101.

Find the correctly matched enzyme with the rRNAs they transcribe

I. RNA polymerase    —   I 28S, 18S and 5.85 rRNAs

II. RNA polymerase   — III 28 S, 18S and 5.85 rRNAs

III. RNA polymerase  — II tRNA, 5srRNA and Sn(1c)RNAs

IV. RNA polymerase   — II hnRNA

• I and II only

• III and III only

• II only

• III and IV only

• III and IV only

If the total amount of adenine and thymine in a double stranded DNA is 55%, the amount of guanine in this DNA will be

• 45%

• 27.5%

• 25%

• 22.5%

• 22.5%

When mendel self-hybridised the F₁ plants of genotype RrYy, in the F₂ generation they yellow and green colour segregated in the ratio

• 1 : 2 : 1

• 3 : 1

• 9 : 3 : 3 : 1

• 1 : 1

• 1 : 1

Structure of a polynucleotide chain of DNA is given below. Identify the locations (numbered 1 to 5) that show errors in the structure

• 1 and 3

• 1 and 4

• 3 and 5

• 2 and 4

• 2 and 4

Which of the following disorder is caused by autosomal aneuploidy?

• Down's syndrome

• Haemophilia

• Sickle cell anemia

• Phenylketonuria

• Phenylketonuria

Identify the scientists from the hints given below

1. They used chromosome movement to explain Mendel's lay
2. They noted that the behaviour of chromosome was parallel to the behaviour of genes.

• Morgan and Correns

• De Vries and Boveri

• Brides and Correns

• Bridges and Sutton

• Bridges and Sutton

The 'terminator/stop codons UGA, UAG and UAA

• Initiate translation

• Do not code for any; amino acids

• Code for only one amino acid

• Code for more than one amino acid

• Code for more than one amino acid

The variable number of tandem repeats' used as a probe in DNA fingerprinting is

• Expressed sequence tag

• Satellite DNA

• Bacterial artificial chromosome

• Restriction enzyme

• Restriction enzyme

Assertion (a) In Eukaryotes, replication and transcription occur in the nucleus but translation occurs in the cytoplasm

Reasoning (R): mRNA is transferred from the nucleus to the cytoplasm where  ribosomes and amino acids are available for protein synthesis

• A is true but R is false

• A is false but R is true

• Both A and R are false

• Both A and R are true but R is not the correct explanation for A

• Both A and R are true but R is not the correct explanation for A

Consider the statements regarding lac operon and choose the correct option

(i) lactose is the substrate for the enzyme beta-galactosidase and regulates switching on and off of the operon

(ii) lac operon consists of three regulatory genes

(iii) lac operon consists of one structural gene

(iv) regulation of lac operon by repressor is referred to as positive regulation.

• (i) and (ii) only are correct

• (iii) and (iv) only are correct

• (i) only is correct

• (iv) only is correct

• (iv) only is correct