Genetic Code and Regulation

Q1: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q2: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q3: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

E

ANS:C - 64

No answer description is available.

Q4: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q5: 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

ANS:C - CAU and CAC

Degeneracy means the first two Nucleotides which are present t-RNA anti-codon that's strictly follow the base pairing rules but third Nucleotide is not follow the base pairing rules. Then changes occurs in only one Amino acid of the protein.

Q6: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q7: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q8: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q9: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q10: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q11: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q12: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q13: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q14: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q15: Codon that specify the amino acids often differs in the

A first base

B second base

C third base

D none of these

ANS:C - third base

No answer description is available.

Q16: The genetic code is

A universal

B universal except for rare exceptions in mitochondria and some protozoa

C species-specific

D kingdom-specific

ANS:B - universal except for rare exceptions in mitochondria and some protozoa

No answer description is available.

Q17: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q18: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q19: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q20: 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

ANS:A - RNA can both code genetic information and act as a catalyst

No answer description is available.

Q21: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q22: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q23: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q24: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q25: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q26: In prokaryotes, AUG encodes

A methionine

B N-formyl methionine

C a stop codon

D alanine

ANS:B - N-formyl methionine

In prokaryotes formylated methionine are attach to large subunit of ribosome.

Q27: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q28: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q29: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q30: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q31: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q32: AUG codes for methionine act as a

A initiation code

B elongation code

C termination code

D propagation code

ANS:A - initiation code

No answer description is available.

Q33: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q34: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q35: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q36: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q37: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q38: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q39: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q40: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q41: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q42: 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

ANS:C - Frameshift mutagenesis

No answer description is available.

Q43: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q44: 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

ANS:C - second type of positive control of gene expression

No answer description is available.

Q45: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q46: How many amino acids will be encoded by 5' GAU GGU UGA UGU 3' sequence?

A One

B Two

C Three

D Four

ANS:B - Two

UGA will stop the translation process therefore only producing two amino acids. To initiate mother start codon must be found.

Q47: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q48: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q49: Translation begins

A at the replication fork

B on the lagging strand

C at the start codon

D in nucleus

ANS:C - at the start codon

No answer description is available.

Q50: 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

ANS:A - differs from that used in prokaryotes

No answer description is available.

Q51: The codons which do not specify an amino acid are called

A initiation code

B termination code

C propagation code

D none of these

ANS:B - termination code

No answer description is available.

Q52: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q53: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q54: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q55: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q56: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q57: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q58: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q59: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q60: 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

ANS:A - In vitro synthesis of a polypeptide using UUUUU

This was the easiest methods to find which codon codes for which Amino acid. If a sequence is generated such that it contains all Uracils or Thymines, e.g UUUU, irrespective of what the reading frame only 1 type of Amino acid will be coded and polymerised.

In the case of UUUU. It ll be a peptide having repeated units of phenylalanine as UUU codes for it. Analysing such a peptide is easy. Further variations in the repeated units led to the discovery of all codons.

Q61: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q62: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q63: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q64: 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'

ANS:B - 5' TGGCAAT 3'

Option B is the correct answer.

Because DNA one strand in 5'to3' direction but another complementary strand in 3'to5' directions.

Q65: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q66: How many different codons are possible?

A 3

B 20

C 64

D An infinite number

Q67: 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

ANS:A - the initiating amino acid is N- formyl methionine

In eukaryotes the initiating amino acid is Methionine encoded by AUG.

Q68: How many different codons are possible?

A 3

B 20

C 64

D An infinite number


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