Question 1

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

Accepted Answer

A) True 
 B)False  True

Question 2

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. 
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. A

Question 3

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

Question 4

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. 
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.

Question 5

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. 
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.

Question 6

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. 
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.

Question 7

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. 
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.

Question 8

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. 
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.

Question 9

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. 
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.

Question 10

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. 
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.

Question 11

The mRNA strand includes both introns and exons.

Accepted Answer

A) True 
 B)False

Question 12

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 gene 
A) p53 gene 
B) hemoglobin gene 
C) ras oncogene 
D) p16 
E) RB tumor-repressor gene

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. 
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.

Question 14

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 DNA 
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 DNA

Question 15

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

Accepted Answer

A) True 
 B)False

Question 16

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

Question 17

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 18

Mutagens and carcinogens are associated with

Accepted Answer

A) induced mutations. 
B) spontaneous mutations. 
C) transposon activity. 
D) None of the above. 
A) induced mutations. 
B) spontaneous mutations. 
C) transposon activity. 
D) None of the above.

Question 19

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 20

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. 
A) regulator gene 
B) promoter 
C) operator 
D) structural gene 
E) All of these are part of an operon.

Exam 13: Regulation of Gene Expression

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

Which statement is NOT correct about the lac operon?

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

In transcriptional control in eukaryotic cells

Androgen insensitivity is characterized by

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

Which of the following is a method of posttranscriptional control?

All of these are considered carcinogens EXCEPT

Thymine dimers

Frameshift mutations

The mRNA strand includes both introns and exons.

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

The universal regulatory mechanism in eukaryotes for controlling gene expression includes

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

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

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

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

Mutagens and carcinogens are associated with

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

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

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