) a 20-carbon isoprene-based intermediate of cholesterol synthesis B) a 20-carbon fatty acid essential for cholesterol synthesis C) a 20-carbon isoprene-based compound used for synthesis of prostaglandins D) a 20-carbon fatty acid used for synthesis of prostaglandins E) a 2-carbon compound that functions in conjunction with a fatty acid carrier protein for transport of primed fatty acids Section: 20.6.C Level of Difficulty: Easy Learning Objective: Synthesis of Other Lipids 27. Which of the following compounds are required to make sphingosine? I. palmitoyl-CoA II. serine III. acetyl-CoA IV. isoprene V. arachidonic acid A) I, II B) I, III C) II, IV D) IV, V E) II, V Section: 20.6.B Level of Difficulty: Moderate Learning Objective: Synthesis of Other Lipids 28. In which location listed below does the following reaction take place? HMG-CoA → acetoacetate + Acetyl-CoA A) cytosol of cardiomyocytes B) mitochondria of cardiomyocytes C) cytosol of liver cells D) mitochondria of liver cells 165 E) all of the above Section: 20.3 Level of Difficulty: Moderate Learning Objective: Ketone Bodies 29. In which cellular compartment does the following reaction take place? HMG-CoA + 2 NADPH → mevalonate + 2 NADP+ + Acetyl-CoA A) cytosol of liver cells B) mitochondria of liver cells C) cells in the intestinal lumen D) lysosomal fluid E) all of the above Section: 20.7.A Level of Difficulty: Moderate Learning Objective: Cholesterol Metabolism 30. Which enzyme catalyses the key regulatory step of cholesterol synthesis? A) b-ketothiolase B) HMG-CoA synthase C) HMG-CoA reductase D) mevalonate-5-phosphotransferase E) phenyltransferase Section: 20.7.A Level of Difficulty: Easy Learning Objective: Cholesterol Metabolism 31. Sphinganine is an intermediate in the synthesis of which of the following? I. ceramides II. spingomyelins III. cerebrosides IV. prostaglandins A) I only B) I, II C) I, II, III D) II, III E) I, II, IV Section: 20.6.B Level of Difficulty: Difficult Learning Objective: Synthesis of Other Lipids 166 32. Which of the following is TRUE regarding the enzyme acetyl-CoA carboxylase? I. It catalyzes the first committed step in fatty acid oxidation. II. It requires S-adenosylmethionine. III. It produces malonyl CoA IV. It uses acetyl CoA A) I, II, III, IV B) I only C) I, III, IV D) III, IV E) III only Section: 20.4.B Level of Difficulty: Difficult Learning Objective: Fatty Acid Biosynthesis 33. What is the net production of ATP from complete catabolism of the following fatty acid to CO2 and H2O? A) < 50 B) 51 – 90 C) 91 – 120 D) 121 – 150 E) 151 + Section: 20.4.B Level of Difficulty: Moderate Learning Objective: Fatty Acid Biosynthesis 34. Which of the following could be produced by the reaction of two or more of phosphatidic acids with two or more glycerol-3-phosphates? I. phosphatidylglycerol II. cardiolipin III. phosphatidylinositol IV. gangliosides A) I, II, III, IV B) II, III C) I, III D) I, II E) III only Section: 20.6.A Level of Difficulty: Difficult Learning Objective: Synthesis of Other Lipids 35. The mechanism of the condensing enzyme (KS) of fatty acid synthase is best described as 167 A) base catalysis using a glu residue in the active site B) acid catalysis using a glu residue in the active site C) base catalysis using a cys residue in the active site D) acid catalysis using a cys residue in the active site E) covalent catalysis using a cys residue in the active site Section: 20.4.C Level of Difficulty: Difficult Learning Objective: Fatty Acid Biosynthesis 36. Which statement concerning fatty acid synthesis is TRUE? I. The process occurs in the cytosol. II. In eukaryotes, the process occurs on a single large protein. III. The growing acyl chain is carried on an acyl carrier protein instead of coenzyme A. IV. The process requires two NADPH per acetyl group (2 carbons) added. A) I, II B) II, III C) I, II, III, IV D) III, IV E) I, III, IV Section: 20.4.C Level of Difficulty: Moderate Learning Objective: Fatty Acid Biosynthesis 37. Which of the following diets would most likely promote the formation of ketone bodies? A) high simple carbohydrates, low fat B) high complex carbohydrates, high fructose C) high fat, high protein, low carbohydrate D) low fat, high protein, high complex carbohydrates E) high fructose; high whole grain carbohydrates Section: 20.3 Level of Difficulty: Difficult Learning Objective: Ketone Bodies 38. Which statement concerning phospholipid synthesis is true? A) Addition of polar “head groups” to diacylglycerol usually involves CDP derivatives. B) Addition of polar “head groups” to diacylglycerol usually involves UDP adducts. C) Addition of fatty acyl “tails” to glycerol usually involves CDP