The most abundant chemical in living organisms could be
1. Protein
2. Water
3. Sugar
4. Nucleic acid

A homopolymer has only one building block called monomer repeated ‘n’ number of times. A heteropolymer has more than one type of monomers. Proteins are heteropolymers made of amino acids. While a nucleic acid-like DNA or RNA is made of only 4 types of nucleotide monomers, proteins are made up of
1. 20 types of monomers
2. 40 types of monomers
3. 3 types of monomers
4. Only one type of monomer

Proteins perform many physiological functions. For example, some functions as enzymes. One of the following represents an additional function that some proteins discharge.
1. Antibiotics
2. Pigment conferring colour to skin
3. Pigment making colours of flowers
4. Hormones

Glycogen is a homopolymer made of
1. Glucose units
2. Galactose units
3. Ribose units
4. Amino acids

The number of ends in a glycogen molecule
1. Equal to the number of branches plus one
2. Equal to the number of branch points
3. One
4. Two, one on the left side and another on the right side

A pure protein should normally have

Enzymes are biocatalysts. They catalyse biochemical reactions. In general they reduce activation energy of reactions. Many physic-chemical processes are enzyme mediated. Some examples of enzyme mediated reactions are given below. Tick the wrong entry
1. Dissolving CO2 in water
2. Untwining the two strands of DNA
3. Hydrolysis of sucrose
4. Formation of peptide bond

Which of the following is the best evidence for the 'Lock-and-key model' of enzyme action?                           
1. all isolated enzymes have been identified as proteins
2. compounds similar in structure to the substrate inhibit the reaction
3. enzymes are found in living organisms and speed up certain reactions
4. enzymes determine the direction of reaction

Carbohydrates are commonly found as starch in plant storage organs. Which of the following five properties of starch (a-e) make it useful as a storage material?
(1) easily translocated
(2) chemically non-reactive
(3) easily digested by animals
(4) osmotically inactive
(5) synthesized during photosynthesis
The useful properties are :

1. (1), (2) and (5)
2. (1) and (5)
3. (2) and (3)
4. (2) and (4)

The chitinous exoskeleton of arthropods is formed by the polymerisation of–
1. D- glucosamine
2. N- acetyl glucosamine
3. Lipoglycans
4. Keratin sulphate and chondroitin sulphate