Chemistry

Biomolecules

Question:

Which of the following terms are correct about enzyme?
(a) Proteins (b) Dinucleotides
(c) Nucleic acids (d) Biocatalysts

Answer:

(a, d) Enzymes are protein molecules and they act as biocatalysts for the reactions taking place in the body.

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Biomolecules

Q 1.

The letters ' D ' or ' L' before the name of a stereoisomer of a compound indicate the correlation of configuration of that particular stereoisomer.
ncert-exemplar-problems-class-12-chemistry-biomolecules-21
This refers to their relation with one of the isomers of glyceraldehydes. Predict whether the following compound has ‘D' or ‘L' configuration.

Q 2.

During curdling of milk, what happens to sugar present in it?

Q 3.

What are essential and non-essential amino acids? Give two examples of each type.

Q 4.

Which of the following terms are correct about enzyme?
(a) Proteins (b) Dinucleotides
(c) Nucleic acids (d) Biocatalysts

Q 5.

What is glycogen? How is it different from starch?

Q 6.

Name the linkage connecting monosaccharide units in polysaccharides.

Q 7.

Differentiate between globular and fibrous proteins.

Q 8.

Why are vitamin A and vitamin C essential to us? Give their important sources.

Q 9.

Assertion (A): Deoxyribose, C5H10O4 is not a carbohydrate.
Reason (R): Carbohydrates are hydrates of carbon so compounds which follow Cx(H2O)y formula are carbohydrates.

Q 10.

What are the common types of secondary structure of proteins?

Q 11.

Describe the term D- and L-configuration used for amino acids with examples.

Q 12.

What is the difference between a nucleoside and a nucleotide?

Q 13.

Why must vitamin C be supplied regularly in diet?

Q 14.

When RNA is hydrolysed, there is no relationship among the quantities of different bases obtained. What does this fact suggest about the structure of RNA?

Q 15.

What type of bonding helps in stabilising the α-helix structure of proteins?

Q 16.

Which monosaccharide units are present in starch, cellulose and glycogen and which linkages link these units?

Q 17.

Why cannot Vitamin C be stored in our body?

Q 18.

Three structures are given below in which two glucose units are linked. Which of these linkages between glucose units are between C1 and C4 and which linkages are between C1 and C6?
ncert-exemplar-problems-class-12-chemistry-biomolecules-12

Q 19.

Why does compound (A) given below not form an oxime?
ncert-exemplar-problems-class-12-chemistry-biomolecules-26

Q 20.

ncert-exemplar-problems-class-12-chemistry-biomolecules-23

Q 21.

Assertion (A): Vitamin D can be stored in our body.
Reason (R): Vitamin D is fat soluble vitamin.

Q 22.

What is the effect of denaturation on the structure of proteins?

Q 23.

How are vitamins classified? Name the vitamin responsible for the coagulation of blood.

Q 24.

Write the important structural and functional differences between DNA and RNA.

Q 25.

How do you explain the presence of all six carbon atoms in glucose in a straight chain?

Q 26.

Carbohydrates are essential for life in both plants and animals. Name the carbohydrates that are used as storage molecules in plants and animals, also name the carbohydrate which is present in wood or in the fibre of cotton cloth.

Q 27.

What are enzymes?

Q 28.

α-Helix is a secondary structure of proteins formed by twisting of polypeptide chain into right handed screw like structures. Which type of interactions are responsible for making the a-helix structure stable?

Q 29.

Where does the water present in the egg go after boiling the egg?

Q 30.

What are reducing sugars?

Q 31.

Which of the following monosaccharides are present as five membered cyclic structure (foranose structure)?
(a) Ribose (b) Glucose (c) Fructose (d) Galactose

Q 32.

Some enzymes are named after the reaction, where they are used. What name is given to the class of enzymes which catalyse the oxidation of one substrate with simultaneous reduction of another substrate?

Q 33.

How do enzymes help a substrate to be attacked by the reagent effectively?

Q 34.

Match the following enzyme given in Column I with the reactions they catalyse given in Column II.
ncert-exemplar-problems-class-12-chemistry-biomolecules-38

Q 35.

Assertion (A): β-glycosidic linkage is present in maltose.
ncert-exemplar-problems-class-12-chemistry-biomolecules-39
Reason (R): Maltose is composed of two glucose units in which C-l of one glucose unit is linked to C-4 of another glucose unit.

Q 36.

Assertion (A): Glycine must’be taken through diet.
Reason (R): It is an essential amino acid.

Q 37.

The two strands in DNA are not identical but are complementary. Explain.

Q 38.

Carbohydrates are classified on the basis of their behaviour on hydrolysis and also as reducing or non-reducing sugar. Sucrose is a .
(a) monosaccharide (b) disaccharide
(c) reducing sugar (d) non-reducing sugar

Q 39.

Which of the following carbohydrates are branched polymer of glucose?
(a) Amylose (b) Amylopectin (c) Cellulose (d) Glycogen

Q 40.

Under what conditions glucose is converted to gluconic and saccharic acid?

Q 41.

Monosaccharides contain carbonyl group hence are classified, as aldose or ketose. The number of carbon atoms present in the monosaccharide molecule are also considered for classification. In which class of monosaccharide will you place fructose?  

Q 42.

What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?

Q 43.

What is the basic structural difference between starch and cellulose?

Q 44.

How do you explain the presence of an aldehydic group in a glucose molecule?

Q 45.

Match the vitamins given in Column I with the deficiency disease they cause given in Column II.
ncert-exemplar-problems-class-12-chemistry-biomolecules-37

Q 46.

How do you explain the absence of aldehyde group in the pentaacetate of D-glucose?

Q 47.

What are glycosidic linkages? In which type of biomolecules are they present?

Q 48.

Assertion (A): All naturally occurring a-amino acids except glycine are optically active.
Reason (R): Most naturally occurring amino acids have L-configuration.

Q 49.

Write two main functions of carbohydrates in plants.

Q 50.

Classify the following into monosaccharides and disaccharides. Ribose, 2-deoxyribose, maltose, galactose, fructose and lactose.