2013 Block 1 Week 1 Practice Questions
Written/Compiled by John Luckoski
Many of these questions are gathered from previously made practice quizzes and exams, and are largely not my work.
Thanks go to Dan Feldman, Kristopher Carbone, and other previous students. Also I highly suggest looking at the formative questions written b y the professors that is on blackboard. Hopefully this will give you a good sense of the level of detail you’ll need to dive to while studying. This is all student-made, and thus prone to error. If you find any mistakes make it known!
1. Gated transport involves: a. The transport of marcomolecules from the cytosol to the ER lumen or mitochondria b. The transport of macromolecules from the cytosol to the nucleus through nuclear pores c. The transport of soluble proteins from the ER to the golgi to the cell exterior d. The transport of proteins from the cell exterior through the cytosol into the nucleus
2. Which technique would be best in order to determine the biochemical composition of a cell? a. Differential centrifugation b. Light Microscopy c. Cell culture d. Electron microscopy
3. Which chemical bond does not rely on electrostatic interactions? a. Covalent Bond b. Van der Waals bond c. Hydrogen bond d. Ionic bond
4. What is the hydrophobic effect? a. When water surrounds and dissolves other molecules, yielding increased entropy b. When water forms H-bonds with polar substances, yielding decreased entropy c. When water forms H-bonds with non-polar substances, yielding decreased entropy d. When non-polar aggregates disrupt water molecules, yielding increased entropy
5. Which is true about a zwitterions? a. At neutral pH, it is negatively charged b. The isoelectric point is when it moves the fastest in electric fields c. It is charged but neutral d. At high pH, it is positively charged
6. Which is the best buffer? a. A strong acid and its weak conjugate base b. A weak acid and its strong conjugate base c. An acid and base which completely ionize in water d. A strong base and its weak conjugate acid
7. Which amino acid has a nonpolar, aliphatic R group? a. Tyrosine b. Glycine c. Arginine d. Serine

8. Which amino acid is acidic? a. E b. Arg c. C d. Trp
9. Which is a measure of rotation between the N and the α-Carbon in a peptide? a. Pi b. Phi c. ψ d) Psi
10. How many amino acids are in a protein with molecular weight 22000 D? a. 200 b. 60 c. 2000 d. 180
11. Which has each amino acid on one strand H-bonded to two amino acids on the opposite strand? a. Anti parallel beta pleated sheet b. B alpha helix c. Parallel Beta pleated sheet d. Z alpha helix
12. Which is incorrect? a. A polypeptide chain is covalently linked by amide bonds b. Trans peptide bonds are more frequent because cis cause steric hindrance c. Reverse turns give compact globular shapes to many proteins d. The main features of a polypeptide chain are the R-groups and the dihedral angles
13. Which is incorrect about proteins? a. Primary structure is amino acid sequence b. Examples of secondary structures are alpha helices or beta sheets c. Tertiary structure would be exactly one folded protein chain and reverse loops d. Quaternary structure is 2 or more chains (dimers, tetrameters)
14. Which of the following membrane bound cellular organelles is approximately 0.5-1.0 µm and is important for the utilization of oxygen to provide ATP which drives cellular processes? a. Peroxisome b. Lysosome c. Mitochondria d. Smooth Endoplasmic Reticulum

15. In the process of detoxification of a potent drug, part of a liver cells smooth endoplasmic reticulum is damaged beyond repair. In order to recycle the components of this organelle the liver cell will undergo a. Autophagy b. Endocytosis c. Receptor-Mediated Endocytosis d. Vesicular Transport
16. During apoptosis after the cell’s DNA has become pyknotic and the cells have started to form blebs what happens to these blebs? a. Nothing these blebs remain in the extracellular matrix b. The blebs are recognized and cleared away by macrophages c. The surrounding cells take up the blebs to degrade them d. The blebs coalesce to reform a functional cell e. B&C
17. The strongest type of bond that exists between two atoms within one or more molecules is a. Hydrogen Bond b. Covalent Bonds c. Electrostatic Bonds d. Van Der Waals Bonds
18. You are making salad dressing using white balsamic vinegar (water based) and olive oil when you notice that after letting the dressing sit after mixing it begins to separate into two layers. Which statement best describes this phenomenon? a. The electrostatic charged molecules within the two ingredients separate into two layers with one being more positive and one being more negative b. The two layers are created because of the separation of proteins from fat c. The two layers separate because the hydrophobic fatty acid molecules found in the olive oil try to coalesce together to form larger fatty acid globules by the hydrophobic effect to free water molecules to increase the available amount of free energy d. The two layers separate because the water molecules utilize the hydrophilic effect to interact with molecules within the oil layer of the mixture

