Chapter 14 & 15 (Combined)

Question 1

1) Nutritional mutations can be defined as ________.
A) those mutations that do not allow a bacterium or fungus to grow on minimal medium but do allow growth on complete medium
B) those mutations that change the composition of the medium
C) those mutations belonging to the group called prototrophs
D) those mutations caused by site-specific mutagenesis
E) all strains that are not auxotrophic

Answer 1

A) those mutations that do not allow a bacterium or fungus to grow on minimal medium but do allow growth on complete medium

Question 2

3) A class of mutations that results in multiple contiguous amino acid changes in proteins is likely to be which of the following?
A) base analog
B) transversion
C) transition
D) frameshift
E) recombinant

Answer 2

D) frameshift

Question 3

7) Ultraviolet light causes pyrimidine dimers to form in DNA. Some individuals are genetically incapable of repairing some dimers at "normal" rates.  Such individuals are likely to suffer from \_\_\_\_\_\_\_\_.  
A) xeroderma pigmentosum
B) SCID 
C) phenylketonuria
D) muscular dystrophy
E) Huntington disease

Answer 3

A) xeroderma pigmentosum

Question 4

8) Transposons, or jumping genes, are DNA elements that move within the genome. In which organismic groups are transposons found?
A) bacteria
B) eukaryotes
C) mammals
D) ancient bacteria
E) all organismic groups

Answer 4

E) all organismic groups

Question 5

6) Which of the following name two mutagens that would be classified as base analogs?
A) acridine orange and proflavin
B) ethylmethane sulfonate and ethylmethylketone peroxide
C) ultraviolet light and cosmic radiation
D) 5-bromouracil and 2-amino purine
E) hydroxyurea and peroxidase

Answer 5

D) 5-bromouracil and 2-amino purine

Question 6

9) All insertion sequences (IS elements) contain two features that are essential for their movement. What are these two elements?
A) transposase and inverted terminal repeats
B) integrase and pseudogenes
C) integrase and oncogenes
D) proto-oncogenes and oncogenes
E) transposase and oncogenes

Answer 6

A) transposase and inverted terminal repeats

Question 7

11) Barbara McClintock discovered mobile elements in corn by analyzing the genetic behavior of two elements, Ds and Ac. The interplay between these two elements has become one of the most interesting stories of discovery in the field of genetics. How do Ds and Ac interact?
A) Ds causes a deletion next to the insertion site of Ac.
B) Ac causes a deletion next to the insertion site of Ds.
C) Ds moves only if Ac is present in the genome; Ac is capable of autonomous movement.
D) The movement of Ac is dependent on two forms of Ds.
E) Both elements can move only within chromosome 9.

Answer 7

C) Ds moves only if Ac is present in the genome; Ac is capable of autonomous movement.

Question 8

19) In general, mutation rates in humans occur in the range of ________ (frequency) per gamete per generation.

Answer 8

10-5 to 10-6

Question 9

25) Considering the electromagnetic spectrum, identify likely mutagens from the following list: radio waves, microwaves, infrared, ultraviolet, X-rays, gamma rays, cosmic rays.

Answer 9

ultraviolet, X-rays, gamma rays, cosmic rays

Question 10

29) Recent discoveries on causes of fragile-X syndrome, myotonic dystrophy, and Huntington disease indicate which type of genetic alteration?

Answer 10

changes in trinucleotide repeats

Question 11

34) What is meant by the term photoreactivation repair?

Answer 11

Photoreactivation repair, discovered in 1949, is a process described in E. coli in which UV-induced DNA damage can be partially reversed if cells are briefly exposed to light in the blue range of the visible spectrum.

Question 12

38) What is the Ames test, and how does it work?

Answer 12

Four tester strains of Salmonella typhimurium are used to test for sensitivity and specificity of mutagenesis.

Question 13

42) Loss-of-function mutations eliminate the function of a gene product and may be dominant or recessive.

True or False

Answer 13

True

Question 14

43) Of the two cell lines that can contain a mutation in an organism, somatic line and germ line, the latter is more consequential to subsequent generations.

True or False

Answer 14

True

Question 15

2) Which term refers to a contiguous genetic complex that is under coordinated control?  
A) lysogen
B) prototroph 
C) operon
D) allosteric
E) attenuation

Answer 15

C) operon

Question 16

3) Which term most appropriately refers to a regulatory protein in prokaryotes?
A) translation
B) RNA processing
C) DNA binding protein
D) gyrase action
E) helicase activation

Answer 16

C) DNA binding protein

Question 17

4) In the lac operon, the product of structural gene lacZ is capable of ________.
A) nonautonomous replication
B) forming lactose from two glucose molecules
C) replacing hexokinase in the early steps of glycolysis
D) splitting the β-linkage of lactose
E) forming ATP from pyruvate

Answer 17

D) splitting the β-linkage of lactose

Question 18

5) Which of the following terms best characterizes catabolite repression associated with the lac operon in E. coli?
A) inducible system
B) repressible system
C) negative control
D) positive control
E) constitutive

Answer 18

D) positive control

Question 19

6) When referring to attenuation in regulation of the trp operon, it would be safe to say that when there are high levels of tryptophan available to the organism, ________.
A) the trp operon is being transcribed at relatively high levels
B) translational termination is likely
C) transcriptional termination is likely
D) tryptophan is inactivating the repressor protein
E) ribosomes are stalling during translation of the attenuator region

Answer 19

C) transcriptional termination is likely

Question 20

7) Genetic regulation in eukaryotes can take place at a variety of levels from transcriptional to posttranslational. At what level is genetic regulation considered most likely in prokaryotes?
A) transcriptional
B) capping
C) polyadenylation of the 3’ end of the mRNAs
D) intron processing
E) exon processing

Answer 20

A) transcriptional

Question 21

8) Regarding eukaryotic and prokaryotic genetic regulation, what process seems to be the most similar between the two?   
A) transcriptional regulation  
B) RNA splicing regulation  
C) intron/exon shuffling  
D) 5'-capping regulation  
E) poly-A tail addition

Answer 21

A) transcriptional regulation

Question 22

14) In the diagram below, what type of control, positive or negative, is operating?

Answer 22

Positive

Question 23

29) The cAMP-CAP complex and RNA polymerase bind more efficiently to the lac operon together than either does alone. What term is applied to this increased efficiency of binding?

Answer 23

cooperative binding

Question 24

31) Regarding regulation of the trp operon, what might one appropriately call the amino acid tryptophan?

Answer 24

corepressor

Question 25

39) Approximately 5 percent of the cytosine residues are methylated in the genome of any given eukaryote. In what way is DNA methylation related to genetic regulation?

Answer 25

There is an inverse relationship between the degree of methylation of eukaryotic DNA and the degree of gene expression

Question 26

59) The enzyme permease cleaves the linkage between glucose and galactose residues in lactose.

True or False

Answer 26

False

Question 27

64) Transcription in eukaryotes is generally influenced by enhancers, just as in prokaryotes.

True or False

Answer 27

False