adducts. D) Addition of fatty acyl “tails” to glycerol usually involves UDP adducts. E) None of the above is true. 168 Section: 20.6.A Level of Difficulty: moderate Learning Objective: Synthesis of Other Lipids 39. An enzyme that is inhibited by the statin group of drugs (e.g. Lipitor®) is A) phospholipase a2. B) hormone sensitive lipase. C) HMG CoA reductase. D) desaturase. E) glycerol kinase. Section: 20.7 Level of Difficulty: Easy Learning Objective: Cholesterol Metabolism 40. Which of the following is the source of the two carbon fragments in fatty acids biosynthesis? A) acetyl CoA B) malonyl CoA C) palmitic acid D) propionyl CoA E) ceramides Section: 20.4.C Level of Difficulty: Easy Learning Objective: Fatty Acid Biosynthesis 41. Which of the following is the starting metabolite in ketone body biosynthesis? A) acetyl CoA B) malonyl CoA C) propionlyl CoA D) acetyl CoA and propionyl CoA E) acetyl CoA and malonyl CoA Section: 20.3 Level of Difficulty: Learning Objective: Ketone Bodies 42. Which of the following is FALSE regarding HMG-CoA reductase? A) HMG-CoA reductase is highly regulated. B) The active site is tightly bound by statins. C) HMG-CoA reductase levels are increased as a result of high cholesterol concentrations in the ER D) HMG-CoA reductase levels are decreased as a result of high cholesterol concentrations in the ER. 169 E) HMG-CoA reductase is levels are decreased by the same factor that down regulated production of the LDL receptors Section: 20.7.A.B Level of Difficulty: Moderate Learning Objective: Cholesterol Metabolism 43. Considering the figure below, what compound would be formed by action of acyl-CoA dehydrogenase? A) B) C) D) E) Section: 20.2.C Level of Difficulty: Moderate Learning Objective: Fatty Acid Oxidation 44. Which of the following drugs acts by acetylating a serine residue preventing adequate enzyme activity? A) ibuprofen B) acetaminophen C) Vioxx® D) aspirin E) Celebrex® 170 Section: 20.6.C Level of Difficulty: Easy Learning Objective: Synthesis of Other Lipids 45. PGH2 is synthesized from and triggers pain and . A) cardiolipins; foam cell development B) steroids; fever C) salicylic acid; foam cell development D) NSAIDS; COX-1 E) arachidonate; inflammation Section: 20.6.C Level of Difficulty: Easy Learning Objective: Synthesis of Other Lipids 46. Which of the following enzymes is NOT involved in the tricarboxylate transport system? A) citrate synthase B) ATP citrate lyase C) malate dehydrogenase D) malic enzyme E) All are involved in the transport of acetyl-CoA into the cytosol Section: 20.4.A Level of Difficulty: Easy Learning Objective: Fatty Acid Biosynthesis 47. Which of the following components would be condensed to form acetoacetate? A) acetyl CoA and acetyl-CoA B) HMG-CoA and acyl-CoA C) acetone and betahydroxybutyrate D) malonyl-CoA and acyl-CoA E) DHAP and glycerol-3-phosphate Section: 20.3 Level of Difficulty: Easy Learning Objective: Ketone Bodies 48. Which of the following is the correct sequence of events in cholesterol synthesis? (Note: not all events in the sequence are included) A) HMG-CoA > isopentyl pyrophosphate > farnesyl pyrophosphate > geranyl pyrophosphate B) isopentyl pyrophosphate > squalene > oxidosqualene > geranyl pyrophosphate C) dimethylallyl pyrophosphate > geranyl pyrophosphate > farnesyl pyrophosphate > squalene D) HMG –CoA > phosphomevalonate > squalene > farnesyl pyrophosphate 171 E) mevalonate > dimethylallyl pyrophosphate > farnesyl pyrophosphate > gernayl pyrophosphate Section: 20.7 Level of Difficulty: Difficult Learning Objective: Cholesterol Metabolism 49. Which of the following compounds is produced by the multistep cyclization of squalene? A) lanosterol B) geranyl pyrophosphate C) fanesyl pyrophosphate D) isoprene E) isopentyl pyrophosphate Section: 20.7 Level of Difficulty: Easy Learning Objective: Cholesterol Metabolism 50. Which of the following is NOT an example of a problem sometimes associated with unsaturated fatty acid breakdown? A) β, g double bond B) α, β double bond C) unanticipated isomerization D) inhibition of hydratase by a double bond E) All of the above are problems. Section: 20.2.D Level of Difficulty: Moderate Learning Objective: Fatty Acid Oxidation 51. LDL taken up by the liver is A) broken down into fatty acids and amino acids. B) taken up by the ER and used to control synthesis of HMG CoA reductase and LDL receptor synthesis. C) converted into clathrin and recycled. D) irreversibly bound to LDL receptors. E) excreted in a clathrin coated vesicle. 172 Section: 20.2.B Level of Difficulty: Moderate Learning Objective: Lipid Digestion, Absorption, and Transport 173 S
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