GCU BIO 181 FINAL EXAM 4 | 80 Questions And
Answers | Latest Updates
The tryptophan operon is a repressible operon that is: ANS Turned off whenever tryptophan is added to the
growth medium.
The lactose operon is likely to be transcribed when: ANS The cyclic AMP and lactose levels are both high
within the cell.
For a repressible operon to be transcribed, which of the following must occur? ANS RNA polymerase must
bind to the promoter, and the repressor must be inactive.
Which of the following, when taken up by the cell, binds to the repressor so that the repressor no longer binds
to the operator? ANS Inducer
What is a promoter? ANS Sequence where the RNA polymerase binds and begins transcription. It is
upstream of the sequence encoding the protein
Which of the following is a protein produced by a regulatory gene? ANS Repressor
What is a corepressor? ANS A small molecule that combines with and activates a repressor produced by a
regular gene
What is an operator? ANS A regulatory sequence that a repressor can bind to
What is a regulatory gene? ANS Genes that encode a protein involved in regulation of gene expression
What has to happen for a gene to be transcribed? ANS RNA polymerase, which makes new RNA
molecules from a DNA template, must attach to the DNA of the gene.
In eukaryotes, general transcription factors: ANS Bind to other proteins or to a sequence element within
the promoter called the TATA box.
, What is a TATA box? ANS DNA sequence that indicates where a genetic sequence can be read and
decoded
Two potential devices that eukaryotic cells use to regulate transcription are ANS DNA methylation and
histone modification. (epigenetic phenomena)
Why are viruses obligate parasites? ANS They cannot reproduce outside of the host cell
Which characteristic is common to all viruses? ANS A genome (nucleic acid) enclosed in a protein capsid
All viruses contain what? ANS A genome and a protein capsid
What determines the host range of a virus? ANS The receptor protein that is on the cell surface
Virulent envelope is made of molecules called? ANS Viral glycoproteins that help with attachment to the
surface of animal viruses, which are proteins plus carbohydrates
Virulent phages undergo what? ANS Lytic life cycle
Temperature changes are capable of undergoing what? ANS Lytic and lysogenic cycles
What is the Lytic cycle? ANS A large number of phages are released at a time. Results in the death of the
host cell
What is the lysogenic cycle? ANS Replicates the phage genome without destroying the host. The viral
DNA molecule is incorporated into the host cell's chromosome. The integrated viral DNA is known as a
prophage. Every time the host divides, the phage genome replicates along with the host genome.
What is a bacteriophage? ANS Viruses that infect bacteria
RNA viruses replication- does not involve the proofreading steps of DNA replication
Answers | Latest Updates
The tryptophan operon is a repressible operon that is: ANS Turned off whenever tryptophan is added to the
growth medium.
The lactose operon is likely to be transcribed when: ANS The cyclic AMP and lactose levels are both high
within the cell.
For a repressible operon to be transcribed, which of the following must occur? ANS RNA polymerase must
bind to the promoter, and the repressor must be inactive.
Which of the following, when taken up by the cell, binds to the repressor so that the repressor no longer binds
to the operator? ANS Inducer
What is a promoter? ANS Sequence where the RNA polymerase binds and begins transcription. It is
upstream of the sequence encoding the protein
Which of the following is a protein produced by a regulatory gene? ANS Repressor
What is a corepressor? ANS A small molecule that combines with and activates a repressor produced by a
regular gene
What is an operator? ANS A regulatory sequence that a repressor can bind to
What is a regulatory gene? ANS Genes that encode a protein involved in regulation of gene expression
What has to happen for a gene to be transcribed? ANS RNA polymerase, which makes new RNA
molecules from a DNA template, must attach to the DNA of the gene.
In eukaryotes, general transcription factors: ANS Bind to other proteins or to a sequence element within
the promoter called the TATA box.
, What is a TATA box? ANS DNA sequence that indicates where a genetic sequence can be read and
decoded
Two potential devices that eukaryotic cells use to regulate transcription are ANS DNA methylation and
histone modification. (epigenetic phenomena)
Why are viruses obligate parasites? ANS They cannot reproduce outside of the host cell
Which characteristic is common to all viruses? ANS A genome (nucleic acid) enclosed in a protein capsid
All viruses contain what? ANS A genome and a protein capsid
What determines the host range of a virus? ANS The receptor protein that is on the cell surface
Virulent envelope is made of molecules called? ANS Viral glycoproteins that help with attachment to the
surface of animal viruses, which are proteins plus carbohydrates
Virulent phages undergo what? ANS Lytic life cycle
Temperature changes are capable of undergoing what? ANS Lytic and lysogenic cycles
What is the Lytic cycle? ANS A large number of phages are released at a time. Results in the death of the
host cell
What is the lysogenic cycle? ANS Replicates the phage genome without destroying the host. The viral
DNA molecule is incorporated into the host cell's chromosome. The integrated viral DNA is known as a
prophage. Every time the host divides, the phage genome replicates along with the host genome.
What is a bacteriophage? ANS Viruses that infect bacteria
RNA viruses replication- does not involve the proofreading steps of DNA replication
