BIO 302 hw and practice Exam 2|30 Questions with Verified Answers
Which form of control directly influences which mRNAs are selected by ribosomes for
... [Show More] the synthesis of proteins?
a. mRNA degradation control
b.mRNA processing and localization control
c. Protein activity control
d. Transcriptional control
e. Translational control - CORRECT ANSWER translation control
Transcription regulators usually bind where on a DNA double helix?
a. 3' End
b. 5' End
c. Major groove
d. Minor groove
e. Single-stranded regions - CORRECT ANSWER major groove
A cell can change the expression of its genes in response to external signals.
True
False - CORRECT ANSWER true
What is the ultimate fate of an mRNA that is targeted by a microRNA (miRNA)?
a. The mRNA will be destroyed by nucleases.
b. The mRNA will be destroyed by the proteasome.
c. The mRNA will be secreted from the cell.
d. The mRNA will be translated more efficiently by ribosomes.
e. The mRNA will be transported to the nucleus. - CORRECT ANSWER The mRNA will be destroyed by nucleases
At any given time, a typical differentiated human cell will express how many of its approximately 25,000 protein-coding genes?
a. About 200
b. About 2,000
c. All 25,000
d. From 5,000 to 15,000
e. None of the above - CORRECT ANSWER 5000-15000
When a transcription regulator binds to DNA, it typically disrupts the hydrogen-bonding between base pairs.
True
False - CORRECT ANSWER false
Which of the following statements is NOT true about the differences between liver cells and kidney cells in the same organism?
a. They contain different genes.
b. They contain different proteins.
c. They contain the entire set of instructions needed to form the whole organism.
d. They contain the same genes.
e. They express different genes. - CORRECT ANSWER they contain different genes
Two types of noncoding regulatory RNAs are:
a. mRNAs and siRNAs.
b. mRNAs and rRNAs.
c. rRNAs and mrRNAs
d. siRNAs and miRNAs
e. sirRNAs and mrRNAs. - CORRECT ANSWER siRNAs and miRNAs
What is an operon?
a. A short sequence of DNA to which a transcription regulator binds
b. A set of genes that is controlled by the binding of two or more transcription regulators
c. A set of genes that is constitutively active
d. A sequence of DNA that produces a variety of mRNAs
e. A set of genes transcribed as a single mRNA from a single promoter - CORRECT ANSWER a set of genes transcribed as a single mRNA from a single promoter
In bacteria, what would be the consequence of a protein binding to, and blocking, the ribosome-binding site on an mRNA?
a. The protein will be incorporated into the growing polypeptide chain.
b. The protein will enhance the stability of the mRNA.
c. The protein will recruit the small ribosomal subunit to the mRNA, increasing translation efficiency.
d. The ribosome will begin translation at a new location on the mRNA.
e. The small ribosomal subunit will not be able to bind to the mRNA, and translation will be inhibited - CORRECT ANSWER The small ribosomal subunit will not be able to bind to the mRNA, and translation will be inhibited
Although all of the steps involved in expressing a gene can in principle be regulated, for most genes the most important point of control is:
a.
mRNA degradation.
b.
mRNA translation.
c.
RNA processing.
d.
RNA transport and localization.
e.
transcription initiation. - CORRECT ANSWER transcription initiation
When a transcription regulator binds to DNA, its most important interactions occur with:
a.
general transcription factors.
b.
nucleotide pairs in the major groove of the double helix.
c.
phosphate groups in the DNA backbone.
d.
sugar groups in the DNA backbone. - CORRECT ANSWER nucleotide pairs in the major groove of the double helix
you have a piece of DNA that includes the following sequence:
5′-ATAGGCATTCGATCCGGATAGCAT-3′
3′-TATCCGTAAGCTAGGCCTATCGTA-5′
Assuming that the top strand is the coding strand, which of the following RNA molecules could be transcribed from this piece of DNA?
(a) 5′-UAUCCGUAAGCUAGGCCUAUGCUA-3′
(b) 5′-AUAGGCAUUCGAUCCGGAUAGCAU-3′
(c) 5′-UACGAUAGGCCUAGCUUACGGAUA-3′
(d) none of the above - CORRECT ANSWER (b) 5′-AUAGGCAUUCGAUCCGGAUAGCAU-3′
Using the transcript information from question above, which of the following choices best describes the direction of transcription in this example?
(a) The top strand is the template strand; RNA polymerase reads this strand from 5′ to 3′.
(b) The top strand is the template strand; RNA polymerase reads this strand from 3′ to 5′.
(c) The bottom strand is the template strand; RNA polymerase reads this strand from 5′ to 3′.
