Question 1

Active genes in eukaryotic cells are associated with

Accepted Answer

A)  euchromatin.
B)  heterochromatin.
C)  methylated RNA and histones.
D)  DNA with many methyl groups.E) C) and D)
F) B) and C)

Question 2

Explain how the trp operon is regulated in a prokaryotic cell when tryptophan is present.

Accepted Answer

Answers may vary but should include the ...

Question 3

When a bacterium is introduced to a new environment with plenty of nutritional resources,binary fission will allow for rapid growth of the population (2-4-8-16-32-64 ...etc.) .However,there is usually a slight lag before the rapid growth begins.What is the best explanation for this lag period?

Accepted Answer

A)  It takes time for bacterial cells to duplicate enough organelles to digest new media.
B)  It takes time to induce and amplify the production of the enzymes needed for binary fission.
C)  Binary fission becomes more and more efficient after each cell division.
D)  The new media contains compounds that turn on repressor proteins.
E)  Structural genes act more slowly than metabolic genes.F) A) and E)
G) C) and E)

Question 4

The genes of a single operon are all regulated by the same repressor,operator,and promoter.

Accepted Answer

A) True 
 B)False

Question 5

You are more likely to develop some form of cancer if you

Accepted Answer

A)  are exposed to higher doses of radiation including X-rays.
B)  are exposed to carcinogens.
C)  have a high incidence of cancer in your family history.
D)  All of the choices are correct.E) A) and B)
F) A) and C)

Question 6

The most critical level of eukaryotic genetic control is ________ control.

Accepted Answer

A)  feedback
B)  translational
C)  transcriptional
D)  posttranscriptional
E)  posttranslationalF) B) and D)
G) C) and D)

Question 7

An oncogene is

Accepted Answer

A)  a viral gene with no relation to the host cell's genes.
B)  a mutated form of a proto-oncogene.
C)  a bacterial gene that causes cancer in the host.
D)  always seen in human cancer cells.
E)  a gene that turns off cellular reproduction.F) A) and C)
G) A) and B)

Question 8

Transposons

Accepted Answer

A)  are specific DNA sequences that move within and between chromosomes.
B)  alter the expression of neighboring genes especially if the transposon is a regulator gene.
C)  have been discovered in corn,fruit flies,bacteria,and humans.
D)  All of the choices are correct.E) C) and D)
F) B) and C)

Question 9

Point mutations

Accepted Answer

A)  are due to a change in one DNA nucleotide.
B)  may change a specific codon.
C)  can cause a genetic disease such as sickle-cell disease that is due to a base change that codes for valine rather than glutamate.
D)  All of the choices are correct.E) None of the above
F) All of the above

Question 10

Compared to just a century ago,a much larger percentage of the population is living to be 80-90 years old.Why does cancer seem to be a much larger problem today than a century ago?

Accepted Answer

Answers may vary.There is currently much...

Question 11

Which of the following series of events is associated with the formation of cancer?

Accepted Answer

A)  The proto-oncogenes mutate and become oncogenes which are continuously active.There is also an associated loss of tumor suppressor gene activity allowing uncontrolled growth of cells.
B)  The oncogenes mutate and become proto-oncogenes which are continuously active.There is also an associated loss of tumor suppressor gene activity allowing uncontrolled growth of cells.
C)  The proto-oncogenes mutate and become oncogenes which stop functioning altogether.There is also an associated increase in the tumor suppressor gene activity allowing uncontrolled growth of cells.
D)  The oncogenes mutate and become proto-oncogenes which stop functioning altogether.There is also an associated increase in the tumor suppressor gene activity allowing uncontrolled growth of cells.E) A) and B)
F) A) and C)

Question 12

A form of gene regulation that occurs while RNA is still in the nucleus is

Accepted Answer

A)  differential intron removal and exon splicing.
B)  feedback control.
C)  enzymatic cleavage of a polypeptide.
D)  rate of binding to ribosomes.E) All of the above
F) A) and B)

Question 13

The level of genetic control that involves the life span of the mRNA molecule and the ability of the mRNA to bind to ribosomes is ________ control.

Accepted Answer

A)  feedback
B)  translational
C)  transcriptional
D)  posttranscriptional
E)  posttranslationalF) A) and D)
G) None of the above

Question 14

A deletion of one base pair that alters the sequence of codons is called a(n)

Accepted Answer

A)  transposon.
B)  substitution mutation.
C)  carcinogen.
D)  oncogene.
E)  frameshift mutation.F) A) and B)
G) D) and E)

Question 15

The level of genetic control that involves the processing of early RNA transcripts to mRNA and the rate at which mRNA leaves the nucleus is

Accepted Answer

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

Question 16

If CAP is absent from a cell,what are the potential consequences?