19. An Emergency Medical Technician arrives to a scene where a 40 year old man is seen to be seated and slouched over. The man’s breathing is extremely fast and shallow (hyperventilating). In order to slow and deepen the man’s breathing down the EMT recommends breathing into a paper bag. What is the basis for this suggestion by the EMT? a. This will provide the man with less oxygen and will cause him to pass out which will bring his breathing back to normal. b. This will cause the man to increase the amount of CO2 within his blood helping to increase its pH and bring it back within normal ranges. c. Breathing into a bag will help increase the amount of CO2 diffusing into the blood resulting in more carbonic acid production which will help bring blood pH back to about 7.4 d. Breathing into the bag will cause more CO2 to be exhaled by the lungs further increasing the pH of the blood
20. Insulin is first synthesized as one polypeptide. It is then processed by cleavage to yield the insulin molecule which is composed of two chains of amino acids covalently linked together, but can be broken up by 2-mercapotethanol. What amino acid could be responsible for this covalent linkage? a. Alanine b. Proline c. Lysine d. Cysteine
21. A protein has been isolated and purified. By using Edman Degradation it was found that this protein was 30 amino acids long. What is the approximate Molecular weight of this protein? a. 300 daltons b. 3300 daltons c. 3000 daltons d. 150 daltons
22. Two proteins were examined and although they had similar primary amino acid sequences they had greatly differing secondary structures. What factors contribute to these differences in secondary structure? a. Amino Acid sequence b. ψ and ϕ angles c. rigidity of the peptide bond d. A, B, & C e. B & C
23. What is the approximate resolving power of a light microscope? a. 0.02 µm b. 0.2 µm c. 20 µm d. 200 µm e. 1 cm

24. Which of these organelles uses enzymes in the cytochrome P450 family to help detoxify drugs? a. Smooth Endoplasmic Reticulum b. Rough Endoplasmic Reticulum c. Mitochondria d. Lysosomes e. Peroxisomes
25. Which statement is true about the functions of mitochondria and peroxisomes? a. Mitochondria utilize oxygen, but peroxisomes do not. b. Peroxisomes utilize oxygen, but mitochondria do not. c. Both mitochondria and peroxisomes utilize oxygen. d. Neither mitochondria nor peroxisomes utilize oxygen.
26. Selected proteins are transported from the cytosol to the mitochondria using a. Gated transport. b. Transmembrane transport. c. Vesicular transport. d. None of the above.
27. Choose the correct statement about apoptosis and necrosis. a. Chromatin condensation is characteristic of apoptosis. b. In both necrosis and apoptosis, macrophages engulf the contents of the cells. c. Necrosis is the organized breakdown of tissue in multi-cellular organisms. d. Apoptosis is usually the result of cell injury. e. Necrosis will never trigger an immune response.
28. Which of these bonds is the strongest? a. Ionic bonds b. Hydrogen bonds c. Covalent bonds d. Van der Waals interactions e. There is no significant difference in the strengths of these bonds.
29. The hydrophobic effect describes the aggregation of ______ molecules in water, which leads to a/an ______ of free energy and a subsequent ______ in entropy. a. Polar; release; increase b. Nonpolar; release; decrease c. Polar; absorption; increase d. Nonpolar; absorption; decrease e. Nonpolar; release; increase
30. Consider a weak acid HA with Ka=1x10-6. If [HA]=[A-], what is the pH of the solution? a. 10-6 b. 10 c. 6 d. 0.001 e. 0.06