(d) The bottom strand is the template strand; RNA polymerase reads this strand from 3′ to 5′. - CORRECT ANSWER (d) The bottom strand is the template strand; RNA polymerase reads this strand from 3′ to 5′.
7. Which of the following statements is NOT true about the differences between liver cells and kidney cells in the same organism?
(a) They contain different genes.
(b) They contain different proteins.
(c) They contain the entire set of instructions needed to form the whole organism.
(d) They contain the same genes.
(e) They express different genes. - CORRECT ANSWER (a) They contain different genes.
A cell can change the expression of its genes in response to external signals.
(a) False
(b) True - CORRECT ANSWER (b) True
Although all of the steps involved in expressing a gene can in principle be regulated, for most genes the most important point of control is:
(a) mRNA degradation.
(b) mRNA translation.
(c) RNA processing.
(d) RNA transport and localization.
(e) transcription initiation. - CORRECT ANSWER (e) transcription initiation
Which form of control directly influences which mRNAs are selected by ribosomes for the synthesis of proteins?
(a) mRNA degradation control
(b) mRNA processing and localization control
(c) Protein activity control
(d) Transcriptional control
(e) Translational control - CORRECT ANSWER (e) Translational control
Transcription regulators usually bind where on a DNA double helix?
(a) 3' End
(b) 5' End
(c) Major groove
(d) Minor groove
(e) Single-stranded regions - CORRECT ANSWER (c) Major groove
When a transcription regulator binds to DNA, its most important interactions occur with:
(a) general transcription factors.
(b) nucleotide pairs in the major groove of the double helix.
(c) phosphate groups in the DNA backbone.
(d) sugar groups in the DNA backbone. - CORRECT ANSWER (b) nucleotide pairs in the major groove of the double helix
When a transcription regulator binds to DNA, it typically disrupts the hydrogen-bonding between base pairs.
(a) False
(b) True - CORRECT ANSWER (a) False
What is an operon?
(a) A short sequence of DNA to which a transcription regulator binds
(b) A set of genes that is controlled by the binding of two or more transcription regulators
(c) A set of genes that is constitutively active
(d) A sequence of DNA that produces a variety of mRNAs
(e) A set of genes transcribed as a single mRNA from a single promoter - CORRECT ANSWER (e) A set of genes transcribed as a single mRNA from a single promoter
What is the ultimate fate of an mRNA that is targeted by a microRNA (miRNA)?
(a) The mRNA will be destroyed by RISC.
(b) The mRNA will be destroyed by the proteasome.
(c) The mRNA will be secreted from the cell.
(d) The mRNA will be translated more efficiently by ribosomes.
(e) The mRNA will be transported to the nucleus. - CORRECT ANSWER (a) The mRNA will be destroyed by RISC.
Which of the following form tiny hydrophilic pores in the membrane through which solutes can pass by diffusion?
(a) Anions
(b) Channels
(c) Liposomes
(d) Pumps
(e) Transporters - CORRECT ANSWER (b) Channels
Which of the following inhibits inorganic ions, like Na+ and Cl-, from passing through a lipid bilayer?
(a) The carbohydrate layer on the surface of the lipid bilayer
(b) The hydrophilic exterior of the lipid bilayer
(c) The hydrophobic interior of the lipid bilayer
(d) The watery environment on either side of the lipid bilayer - CORRECT ANSWER (c) The hydrophobic interior of the lipid bilayer
The voltage difference across a membrane of a cell is called the:
(a) electrical current.
(b) electrical potential.
(c) membrane potential.
(d) potential balance.
(e) potential voltage. - CORRECT ANSWER (c) membrane potential
The glucose-Na+ symport in epithelial cells uses the electrochemical gradient of Na+ to draw glucose into the cell.
(a) False
(b) True - CORRECT ANSWER (b) True
The Na+/K+ pump in the plasma membrane of animal cells uses energy from ATP hydrolysis to pump sodium and potassium ions against their electrochemical gradients. In which direction are the ions pumped across the membrane?
(a) Na+ and K+ both in
(b) Na+ and K+ both out
(c) Na+ in and K+ out
(d) Na+ out and K+ in - CORRECT ANSWER (d) Na+ out and K+ in
Auditory hair cells in the ear depend on what type of ion channel to detect sound vibrations?
(a) Ligand-gated
(b) Mechanically gated
(c) Voltage-gated
(d) All of the above
(e) None of the above - CORRECT ANSWER (b) Mechanically gated
In most animal cells, which ion can move through "leak" channels?
(a) Ca2+
(b) Cl-
(c) H+
(d) K+
(e) Na+ - CORRECT ANSWER (d) K+ [Show Less]