Chemistry

Biomolecules

Question:

Amino acids are classified as acidic, basis or neutral depending upon the relative number of amino and carboxyl groups in their molecule. Which of the following are acidic?
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Answer:

(b, d) Amino acids with more than one -COOH group one against – NH2 group are acidic in nature.
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Biomolecules

Q 1.

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 2.

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

Q 3.

Aldopentoses named ribose and 2-deoxyribose are found in nucleic acids.
What is their relative configuration?

Q 4.

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?
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Q 5.

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

Q 6.

Why does compound (A) given below not form an oxime?
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Q 7.

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

Q 8.

What is glycogen? How is it different from starch?

Q 9.

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

Q 10.

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

Q 11.

Assertion (A): In presence of enzyme, substrate molecule can be attacked by the reagent effectively.
Reason (R): Active sites of enzymes hold the substrate molecule in a suitable position.

Q 12.

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

Q 13.

Name the sugar present in milk. How many monosaccharide units are present in it? What are such oligosaccharides called?

Q 14.

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

Q 15.

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

Q 16.

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 17.

Structure of a disaccharide formed by glucose and fructose is given below. Identify anomeric carbon atoms in monosaccharide units.
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Q 18.

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

Q 19.

Structures of glycine and alanine are given below. Show the peptide linkage in glycylalanine.
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Q 20.

What are monosaccharides ?

Q 21.

In disaccharides, if the reducing groups of monosaccharides, i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars. Which of the following disaccharide is a non-reducing sugar?
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Q 22.

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Q 23.

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

Q 24.

Name the linkage connecting monosaccharide units in polysaccharides.

Q 25.

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

Q 26.

Coagulation of egg white on boiling is an example of denaturation of protein. Explain it in terms of structural changes.

Q 27.

Match the vitamins given in Column I with the deficiency disease they cause given in Column II.
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Q 28.

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

Q 29.

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 30.

What is the difference between a nucleoside and a nucleotide?

Q 31.

Which of the following pairs represents anomers?
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Q 32.

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 33.

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

Q 34.

How will you distinguish 1 ° and 2 ° hydroxyl groups present in glucose? Explain with reactions.

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.

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

Q 37.

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

Q 38.

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 39.

What happens when D-glucose is treated with . the following reagents.
(i)HI (ii) Bromine water (iii) HNO3

Q 40.

Differentiate between globular and fibrous proteins.

Q 41.

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

Q 42.

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

Q 43.

How do you explain the presence of five -OH groups in glucose molecule?

Q 44.

Why must vitamin C be supplied regularly in diet?

Q 45.

Amino acids behave like salts rather than simple amines or carboxylic acids. Explain.

Q 46.

Activation energy for the acid catalysed hydrolysis of sucrose is 6.22 kJ mol-1, while hydrolysis is catalysed by the enzyme sucrase. Explain.

Q 47.

Match the following enzyme given in Column I with the reactions they catalyse given in Column II.
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Q 48.

What are the expected products of hydrolysis of lactose?

Q 49.

Write two main functions of carbohydrates in plants.

Q 50.

What do you understand by the term glycosidic linkage?