12th Chemistry - Book Back Answers - Unit 14 Biomolecules - English Medium Guides

  

 

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Tamil Nadu Board 12th Standard Chemistry - Unit 14: Book Back Answers and Solutions

    This post covers the book back answers and solutions for Unit 14 from the Tamil Nadu State Board 12th Standard Chemistry textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.

    We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.

    By going through this material, you’ll gain a strong understanding of Unit 14 along with the corresponding book back questions and answers (PDF format).

Question Types Covered:

• 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following 
• 2 Mark Questions: Answer briefly 
• 3, 4, and 5 Mark Questions: Answer in detail

All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.

All the best, Class 12 students! Prepare well and aim for top scores. Thank you!

Unit 14 - Biomolecules

I. Multiple Choice Questions

1. Which one of the following rotates the plane polarized light towards left?

a) D(+) Glucose

b) L(+) Glucose

c) D(-) Fructose

d) D(+) Galactose

Answer Key:

c) D(-) Fructose 

  

2. The correct corresponding order of names of four aldoses with configuration given below Respectively is,

a) L-Erythrose, L-Threose, L-Erythrose, D-Threose

b)D-Threose,D-Erythrose, L-Threose, L-Erythrose,

c)L-Erythrose, L-Threose, D-Erythrose, D-Threose

d) D-Erythrose, D-Threose, L-Erythrose, L-Threose

Answer Key:

d) D-Erythrose, D-Threose, L-Erythrose, L-Threose

 

3. Which one given below is a non-reducing sugar?

a) Glucose

b) Sucrose

c) maltose

d) Lactose.

Answer Key:

b) Sucrose

  

4. Glucose $\stackrel{\mathbf{H}\mathbf{C}\mathbf{N}}{\mathbf{\to }}\mathbf{P}\mathbf{r}\mathbf{o}\mathbf{d}\mathbf{u}\mathbf{c}\mathbf{t}\stackrel{\mathbf{\left(}\mathbf{h}\mathbf{y}\mathbf{d}\mathbf{r}\mathbf{o}\mathbf{l}\mathbf{y}\mathbf{s}\mathbf{i}\mathbf{s}\mathbf{\right)}}{\mathbf{\to }}\mathbf{P}\mathbf{r}\mathbf{o}\mathbf{d}\mathbf{u}\mathbf{c}\mathbf{t}\stackrel{\mathbf{(}\mathbf{H}\mathbf{I}\mathbf{+}\mathbf{H}\mathbf{e}\mathbf{a}\mathbf{t}\mathbf{)}}{\mathbf{\to }}$ A, the compound A is

a) Heptanoic acid

b) 2-Iodohexane

c) Heptane

d) Heptanol

Answer Key:

a) Heptanoic acid 

  

5. Assertion: A solution of sucrose in water is dextrorotatory. But on hydrolysis in the presence of little hydrochloric acid, it becomes levorotatory. (AIIMS)

Reason: Sucrose hydrolysis gives equal amounts of glucose and fructose. As a result of this change in sign of rotation is observed.

a)If both accretion and reason are true and reason is the correct explanation of assertion

b) If both assertion and reason are true but reason is not the correct explanation of

assertion

c) If assertion is true but reason is false.

d) if both assertion and reason are false.

Answer Key:

a)If both accretion and reason are true and reason is the correct explanation of assertion

  

6. The central dogma of molecular genetics states that the genetic information flows from

a) Amino acids $\mathbf{\to }$ Protein $\mathbf{\to }$DNA

b) DNA $\mathbf{\to }$Carbohydrates $\mathbf{\to }$Proteins

c) DNA $\mathbf{\to }$RNA $\mathbf{\to }$Proteins

d) DNA $\mathbf{\to }$RNA $\mathbf{\to }$Carbohydrates

Answer Key:

c) DNA $\mathbf{\to }$RNA $\mathbf{\to }$Proteins

 

7. In a protein, various amino acids linked together by

a) Peptide bond

b) Dative bond

c) α - Glycosidic bond

d) β - Glycosidic bond

Answer Key:

a) Peptide bond 

  

