Molecular Basis of Inheritance

The equivalent of a structural gene is -

1. cistron
2. recon
3. muton
4. operon

Which of the following rRNAs acts as structural RNA as well as ribozyme in bacteria ?

1. 5.8 S rRNA
2. 23 S rRNA
3. 18 S rRNA
4. 5 S rRNA

A molecule that can act as a genetic material must fulfill the traits given below, except

1. it should be able to express itself in the form of ‘Mendelian characters’
2. it should be unstable structurally and chemically
3. it should provide the scope for slow changes that are required for evolution
4. it should be able to generate its replica

DNA-dependent RNA polymerase catalyzes transcription on one strand of the DNA which is called the

1. coding strand
2. antistrand
3. template strand
4. alpha strand

Which one of the following is not applicable to RNA?

1. Complementary base pairing
2. 5' phosphoryl and 3' hydroxyl ends
3. Heterocyclic nitrogenous bases
4. Chargaff's rule

Identify the correct order of organisation of genetic material from largest to smallest :

1. Chromosome, genome, nucleotide, gene
2. Genome, chromosome, nucleotide, gene
3. Genome, chromosome, gene, nucleotide
4. Chromosome, gene, genome, nucleotide

Satellite DNA is important because it :

1. Shows high degree of polymorphism in population and also the same degree of polymorphism in an individual, which is heritable from parents to children.
2. does not code for proteins and is same in all members of the population.
3. codes for enzymes needed for DNA replication.
4. codes for proteins needed in cell cycle.

Gene regulation governing lactose operon of E. coli that involves the lac I gene product is

1. negative and inducible because repressor protein prevents transcription.
2. positive and inducible because it can be induced by lactose
3. negative and repressible because repressor protein prevents transcription
4. feedback inhibition because excess of -galactosidase can switch off transcription

In sea urchin DNA, which is double stranded, 17% of the bases were shown to be cytosine. The percentages of the other three bases expected to be present in this DNA are

1. G 17%, A 16.5%, T 32.5%
2. G 17%, A 33%, T 33%
3. G 8.5%, A 50%, T 24.5%
4. G 34%, A 24.5%, T 24.5%

Which one of the following is wrongly matched?

1. Transcription – Writing information from DNA to t-RNA
2. Operon – Structural genes, operator and promoter
3. Repressor protein – Binds to operator to stop enzyme synthesis
4. Translation – Using information in m-RNA to make protein.