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 parallel in 5'$\to$3' direction

3. The proportion of adenine in relation to thymine varies with the organism

4. There are two strands which run antiparallel one in 5'$\to$3' direction and other in 3'$\to$5' direction 

The major portion of the dry weight of plants comprises of                  [2003]

1. Carbon, nitrogen and sulphur

2. Carbon, nitrogen and oxygen

3. Nitrogen, phosphorous and potassium

4. Calcium, magnesium and sulphur

Select the option which is not correct with respect to enzyme action.

1. Substrate binds with enzyme as its active site

2. Addition of lot of succinate does not reverse the inhibition of succinic dehydogenase by malonate.

3. A non-competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate

4. Malonate is a competitive inhibitor of succinic dehydrogenase

A competitive inhibitor of succinic dehydrogenase is                         

1. Malonate

2. Fumarate

3. $\mathrm{\alpha }$-ketoglutarate

4. Malate

Two free ribonucleotide units are interlinked with

1. Peptide bond

2. Covalent bond

3. Hydrogen bond

4. Phosphodiester bond

Genes are packaged into a bacterial chromosome by                           [1997]

1. Histones

2. Basic proteins

3. Acidic proteins

4. Actin

Lactose is composed of                      [1998]

1. Glucose+Glucose

2. Glucose+Fructose

3. Fructose+Galactose

4. Glucose+Galactose

In which of the following groups, all the three are examples of polysaccharides?           

1. Starch, glycogen, cellulose

2. Sucrose, maltose, glucose

3. Glucose, fructose, lactose

4. Galactose, starch, sucrose 

Most abundant organic compound on earth is                     [2001,2004]

1. Protein

2. Cellulose

3. Lipids

4. Steroids

The curve given below shows enzymatic activity with relation to three conditions (pH, temperature and substrate concentration).                                                                                   

What do the two axis (X and Y) represent?

          X-axis                                      Y-axis

1. Temperature                       -    Enzyme activity

2. Substrate concentration       -    Enzymatic activity

3. Enzymatic activity               -     Temperature

4. Enzymatic activity               -     pH