8. Among the following the achiral amino acid is (AIIMS)

a) 2-ethylalanine

b) 2-methylglycine

c) 2-hydroxymethylserine

d) Tryptophan

Answer Key:

c) 2-hydroxymethylserine 

  

9. The correct statement regarding RNA and DNA respectively is

a) the sugar component in RNA is an arabinos and the sugar component in DNA is

ribose

b) the sugar component in RNA is 2’-deoxyribose and the sugar component in DNA is

arabinose

c) the sugar component in RNA is an arabinose and the sugar component in DNA is

2’-deoxyribose

d) the sugar component in RNA is ribose and the sugar component in DNA is

2’-deoxyribose

Answer Key:

d) the sugar component in RNA is ribose and the sugar component in DNA is

2’-deoxyribose

 

10. In aqueous solution of amino acids mostly exists in,

a) NH₂-CH(R)-COOH

b) NH₂-CH(R)-COO^-

c) H₃N⁺-CH(R)-COOH

d) H₃N⁺-CH(R)-COO^-

Answer Key:

d) H₃N⁺-CH(R)-COO^-

  

11. Which one of the following is not produced by body?

a) DNA

b) Enzymes

c) Harmones

d) Vitamins

Answer Key:

d) Vitamins

  

12. The number of sp² and sp³ hybridised carbon in fructose are respectively

a) 1 and 4

b) 4 and 2

c) 5 and 1

d) 1 and 5

Answer Key:

d) 1 and 5

  

13. Vitamin B2 is also known as

a) Riboflavin

b) Thiamine

c) Nicotinamide

d) Pyridoxine

Answer Key:

a) Riboflavin

  

14. The pyrimidine bases present in DNA are

a) Cytosine and Adenine

b) Cytosine and Guanine

c) Cytosine and Thiamine

d) Cytosine and Uracil

Answer Key:

c) Cytosine and Thiamine 

  

15. Among the following L-serine is

a) 

b) 

c)  

d) 

Answer Key:

 

16. The secondary structure of a protein refers to

a) fixed configuration of the polypeptide backbone

b) hydrophobic interaction

c) sequence of α-amino acids

d) α-helical backbone.

Answer Key:

d) α-helical backbone.

 

17. Which of the following vitamins is water soluble?

a) Vitamin E

b) Vitamin K

c) Vitamin A

d) Vitamin B

Answer Key:

d) Vitamin B

  

18. Complete hydrolysis of cellulose gives

a) L-Glucose

b) D-Fructose

c) D-Ribose

d) D-Glucose

Answer Key:

d) D-Glucose

  

19. Which of the following statement is not correct?

a) Ovalbumin is a simple food reserve in egg-white

b) Blood proteins thrombin and fibrinogen are involved in blood clotting

c) Denaturation makes protein more active

d) Insulin maintains the sugar level of in the human body.

Answer Key:

c) Denaturation makes protein more active

  

20. Glucose is an aldose. Which one of the following reactions is not expected with glucose?

a) It does not form oxime

b) It does not react with Grignard reagent

c) It does not form osazones

d) It does not reduce tollens reagent

Answer Key:

b) It does not react with Grignard reagent

  

21. If one strand of the DNA has the sequence ‘ATGCTTGA’, then the sequence of complementary strand would be

a) TACGAACT

b) TCCGAACT

c) TACGTACT

d) TACGRAGT

Answer Key:

a) TACGAACT 

  

22. Insulin, a hormone chemically is

a) Fat

b) Steroid

c) Protein

d) Carbohydrates

Answer Key:

c) Protein 

  

23. α -D (+) Glucose and β-D (+) glucose are

a) Epimers

b) Anomers

c) Enantiomers

d) Conformational isomers

Answer Key:

b) Anomers

  

24. Which of the following are epimers

a) D(+)-Glucose and D(+)-Galactose

b) D(+)-Glucose and D(+)-Mannose

c) Neither (a) nor (b)

d) Both (a) and (b)

Answer Key:

d) Both (a) and (b)

  

25. Which of the following amino acids are achiral?

a) Alanine

b) Leucine

c) Proline

d) Glycine

Answer Key:

d) Glycine 

II. Short Answer Questions.

12th Chemistry

III. Long Answer Questions. 

12th Chemistry

IV. Exercise.   

12th Chemistry