AP Biology (Mader), 11th Edition

Chapter 13: Regulation of Gene Activity

Post-Test

1
The _____ model proposed by Jacob and Monod explains gene regulation in prokaryotes.
A)endosymbiotic
B)cohesion-tension
C)operon
D)fluid mosaic
2
The short sequence of DNA where RNA polymerase first attaches when a gene is to be transcribed is called the _____.
A)promoter
B)operator
C)active site
D)replication fork
3
All of the following statements about the lac operon are true EXCEPT:
A)The lac operon is turned on in the presence of lactose.
B)The lac operon is an inducible operon.
C)The default position of the lac operon is 'ON'.
D)There are three structural genes in the lac operon.
4
After DNA is transcribed and preliminary mRNA is formed, _____ control occurs in the nucleus.
A)transcriptional
B)posttranscriptional
C)translational
D)posttranslational
5
_________ control changes the polypeptide product to make it biologically functional.
A)Transcriptional
B)Posttranscriptional
C)Translational
D)Posttranslational
6
If a point mutation occurs midway through the DNA code for a protein and a stop codon results, the protein will _____.
A)function normally
B)be incomplete
C)have a different sequence of amino acids
7
Chromatin that is extended and accessible for transcription is:
A)euchromatin.
B)a Barr body.
C)heterochromatin.
D)appears as darkly stained areas within the nucleus.
8
Why can transcription and translation occur simultaneously in prokaryotes but not in eukaryotes?
A)Both processes occur in the cytoplasm in prokarytoes but in eukaryotes transcription occurs in the nucleus and translation occurs in the cytoplasm.
B)Both processes occur in the cytoplasm in eukaryotes, but in prokaryotes translation occurs in the cytoplasm and transcription occurs in the nucleus.
C)They can occur simultaneously in both prokaryotes and eukaryotes.
D)In eukaryotes, translation occurs in the nucleus and transcription occurs in the cytoplasm, but in prokaryotes both processes occur in the nucleus.
9
The most frequently mutated tumor-suppressor gene in human cancers is the _____.
A)ras oncogene
B)RB gene
C)p53 gene
D)BRCA1 gene
10
Which of the following statements about oncogenes is NOT true?
A)These genes may code for a product that overstimulates the cell cycle.
B)The result is that a cell signaling pathway no longer functions as it should.
C)An abnormal protein product is produced.
D)When oncogenes mutate, they become proto-oncogenes.
11
The prevention of cancer may be accomplished by all of the following EXCEPT:
A)High-fiber foods
B)Eating more fruits and vegetables
C)Less sunbathing
D)Meditation
12
Thymine dimers are caused by _____.
A)UV radiation
B)X-rays
C)organic chemicals in tobacco smoke
D)Vitamin D
13
Very few spontaneous mutations due to DNA replication occur because of the proofreading performed by _____.
A)helicase
B)RNA polymerase
C)DNA ligase
D)DNA polymerase
14
A condensed, inactive X chromosome is referred to as _____.
A)a telomere
B)euchromatin
C)a Barr body
D)a transposon
15
All of the following statements describe the trp operon EXCEPT?
A)It is a repressible operon.
B)Tryptophan is the corepressor.
C)The default position is 'on'.
D)The repressor is normally active and able to attach to the operator.
16
What type of control deals with the differential processing of the primary mRNA and the speed with which the mature mRNA leaves the nucleus?
A)transcriptional
B)posttranscriptional
C)translational
D)posttranslational
17
The lac operon's promoter is better exposed to RNA polymerase when _____ binds to the DNA next to lac promoter.
A)ATP
B)glucose
C)a catabolic activator protein
D)tryptophan
18
When the repressor is altered by the substrate in the lac operon, the _______.
A)genes for the three digestive enzymes cannot be transcribed
B)repressor cannot bind to the operator
C)concentration of lactose is low
D)operon is 'turned off'
19
When do cAMP molecules accumulate, then bind to and activate CAP (catabolic activator protein)?
A)When RNA polymerase does not bind fully with the promoter.
B)When lactose is absent.
C)When lactose is present.
D)When glucose is absent.
20
In sickle cell anemia, a point mutation occurs which replaces the amino acid valine with glutamic acid. In which level of protein structure does this mutation physically occur first?
A)Quaternary
B)Tertiary
C)Secondary
D)Primary
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