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26t. Which of the following groups will have submetacentric chromosomes? a. B b. C c. E d. Both A and C e. all of the above

27t. What type of chromosome band has a AT rich base composition in DNA? a. R-band b. C-band c. Q-band d. G-band e. Both C and D

28t. Tripoloidy and trisomy occur by: a. fertilization b. meiotic nondisjunction c. deletion d. translocation e. centric fragments

29t. The number of chromosomes in a monosomic abnormality is? a. 45 (2n-1) b. 23n c. 45 d. 46(2n) e. 45 (2n+1)

30t. The rate of structural aberrations is markedly increased by: a. exposure to ionizing radiation b. rare inherited conditions c. x-rays d. chemical mutagens e. all of the above.

31t. The polymerase chain reaction: a. Allows for the amplification of a specific DNA sequence b. Allows for the amplification of an RNA sequence c. does not require a thermostable DNA polymerase d. does not require knowledge of the DNA sequence for the synthesis of primers e. none of the above

32t. The primer for DNA synthesis: a. can be RNA b. can be DNA c. must have a 3’ –OH d. uses primase e. all of the above

33.t Type II toposiomerases requires energy from: a. require NADH b. require NADPH c. require ATP d. require FADH e. require a, b and c

34t. Which polymerase is an error prone enzyme that helps rescue replication forks stalled as a result of misalignment of the primer end. It is also part of the SOS response. a. DNA polymerase II b. DNA polymerase I c. DNA polymerase beta d. DNA polymerase IV e. DNA polymerase gamma

35t. What enzyme is specialized to create termini at the ends of chromosomes consisting of a simple repeated sequence TTAGGG in humans? a. helicase b. telomerase c. DNA ligase d. RNAase e. Polymerase I

36t. Repair of spontaneous, chemical or radiation induced damage to a DNA segment characterizes: a. Mismatch repair b. Base excision repair c. Nucleotide excision repair d. Sugar excision repair e. Photoenyzmatic repair

37t. What enzymes in humans require B12? a. methylsuccinyl CoA mutase b. methylmalonyl CoA mutase c. methionine synthase d. A and B e. B and C

38t. Where is methionine synthase located in the cell? a. cytosol b. mitochondria c. golgi d. ER e. nucleus

39t. B12 deficiency results from: a. not enough B12 in diet b. lack of IF-B12 c. too much extrinsic factor d. too much transcobalamin I in the liver e. none of the above

40t. If you were stuck on an island for 2 months without any source of dietary folate: a. you would develop homocysteinemia b. you would develop megaloblastic anemia c. you would have a decrease of THF d. all of the above e. none of the above

41t. Folate can serve as a: a. donor of 2 carbon units b. donor of 1 carbon units c. donor of 3 carbon units d. donor of 4 carbon units 3. folate does not serve as a carbon donor

42t. Sulfa drugs: a. help folic acid synthesis b. have no effect on bacteria virus c. act as analogs of p-aminobenzoic acid d. act as an anti-inflammatory agent e. should be taken with methylmalonic acid

43t. E. coli DNA polymerase I and III: a. synthesize DNA in a 3’- 5’ direction b. Requires Ca c. requires a 3’-OH group d. requires and RNA template e. requires dNMPS

44t. DNA gyrase: a. removes negative supercoils b. introduces negative supercoils c. can be considered topoismerase I d. does not require ATP e. cleaves one strand of DNA

45t. Enzymes lacking the 3’-5’ exonuclease activity have: a. higher error rates b. lower error rates c. responsible for the high fidelity of DNA replication d. all of the above e. none of the above

46t. The enzyme which adds a 10 nucleotide RNA primer followed by a 10-20 DNA segment is: a. polymerase I b. polymerase alpha c. polymerase gamma d. polymerase zeta e. primase

47t. What are DNA ligases? a. enzymes that remove the RNA primer b. enzymes that join okazaki fragments c. enzymes that bind to single stranded DNA d. both A and B e. both C and D

48t. In Base excision repair: a. DNA glycoslyase cleaves the damaged base from deoxyribose sugar b. a pyrimdine dimmer resulting from UV light is restored to its original form c. the DNA segment is unwound and an excision nuclease cuts the DNA strand at sites flanking the lesion d. DNA gyrase seals the filled in gap e. keeps thymine and xanthine out of DNA

49t. What is necessary for the elongation of a prokaryotic RNA a. RNA polymerase b. Mg+ c. alpha 2, B, B’ d. none of the above e. all of the above

50t. RNA transcription is more error prone because a. RNA polymerases do not have exonuclease activities b. RNA is highly unstable c. RNA nucleotides are not abundant d. RNA does not require a primer e. none of the above

51t. Rho functions to: a. anneal DNA b. anneal RNA c. displace the new strand of RNA from the template d. makes hairpins e. has a n A-U rich sequence

52t. When glucose levels are low in a bacteria medium: a. bacteria thrive b. bacteria turn on the lac operon c. bacteria turn off the lac operon d. bacteria turn off permease e. none of the above

53t. What is a promoter? a. RNA sequences that signal the RNA polymerase to stop synthesizing RNA b. RNA sequences that signal the DNA polymerase to stop synthesizing DNA c. DNA sequences that are recognized as initiation sites for RNA synthesis d. Terminate transcription e. Terminate replication

54t. The sense strand is: a. corresponds to the mRNA and is read in the 5’ to 3’ direction b. corresponds to the DNA and is read in the 5’ to 3’ direction c. complement to the template strand d. complement to the mtDNA e. all of the above.

