Gentics And Evoloution - Study Mode

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[#146] Ribose, the pentose sugar of RNA, has an identical structure to DNA except that there is

(A) An H atom instead of -OH group on carbon atom 2'

(B) An -OH group instead of H on carbon atom 2'

(C) A -COOH group instead of -OH on carbon atom 1'

(D) An -OH group instead of -COOH on carbon atom 2'

Correct Answer

(B) An -OH group instead of H on carbon atom 2'

[#147] Consider the following statements and choose the correct answer: 1. The structural genes direct the synthesis of cellular proteins through messenger RNA (mRNA) 2. The promoter gene determines whether or not the structural genes are to be repressed by the repressor 3. The regulator gene directs the synthesis of a protein which may be an active repressor or an inactive repressor

(A) 1, 2 and 3 are true

(B) Only 2 and 3 are true

(C) Only 1 and 3 are true

(D) Only 1 and 2 are true

Correct Answer

(C) Only 1 and 3 are true

[#148] Consider the following statements regarding aneuploids and choose the correct answer: 1. Aneuploidy may arise by the perpetuation of a cell in which, through a failure of anaphase of mitosis, one or more chromosomes may be lost 2. Aneuploidy in diploids is much less viable than aneuploidy in polyploids 3. In true aneuploids there are complete genomes, plus a fraction of a genome 4. False aneuploids may contain supernumerary chromosomes

(A) Only 1, 2 and 3 are true

(B) 1, 2, 3 and 4 are true

(C) Only 2, 3 and 4 are

(D) Only 1 is true

Correct Answer

(B) 1, 2, 3 and 4 are true

[#149] The universality of genetic code was demonstrated by

(A) Watson, Crick and Grunberg

(B) Marshall, Gamow and Nirenberg

(C) Caskey, Gamow and Watson

(D) Marshal, Caskey and Nirenberg

Correct Answer

(D) Marshal, Caskey and Nirenberg

[#150] Consider the following statements regarding Natural Selection and choose the correct answer: 1. Organisms produce many more offsprings than can possibly survive 2. In a population some variability is always present for almost every characteristic 3. All offsprings are able to survive to reach adulthood

(A) 1, 2 and 3 are correct

(B) Only 1 and 3 are correct

(C) Only 1 and 2 are correct

(D) Only 2 and 3 are correct

Correct Answer

(C) Only 1 and 2 are correct