Accepted Answer

A)  The individual cannot activate the catabolism of various other metabolites in the absence of glucose.
B)  The individual does not have a backup system for survival when glucose is absent.
C)  The individual will not be able to metabolize enough energy if glucose is absent.
D)  All of these are consequences of the absence of CAP.E) B) and D)
F) All of the above

Question 17

In the transcription of DNA,remodeling proteins push the histone portion of the nucleosome aside so that transcription may begin.

Accepted Answer

A) True 
 B)False

Question 18

________ occurs as ________ builds up in the system if Enzyme A is nonfunctional because of an inherited mutation.  AEABEBC (phenylalanine)  ⟶ (tyrosine)  ⟶ (melanin)  \begin{array} { l  }A&E_A&B&E_B&C\	ext { (phenylalanine)  }&\longrightarrow&	ext { (tyrosine)  }&\longrightarrow&	ext { (melanin)  }\end{array}A (phenylalanine)  ​EA​⟶​B (tyrosine)  ​EB​⟶​C (melanin)  ​

Accepted Answer

A)  albinism; melanin
B)  xeroderma pigmentosum; tyrosine
C)  phenylketonuria; phenyalanine
D)  androgen insensitivity; tyrosine E) None of the above
F) B) and C)

Question 19

A Barr body

Accepted Answer

A)  exists within the cell in the form of euchromatin.
B)  is an inactive Y chromosome that produces reduced amount of gene products.
C)  is an inactive X chromosome that does not produce gene products.
D)  exists within the cell in the form of heterochromatin.
E)  Two of the above answers are correct.F) B) and E)
G) C) and E)

Question 20

Identify which of the operon elements plays the most critical role in determining gene regulation in prokaryotes.

Accepted Answer

Answers may vary.The operon elements sho...

Exam 13: Regulation of Gene Expression

Explain how the trp operon is regulated in a prokaryotic cell when tryptophan is present.

Correct AnswerverifiedAnswers may vary but should include the ...View AnswerShow Answer

A form of gene regulation that occurs while RNA is still in the nucleus is

Correct AnswerverifiedShow Answer

In the transcription of DNA,remodeling proteins push the histone portion of the nucleosome aside so that transcription may begin.

Correct AnswerverifiedShow Answer

The genes of a single operon are all regulated by the same repressor,operator,and promoter.

Correct AnswerverifiedShow Answer

Compared to just a century ago,a much larger percentage of the population is living to be 80-90 years old.Why does cancer seem to be a much larger problem today than a century ago?

Correct AnswerverifiedAnswers may vary.There is currently much...View AnswerShow Answer

Identify which of the operon elements plays the most critical role in determining gene regulation in prokaryotes.

Correct AnswerverifiedAnswers may vary.The operon elements sho...View AnswerShow Answer

The most critical level of eukaryotic genetic control is ________ control.

Correct AnswerverifiedShow Answer

Active genes in eukaryotic cells are associated with

Correct AnswerverifiedShow Answer

Point mutations

Correct AnswerverifiedShow Answer

When a bacterium is introduced to a new environment with plenty of nutritional resources,binary fission will allow for rapid growth of the population (2-4-8-16-32-64 ...etc.) .However,there is usually a slight lag before the rapid growth begins.What is the best explanation for this lag period?

Correct AnswerverifiedShow Answer

The level of genetic control that involves the life span of the mRNA molecule and the ability of the mRNA to bind to ribosomes is ________ control.

Correct AnswerverifiedShow Answer

An oncogene is

Correct AnswerverifiedShow Answer

A deletion of one base pair that alters the sequence of codons is called a(n)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

If CAP is absent from a cell,what are the potential consequences?

Correct AnswerverifiedShow Answer

The level of genetic control that involves the processing of early RNA transcripts to mRNA and the rate at which mRNA leaves the nucleus is

Correct AnswerverifiedShow Answer

You are more likely to develop some form of cancer if you

Correct AnswerverifiedShow Answer

Which of the following series of events is associated with the formation of cancer?

Correct AnswerverifiedShow Answer

A Barr body

Correct AnswerverifiedShow Answer

Transposons

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