Practice test Flashcards
(17 cards)
Where will the tRNA carrying Met in the picture above be located after the Met-Val peptide
bond is transferred to the incoming RNA?
A) in the E site of the ribosome
B) in the A site of the ribosome
C) in the P site of the ribosome
A) in the E site of the ribosome
What is the type of incoming RNA shown in the picture above carrying Val
A) m-RNA
B) t-RNA
C) r-RNA
B) t-RNA
What amino acid sequence will be generated, based on the following mRNA codon
sequence? Use the provided codon table to answer the following question.
5’ AUG-UCU-UCG-UUA-UCC-UUG 3’
A) met-arg-glu-arg-glu-arg
B) met-glu-arg-arg-glu-leu
C) met-ser-leu-ser-leu-ser
D) met-ser-ser-leu-ser-leu
E) met-leu-phe-arg-glu-glu
D) met-ser-ser-leu-ser-leu
Imagine a cell with a dysfunctional Golgi apparatus. Which of the following statements best
predicts and explains the impact this dysfunction would have on the pathway taken by a newly
synthesized protein intended for secretion?
A) The protein would accumulate in the nucleus, as it cannot be properly transported to the ER.
B) The protein would be transported from the ER directly to the lysosomes where it would be
degraded.
C) The protein would be trapped in the ER, leading to potential accumulation and stress, due to
the inability to be processed and sorted by the Golgi.
D) The protein would bypass the Golgi and be secreted directly from the ER to the plasma
membrane, though possibly in an unmodified form.
E) The protein would be redirected to the mitochondria for alternative processing and export
out of the cell.
C) The protein would be trapped in the ER, leading to potential accumulation and stress, due to
the inability to be processed and sorted by the Golgi
In response to changes in environmental temperature, many organisms must adjust the
composition of their plasma membranes to maintain appropriate membrane fluidity. The
structure of fatty acids in phospholipids, particularly their saturation levels, plays a crucial role in
these adjustments.
Which change in the saturation of phospholipid fatty acid side chains would be most effective in
maintaining membrane fluidity in a hot environment?
A) A decrease in side chain saturation.
B) An increase in side chain saturation.
C) An increase in side chain length and an increase in side chain saturation.
D) A decrease in side chain length and a decrease in side chain saturation.
B) An increase in side chain saturation
Which of these best reflects the following relationship: monosaccharide versus
polysaccharide?
A) Glucose versus glycogen
B) Glucose versus fructose
C) 1,4-glycosidic linkage versus 1,6-glycosidic linkage
D) α-linkage versus β-linkage
A) Glucose versus glycogen
- When a cholesterol molecule is inserted into a phospholipid bilayer, the hydrocarbon rings of
the cholesterol are located in _________
A) the polar head region of the bilayer
B) the nonpolar tail region of the bilayer
C) the hydrophobic core of the bilayer
D) the aqueous environment outside the bilayer
E) the polar tail region of the bilayer
C) the hydrophobic core of the bilayer
Membrane proteins will be threaded thru the ER membrane as they are being synthesized.
Where would you expect the N-terminus of these proteins to be located?
A) ER lumen
B) Cytosol
C) ER membrane
D) Nucleus
A) ER lumen
- Proteins rejected by the quality control mechanism are primarily ______________ degraded
by the ER-associated degradation mechanism in the ______________
A) The cell transports misfolded proteins to the Golgi apparatus for further processing
B) degradation of misfolded proteins through ER-associated degradation (ERAD) by the
proteosome
C) The cell exclusively targets misfolded proteins for lysosomal degradation
D) The cell sends misfolded proteins back to the nucleus to be refolded
B) degradation of misfolded proteins through ER-associated degradation (ERAD) by the
proteosome
Eukaryotic cells manufacture cytosolic enzymes, which are crucial for metabolic activities
within the cell. What would you predict about these proteins?
A) They initially contain signal sequences that direct them into the endoplasmic reticulum.
B) They are produced by ribosomes floating freely within the cytosol.
C) They undergo processing in the Golgi apparatus.
D) They are transported to the nucleus in vesicles with specific targeting sequences.
B) They are produced by ribosomes floating freely within the cytosol
Which of the following increases the strength of the hydrophobic interactions in
lipid bilayers and thus makes them less permeable to polar molecules?
A) The presence of double bonds
B) Increasing temperature
C) Removing cholesterol
D) Increasing length of the hydrocarbon chains
D) Increasing length of the hydrocarbon chains
. Under what circumstances does membrane transport require energy?
A) Wherever large molecules are moved within a cell
B) Whenever a solute is moved against its concentration gradient
C) Whenever an ion moves through a phospholipid bilayer membrane
D) Whenever oxygen moves through a phospholipid bilayer membrane
B) Whenever a solute is moved against its concentration gradient
Which of the following macromolecules leaves the nucleus of a eukaryotic cell through
pores in the nuclear membrane?
A) DNA
B) Amino acids
C) mRNA
D) Phospholipids
C) mRNA
In eukaryotic cells, transcription cannot begin until ________.
A) the two DNA strands have completely separated and exposed the promoter
B) several transcription factors have bound to the promoter
C) the 5’ caps are removed from the mRNA
D) the DNA introns are removed from the template
E) DNA nucleases have isolated the transcription unit
B) several transcription factors have bound to the promoter
What is responsible for termination of transcription in eukaryotic protein-coding genes?
A) A polyadenylation, or poly (A), signal
B) A termination loop composed of guanine
C) A sigma factor
D) A portion of the polymerase holoenzyme
E) Three nonsense mutations in sequence
A) A polyadenylation, or poly (A), signal
A particular triplet of bases in the template strand of a coding sequence of DNA is AAA. The
anticodon on the tRNA that binds the corresponding mRNA codon is ________.
A) TTT
B) UUA
C) UUU
D) AAA
C) UUU
If the sequence in the coding strand of DNA for a particular amino acid is 5’AGT3’ , then
the anticodon on the corresponding tRNA would be ________.
A) 5’ACU3’
B) 5’TCA3’
C) 5’UCA3’
D) 5’AGU3’
E) 5’ACT3
C) 5’UCA3’
