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Mixed statements: transcription, lac operon, HGP
Concepts tested here
- Transcription and gene regulation
All Questions
2012 AIPMT-MAINS 1 question
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Read the following four statements (A – D).
(A) In transcription, adenosine pairs with uracil
(B) Regulation of lac operon by repressor is referred to as positive regulation
(C) The human genome has approximately 50,000 genes
(D) Haemophilia is a sex-linked recessive disease
How many of the above statements are right?(A) is right: during transcription the complementarity rule is followed, except that adenosine of the DNA template pairs with uracil (instead of thymine) in the RNA.
(B) is wrong: regulation of the lac operon by the repressor is referred to as negative regulation, because the repressor switches the operon off.
(C) is wrong: the Human Genome Project showed that the human genome has about 30,000 genes, far fewer than earlier estimates of 80,000 to 1,40,000.
(D) is right: haemophilia is a sex-linked (X-linked) recessive disease, transmitted from an unaffected carrier female to some of her sons.
Statements (A) and (D) are right, so two statements are right.