Nucleic acids are polymers of:
1. Nucleosides
2. Nucleotides
3. Amino acids
4. Polypeptides
To form a nucleoside, a nitrogenous base is linked to a pentose sugar:
1. Through a P-Glycosidic linkage at carbon atom number 1
2. Through a P-Glycosidic linkage at carbon atom number 5
3. Through a N-Glycosidic linkage at carbon atom number 1
4. Through a N-Glycosidic linkage at carbon atom number 5
At which position in the ribose is an additional –OH present [with respect to Deoxyribose]?
1. 1’
2. 2’
3. 3’
4. 5’
DNA was first identified by:
1. Friedrich Meischer
2. Phoebus Levene
3. Linus Pauling
4. Erwin Chargaff
The base pairing in a double stranded DNA is correctly described as:
1. Similar
2. Identical
3. Complementary
4. Synergistic
The distance between a base pair in the DNA double helix is approximately:
1. 2.0 nm
2. 0.34 nm
3. 20 nm
4. 3.4 nm
The length of DNA in atypical mammalian cell is approximately:
1. 1.1 meter
2. 1.5 meter
3. 2.2 meter
4. 3.3 meter
Histones are rich in amino acids:
1. Arginine and Lysine
2. Argine and Leucine
3. Arginine and Isoleucine
4. Aspartate and Glutamate
Transcriptionally active chromatin is termed as:
1. Heterochromatin
2. Euchromatin
3. Prechromatin
4. Prochromatin
Frederick Griffith discovered:
1. DNA is the genetic material
2. RNA can be the genetic material
3. Sterptococcus has two strains
4. Bacterial transformation
The unequivocal proof that DNA is the genetic material was provided by:
1. Avery, Macleod and McCarty
2. Hershey and Chase
3. Meselson and Stahl
4. Watson and Crick
RNA is not the genetic material in:
1. Tobacco mosaic virus
2. QB bacteriophage
3. HIV
4. Archaebacteria
The protein synthesizing machinery of a cell has evolved around:
1. DNA
2. RNA
3. Protein itself
4. Viroids
The density gradient in Meselson and Stahl experiment was of:
Any mistakes during DNA replication by the enzyme would result into:
1. Cancer
2. Apoptosis
3. Cell fragmentation
4. Mutation
The DNA dependent polymerases catalyze:
1. Only in 3’ – 5’ direction
2. Only in 5’ – 3’ direction
3. In both directions
4. In neither directions
A failure in cell division after DNA replication results in:
1. Point mutation
2. Aneuploidy
3. Polyploidy
4. Apoptosis
DNA dependent RNA polymerase catalyzes polymerization in:
1. Only in 3’ – 5’ direction
2. Only in 5’ – 3’ direction
3. In both directions
4. In neither directions
What defines a coding and a template strand in the transcription unit?
1. Structural gene
2. Ori
3. Terminator
4. Promoter
In eukaryotes the sequences that appear in mature or processed mRNA are called:
1. Introns
2. Cistrons
3. Exons
4. Mutons
What facilitates the opening of the helix during elongation step of transcription?
1. RNA polymerase
2. Helicase
3. Topoisomerase
4. Gyrase
Transcription and translation can be coupled in:
1. Bacteria
2. Yeast
3. Plants
4. Animals
What is added to the 5’ end of hnRNA in Eukryotes?
1. Poly A tail
2. Methyl cytosine triphosphate
3. Methyl guanosine triphosphate
4. Poly U tail
Whose cell free system finally helped the genetic code to be deciphered?
1. Gamow
2. Severo Ochoa
3. Hargobind Khorana
4. Marshall Nirenberg
Some amino acids are coded by more than one codon. Hence genetic code is:
1. Unambiguous
2. Non specific
3. Degenerate
4. Universal
Sickle cell anemia is caused by:
1. Chromosomal aberration
2. Point mutation
3. Non disjunction event
4. An arthropod vector
The amino acid acceptor arm of the tRNA is at its:
1. DHU loop
2. TψC loop
3. 5’ end
4. 3’ end
Which of the following anticodons will hybridize with the mRNA codon 5’ – AUG – 3’?
1. 5’ – UAC – 3’
2. 5’ – TAC – 3’
3. 3’ – UAC – 5’
4. 3’ – TAC – 5’
Gene regulation in prokaryotes is carried out exclusively at the level of:
1. Initiation of transcription
2. Post transcriptional modifications
3. Translation
4. Post translational modifications
The lac Y gene codes for permease which increases the permeability of the cell to:
1. Glucose
2. Galactose
3. cAMP
4. β-galactosides