BIOL 2321: UNIT 3 EXAM QUESTIONS
AND ANSWERS
The process of transcription and translation is carried out in a test tube. To a test tube is
added:
1. from a zebra: transfer RNA's (tRNA), ribosomes
2. from a dragon: messenger RNA (mRNA); RNA polymerase + other necessary
enzymes; ribonucleotides & amino acids.
3. from a dog: DNA
Assume some new protein is synthesized by this cell-free system in the test tube. The
proteins of which animal(s) will be expressed?
Zebra
Dragon
Dragon and Dog
Zebra and Dog
Dog - Correct Answers -Dragon and Dog
plasmid - Correct Answers -some are transferable to cell
promoter strength - Correct Answers -related to the extent amount of the gene
expression
sigma factor - Correct Answers -in bacteria, it helps RNA polymerase bind to the
promoter
regulon - Correct Answers -combind of many operon
Lactose-fermenting bacteria metabolize lactose using two proteins, one binds external
lactose and transports it into the cell, the other breaks down the lactose that comes into
the cell. The two proteins are coded for by two genes that are under the control of a
single promoter. You carry out a lactose fermentation test on an unknown bacterium
and find that the result is positive. All of the following among A - E are applicable to this
bacterium growing in the lactose broth, EXCEPT:
A. An operon specific to lactose metabolism is being expressed.
B. The proteins involved in lactose metabolism represent part of the bacterium's
transcriptome.
C. The fact that the bacterium possesses the genes for lactose metabolism means that
they are part of its genome.
D. Sigma factor would have been involved in initiating expression of the lactose
metabolizing genes.
,E. The lactose metabolism genes would likely have been expressed a - Correct
Answers -B. The proteins involved in lactose metabolism represent part of the
bacterium's transcriptome.
Transformation:
A. is the process by which a bacterium converts genetic information into a protein
B. may involve the formation and accumulation of competence factors
C. requires cell-to-cell contact
D. is a process initiated by the detection of DNA in the external environment of a
bacterium.
E. two of A-D are correct
F. three of A-D are correct - Correct Answers -E. two of A-D are correct ( B & D )
Of the choices given below, which would be required to move an F factor from one cell
to another?
A. a sex pilus.
B. competence factors
C. DNA fragments in the environment.
D. a virus
E. an F- cell
F. two of the above - Correct Answers -F. two of the above ( A & E )
Which of the following is in the correct sequence (left to right) of largest to smallest in
terms of the amount of information in a bacterial cell?
1. 1 nucleotide 2. regulon 3. gene 4. genome 5. operon
2, 4, 3, 5, 1
2, 5, 4, 1, 3
4, 2, 3, 5, 1
4, 2, 5, 3, 1
5, 4, 2, 3, 1 - Correct Answers -4, 2, 5, 3,1
genome > regulon > operon > gene > nucleotide
The recipient of Hfr conjugation __________ becomes an F+ cell.
usually
rarely
always
, frequently - Correct Answers -rarely
Which statement(s) among A-D is/are not applicable to plasmids?
A. They only replicate the same time as the larger chromosome.
B. A plasmid may integrate into the chromosome.
C. They may be of low or high copy number.
D. Plasmids undergoing conjugation duplicate themselves by rolling circle replication.
E. Two of the above statements are not applicable to plasmids. - Correct Answers -They
only replicate the same time as the larger chromosome.
Plasmids can replicate independently of the chromosomal replication, and their
replication is not necessarily synchronized with the chromosome. Therefore, the
statement in option A is not applicable to plasmids.
Various sigma factors play a role in gene expression by
A. bringing about an early termination due to hairpins in the message.
B. allowing for binding of various enhancer proteins to aid initiation.
C. binding to a variety of different -10 and -35 sequences.
D. using alternate nucleotides to promote different genes.
F. two of the above - Correct Answers -C. binding to a variety of different -10 and -35
sequences.
For a certain bacterium, it has been found that a region of thechromosome designated
"X" comprises a specific protein-codingsequence of DNA nucleotides.This sequence
can be converted into protein only when the cells aregrown on galactose as a sole
carbon source. Which of the following statements among A-D is true regarding the
information about this bacterium?
A. The "X" phenotype is revealed when cells are grown on glucose as acarbon source.
B. The "X" sequence is a protein.
C. The "conversion" - Correct Answers -D. The "X" sequence is a gene
Which of the following statements is true about genotype and phenotype?
