Class 12 Biomolecules MCQs and Important Questions
Following are the Chemistry Class 12 Biomolecules MCQs, You can download the Word file format of these questions, scroll below to get the link.
1. Glycogen is a branched chain polymer of α-D-glucose units in which the chain is formed by C1—C4 glycosidic linkage whereas branching occurs by forming C1-C6 glycosidic linkage. The structure of glycogen is similar to
(a) Amylose (b) Amylopectin (c) Cellulose (d) Glucose
2. Which of the following polymers is stored in the liver of animals?
(a) Amylose (b) Cellulose (c) Amylopectin (d) Glycogen
3. Sucrose (cane sugar) is a disaccharide. One molecule of sucrose on hydrolysis gives
(a) 2 molecules of glucose
(b) 2 molecules of glucose + 1 molecule of fructose
(c) 1 molecule of glucose + 1 molecule of fructose
(d) 2 molecules of fructose
4. Proteins have two types of secondary structures viz. α-helix and β-pleated sheet structure. α-helix structure of the protein is stabilized by:
(a) Peptide bonds (b) van der Waals forces
(c) Hydrogen bonds (d) Dipole-dipole interactions
5. Which of the following acids is a vitamin?
(a) Aspartic acid (b) Ascorbic acid (c) Adipic acid (d) Saccharic acid
6. Dinucleotide is obtained by joining two nucleotides together by phosphodiester linkage. Between which carbon atoms of pentose sugars of nucleotides are these linkages present?
(a) 5′ and 3′ (b) 1′ and 5′ (c) 5′ and 5′ (d) 3′ and 3′
7. Nucleic acids are the polymers of
(a) Nucleosides (b) Nucleotides (c) Bases (d) Sugars
8. Which of the following statements is not true about glucose?
(a) It is an aldohexose. (b) On heating with HI it forms n-hexane.
(c) It is present in furanose form. (d) It does not give 2,4-DNP test.
9. Each polypeptide in a protein has amino acids linked with each other in a specific sequence. This sequence of amino acids is said to be ____________.
(a) primary structure of proteins. (b) secondary structure of proteins.
(c) tertiary structure of proteins. (d) quaternary structure of proteins.
10. DNA and RNA contain four bases each. Which of the following bases is not present in RNA?
(a) Adenine (b) Uracil (c) Thymine (d) Cytosine
Coordination Chemistry MCQs and Important Questions
11. Which of the following B-group vitamins can be stored in our body?
(a) Vitamin B1 (b) Vitamin B2 (c) Vitamin B6 (d) Vitamin B12
12. Which of the following bases is not present in DNA?
(a) Adenine (b) Thymine (c) Cytosine (d) Uracil
13. Which of the following reactions of glucose can be explained only by its cyclic structure?
(a) Glucose forms pentaacetate.
(b) Glucose reacts with hydroxylamine to form an oxime.
(c) Pentaacetate of glucose does not react with hydroxylamine.
(d) Glucose is oxidized by nitric acid to gluconic acid.
14. Carbohydrates are classified based on their behavior on hydrolysis and as reducing or non-reducing sugar. Sucrose is a
(a) monosaccharide (b) disaccharide (c) reducing sugar (d) non-reducing sugar
15. Proteins can be classified into two types based on their molecular shape i.e., fibrous proteins and globular proteins. Examples of globular proteins are:
(a) Insulin (b) Keratin (c) Albumin (d) Myosin
16. Which of the following carbohydrates are branched polymer of glucose?
(a) Amylose (b) Amylopectin (c) Cellulose (d) Glycogen
17. Which of the following monosaccharides are present as five-membered cyclic structure (furanose structure)?
(a) Ribose (b) Glucose (c) Fructose (d) Galactose
18. In fibrous proteins, polypeptide chains are held together by
(a) van der Waals forces (b) disulphide linkage
(c) electrostatic forces of attraction (d) hydrogen bonds
19. Which of the following are purine bases?
(a) Guanine (b) Adenine (c) Thymine (d) Uracil
20. Which of the following terms are correct about enzymes?
(a) Proteins (b) Dinucleotides (c) Nucleic acids (d) Biocatalysts
Class 12 Chemical Kinetics MCQs and Important Questions
Class 12 Biomolecules Assertion-Reason Questions
(a)Assertion and reason both are correct statements and reason is the correct explanation for assertion.
(b) Assertion and reason both are correct statements and reason is not the correct explanation for assertion.