31. Which of these groups is/are present in an amino acid at pH 7.4? a. NH3+ and COO- b. NH2 and COO- c. NH3+ and COOH d. NH2 and COOH e. COO- only
32. What is the only achiral amino acid? a. Leucine b. Proline c. Serine d. Valine e. Glycine
33. In proteins, all bonds except peptide bonds are described by angles of rotation. For instance, psi (ψ) is the angle of rotation between a. The carbon atom of the carbonyl group and the nitrogen atom of the amino group. b. The oxygen atom of the carbonyl group and the alpha carbon c. The alpha carbon and the carbon atom of the carbonyl group d. The hydrogen atom of the amino group and the alpha carbon e. The nitrogen atom of the amino group and the alpha carbon
34. What is the approximate molecular weight of a protein that consists of 20 amino acids? Note:
D=daltons a. 2.2 kD b. 220 daltons c. 22000 daltons d. 220 kD e. 2200 kD
35. The Hill Equation can be useful to describe the binding of a ligand to multiple sites on the protein.
Which of these is true about n, the Hill Coefficient? a. There is positive cooperativity when n=1 b. There is negative cooperativity when n>1 c. There is positive cooperativity when n>1 d. There is no cooperativity when n<1 e. The value of n corresponds to the maximum number of sites.
36. One major difference between the Koshland Sequential Model and the Monod Model for
Cooperativity is that, unlike the Monod Model, the Koshland Model a. Is useful for explaining negative cooperativity b. Is useful for explaining positive cooperativity c. Does not require symmetry d. A and C are correct e. A, B, and C are correct

37. “The more oxygenated blood is, the lower its capacity for carbon dioxide.” This statement describes the a. Bohr Effect b. Haldane Effect c. Monod Model d. Koshland Model e. Hill Coefficient
38. The T state must be stabilized in order for deoxygenated hemoglobin to be able to effectively carry
CO2. This stabilization occurs with the formation of a salt bridge between residues of which two amino acids? a. Arginine and Valine b. Valine and Histidine c. Proline and Arginine d. Leucine and Glycine e. Histidine and Arginine
39. Increasing the concentration of which of these will result in a decreased affinity of hemoglobin for oxygen? a. CO2 and H+, but not 2,3-BPG b. CO2 but not H+ or 2,3-BPG c. 2,3-BPG and H+, but not CO2 d. CO2 and 2,3-BPG, but not H+ e. CO2, H+, and 2,3-BPG.
40. Which statement is false about carbon monoxide (CO) binding to oxygen? a. This binding is irreversible. b. CO binds to the O2 binding site with an affinity that is approximately 200 times greater than that of oxygen. c. 50% saturation with CO is likely fatal. d. CO binding causes Hb to be trapped in a high affinity state. e. CO inhibits O2 delivery.
41. Which of these describes the mutation that causes Sickle Cell Disease? a. Glu -> Lys b. Val -> Glu c. Pro -> Lys d. Glu -> Val e. Lys -> Val
42. During which phase of mitosis does the does the nuclear envelope break down? a. Prophase b. Pro-metaphase c. Metaphase d. Anaphase e. Telophase

43. Choose the correct statement about RB and p53. a. RB inhibits the cell cycle, but p53 does not. b. Li-Fraumeni syndrome is caused by mutations in RB. c. Phosphorylation inactivates RB. d. P53 inhibits the cell cycle, but RB does not. e. RB is the most commonly mutated gene in cancer.
44. Which statement is true about the mechanism of RNAse? a. It involves a cyclic phosphate intermediate. b. Lys41 acts as a catalyst. c. His12 stabilizes the negative charge on the phosphate. d. RNAse does not recognize cytosine. e. RNAse is generally a very unstable enzyme.
45. Choose the correct statement about serine proteases. a. Trypsin cleaves at hydrophobic residues b. Chymotrypsin is not a serine protease c. Elastase cleaves at lysyl residues d. Elastase would be expected to cleave at small, aliphatic residues e. Chymotrypsin would be expected to cleave at the N-terminal side of hydrophobic residues.
46. Riboflavin is a vitamin that generally participates in what type of reaction? a. Group transfer b. Proton transfer c. Carboxyl transfer d. Acyl-group transfer e. One-carbon reaction
47. Competitive enzyme inhibitors: a. Increase both Km and Vmax b. Increase Km but decrease Vmax c. Increase Vmax but decrease Km d. Decrease both Vmax and Km e. None of the above
48. Noncompetitive inhibitors: a. Usually resemble the substrate in question, unlike competitive inhibitors b. Can be overcome by increasing substrate concentrations. c. Lower Vmax d. Increase Km in simple unireactant systems. e. Never resemble cosubstrates in multireactant systems.

