BIO202 Final Term Past Papers Set 3

MUHAMMAD IMRAN

BIO-202-Biochemistry-l FINAL TERM PAPER

Q1. Name two second messenger of nucleotides? (2 marks)

Second messengers: Nucleotides, such as

1. Cycloadenosine mono phosphate(cAMP)
2. Cyclic Gaunoadenosine mano phosphate(cGMP)

Q2. What are simple lipids? give two types of simple lipids. (2 marks)

A simple lipid is a fatty acids of different type of alcohol and carry no other substances . A simple lipid is belog to the hetrogenous class of predomentaly non polar in nature. They are in soluble in water but soluble in organic solvent, such as chloroform and benzene. Simple Lipids: Fatty acids easter of different alcohol. Fats: Fatty acid easter of different glycerol. Oil and fats are in liquid state. They are insoulible in water but soluble in organic solvent such as chloroform and benzene. Waxes: Solid easter of fatty acid easter .They are insoluble in water due to weak polar nature of easter group.

Q3. Define buffer? write its composition. (2 marks)

Buffers are aqueous systems that tend to resist changes in pH when small amounts of acid (H+) or base (OH-) are added

A buffer system consists of a weak acid (the proton donor) and its conjugate base (the proton acceptor)

As an example, a mixture of ; acetic acid and acetate ion, is a buffer system,

A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is added to it.

A buffer is a solution that can resists the ph changes upon the addition of acidic or basic components.

It is able to neutralize to very small amount of acid or base is added to it .

It is important for the process or reaction in which is require for the stable and pH ranges.

Buffer Composition:

To reletively the maintaing the pH of the solution , a buffer is must cosist the acid-base pair meaning either:

i) A weak base and a conjugate acid. ii) A

weak acid and conjugate base .

The use of one or more ,depend upon the desired pH when preparing the buffer.

Eample:

Acetic acid such as sodium acetate (CH3COOH) in which they have conjugate acid .

Ammonia(NH3) and a salt(Nacl) in which they have conjugate base.

Q4. Define saponifiaction Number? (3 marks)

The number of milligrams of the sodium hydroxide and potassium hydroxide of free or combined state of fats or wax to completely sponifying are called Sponification number.

Saponification Hydrolysis of a fat by an alkali is called saponification The resultant products are glycerol and the alkali salts of the fatty acids, which are called “soaps” The number of mgs of NaOH/KOH required to saponify the free and combined FA

in one gram of a given fat is called its saponification number

The amount of alkali needed to saponify a given quantity of fat will depend upon the number of carboxylic (–COOH) group present Thus fats containing short chain fatty acids will have more –COOH groups per gram than longchain fatty acids and this will take up more alkali And hence will have higher saponification number

Q5. Define enzyme kinetics? (3 marks)

Enzyme Kinetics. Enzymes are protein catalysts that, like all catalysts, speed up the rate of a chemical reaction without being used up in the process. They achieve their effect by temporarily binding to the substrate and, in doing so, lowering the activation energy needed to convert it to a product. Enzyme kinetics is the study of the chemical reactions that are catalysed by enzymes. In enzyme kinetics, the reaction rate is measured and the effects of varying the conditions of the reaction are investigated. Studying an enzyme's kinetics in this way can reveal the catalytic mechanism of this enzyme, its role in metabolism, how its activity is controlled, and how a drug or an agonist might inhibit the enzyme.

Enzyme kinetics is the investigation of how subsrtate bind with enzyme them into product. They are used to kinetic analysis are commenly obtained from an enzyme. In 1913 the leonor Machalis and Muad leonora Menton are proposed quantative theory of enzyme.

The molecules of the substrate bind reversibly with enzyme are called enzyme substrate complex.

These molecules are converted into product are called enzyme product complex.

These theory are further are further developed by J.B.S haldan and G.E briggs who derived equation to still widely used today.

Enzyme Kinetics depend upon the solution condition and saturation concertration.

Q6. Medical applications of Nucleotides and nucleic acid. (3 marks)

Medical applications Specifically medical applications include the use of synthetic purine and pyrimidine analogs that contain halogens, thiols, or additional nitrogen atoms; There use include chemotherapy for cancer as suppressors of the immune response during organ transplantation. as anti-viral drugs such as in the treatment of AIDS

Q7. Properties of waxes (5 marks)

Waxes are insoluble in water, but soluble in fat solvents and are negative for acrolein test. very resistant to rancidity. Waxes are not easily hydrolyzed as the fats and are indigestible by lipases (enzymes responsible for fat digestion in body) they are of no nutritional value

8) nucleotides as 'energy currency' of the

cell? (5 marks)

Energy currency: Nucleotides play an important role as "energy currency" in the cell. Nucleoside triand diphosphates such as ATP and ADP are the principal donors and acceptors of phosphoryl group in metabolism. By doing this, they play a key role in the energy transduction.

This energy is used in almost every energy requiring process in the body, such as; Muscle contraction, Transmission of nerve impulse, Transports of nutrients across cell membrane Motility of spermatozoa And many more energy dependent processes

Q9. classification of enzymes? (5 marks)

There were six classes of enzymes that were created so that enzymes could easily be named. These classes are:

1. Oxidoreductases,
2. Transferases,
3. Hydrolases,
4. Lyases,
5. Isomerases, 6) Ligases.

This is the international classification used for enzymes.

Q10. Define enzymes? Write classification of enzymes? (10 marks)

Enzymes are protein molecules in cells which work as catalysts. Enzymes speed up chemical reactions in the body, but do not get used up in the process. Almost all biochemical reactions in living things need enzymes. With an enzyme, chemical reactions go much faster than they would without the enzyme.

There were six classes of enzymes that were created so that enzymes could easily be named. These classes are:

1. Oxidoreductases,
2. Transferases,
3. Hydrolases,
4. Lyases,
5. Isomerases, 6) Ligases.

This is the international classification used for enzymes.