(c)Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
1. Assertion: D-(+)-Glucose is dextrorotatory.
Reason: D represents its dextrorotatory nature.
2. Assertion: Vitamin D can be stored in our body.
Reason: Vitamin D is fat soluble vitamin.
3. Assertion: Glycine must be taken through diet.
Reason: It is an essential amino acid.
4. Assertion: Fructose does not contain an aldehydic group but still reduces Tollen’s reagent.
Reason: In the presence of base fructose undergoes rearrangement to give glucose.
5. Assertion: Glucose and fructose can be distinguished by silver mirror test.
Reason: Glucose contains an aldehydic group while fructose contains ketonic group.
6. Assertion: The chemical name of vitamin A is Retinol.
Reason: A deficiency of Vitamin A causes Scurvy.
7. Assertion: Enzyme hydrolysis of sucrose is called inversion.
Reason: The configuration of sucrose gets converted under these conditions.
8. Assertion: All naturally occurring α-amino acids except glycine are optically active.
Reason: Most natural occurring amino acids have L-configuration.
9. Assertion: Deoxyribose, C5H10H4 is not a carbohydrate.
Reason: Compounds which follow Cx(H2O)y formula are carbohydrates.
10. Assertion: The Ka value of α-Amino acids is very low.
Reason: α-Amino acids have zwitter ionic structure.
Download the Word file of Class 12 Biomolecules MCQs and Important questions
BIOMOLECULES CASE STUDY-BASED QUESTIONS
Read the passage given below and answer the following questions.
1. Carbohydrates are polyhydroxy aldehydes and ketones and those compounds which on hydrolysis give such compounds are also carbohydrates. The carbohydrates which are not hydrolysed are called monosaccharides. Other saccharides are oligosaccharides and polysaccharides. Monosaccharides with aldehyde group are called aldose and those with free ketonic groups are called ketose. Carbohydrates are optically active and mainly synthesized by plants during photosynthesis. Glucose has Pyranose ring structure.
(a) What is glycosidic linkage?
(b) Which aldose sugar is present in DNA?
(c) What are reducing and non-reducing sugars? Give examples.
OR
(c) Which facts are not explained by open chain structure of glucose.
2. Glucose is known as dextrose because it occurs in nature as the optically active dextrorotatory isomer. It is essential constituent of human blood. The blood normally contains 65 to 110 mg of glucose per 100 mL, hence named Blood sugar. The level may be much higher in diabetic persons. The urine of diabetic persons also contains considerable amount of glucose. In combined form, it occurs in cane sugar and polysaccharides such as starch and cellulose.
Glucose has an aldehyde group (-CHO), one primary alcoholic group (-CH2OH) and four secondary alcoholic groups (-CHOH) in their structure. Due to the presence of five hydroxyl groups (-OH), glucose on acetylation forms Glucose pentaacetate. Glucose also undergoes oxidation with mild oxidizing agents like bromine water as well as with strong oxidizing agents like nitric acid. Since glucose is readily oxidized, it acts as a strong reducing agent and reduces Tollen’s reagent and Fehling solution.
Glucose exists in two crystalline forms: α -D-glucose and β -D-glucose. If either of the two forms is dissolved in water and allowed to stand, the specific rotation of the solution changes gradually, until a constant value is obtained. This change is called mutarotation.
(a) What happens when Glucose reacts with concentrate nitric acid?
(b) What happens when Glucose reacts with Acetic anhydride?
(c)Draw the structure of α and β-Glucopyranose.
OR
(c) (i)What are the expected products of hydrolysis of lactose?
(ii)How do you explain the absence of aldehyde group in the pentaacetate of D-glucose?
3. Certain organic compounds are required in small amounts in our diet but their deficiency causes specific diseases. These compounds are called vitamins. Most of the vitamins cannot be synthesized by our body but plants can synthesize almost all of them. So, they are considered as essential food factors. However, the bacteria of the gut can produce some of the vitamins required by us. All the vitamins are generally available in our diet. The term vitamin was coined from the words vital + amine, since the earlier identified compounds had amino group. Vitamins are classified into two groups depending on their solubility in water or fat namely- fat soluble and water-soluble vitamins.
Answer the following questions-:
- Why Vitamin C cannot be stored in our body?
- Name the vitamin whose deficiency causes increased blood clotting time.
- Xerophthalmia is caused by a deficiency of which vitamins. Write the chemical name of this Vitamin.
OR
Which vitamins are water soluble and which vitamins are fat-soluble vitamins?