Antiparallel strands of a DNA molecule means that

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

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

The two polynucleotide chains in DNA are
1. parallel
2. discontinuous
3. antiparallel
4. semi - conservative

About 98 percent of the mass of every living organism is composed of just six elements including carbon, hydrogen, nitrogen, oxygen and
1. phosphorus and sulphur
2. sulphur and magnesium
3. magnesium and sodium
4. calcium and phosphorus

Which one of the following is not a constituent of cell membrane
1. Cholesterol
2. Glycolipids
3. Proline
4. Phospholipids

A competitive inhibitor of succinic dehydrogenase is
1. malonate
2. oxaloacetate
3. α-ketoglutarate
4. malate

Three of the following statements about enzymes are correct and one is wrong, which one is wrong
1. Most enzymes are proteins but some are lipids
2. Enzymes require optimum pH for maximal activity
3. Enzymes are denatured at high temperatures but in certain exceptional organisms they are effective even at temperatures 80°- 90°C
4. Enzymes are highly specific

In curve of enzyme catalyzed reaction, the value of velocity of enzyme reaction at point A will be

1. $\frac{1}{2}{V}_{max}$ and velocity may increase by increasing temperature
2.  $\frac{1}{2}{V}_{max}$ and velocity may increase by increasing substrate
3.$\frac{1}{2}{V}_{max}$ and velocity may increase by increasing by catalyst
4. $\frac{1}{2}{V}_{max}$ and velocity remain constant even changing any factor in to the medium.

Which one of the following enzymes carries out the initial step in the digestion of milk in humans?
1. Pepsin                                                                   
2. Rennin
3. Lipase
4. Trypsin

Given below is the diagrammatic representation of one of the categories of small molecular weight organic compounds in the living tissues. Identify the category shown and the one blank component "X" in it.

   Category                                Component

1. Cholesterol                                Guanine
2. Amino acid                                 NH₂
3. l Nucleotide                               Adenine
4. Nucleoside                                 Uracil