1. Which of the following techniques was carried out by
Nirenberg and Matthaei in 1961 to determine the first codon?
A. In vitro synthesis of a polypeptide using UUUUU
B. Labeled peptide binding to a ribosome
C. Mixed co-polymer mRNA synthesis
D. none of the above
B. Labeled peptide binding to a ribosome
C. Mixed co-polymer mRNA synthesis
D. none of the above
Answer: A
2. Bacterial protein called catabolic activator protein (CAP) is
an example of
A. negative control of gene expression
B. positive control of gene expression
C. second type of positive control of gene expression
D. none of the above
B. positive control of gene expression
C. second type of positive control of gene expression
D. none of the above
Answer: C
3. How many different codons are possible?
A. 3
B. 20
C. 64
D. An infinite number
B. 20
C. 64
D. An infinite number
Answer: C
4. The genetic code is
A. universal
B. universal except for rare exceptions in mitochondria and some protozoa
C. species-specific
D. kingdom-specific
B. universal except for rare exceptions in mitochondria and some protozoa
C. species-specific
D. kingdom-specific
Answer: B
5. Which of the following has been used as an evidence that
primitive life forms lacked both DNA and enzymes?
A. RNA can both code genetic information and act as a catalyst
B. DNA and enzymes are only present in the most advanced cells
C. Advanced cells lack RNA
D. All of the above
B. DNA and enzymes are only present in the most advanced cells
C. Advanced cells lack RNA
D. All of the above
Answer: A
6. Crick demonstrated that the genetic code involved three bases
and suggested that the code was degenerated. What experimental technique Crick
conducted to suggest genetic code degeneration?
A. Gel electrophoresis
B. Density gradient centrifugation
C. Frameshift mutagenesis
D. Restriction digests of the rII gene
B. Density gradient centrifugation
C. Frameshift mutagenesis
D. Restriction digests of the rII gene
Answer: C
7. Codon that specify the amino acids often differs in the
A. first base
B. second base
C. third base
D. none of these
B. second base
C. third base
D. none of these
Answer: C
8. In some organelles in eukaryotes, the genetic code for some
codons
A. differs from that used in prokaryotes
B. are same
C. are partially same
D. none of the above
B. are same
C. are partially same
D. none of the above
Answer: A
9. The codons which do not specify an amino acid are called
A. initiation code
B. termination code
C. propagation code
D. none of these
B. termination code
C. propagation code
D. none of these
Answer: B
10. The genetic code is degenerated. Which of the following
codons represents the principle of degeneracy?
A. UAA and UAC
B. AUG and AUA
C. CAU and CAC
D. UUA and UUC
B. AUG and AUA
C. CAU and CAC
D. UUA and UUC
Answer: C
GENETIC
CODE and REGULATION Questions and Answers ::
11. The sequence of one strand of DNA is: 5′ ATTGCCA 3′, what is
the sequence of the other strand?
A. 5′ TAACGGT 3′
B. 5′ TGGCAAT 3′
C. 5′ ATTGCCA 3′
D. 5′ UAAGCCU3′
B. 5′ TGGCAAT 3′
C. 5′ ATTGCCA 3′
D. 5′ UAAGCCU3′
Answer: B
12. In prokaryotes, AUG encodes
A. methionine
B. N-formyl methionine
C. a stop codon
D. alanine
B. N-formyl methionine
C. a stop codon
D. alanine
Answer: B
13. How many amino acids will be encoded by 5′ GAU GGU UGA UGU
3′ sequence?
A. One
B. Two
C. Three
D. Four
B. Two
C. Three
D. Four
Answer: B
14. In protein synthesis in prokaryotes
A. the initiating amino acid is N- formyl methionine
B. the initiating amino acid is methionine
C. the initiating amino acid is phenyl alanine
D. none of the above
B. the initiating amino acid is methionine
C. the initiating amino acid is phenyl alanine
D. none of the above
Answer: A
15. AUG codes for methionine act as a
A. initiation code
B. elongation code
C. termination code
D. propagation code
B. elongation code
C. termination code
D. propagation code
Answer: A
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