49. A transmembrane protein is composed of one subunit with three domains. These three domains consist of an internal domain for an ion pore, a domain that is responsible for traversing the membrane, and a ligand binding domain. What can be deduced about the pore domain and the domain traversing the membrane? a. The pore domain most likely contains charged or polar amino acids b. The membrane traversing domain contains mostly hydrophobic amino acids c. The pore domain and membrane traversing domain have about the same proportions of hydrophilic and hydrophobic amino acids d. The pore and membrane traversing domains contain mostly charged amino acids e. A & B
50. Creutzfeldt-Jakob disease is caused by a. A mutated prion protein b. A mutated enzyme c. A virus d. A bacterium
51. Vitamin C is an important cofactor that helps facilitate what type of post translational modification of the lysine and proline residues during the synthesis of collagen fibrils? a. Phosphorylation b. Methylation c. Hydroxylation d. Ubiquitination
52. While looking at a microscope slide of all the stages of mitosis you notice two cells that contain their own nuclei with decondensed chromatin but whose cytoplasms are connected by a thin piece of membrane. What stage of the cell cycle are these cells in? a. Anaphase b. Telophase with Cytokinesis c. Interphase d. Prophase
53. A biopsy was taken from a cancerous tumor. Upon protein analysis which cyclin/cyclin-dependent kinase would you expect to be most likely elevated? a. Cdk4/6-Cyclin A b. Cdk5-Cyclin A c. Cdk4/6-Cyclin D d. None of the above
54. A biopsy of a cancerous tumor was obtained and protein analysis was conducted. Which protein is most likely to be mutated or lost in these cancer cells? a. Retinoblastoma Protein b. p53 c. p16 d. E2F

55. Isocitrate Dehydrogenase is involved in the production of a high energy intermediate in the TCA cycle in the form of NADH. NADH is produced by this enzyme by oxidizing Isocitrate to αketoglutarate. This an example of which type of enzyme? a. Lyase b. Hydrolase c. Oxidoreductase d. Transferase e. Ligase
56. Which of the following best describes an enzyme a. It is a catalyst that lowers the activation energy to make reaction proceed faster b. It is a catalyst that changes the equilibrium to make more products in a reaction c. It is a catalyst that makes a reaction more favorable by making the Gibbs Free Energy of reaction more negative than if it were uncatalyzed d. It is a catalyst that typically compresses a reaction into one steps to make it proceed quicker
57. Each of the following are ways that enzyme catalyze reactions EXCEPT a. Covalent Catalysis b. Acid/Base Catalysis c. Proximity Catalysis d. Bond Distortion Catalysis e. None of the Above
58. Based on the graph below what type of inhibitor is acting on this enzyme? a. Competitive b. Noncompetitive c. Irreversible d. Suicide

59. What type of inhibition can be reversed by increasing the substrate concentration? a. Noncompetitive Inhibitor b. Competitive Inhibitor c. Irreversible Inhibitor d. Suicide Inhibitor
60. Identify the nucleic acid below
A.
Cytosine
B.
Guanine
C.
Adenine
D.
Thymine
E.
Uracil
61. What is the nucleotide content of this DNA sequence?
5’ _ T _ A _ T T A _A 3’
3’ _ A _ T _ A A T _T 5’
A. 40 % A, 40% T
B. 30 % G, 30% C
C. 20 % A, 20 % T
D. 20 % G, 20% C
62. What is the DNA complement of this DNA sequence?
5’ GATTACAT 3’
A.
5’ CTACAGAA 3’
B.
5’ GATTACAT’ 3’
C.
5’ ATGTAATC 3’
D.
5’AUGUAAUC 3’

