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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) 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
One
B
Two
C
Three
D
Four
Detailed Solution
(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.
(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.