Practice Exam On Biochemistry: Quiz!
.jpg "Practice Exam On Biochemistry: Quiz! - Quiz")
Can you complete this quiz on biochemistry? Many chemists work in chemistry laboratories. Some biochemists may concentrate on modeling, which would allow them to work with computers. Some biochemists operate in the field of studying a biochemical system in an organism. Biochemists are typically associated with other scientists and engineers. This quiz will provide you with the answers to all the questions you may have about biochemistry.
- 1.
The component(s) of DNA which is responsible for the absorbance band at 250-270 nm is:
- A.
Bases, pentoses, and phosphates all contribute
- B.
Only bases
- C.
Only bases and pentoses
- D.
Only pentoses and phosphates
Correct Answer
B. Only bases -
- 2.
The oligonucleotide, AUGGp, has all these properties except:
- A.
Composed of ribonucleotides
- B.
Contains a 3' phosphate
- C.
Composed of deoxyribonucleotides
- D.
Contains three phosphodiester bonds
Correct Answer
C. Composed of deoxyribonucleotides -
- 3.
An individual heterogeneous nuclear RNA (hnRNA)
- A.
Contains intron sequences not found in the final mature mRNA.
- B.
Contains exon sequences which are removed prior to translation.
- C.
Encodes more than one protein.
- D.
Can be found in the cytoplasm.
Correct Answer
A. Contains intron sequences not found in the final mature mRNA. -
- 4.
The RNA molecules which are involved in processing the hnRNA are:
- A.
MRNA
- B.
TRNA
- C.
RRNA
- D.
SnRNA
Correct Answer
D. SnRNA -
- 5.
What statement is incorrect about the different RNA molecules?
- A.
TRNAs contain numerous intramolecular hydrogen bonds between bases.
- B.
There are more distinct tRNA molecules than there are rRNA molecules.
- C.
RRNAs are complexed to proteins in the ribosome.
- D.
The most abundant RNA molecule in the cell is mRNA.
Correct Answer
D. The most abundant RNA molecule in the cell is mRNA. -
- 6.
Which of the following is not a characteristic for DNA synthesis?
- A.
DNA polymerase adds nucleotides in a 5'--> 3' direction
- B.
A primer strand of DNA must contain a free 3'-OH end
- C.
The primer strand of DNA determines which nucleotides are added next
- D.
The correct complementary hydrogen bonding between base pairs is the primary check on the fidelity of the newly synthesized DNA
Correct Answer
C. The primer strand of DNA determines which nucleotides are added next -
- 7.
A DNA is found to exhibit a melting temperature of 75 C in 0.1 M NaCl. Under what experimental conditions would the Tm be increased?
- A.
Decreasing the concentration of DNA.
- B.
Increasing the concentration of NaCl in the solution.
- C.
Adding 1% urea (an organic denaturant).
- D.
All of the above.
Correct Answer
B. Increasing the concentration of NaCl in the solution. -
- 8.
A feature which is distinctive to Z-DNA is
- A.
A left-handed helix
- B.
It has 12 bases per turn
- C.
It is found in vivo
- D.
All of the above
Correct Answer
D. All of the above -
- 9.
The linking number of a highly supercoiled plasmid can be readily changed without producing a relaxed DNA by
- A.
Changing the temperature
- B.
Increasing salt concentration
- C.
The action of topoisomerase
- D.
The action of a nuclease such as pancreatic DNase
Correct Answer
C. The action of topoisomerase -
- 10.
Which of the following double-stranded DNAs may convert to a cruciform structure?
- A.
ATGCATGCATGCATGC / TACGTACGTACGTACG
- B.
CATTAAGCAGTGCTTAAGA / GTAATTCGTCACGAATTCT
- C.
ATATATATGCGCGCGCGC / TATATATACGCGCGCGCG
- D.
AAAAAAAAACCCCCCCCC / TTTTTTTTTGGGGGGGG
Correct Answer
B. CATTAAGCAGTGCTTAAGA / GTAATTCGTCACGAATTCT -
- 11.
Which statement is incorrect about the structure of native E. coli chromosomal DNA?
- A.
The DNA is primarily in the B-helix.
- B.
The DNA is circular and supercoiled
- C.
The DNA exists as a right-handed double helix.
- D.
The DNA is one large linear piece about 4000 kb in length.
Correct Answer
D. The DNA is one large linear piece about 4000 kb in length. -
- 12.
E. coli DNA polymerase I has all the following characteristics except
- A.