A. Genotype and phenotype are the same thing and can be used interchangeably.
B. The genotype is always constant, while aparticular phenotype may not be.
C. The phenotype represents the expressionof the genotype.
D. A, B, and C are all true.
E. Two of A, B, C are true (B & C) - Correct Answers -E. Two of A, B, C are true (B & C)
AND ANSWERS
The process of transcription and translation is carried out in a test tube. To a test tube is
added:
1. from a zebra: transfer RNA's (tRNA), ribosomes
2. from a dragon: messenger RNA (mRNA); RNA polymerase + other necessary
enzymes; ribonucleotides & amino acids.
3. from a dog: DNA
Assume some new protein is synthesized by this cell-free system in the test tube. The
proteins of which animal(s) will be expressed?
Zebra
Dragon
Dragon and Dog
Zebra and Dog
Dog - Correct Answers -Dragon and Dog
plasmid - Correct Answers -some are transferable to cell
promoter strength - Correct Answers -related to the extent amount of the gene
expression
sigma factor - Correct Answers -in bacteria, it helps RNA polymerase bind to the
promoter
regulon - Correct Answers -combind of many operon
Lactose-fermenting bacteria metabolize lactose using two proteins, one binds external
lactose and transports it into the cell, the other breaks down the lactose that comes into
the cell. The two proteins are coded for by two genes that are under the control of a
single promoter. You carry out a lactose fermentation test on an unknown bacterium
and find that the result is positive. All of the following among A - E are applicable to this
bacterium growing in the lactose broth, EXCEPT:
A. An operon specific to lactose metabolism is being expressed.
B. The proteins involved in lactose metabolism represent part of the bacterium's
transcriptome.
C. The fact that the bacterium possesses the genes for lactose metabolism means that
they are part of its genome.
D. Sigma factor would have been involved in initiating expression of the lactose
metabolizing genes.
,E. The lactose metabolism genes would likely have been expressed a - Correct
Answers -B. The proteins involved in lactose metabolism represent part of the
bacterium's transcriptome.
Transformation:
A. is the process by which a bacterium converts genetic information into a protein
B. may involve the formation and accumulation of competence factors
C. requires cell-to-cell contact
D. is a process initiated by the detection of DNA in the external environment of a
bacterium.
E. two of A-D are correct
F. three of A-D are correct - Correct Answers -E. two of A-D are correct ( B & D )
Of the choices given below, which would be required to move an F factor from one cell
to another?
A. a sex pilus.
B. competence factors
C. DNA fragments in the environment.
D. a virus
E. an F- cell
F. two of the above - Correct Answers -F. two of the above ( A & E )
Which of the following is in the correct sequence (left to right) of largest to smallest in
terms of the amount of information in a bacterial cell?
1. 1 nucleotide 2. regulon 3. gene 4. genome 5. operon
2, 4, 3, 5, 1
2, 5, 4, 1, 3
4, 2, 3, 5, 1
4, 2, 5, 3, 1
5, 4, 2, 3, 1 - Correct Answers -4, 2, 5, 3,1
genome > regulon > operon > gene > nucleotide
The recipient of Hfr conjugation __________ becomes an F+ cell.
usually
rarely
always
, frequently - Correct Answers -rarely
Which statement(s) among A-D is/are not applicable to plasmids?
A. They only replicate the same time as the larger chromosome.
B. A plasmid may integrate into the chromosome.
C. They may be of low or high copy number.
D. Plasmids undergoing conjugation duplicate themselves by rolling circle replication.
E. Two of the above statements are not applicable to plasmids. - Correct Answers -They
only replicate the same time as the larger chromosome.
Plasmids can replicate independently of the chromosomal replication, and their
replication is not necessarily synchronized with the chromosome. Therefore, the
statement in option A is not applicable to plasmids.
Various sigma factors play a role in gene expression by
A. bringing about an early termination due to hairpins in the message.
B. allowing for binding of various enhancer proteins to aid initiation.
C. binding to a variety of different -10 and -35 sequences.
D. using alternate nucleotides to promote different genes.
F. two of the above - Correct Answers -C. binding to a variety of different -10 and -35
sequences.
For a certain bacterium, it has been found that a region of thechromosome designated
"X" comprises a specific protein-codingsequence of DNA nucleotides.This sequence
can be converted into protein only when the cells aregrown on galactose as a sole
carbon source. Which of the following statements among A-D is true regarding the
information about this bacterium?
A. The "X" phenotype is revealed when cells are grown on glucose as acarbon source.
B. The "X" sequence is a protein.
C. The "conversion" - Correct Answers -D. The "X" sequence is a gene
Which of the following statements is true about genotype and phenotype?
A. Genotype and phenotype are the same thing and can be used interchangeably.
B. The genotype is always constant, while aparticular phenotype may not be.
C. The phenotype represents the expressionof the genotype.
D. A, B, and C are all true.
E. Two of A, B, C are true (B & C) - Correct Answers -E. Two of A, B, C are true (B & C)
