Spectrum Biology - September 2016

22.The sequence of structural gene in lac operon

concept is

(a) lac a, lac y, lac z (b) lac a, lac z, lac y

(c) lac y, lac z, lac a (d) lac z, lac y, lac a

23.In E. coli, an operator gene combines with

(a)inducer gene to switch on structural gene action

(b) inducer gene to switch off structural gene action

(c) regulator protein (repressor) to switch off structural

gene action

(d)regulator protein to switch on gene action

24.In the protein synthesis, tRNA carrying the

amino acid enters from which site of ribosome?

(a) ‘A’ site (b) ‘P’ site

(c) Anticodon site (d) Recognition site

25.The diagram represents the ‘central dogma’ of

molecular biology. Choose the correct

combination of labelling.

(a) A–Protein B–RNA C–DNA

D–Translation E–Transcription

(b) A–RNA B–DNA C–Protein

D–Transcription E–Translation

(c) A–Transcription R–Translation C–Translation

D–DNA E–RNA

(d) A–DNA B–RNA C–Protein

D–Transcription E–Translation

26.Match the following Columns.

Column I Column II

A. Chargaff 1 Wilkins and Franklin

B. Replicon 2. Uptake of lactose

C. Permease 3. hnRNA

D. Split gene 4. Length of DNA

E. X-ray diffraction studies 5. ()AG)(CT+=+

Codes

AB C DE

(a)54 2 31

(b)54 1 32

(c)54 2 13

(d)51 2 34

27.The sequence of nitrogen bases in a particular

region of the non-coding strand of a DNA

molecule was found to be CAT GTT TAT

CGC. What would be the sequence of nitrogen

bases in the mRNA that is synthesised by the

corresponding region of the coding strand in

that DNA?

(a) GUA CAA AUA GCG

(b) GTA CAA ATA GCC

(c) CAU GUU UAU CGC

(d) CAA GAA TAU GCC

28.Some of the inhibitors of bacterial protein

synthesis and their effects are listed in

Column I and Column II below. Match them

and choose the correct option from answer key.

Column I Column II

A. Chloramphenicol 1. Inhibits binding of aminoacyl

tRNA to ribosome

B. Erythromycin 2. Inhibits interaction between

tRNA and mRNA

C. Neomycin 3. Inhibits initiation of

translation

D. Streptomycin 4. Inhibits peptidyl transferase

activity

E Tetracycline 5. Inhibits translocation of

mRNA along ribosomes

Codes

AB C DE

(a)12 3 54

(b)31 5 42

(c)23 4 15

(d)45 2 31

29.Synthesis of RNA molecule is terminated by a

signal which is recognised by

(a) α (alpha) factor

(b) γ (gama) factor

(c) ρ (rho) factor

(d) δ (delta) factor

30.DNA consists of two complementary nucleotide

chains. If the sequence of nucleotides in one

of the chains is AGCTTCGA then the

complementary sequence of the other chain

will be

(a) TCGAAGCT (b) TCGTATCG

(c) AATTCCGG (d) TCGAACTG

Answers

1.(d) 2.(b) 3.(a) 4.(d) 5.(d) 6.(a) 7.(c) 8.(a) 9.(c) 10.(c)

11.(d) 12.(c) 13.(b) 14.(d) 15.(a) 16.(a) 17.(c) 18.(b) 19.(b) 20.(d)

21.(a) 22.(d) 23.(a) 24.(a) 25.(d) 26.(a) 27.(a) 28.(d) 29.(c) 30.(a)

A

B

C

D

E

Replication

Replication