A 5'-3' exonuclease activity on a second subunit in the polymerase
- B.
A 3'-5' exonuclease activity
- C.
A 5'-3' DNA polymerase activity
- D.
Modest processivity (ca. 20 nucleotides)
Correct Answer
A. A 5'-3' exonuclease activity on a second subunit in the polymerase -
- 13.
In the repair of DNA, the E. coli DNA polymerase involved performs which function in addition to its polymerase activity?
- A.
It recognizes the abnormality in the duplex DNA structure.
- B.
It nicks the DNA to provide a 3'-OH.
- C.
It removes the damaged section of DNA with its 5'-3' exonuclease activity.
- D.
It ligates the DNA after the repair synthesis.
Correct Answer
C. It removes the damaged section of DNA with its 5'-3' exonuclease activity. -
- 14.
The Klenow fragment of E. coli DNA polymerase I can be used to add nucleotides to a DNA with staggered ends if the ends
- A.
Are recessed with 5'-phosphates
- B.
Are recessed with 3'-OHs
- C.
Are extended with 5'-phosphates
- D.
Are extended with 3'-OHs
Correct Answer
B. Are recessed with 3'-OHs -
- 15.
Which of the following is not a characteristic of replication of the E. coli circular chromosome?
- A.
Replication is bidirectional.
- B.
It initiates at a unique position called oriC.
- C.
Torsional stress introduced in the duplex DNA is relieved by DNA gyrase.
- D.
The unwinding of the duplex DNA is driven by the translocation of the DNA polymerase.
Correct Answer
D. The unwinding of the duplex DNA is driven by the translocation of the DNA polymerase. -
- 16.
E. coli replication on the lagging strand
- A.
Is primarily carried out by DNA polymerase I
- B.
Is synthesized continuously
- C.
This DNA strand is synthesized in a 3'-5'direction of synthesis
- D.
Is initially synthesized as Okazaki fragments
Correct Answer
D. Is initially synthesized as Okazaki fragments -
- 17.
Which one of the following characteristics is not associated with E. coli primase?
- A.
It synthesizes the RNA primer in DNA replication.
- B.
It is a specific RNA polymerase.
- C.
It is essential for DNA replication.
- D.
It is also a gyrase
Correct Answer
D. It is also a gyrase -
- 18.
The polymerase which plays a similar role as that of Prokaryotic polII in eukaryotic replication is?
- A.
DNA polymerase alpha
- B.
DNA polymerase delta
- C.
DNA polymerase gamma
- D.
DNA polymerase kappa
Correct Answer
B. DNA polymerase delta -
- 19.
Which is not a property of E. coli DNA polymerase III?
- A.
It is responsible for incorporating most of the nucleotides in the lagging strand.
- B.
It synthesizes most of the leading strand prior to aiding in the synthesis of the lagging strand.
- C.
It contains a 3¨ to 5¨ exonuclease activity.
- D.
It synthesizes the leading strand and the lagging strand at the same time
Correct Answer
B. It synthesizes most of the leading strand prior to aiding in the synthesis of the lagging strand. -
- 20.
Which statement is incorrect about E. coli DNA polymerase I?
- A.
The cell contains more molecules of DNA pol I than DNA pol III.
- B.
DNA pol I is a single polypeptide with three domains.
- C.
DNA pol I is involved in the repair of UV damaged DNA.
- D.
DNA pol I has a larger turnover number than DNA pol III.
Correct Answer
D. DNA pol I has a larger turnover number than DNA pol III. -
- 21.
Which E. coli enzyme has the greatest frequency of incorporating the incorrect nucleotide into its nucleic acid polymer?
- A.
RNA polymerase
- B.
DNA polymerase I
- C.
DNA polymerase III
- D.
Klenow fragment from DNA polymerase I
Correct Answer
A. RNA polymerase -
- 22.
DNA-dependent RNA polymerase acts on the DNA template in eukaryotic cells in the synthesis of
- A.
A 5'-3' hnRNA transcript as the RNA polymerase moves in the 3'-5' direction on the DNA template
- B.
A mature RNA transcript as the RNA polymerase moves in the 5'-3' direction
- C.
An RNA transcript, with the sigma subunit of polymerase dissociating after the initiation event
- D.
An RNA transcript, which is complementary to the sense strand of the DNA, except for the replacement of uridines for the thymidines
Correct Answer
A. A 5'-3' hnRNA transcript as the RNA polymerase moves in the 3'-5' direction on the DNA template -
- 23.
