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Right option is (d) glycosidic

For explanation: In nucleotides, the sugar ring is attached to the BASE by a bond between C1 CARBON of the sugar and the nitrogen atom of the heterocyclic ring. This is a N-glycosidic bond. The PHOSPHATE GROUP is bonded to the HYDROXYL group of the C5 carbon of sugar.

Correct option is (d) polypeptides

To explain: When the number of amino acids in a peptide is more than ten, it is a polypeptide. But when a polypeptide has more than a 100 amino acid residues, with MOLECULAR MASS higher than 10000u, it is CALLED a PROTEIN. However, this is not true in all cases (LIKE insulin).

The correct option is (b) False

Best EXPLANATION: Riboflavin is vitamin B2, the deficiency of which causes cheilosis and DIGESTIVE disorders. Beri beri is CAUSED by the deficiency of thiamine, or vitamin B1.

Correct choice is (a) True

Explanation: Enzymes are highly specific in nature. ALMOST all biochemical REACTIONS AE CONTROLLED by its own specific enzyme.

Right option is (b) coenzymes

To explain I WOULD SAY: Most active enzymes are associated with some non-protein COMPONENTS required for their activity. These are called PROSTHETIC groups and they may be cofactors or coenzymes.

Correct choice is (b) hydrolysis

The best I can EXPLAIN: Disaccharides REACT with water in the presence of dilute acids or ENZYMES to give two MONOSACCHARIDE UNITS. These units may be same of different.

The correct choice is (b) It RESULTS in the formation of a glycosidic bond.

The best explanation: Hydrolysis of SUCROSE (in the presence of either dilute acid, INVERTASE or SUCRASE) results in the cleavage of glycosidic bond to give glucose and fructose. Sucrase results in the cleavage of O-C(glucose) bond, whereas invertase results in the cleavage of O-C(fructose bond).

Correct choice is (a) Glycine

Best explanation: Neutral amino acids contain equal number of amino and carboxyl GROUPS. LYSINE, arginine and histidine contain TWO NH2 groups are ONE COOH group, and are hence BASIC amino acids.

Correct choice is (b) Y

To explain I would say: Tyrosine is a natural amino acid FIRST obtained from CHEESE, hence the name. It has a 4-hydroxyphenylmethyl side CHAIN. Its three-letter symbol is Tyr and its CODE is Y.

Correct option is (d) Uracil

Easiest explanation: DNA contains FOUR BASES NAMELY adenine (A), guanine (G), cytosine (C) and thymine (T). RNA ALSO contains four bases, A, T, G and uracil (U).

The correct choice is (a) Glucocorticoids

For explanation: If adrenal cortex does not function properly then one of the results may be Addison’s disease CHARACTERIZED by hypoglycaemia, weakness and INCREASED susceptibility to stress. This may be fatal UNLESS TREATED by glucocorticoids and mineralocorticoids.

The correct choice is (c) tertiary

The explanation is: Tertiary structure represents the overall folding of the POLYPEPTIDE chains or the further folding of secondary STRUCTURES. It gives rise to two major molecular shapes, i.e., FIBROUS and GLOBULAR.

Right ANSWER is (C) 5

Explanation: The reaction of glucose with (CH3CO)2O GIVES glucose pentaacetate, which has five acetyl GROUPS in the structure. This reaction also proves that all the five OH groups are present at different CARBON atoms, because of the stable nature of glucose.

Correct answer is (b) Hydrogen

To explain I would say: The secondary STRUCTURE refers to the SHAPE in which the polypeptide chain exists. There are two possible structures which arise due to the regular folding of the BACKBONE of the polypeptide chain due to hydrogen bonding between CO and NH GROUPS of peptide bond.

Correct option is (a) True

The EXPLANATION is: In the free STATE, D-fructose exists as a six-membered ring (fructopyranose). HOWEVER, in the combined state as a constituent in DISACCHARIDES, it exists in FURANOSE form (five-membered hemiketal).

Right answer is (a) Tollen’s test

Explanation: Despite having a CHO group, GLUCOSE does not react with NAHSO3 to form an addition product and GIVE EITHER Schiff’s test or 2,4-DNP test like other aldehydes. However, it forms a silver mirror on treatment with Tollen’s reagent. These observations INDICATE the existence of glucose in other forms and gave way to the cyclic structure of glucose.

