21.

On the molar scale which of the following interactions in a non-polar environment provides highest contribution to the bio-molecule?

• van der Waals interaction   

• Hydrogen bonding   

• Salt bridge   

• Hydrophobic interaction    

Michaelis and Menten derived their equation using which of the following assumption?

• Rate limiting step in the reaction is the breakdown of ES complex to product and free enzyme.   

• Rate limiting step in the reaction is the formation of ES complex.

• Concentration of the substrate can be ignored.   

• Non-enzymatic degradation of the substrate is the major step.  

In which form of DNA, the number of base pairs per helical turn is 10.5?

• A

• B

• X

• Z

In contrast with plant cells, the most distinctive feature of cell division in animal cells is

• Control of cell cycle transitions by protein kinases.  

• Enzymes responsible for DNA replication.  

• Ubiquitin-dependent pathway for protein degradation

• Pattern of chromosome movement.  

Most common type of phospholipids in the cell membrane of nerve cells is

• Phosphatidylcholine 

• Phosphatidylinositol 

• Phosphatidylserine 

• Sphingomyelin

Reverse transcriptase has both ribonuclease and polymerase activities. Ribonuclease activity is required for?

• The synthesis of new RNA strand.  

• The degradation of RNA strand.

• The synthesis of new DNA strand  

• The degradation of DNA strand 

The membrane lipid molecules assemble spontaneously into bilayers when placed in water and form a closed spherical structure known as

• Lysosome

• Peroxisome

• Liposome

• Endosome

In gene regulation, Open Reading Frame (ORF) implies

• Intervening nucleotide sequence in between two genes.  

• A series of triplet codons not interrupted by a stop codon.

• A series of triplet codons that begins with a start codon and ends with a stop codon.  

• The exonic sequence of a gene that corresponds to the 5’UTR of the mRNA and thus does not code for the protein

Amino acid selenocysteine (Sec) is incorporated into polypeptide chain during translation by

• Charging of Sec into tRNA^ser followed by incorporation through serine codon.

• Charging of serine into tRNA^ser followed by modification of serine into selenocysteine and then incorporation through serine codon.  

• Charging of sec into tRNA^sec and then incorporation through selenocysteine codon. 

• Charging of serine into tRNA^ser, modification of serine into selenocysteine and then incorporation through a specially placed stop codon.  

α-amanitin inhibits

• Only RNA polymerase I   

• Only RNA polymerase II

• Only RNA polymerase III

• All RNA Polymerases