The shorter the primer, the more specific the DNA.
- A.
True
- B.
False
Correct Answer
A. True -
- 24.
Z-DNA can be stable in A:T-rich regions allowing its transition from B-DNA form.
- A.
True
- B.
False
Correct Answer
A. True -
- 25.
Due to nitrogenous bases, UV abs. of DNA increases when heated above body temperature.
- A.
True
- B.
False
Correct Answer
A. True -
- 26.
The rate of DNA renaturation is an index of its homology.
- A.
True
- B.
False
Correct Answer
A. True -
- 27.
Stacked base pairs absorb less light in native DNA.
- A.
True
- B.
False
Correct Answer
A. True -
- 28.
________studies the way genes express, determining the differences between vertebrates.
Correct Answer
later - 29.
In a duplex circular DNA, the _____________ state has around ____________ per turn. (answer, answer)
Correct Answer
later, later - 30.
____________is a topoisomerase II that introduces ______________ supercoiling and promote ________________. (answer, answer, answer)
Correct Answer
later, later, later - 31.
A _______________ region is the same DNA sequence read either 5’ to 3’ or viceversa.
Correct Answer
later - 32.
When supercoiled, the _____________number increases when there are more twists.
Correct Answer
later - 33.
Part 2. Determine W, T and L respectively if DNA gyrase puts 4 negative supercoils into the 200-bp circular DNA. If relaxed, what would the value of L be?
Correct Answer
later - 34.
Under which of the following conditions does the melting temp. for DNA denaturation increase?
- A.
Smaller DNA fragments
- B.
Higher G-C contents in DNA
- C.
Higher A-T contents in DNA
- D.
A and c are correct
- E.
None are correct
Correct Answer
E. None are correct -
- 35.
Which of the following statements is true about chromosomes?
- A.
They must be packed around the cell membrane.
- B.
They can exist as unwrapped DNA.
- C.
Genetic information is not located in these structures.
- D.
As part of their structure, chromatin contains histones wrapped by DNA.
- E.
None of the above.
Correct Answer
E. None of the above. -
- 36.
Which of the following is not true about tRNA and rRNA?
- A.
TRNA can self-base pair forming loops and base pair with non-canonical bases
- B.
TRNA can carry at least one amino acid and contain an anticodon.
- C.
RRNA is used for ribosome assembly as large and small units that are exported to the cytosol.
- D.
RRNA can self-base pair with its complementary strand in a double stranded structure.
- E.
Ribosomes contain rRNA as well as proteins except that the former is greater in number.
Correct Answer
E. Ribosomes contain rRNA as well as proteins except that the former is greater in number. -
- 37.
The separation of a double-stranded DNA will form two template strands.
- A.
True
- B.
False
Correct Answer
A. True -
- 38.
DNA replication mainly occurs in a conservative manner.
- A.
True
- B.
False
Correct Answer
A. True -
- 39.
In E.coli, only one replication fork is needed to replicate a new DNA strand.
- A.
True
- B.
False
Correct Answer
A. True -
- 40.
RNA can form an unstable hybrid structure with DNA.
- A.
True
- B.
False
Correct Answer
A. True -
- 41.
The unwinding of DNA is an energetically favorable process to allow replication.
- A.
True
- B.
False
Correct Answer
A. True -
- 42.
Template strands are only copied continuously.
- A.
True
- B.
False
Correct Answer
A. True -
- 43.
In E. coli, the replication fork copies DNA continuously and segmented in a 360o direction.
- A.
True
- B.
False
Correct Answer
A. True -
- 44.
DNA is unwound by gyrase without breaking it.
- A.
True
- B.
False
Correct Answer
A. True -
- 45.
Eukaryotic DNA can contain more than 2 replication forks.
- A.
True
- B.
False
Correct Answer
A. True -
- 46.
Replication occurs mainly during the G2 and G1 phases where cell growth occurs.
- A.
True
- B.
False
Correct Answer
A. True -
- 47.
Bidirectional replication starts at the_______________, moving replication forks in opposite direction.
Correct Answer
later - 48.
A_______________ is bound to Ter locus to prevent helicase activity.
Correct Answer
later - 49.
High_______________means a high number of successive cycles of nucleotide addition.
Correct Answer
later - 50.
A primer needed for replication is formed by a_________________.
Correct Answer
later
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Mar 19, 2022Quiz Edited by
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Oct 31, 2012Quiz Created by
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