When the co-factor is removed from the enzyme, the catalytic activity:

1. is lost.

2. is reduced.

3. is increased.

4. is unaffected.

The tail of the phospholipid molecule:

1. is hydrophilic and composed of phosphate

2. is hydrophilic and composed of saturated hydrocarbons

3. is hydrophobic and composed of saturated hydrocarbons

4. is hydrophobic and composed of unsaturated hydrocarbons

In animal cells, lipid-like steroidal hormones are synthesized in the:

1. Nucleus

2. Rough endoplasmic reticulum

3. Smooth endoplasmic reticulum

4. Golgi apparatus

Lignin is a component of the secondary walls of:-

1. Epidermis

2. Collenchyma

3. Sclerenchyma

4. Parenchyma

Given below is the graph showing the effect of substrate concentration on enzyme activity. In the presence of a competitive inhibitor, when the concentration of the substrate is progressively increased :

1. The ${\mathrm{K}}_{\mathrm{m}}$ value is increased but the reaction will not achieve ${\mathrm{V}}_{\max }$

2. The ${\mathrm{K}}_{\mathrm{m}}$ value is increased but the reaction can ultimately achieve ${\mathrm{V}}_{\max }$

3. The ${\mathrm{K}}_{\mathrm{m}}$ value is decreased but the reaction will not achieve ${\mathrm{V}}_{\max }$

4. The ${\mathrm{K}}_{\mathrm{m}}$ value is decreased but the reaction can ultimately achieve ${\mathrm{V}}_{\max }$

Study the primary structure of a part of a hypothetical protein and choose the correct statements:

l. 1 is Serine

ll. 2 is sulfer containing amino acid and can be methionine

lll. 3 is aromatic amino acid and can be tyrosine

lV. 4 is an acidic amino acid

1. l, ll and lll only

2. l, lll and lV only 

3. ll, lll and lV only

4. l, ll, lll and lV

The compound shown below:

1. is a component of ATP molecule
2. is most commonly found in ori region of DNA
3. can have enzymatic activity
4. may be a component of cell membrane

The zwitterion is shown by: 
 

1. Only A

2. Only B

3. Both A and C

4. A, B and C

The four elements making 99 % of living system are: