Which of the following describes the given graph correctly? 
 

1.	Endothermic reaction with energy A in the presence of enzyme and B in the absence of enzyme
2.	Exothermic reaction with energy A in the presence of enzyme and B in the absence of enzyme
3.	Endothermic reaction with energy A in the absence of enzyme and B in the presence of enzyme
4.	Exothermic reaction with energy A in the absence of enzyme and B in the presence of enzyme

The chitinous exoskeleton of arthropods is formed by the polymerization of?

1. Keratine sulphate and chondroitin sulphate

2. D-glucosamine

3. N-acetyl glucosamine

4. Lipoglycans

Which of the following biomolecules have a phosphodiester bond?

1. Fatty acids in a diglyceride

2. Monosaccharides in a polysaccharide

3. Amino acids in a polypeptide

4. Nucleic acids in a nucleotide

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

The essential chemical components of many coenzymes are:
1. Nucleic acid
2. Carbohydrates
3. Vitamins
4. Proteins

Transition state structure of the substrate formed during an enzymatic reaction is:
1. permanent but unstable
2. transient and unstable
3. permanent and stable
4. transient but stable

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:
     

Which one is the most abundant protein in the animal world?
1. Trypsin
2. Haemoglobin
3. Collagen
4. Insulin