Molecular Basis of Inheritance

Removal of introns and joining the exons in a defined order in a transcription unit is called:

1. Transformation
2. Capping
3. Splicing
4. Tailing

What is not true for genetic code?

1. It is nearly universal
2. A codon in mRNA is read in a noncontiguous fashion
3. It is degenerate
4. It is unambiguous

In the DNA molecule:

1. the total amount of purine nucleotides and pyrimidine nucleotides is not always equal
2. there are two strands which run antiparallel one in 5' 3' direction and other in 3' 5'
3. there are two strands which run parallel in the 5' 3' direction
4. the proportion of adenine in relation to thymine varies with the organism

Which one of the following pairs of nitrogenous bases of nucleic acids is wrongly matched with the category mentioned against it?

1. Thymine, Uracil — Pyrimidines
2. Guanine, Adenine — Purines
3. Uracil, Cytosine — Pyrimidines
4. Adenine, Thymine — Purines

Which one of the following pairs of codons is correctly matched with their function or the signal for the particular amino acid?

1. UUA, UCA — Leucine
2. AUG, ACG — Start/Methionine
3. UAG, UGA — Stop
4. GUU, GCU — Alanine

One turn of the helix in a B-form DNA is approximately -

1. 20 nm
2. 3.4 nm
3. 2 nm
4. 0.34 nm

One gene-one enzyme hypothesis was postulated by -

1. A. Garrod
2. Hershey and Chase
3. Beadle and Tatum
4. R. Franklin

Antiparallel strands of a DNA molecule means that-

1. The phosphate groups at the start of two DNA strands are in opposite position (pole)
2. One strand turns anti-clockwise
3. One strand turns clockwise
4. The phosphate groups of two DNA strands, at their ends, share the same position

Which antibiotic inhibits interaction between tRNA and mRNA during bacterial protein synthesis?

1. Neomycin
2. Erythromycin
3. Tetracycline
4. Streptomycin

Amino acid sequence, in protein synthesis is decided by the sequence of -

1. cDNA
2. mRNA
3. tRNA
4. rRNA

E. coli cells with a mutated z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because -

1. They cannot transport lactose from the medium into the cell
2. They cannot synthesize functional -galactosidase
3. In the presence of glucose, E. coli cells do not utilize lactose
4. The lac operon is constitutively active in these cells

Telomerase is an enzyme which is a -

1. RNA
2. Repetitive DNA
3. Simple protein
4. Ribonucleoprotein

Protein synthesis in an animal cell occurs -

1. On ribosomes present in the nucleolus as well as in cytoplasm
2. On ribosomes present in cytoplasm as well as in mitochondria
3. Only on the ribosomes present in cytosol
4. Only on ribosomes attached to the nuclear envelope and endoplasmic reticulum

Which one of the following makes use of RNA as a template to synthesize DNA -

1. Reverse transcriptase
2. DNA dependent RNA polymerase
3. RNA polymerase
4. DNA polymerase

During transcription holoenzyme RNA polymerase binds to a DNA sequence and the DNA assumes a saddle like structure at the point. What is the sequence called?

1. TATA box
2. GGTT box
3. CAAT box
4. AAAT box

Production of a human protein in bacteria by genetic engineering is possible because

1. The human chromosome can replicate in bacterial cell
2. The genetic code is universal
3. Bacterial cell can carry out the RNA splicing reactions
4. The mechanism of gene regulation is identical in humans and bacteria

During replication of a bacterial chromosome DNA synthesis starts from a replication origin site and

1. RNA primers are involved
2. is facilitated by telomerase
3. moves in one direction of the site
4. moves in bi-directional way

Which form of RNA has a structure resembling clover leaf ?

1. r-RNA
2. m-RNA
3. t-RNA
4. hn-RNA

During transcription, if the nucleotide sequence of the DNA strand that is being coded is ATACG, then the nucleotide sequence in the mRNA would be -

1. UAUGC
2. TCTGG
3. UATGC
4. TATGC

The following ratio is generally constant for a given species :-

1. A+CT+G
2. G+CA+T
3. A+GC+T
4. T+CG+A

DNA fingerprinting refers to :-

1. Techniques used for molecular analysis of different specimens of DNA
2. Analysis of DNA samples using imprinting devices
3. Molecular analysis of profiles of DNA samples
4. Techniques used for identification of fingerprints of individuals

The telomeres of eukaryotic chromosomes consist of short sequences of

1. Adenine rich repeats
2. Cytosine rich repeats
3. Thymine rich repeats
4. Guanine rich repeats

What would happen if in a gene encoding a polypeptide of 50 amino acids, 25th codon (UAU) is mutated to UAA?

1. A polypeptide of 49 amino acids will be formed
2. A polypeptide of 25 amino acids will be formed
3. Two polypeptides of 24 and 25 amino acids will be formed
4. A polypeptide of 24 amino acids will be formed

What does "lac" refer to in what we call the lac operon?

1. The number 1,00,000
2. Lac insect
3. Lactase
4. Lactose

During translation initiation in prokaryotes, a GTP molecule is needed in:

1. Association of 30S-mRNA with formyl-met-tRNA
2. Formation of formyl-met-tRNA
3. Association of 50S subunit of ribosome with initiation complex
4. Binding of 30S subunit of ribosome with mRNA

Which one of the following triplet codes, is correctly matched with its specificity for an amino acid in protein synthesis or as 'start' or 'stop' codon?

1. UUU – Stop
2. UAC – Tyrosine
3. UGU – Leucine
4. UCG – Start

During transcription, the DNA site at which RNA polymerase binds is called:

1. Receptor
2. Regulator
3. Enhancer
4. Promoter

Degeneracy of a genetic code is attributed to the:

1. Second member of a codon
2. Third member of a codon
3. First member of a codon
4. Entire codon

In the genetic code dictionary, how many codons are used to code for all the 20 amino acids:

1. 64
2. 20
3. 60
4. 61

In a DNA percentage of thymine is 20% then what is the percentage of guanine : -

1. 40%
2. 20%
3. 30%
4. 60%