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 regulations.
(C) The human genome has approximately 50,000 genes.
(D) Haemophilia is a sex-linked recessive disease.
How many of the above statements are correct

Options

(a) Two
(b) Three
(c) Four
(d) One

Correct Answer:

Two

Explanation:

Statement A & D is correct. Regulation of lac operon by repressor is referred as negative regulation. In negative regulation, a repressor molecule binds to the operator of an operon and terminates transcription. In positive regulation, an activator interacts with the RNA polymerase in the promoter region to initiate transcription. Human genome contains some 20,000 – 25,000 genes billion bases.