Correct option is (C) Bromine water

The best I can explain: On treatment with BR2 water, glucose GETS oxidised to GLUCONIC acid (which is a six-carbon carboxylic acid). This indicates that the carbonyl group is present as an aldehyde group.

Right ANSWER is (a) True

For explanation: Glyceraldehyde is the simplest of the common aldose monosaccharides. It is a TRIOSE monosaccharide with the formula C3H6O3.It consists of two HYDROXY GROUPS and one aldehydic group.

Right answer is (B) False

To explain: HORMONES are compounds having varied chemical STRUCTURES. They may be polypeptide CHAINS or amino acids or contain a steroid nucleus.

The correct choice is (a) True

Easiest explanation: Chromosomes are made up of proteins and NUCLEIC acids. Nucleic acids are of mainly two types, DNA and RNA. Since they are LONG chain polymers of nucleotides, they are also called POLYNUCLEOTIDES.

The correct CHOICE is (a) Phosphodiester

Easy explanation: Fibrous proteins are linear polypeptide chains that lie parallel to each other. PEPTIDE binds are prevalent in the individual chains, whereas the threads are HELD TOGETHER by hydrogen and disulphide bonds, to form a fibre-like structure.

The CORRECT answer is (b) peptide

Explanation: When many alpha amino acid UNITS ARRANGED themselves in a chain (or any other suitable structure), a protein is FORMED. These units are LINKED together by peptide bonds between NH2 groups and COOH groups.

Correct answer is (c) N

The explanation is: For the sake of simplicity, each AMINO ACID has been GIVEN an abbreviation which is either a three-letter symbol or a one-letter code. Asparagine is REPRESENTED as Asn or N.

Right CHOICE is (C) C5

The EXPLANATION: Monosaccharides undergo intramolecular reaction to form cyclic hemiacetal structures. GENERALLY in aldoses, the C4 or C5 carbon is involved in cyclisation. In glucose, the hemiacetal (six-membered RING) is formed between the CHO group andthe OH group on the C5 carbon.

Right CHOICE is (B) presence of a CARBONYL group in glucose

To elaborate: Glucose reacts with hydrogen cyanide to form glucose cyanohydrin, where the carbonyl double bond GETS cleaved to form one C-OH bond and one C-CN bond. This indicates the presence of a carbonyl group but does not confirm whether it is an ALDEHYDIC or a keto group.

Correct option is (c) Vitamins

Best EXPLANATION: Organic chemical substances which are CONSUMED in SMALL quantities through proper diet are called vitamins. These are ESSENTIAL for the proper MAINTENANCE and of health and growth of an individual. These are not synthesized by the human body.

The correct answer is (a) Maltase

The best explanation: Substrate SPECIFIC ENZYMES are those which can act only on one particular COMPOUND to give a product(s). For example, maltase acts only on maltose to BREAK the glycosidic linkage between the two glucose UNITS.

Right answer is (a) True

For explanation I WOULD say: GLUCOSE is an aldehydic carbohydrate (with CHO) group at end of chain) with six carbon atoms (HEXOSE). Its formula is C6H12O6.

Correct choice is (C) Polyhydroxy ketones

Easy explanation: Polyamino ALDEHYDES and polyhalo aldehydes do not CONTAIN an OH group. Polyhydroxy carboxylic acids do not contain a CHO or a keto group. These also do not produce OH substituted compounds on hydrolysis.

Correct choice is (c) Deoxyribose

The explanation: Initially, most of the carbohydrates had the GENERAL FORMULA Cx(H2O)y. Later on it was found out that few of the COMPOUNDS either FIT into this formula but were not carbohydrates or they did not conform to this formula but were hydrates of carbon.

The correct option is (a) Galactose

The best explanation: Galactose is a monosaccharide with the formula C6H12O6. SUCROSE, allolactose and MALTOSE are DISACCHARIDES with the same chemical formula C12H22O11.

Correct answer is (b) Stachyose

The explanation is: POLYSACCHARIDES are those carbohydrates which yield a very large number of MONOSACCHARIDE UNITS (>10) on hydrolysis. Stachyose (C24H42O21) is a tetrasaccharide that GIVES four monosaccharide units on hydrolysis.

Correct answer is (b) carboxylic acid

For explanation: The compound is acetic acid (CH3COOH). EVEN THOUGH it has the GENERAL formula Cx(H2O)y of CARBOHYDRATES, it is not one. This is one the flaws of the general formula definition of carbohydrates.