Biol 1020 Genetics Lesson 8 With Complete Solutions
Use the information below to answer the questions on this page.
Suppose an experimenter becomes proficient with a technique that allows her to move
DNA sequences within a prokaryotic genome.
If she moves the repressor gene, (lac I), along with its promoter, to a position at some
several thousand base pairs away from its normal position, what do you expect will
happen? - ANSWER The lac operon will function normally.
Of the following, which is the most current definition of a gene? - ANSWER a DNA
sequence that is transcribed to produce a functional product: either RNA or polypeptide
Of the following small scale mutations, which would be most likely to have a disastrous
effect on the activity of a protein? - ANSWER a base deletion near the start of a gene
A metabolite that controls an inducible operon works by ANSWER binding to the
repressor protein and thereby inactivating it
The lactose operon would most likely be transcribed when ANSWER cyclic AMP and
lactose levels inside the cell are high
Lack of which of the following molecules would be unable to allow the cell to "turn off"
genes? ANSWER corepressor
What is the effect of a nonsense mutation in a gene? - ANS It introduces a premature
stop codon into the mRNA.
, A transcription unit that is 8000 nucleotides long may use 1200 nucleotides to make a
protein consisting of approximately 400 amino acids. This is best explained by the fact
that - ANS many noncoding stretches of nucleotides are present in mRNA
What does it have to happen when the function of the newly made polypeptide is to be
secreted from the cell where it has been made? - ANSWER Its signal sequence has to
target it to the ER, from which it goes to the Golgi.
A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell
would have what effect on the gene controlled by that regulator? - ANSWER constant
transcription of the gene controlled by that regulator.
A change in one nucleotide pair of a gene is called- ANSWER point mutation.
The following questions refer to this figure of a simple metabolic pathway:
If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding
enzyme A would be able to grow on which of the following media? - ANSWER minimal
medium supplemented with nutrient B only
The next questions refer to this table of codons.
What amino acid sequence will be produced, based on the following mRNA codon
sequence?
5' AUG-UCU-UCG-UUA-UCC-UUG 3' - ANSWER met-ser-ser-leu-ser-leu
Use the information below to answer the questions on this page.
Suppose an experimenter becomes proficient with a technique that allows her to move
DNA sequences within a prokaryotic genome.
If she moves the repressor gene, (lac I), along with its promoter, to a position at some
several thousand base pairs away from its normal position, what do you expect will
happen? - ANSWER The lac operon will function normally.
Of the following, which is the most current definition of a gene? - ANSWER a DNA
sequence that is transcribed to produce a functional product: either RNA or polypeptide
Of the following small scale mutations, which would be most likely to have a disastrous
effect on the activity of a protein? - ANSWER a base deletion near the start of a gene
A metabolite that controls an inducible operon works by ANSWER binding to the
repressor protein and thereby inactivating it
The lactose operon would most likely be transcribed when ANSWER cyclic AMP and
lactose levels inside the cell are high
Lack of which of the following molecules would be unable to allow the cell to "turn off"
genes? ANSWER corepressor
What is the effect of a nonsense mutation in a gene? - ANS It introduces a premature
stop codon into the mRNA.
, A transcription unit that is 8000 nucleotides long may use 1200 nucleotides to make a
protein consisting of approximately 400 amino acids. This is best explained by the fact
that - ANS many noncoding stretches of nucleotides are present in mRNA
What does it have to happen when the function of the newly made polypeptide is to be
secreted from the cell where it has been made? - ANSWER Its signal sequence has to
target it to the ER, from which it goes to the Golgi.
A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell
would have what effect on the gene controlled by that regulator? - ANSWER constant
transcription of the gene controlled by that regulator.
A change in one nucleotide pair of a gene is called- ANSWER point mutation.
The following questions refer to this figure of a simple metabolic pathway:
If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding
enzyme A would be able to grow on which of the following media? - ANSWER minimal
medium supplemented with nutrient B only
The next questions refer to this table of codons.
What amino acid sequence will be produced, based on the following mRNA codon
sequence?
5' AUG-UCU-UCG-UUA-UCC-UUG 3' - ANSWER met-ser-ser-leu-ser-leu
