October 22, 2013

Senior Inter Chemistry - Biomolecules Important Questions and Answers - New Syallabus

Here are some important questions for 2 marks from Senior Intermediate Chemistry as per the new syllabus.

1. What are Anomers?
Ans: Anomers are the stereoisomers which differ in their configuration at C1. Eg.: α − D − Glucopyranose & β − D − Glucopyranose.

2. What is "Zwitter ion"? Give an example.
Ans: A dipolar neutral ion formed when the carboxyl group loses a proton and this proton is gained by amino group in aqueous solution of amino acid is called "Zwitter ion".

3. What is "Glycosidic Linkage"?
Ans: The linkage between two monosaccharide units through Oxygen atom is called "glycosidic linkage".
e.g.: In sucrose, glycosidic linkage is present between C − 1 of α − glucose and C − 2 of β − fructose.

4. What is "denaturation of protein"?
Ans: The lose of biological activity of a native protein due to physical or chemical change or change in pH or temperature is called "denaturation of protein". Denaturation of protein is due to disturbed Hydrogen bonds and destroyed 2° and 3° structures of proteins. e.g.: Coagulation of egg white on boiling.
16bio-online.qxd 19/10.

5. Why cannot vitamin C be stored in our body?
Ans: As vitamin C is water soluble and readily excreted in urine and cannot be stored in our body. So it must be supplied regularly in diet.

6. What are nucleic acids? Mention their 2 important functions.
Ans: Nucleic acids are long chain biopolymers of nucleotides having polyphosphate ester chain.
Functions: ★ DNA is the chemical basis of heredity. Protein synthesis in the cell.

7. What is the difference between a nucleoside and a nucleotide.
Ans: Nucleoside: A unit formed by the attachment of a base to 1' position of sugar is called nucleoside.
Nucleotide: A unit formed by the attachment of phosphoric acid at 5' position of sugar present in nucleoside is called nucleotide.

8. What are essential and non-essential amino acids? Give one example for each.
Ans: The amino acids, which cannot be synthesised in the body and obtained through diet, are called "essential amino acids". e.g.: Leucine, Isoleucine.
The amino acids, which can be synthesised in the body are called "Non essential amino acids".
e.g.: Glycine, Alanine.

9. What do you understand by invert sugar?
Ans: Hydrolysis of sucrose brings about a change in the sign of rotation, from dextro (+) to laevo (−) and the product is called "invert sugar".

10. What are proteins? Give an example.
Ans: Apolypeptide with more than 100 amino acid residues, having molecular mass higher than 10,000 U is called a protein. e.g.: "Keratin" in hair.

11. What is glycogen? How is it different from starch?
Ans: The carbohydrate, whose structure is similar to amylopectin (major part of
starch) is called "glycogen". Carbohydrates are used as a storage molecules as
starch in plants and glycogen in animals.

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