Nucleic Acids - Mock Test 49

Question 481

Restriction endonucleases recognize and cut a certain sequence of?

A) Single stranded DNA B) Double stranded DNA C) RNA D) Protein

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Question 482

The most likely lethal mutation is?

A) Substitution of adenine for cytosine B) Insertion of one nucleotide C) Deletion of three nucleotides D) Substitution of cytosine for guanine

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Question 483

Restriction endonucleases?

A) Cut RNA chains at specific locations B) Excise introns from hnRNA C) Remove Okazaki fragments D) Act as defensive enzymes to protect the host bacterial DNA from DNA of foreign organisms

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Question 484

The enzyme DNA ligase?

A) Introduces superhelical twists B) Connects the end of two DNA chains C) Unwinds the double helix D) Synthesises RNA primers

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Question 485

The catabolite repression is mediated by a catabolite gene activator protein (CAP) in conjunction with?

A) AMP B) GMP C) cAMP D) Cgmp

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Question 486

In the lac operon concept, a protein molecule is?

A) Operator B) Inducer C) Promoter D) Repressor

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Question 487

To commence structural gene transcription the region which should be free on lac operation is?

A) Promoter site B) Operator locus C) Y gene D) A gene

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Question 488

The minimum effective size of an operator for lac repressor binding is?

A) 5 base pairs B) 10 base pairs C) 15 base pairs D) 17 base pairs

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Question 489

The gene of lac operon which has constitutive expression is?

A) i B) c C) z D) p

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Question 490

The gene which is transcribed during repression is?

A) Structural B) Regulator C) Promoter D) Operator

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