Question 1

Thymine dimers

Accepted Answer

A)  form when DNA is exposed to carcinogens such as tobacco smoke.
B)  are rarely removed by DNA repair enzymes.
C)  form when DNA is exposed to UV radiation.
D)  result in abnormal protein structure which causes red blood cells to sickle.E) A) and B)
F) A) and C)

Question 2

The regulator gene codes for the DNA-binding proteins that act as repressors.

Accepted Answer

A) True 
 B)False  True

Question 3

Explain how the actions of the lac operon are different from the trp operon.

Accepted Answer

Answers may vary.The trp operon is a rep...

Question 4

Which statement is NOT correct about the lac operon?

Accepted Answer

A)  It regulates the production of a series of five enzymes.
B)  It is normally turned off if glucose is present.
C)  Lactose binds to the repressor protein and inactivates it.
D)  It is an inducible system.
E)  The structural genes make products that allow lactose metabolism.F) C) and D)
G) A) and B) A

Question 5

Which of the following is a method of posttranscriptional control?

Accepted Answer

A)  transcription factors
B)  the lifespan of an mRNA molecule
C)  differential processing of mRNA
D)  how fast the mRNA leaves the nucleus
E)  Both C and D are methods of posttranscriptional control.F) C) and E)
G) A) and B)

Question 6

Which of the following structures is not part of an operon?

Accepted Answer

A)  regulator gene
B)  promoter
C)  operator
D)  structural gene
E)  All of these are part of an operon.F) All of the above
G) C) and D)

Question 7

Frameshift mutations

Accepted Answer

A)  most often happen when one or more nucleotides are inserted or deleted from the DNA.
B)  can result in a completely new codon sequence that results in the production of non-functional proteins.
C)  applies to the reading frame (sequence of codons) being changed.
D)  All of the choices are correct.E) All of the above
F) C) and D)

Question 8

Which level of primary control in eukaryotic gene activity involves changes in the polypeptide chain before it becomes functional?

Accepted Answer

A)  feedback control
B)  translational control
C)  transcriptional control
D)  posttranscriptional control
E)  posttranslational controlF) B) and D)
G) C) and E)

Question 9

Which of the following situations would be considered an example of positive regulation of gene expression in a prokaryote?

Accepted Answer

A)  The CAP protein activating the lac operon when glucose is absent and lactose is present.
B)  The CAP protein activating the lac operon when lactose is absent and glucose is present.
C)  The repressor protein activating the lac operon when glucose is absent and lactose is present.
D)  The repressor protein activating the lac operon when lactose is absent and glucose is present.E) A) and D)
F) B) and D)

Question 10

In transcriptional control in eukaryotic cells

Accepted Answer

A)  a different combination of DNA-binding proteins (transcriptional factors) may regulate the activity of a particular gene.
B)  enhancers may be involved in the promotion as well as regulation of gene transcription.
C)  the control may be due to the phosphorylation of transcriptional factors by a kinase.
D)  All of the choices are correct.
E)  Only two of the choices are correct.F) A) and E)
G) B) and C)

Question 11

Androgen insensitivity is characterized by

Accepted Answer

A)  a lack of male hormones,such as testosterone.
B)  external female genitalia.
C)  a female karyotype.
D)  the internal sex organs of a female and may bear children.E) A) and B)
F) A) and C)

Question 12

Which component in an operon is incorrectly matched with its function?

Accepted Answer

A)  promoter-where RNA polymerase first binds to DNA
B)  regulator gene-binds to the repressor protein
C)  structural gene-makes mRNA by transcription
D)  operator-if not bound to the repressor,allows RNA polymerase to bind to the DNAE) None of the above
F) A) and C)

Question 13

The universal regulatory mechanism in eukaryotes for controlling gene expression includes

Accepted Answer

A)  control of the genes transcribed and the rate they are transcribed.
B)  control of the processing of mRNA after it is transcribed from DNA but before it leaves the nucleus,and control of the rate it leaves the nucleus.
C)  control of mRNA in the cytoplasm after it leaves the nucleus,including changes to mRNA before translation begins.
D)  control of polypeptides after they have been synthesized but before they are functional.
E)  All of these mechanisms are used; there is no single universal mechanism.F) A) and B)
G) A) and C)

Question 14

One-third of all cancer deaths are due to mutations that arise from smoking tobacco.

