Question

A segment of DNA is replicated. If the original segment reads S'-CGATTC-3', the new segment will read During the cloning of a gene.. a) genes are cut with restriction enzymes, and inserted into bacterial plasmids. b) holes are created in the bacterial cells. c) colour markers or antibiotic resistance genes are attached to the gene. d) b, and c only Restriction enzymes a) cut DNA at specific base sequences. c) punch holes in the bacterial cell membrane. b) proof-read DNA during replication. d) join plasmids to chromosomes. DNA polymerase. a) unwinds the double helix during DNA replication. b) untangles snarls in the new DNA strands. c) catalyses the synthesis of a new DNA strand and proof-reads the strand. d) performs excision repair in RNA. e) prevents twisting and knotting of the old DNA strand DNA is composed of a) pyrimidines, purines, phosphate groups and deoxyribose sugar. b) pyrimidines, purines, phosphate groups and ribose sugar c) ribosomes, tRNA, mRNA d) proteins only. e) amino acids only Which of the following mutations would be expected to have the most harmful effect on the resulting protein? a) a base deletion near the start codon. c) a three-base addition near the stop codon. b) a base deletion near the stop codon. d) a base substitution.

Answer 1

GATTC TAAG 3

DNA replication is semiconservative and occurs in 5 prime to 3 prime direction.

So, the answer will be (A). Half of the strand will be conserved.

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Q.2 The correct answer will be (A). as it is the main process of copying of a foreign DNA in a host cell.

option B is not correct as holes are not created in bacterial cells, during cloning as it will destroy the cells.

option C is not correct as it is used for selection of recombinants.

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Q.3 The correct answer is (A) cut DNA at specific base sequence, They identify a characteristics DNA sequence and cut within that sequence. Ex. ECoRI has a sequence of GAATTC. These names are give as these bacterial enzymes chops the viral DNA.

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Q.4 The correct option is (C) as DNA polymerase adds Nucleotides from 5---3 direction and also has a proof reading ability.

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Q.5 The correct answer is (A) as DNA is composed of Base+ Sugar+ Phosphate.

Base can be a purine or Pyrimidine, But sugar is Deoxyribose.

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Q.6 The correct answer is (D) base substitution can change the reading frame. as in case of sickle cell anaemia.