M26. Phytohemagglutinin is used for: (A) inhibiting cell division (B) staining chromosomes (C) inhibiting microtubule formation (D) lysing RBCs (E) None of the above

M27. R-band stains: (A) Chromosome regions rich with AT (B) Heterochromatin (C) House-keeping genes (D) DNA at Late S phase (E) None of the above

M28. Non-disjunction of chromosomes can cause all of the following except: (A) Triploidy (B) Aneuploidy (C) Klinefelter’s syndrome (D) Trisomy 21 (E) Centric fragments

M29. Y chromosome (A) Is classified in the C group (B) Does not stain G/Q-bands (C) Is metacentric (D) Has no satellite (E) Deficiency is not compatible with live birth

M30. Structural aberrations can cause all of the following except: (A) Deletion (B) Duplication (C) Ring chromosomes (D) Concentric fragments (E) Inversions

M31. Pseudogenes can be best described as (A) group of duplicate genes encoding proteins of a similar amino acid sequence (B) Duplicated or transposed genes that have become nonfunctional (C) Many tandem repeats of identical or related units (D) Dispersed repeating DNA (E) None of the above

M32. Fragile X syndrome results in (A) too few repeats of CGG that inactive FMR1 (B) too few repeats of CGG that activate FMR1 (C) too many repeats of CGG that inactivate FMR1 (D) too many repeats of CGG that activate FMR1 (E) None of the above

M33. All the following are true about restriction endonucleases EXCEPT: (A) Protect microbial DNA by cutting up foreign DNA (B) Can leave staggered or blunt ends (C) Cleave methylated DNA (D) Can be used to generate restriction maps of a DNA sequence (E) All of the above are correct.

M34. A technique to analyze RNA is (A) Northern Blot (B) Southern Blot (C) Western Blot (D) Southwestern Blot (E) Farwestern blot

M35. All of the following is true of RNA structure EXCEPT: (A) RNA uses uracil in place of thymine (B) RNA uses ribose in place of doeoxyribose (C) Can exist in single and double stranded forms (D) Can have unusual base pairing (E) All of the above are correct

M36. All of the following is true of Dideoxynucleotides EXCEPT: (A) are missing a –OH group at the 4’ carbon (B) will cause DNA chain termination (C) can be used to treat HSV infections (D) are integral to enzymatic DNA sequencing (E) All of the above are correct

M37. Which form of Vitamin B12 is used as a coenzyme for methionine synthase? (A) deoxyadenosylcobalamin (B) cyanocobalamin (C) hydroxycobalamin (D) methylcobalamin (E) aminocobalamin

M38. Vitamin B12 is (A) Lipid-soluble (B) Can be synthesized endogenously by humans (C) Richest in diary products (D) Contains p-aminobenzoic acid (E) Stored in the liver

M39. Folate can carry single-carbon groups on (A) N1 position (B) N5 position (C) N10 positon (D) A and B only (E) B and C only

M40. The folate trap hypothesis (A) Explains why a folate deficiency leads to an effective vitamin B12 deficiency (B) Refers to the polyglutamation of folate for storage (C) Recognizes that THF can serve as a precursor for other essential folates (D) Contributes to the accumulation of THF, producing a folate deficiency (E) None of the above are correct

M41. All of the following are true of Sulfa drugs EXCEPT: (A) act as analogsto p-aminobenzoic acid (B) inhibits dihydrofolate reductase (C) inhibit endogenous folate synthesis in bacteria (D) is an early antibiotic (E) Does not affect humans who rely upon ingested folate

M42. What would be indicative of folate deficiency rather than B12 deficiency? (A) Decreased serum folate (B) Increased serum methylmalonic acid (C) Demyelination (D) A and B, only (E) A, B, and C

Answer Key

M26. E (p.126) M27. C (p.133) M28. A (p.139-140) M29. D (p.130) M30. D (p.148) M31. B (p.96) M32. C (p.99) M33. C (p.104) M34. A (p.108) M35. E (p.113-114) M36. A (p.155) M37. D (p.199) M38. E (p.205) M39. E (p.209) M40. C (p.212) M41. B (p.216) M42. A (p.215)

26t. E pg 129 27t. E pg 133 28t. B pg 150 29t. A pg 140 30t. E pg 148 31t. A pg 159 32t. E pg 168 33t. C pg 176 34t. D pg 178 35t. B pg 182 36t. C pg 189 37t. E pg 200 38t. A pg 201 39t. B pg 204 40t. E pg 211 41t. B pg 209 42t. C pg 216 43t. C pg168 44t. B pg 176 45t. A pg 170 46t. B pg 178 47t. B pg 179 48t. A pg 187 49t. E pg 222 50t. A pg 224 51t. C pg 229 52t. B pg 230/231 53t. C pg 225 54t. A pg 222