Match the agent to its associated DNA interaction. Letters may be used more than once, or not at all.
63. Netropsin
64. Mitomycin C
A. Intercalcation
B. Minor groove binding
65. Cro protein
66. Actinomycin D
67. Trp repressor
C. Major groove binding
D. DNA crosslinking
E. More than one of the above
F. None of the above 68. Daunorubicin
69. Which is not a common symptom of both Bloom and Werner syndrome?
A. Increased cancer incidence
B. Premature aging
C. Genomic instability
D. Immunodeficiency
70. A woman has a known family history of Huntington’s, and is having genetic testing done in order to determine if the disease will affect her. After testing she is found to have a specific sequence of segments in her genome that repeats 30 times. What is this specific sequence for Huntington’s, and is
30 repeats enough to result in symptoms?
A. CGG, and 30 repeats is enough to cause symptoms
B. CAG, and 30 repeats is not enough to cause symptoms
C. CGG. And 30 repeats is not enough to cause symptoms
D. CAG, and 30 repeats is enough to cause symptoms
71. A lack of 3’-5’ exonuclease will affect error rates of DNA replication how?
A. Error rates will increase
B. Error rates will be as high as one error per 1 billion base pairs
C. Error rates will decrease
D. Error rates will remain the same
72. During DNA replication, which polymerase is associated with the leading strand?
A. Pol
α
B. Pol
ε
C. Pol
δ
D. Primase
73. What is the proper sequence of events during Base excision repair?
1. Base removed by a DNA glycoslyase, which cleaves the damaged base
2. DNA ligase seals the nick
3. Endonuclease cuts the phosphodiester backbone leaving a gap
4. DNA polymerase inputs the proper base into the gap
A.
2, 3, 1, 4
B.
1, 2, 3, 4
C.
1, 3, 4, 2
D.
4, 3, 2, 1

74. Ataxia telangiectasia is a genetic disorder caused by the loss of DNA damage signaling associated with the ATM gene. What is a noted symptom of this disorder?
A. Sensitivity to damage via x-rays
B. Bone marrow failure
C. Growth retardation
D. Gastrointestinal and kidney abnormalities
75. Which RNA polymerase is responsible for the expression of tRNA?
A. RNA polymerase I
B. RNA polymerase II
C. RNA polymerase III
D. mtRNA polymerase
76. Acetylation of lysine for core histones induces what sort of change in DNA structure?
A. Disallows binding of transcription factors
B. Causes lysine tails to bind tightly to a repressed conformation
C. Allows the binding of transcription factors
C. Acetylation of lysine does not affect the conformation of core histones
77. Which type of mutation will likely result in the least amount of damage?
A. Null mutation
B. Nonsense mutation
C. Point mutation
D. Frameshift mutation

1. B (P. 24)
2. A (P. 12)
3. A (P. 35)
4. D (P. 42)
5. C (P. 55)
6. B (P. 50)
7. B (P. 57)
8. A (P. 59)
9. B (P. 66)
10. A (P. 70)
11. C (P. 74)
12. D (P. 64)
13. C (P.62, 71, 84, 87)
14. C (P. 19)
15. A (P. 26)
16. E (P. 30)
17. B (P. 35)
18. C (P. 42)
19. C (P. 51)
20. D (P. 58)
21. B (P. 70)
22. D (P. 71)
23. B (P. 8)
24. A (P. 15)
25. C (P. 19,20)
26. B (P. 25)
27. A (P. 30)
28. C (P. 35)
29. E (P. 42)
30. C (P. 49)
31. A (P. 55)
32. E (P. 57)
33 C (P. 66)
34. A (P. 70)
35. C (P. 347)
36. D (P. 350,353)
37. B (P. 367)
38. A (P. 365)
39. E (P. 361, 367, 368)
40. A (P. 375)
41. D (P. 378)
42. B (P. 301)
43. C (P. 314,324)
44. A (P. 258)
45. D (P. 262)
46. B (P. 268)
47. E (P. 277)
48. C (P. 279)
49. E (P. 210)
50. A (P. 79)
51. C (P. 218)
52. B (P. 303)
53. C (P. 321)
54. B (P. 224)
55. C (P. 241)
56. A (P. 240)
57. E (P. 246,249)
58. B (P. 279)
59. B (P. 277)
60. C (P. 102)
61. D (P. 105)
62. C (P. 106)
63. B (P. 124)
64. B (P. 124)
65. E (P. 131)
66. A (P. 124)
67. C (P. 129)
68. A (P. 123)
69. D (P. 136)
70. B (P. 144)
71. A (P. 174)
72. B (P. 186)
73. C (P. 198)
74. A (P.206)
75. C (P.404)
76. C (P. 407)
77. C (P. 433)