Accepted Answer

A) True 
 B)False

Question 15

All of these are considered carcinogens EXCEPT

Accepted Answer

A)  cigarette smoke.
B)  ultraviolet light.
C)  cabbage and related vegetables.
D)  ethylene dibromide (ED
B)  .
E)  ziram,a chemical used to prevent fungal diseases on crops.F) A) and B)
G) A) and C)

Question 16

All genes are active at the same time in a prokaryotic cell and controlled by positive regulation,but not in a eukaryotic cell.

Accepted Answer

A) True 
 B)False

Question 17

Mutagens and carcinogens are associated with

Accepted Answer

A)  induced mutations.
B)  spontaneous mutations.
C)  transposon activity.
D)  None of the above.E) A) and D)
F) All of the above

Question 18

Identify the major tumor suppressor gene that is more frequently mutated in human cancers than any other known gene.

Accepted Answer

A)  p53 gene
B)  hemoglobin gene
C)  ras oncogene
D)  p16
E)  RB tumor-repressor geneF) C) and D)
G) None of the above

Question 19

The mRNA strand includes both introns and exons.

Accepted Answer

A) True 
 B)False

Question 20

The DNA of a ________ is wrapped around histone molecules to form a "beaded string."

Accepted Answer

A)  prokaryote
B)  eukaryote
C)  bacterium
D)  All of the answer choices are correct.E) A) and C)
F) All of the above B

Exam 13: Regulation of Gene Expression

Thymine dimers

Correct AnswerverifiedShow Answer

The regulator gene codes for the DNA-binding proteins that act as repressors.

Correct AnswerverifiedTrue

Explain how the actions of the lac operon are different from the trp operon.

Correct AnswerverifiedAnswers may vary.The trp operon is a rep...View AnswerShow Answer

Which statement is NOT correct about the lac operon?

Correct AnswerverifiedA

Which of the following is a method of posttranscriptional control?

Correct AnswerverifiedShow Answer

Which of the following structures is not part of an operon?

Correct AnswerverifiedShow Answer

Frameshift mutations

Correct AnswerverifiedShow Answer

Which level of primary control in eukaryotic gene activity involves changes in the polypeptide chain before it becomes functional?

Correct AnswerverifiedShow Answer

Which of the following situations would be considered an example of positive regulation of gene expression in a prokaryote?

Correct AnswerverifiedShow Answer

In transcriptional control in eukaryotic cells

Correct AnswerverifiedShow Answer

Androgen insensitivity is characterized by

Correct AnswerverifiedShow Answer

Which component in an operon is incorrectly matched with its function?

Correct AnswerverifiedShow Answer

The universal regulatory mechanism in eukaryotes for controlling gene expression includes

Correct AnswerverifiedShow Answer

One-third of all cancer deaths are due to mutations that arise from smoking tobacco.

Correct AnswerverifiedShow Answer

All of these are considered carcinogens EXCEPT

Correct AnswerverifiedShow Answer

All genes are active at the same time in a prokaryotic cell and controlled by positive regulation,but not in a eukaryotic cell.

Correct AnswerverifiedShow Answer

Mutagens and carcinogens are associated with

Correct AnswerverifiedShow Answer

Identify the major tumor suppressor gene that is more frequently mutated in human cancers than any other known gene.

Correct AnswerverifiedShow Answer

The mRNA strand includes both introns and exons.

Correct AnswerverifiedShow Answer

The DNA of a ________ is wrapped around histone molecules to form a "beaded string."

Correct AnswerverifiedB

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