MCQs on Amino Acids

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Amino Acids Introduction

Amino acids make up the proteins. They are organic compounds of nitrogen, carbon, hydrogen, and oxygen with a variable side chain group. Human beings need 20 essential amino acids for the proper development and functioning of various organs in the body. Out of the 20, 9 are deemed as the most important amino acids. 

How Important are Amino Acids

Amino acids are the compounds that form the building blocks of proteins. Proteins are essential components that make up 75% of the human body. Proteins are responsible for proper overall development. 

Types of Amino Acids

There are 7 types of amino acids differentiated on the basis of side chains present. Thus, the seven types of amino acids are-

  • Aliphatic

  • Aromatic

  • Basic

  • Acidic

  • Hydroxylic

  • Sulfur containing

  • Amidic or the one with the amide group

Functions of Essential and Non Essential Amino Acids

  • Essential amino acids like phenylalanine, valine threonine helps maintain the nervous system, promotes muscle growth, and strengthens the immune system.

  • Essential amino acid Tryptophan is involved in the production of vitamin B3 and serotonin hormone that play a vital role in regulating sleep, boosting mood and maintaining appetite.

  • Isoleucine plays a vital role in the formation of haemoglobin along with stimulating the pancreas to synthesize insulin and helps transportation of oxygen in the body.

  • Non essential amino acids like alanine, cysteine, glutamine help in production of glucose and other amino acids, provides resistance, and helps promote a healthy brain function.

There are many such actions of all the amino acids- essential and non essential which help maintain regular processes in the body and promote growth. 

Let’s Practise Some Solved MCQs on Amino Acids and Check Our Knowledge of the Chapter

1. Which of the following is true regarding the solubility of amino acids?

  1. Mostly soluble in water and insoluble in organic solvents

  2. They are only water soluble

  3. They are only soluble in organic solvents

  4. Mostly soluble in organic solvents and insoluble in water

Answer: (a)

2. Which of the following essential amino acids is not synthesized by the body?

  1. Arginine

  2. Glutamine

  3. Histidine

  4. Proline

Anser: (c)

3. From which of the following components amino acids are generally synthesized?

  1. Fatty acids

  2. 𝜶-­ketoglutaric acid

  3. Mineral Salts

  4. Volatile acids

Answer: (b)

4. Amino acids with the non polar aliphatic ‘R’ group are

  1. Glycine, alanine, leucine

  2. Serine, threonine, cysteine

  3. Lysine, arginine, histidine

  4. Phenylalanine, tyrosine and tryptophan

Answer: (a)

5.  Amino acids with aromatic side chain are

  1. tryptophan, asparagine, tyrosine

  2. tryptophan, threonine, tyrosine

  3. phenylalanine, tryptophan, serine

  4. phenylalanine, tryptophan, tyrosine

Answer: (d)

6. Which of the following amino acids yield Acetyl CoA during catabolism?

  1. Ketogenic

  2. Glucogenic

  3. Essential

  4. None of the above

Answer: (a) 

7. Which of the following is a true statement?

  1. Tryptophan and tyrosine are significantly more polar than phenylalanine

  2. Leucine is commonly used as an ingredient in the buffers of SDS page

  3. Aspartate is an essential amino acid

  4. Lysine is a non-essential amino acid

Answer: (a)

8. Out of these, which one is the non essential amino acid?

  1. Lysine

  2. Threonine

  3. Serine

  4. Histidine

Answer: (c)

9. Which of the following is an essential amino acid?

  1. Cysteine

  2. Asparagine

  3. Glutamine

  4. Phenylalanine

Answer: (d)

10. The difference between amino acid and imino acid is

  1. Bonding of carbonyl group with the amide group

  2. Bonding of nitrogen in the amide group

  3. Bonding of nitrogen in the carbonyl group

  4. Presence of covalent bond between amide and carbonyl group

Answer: (b)

11. Which of the following is an example of imino acid?

  1. Alanine

  2. Glycine

  3. Proline

  4. Serine

Answer: (c)

12. Which of the following amino acids is both glucogenic and ketogenic in nature?

  1. Leucine

  2. Lysine

  3. Isoleucine

  4. histidine

Answer: (c) 

13. Which of the following is true in case of an amino acid that yields acetoacetyl CoA during the catabolism of its carbon skeleton?

  1. It’s glycogenic in nature

  2. It’s ketogenic in nature

  3. It’s an essential amino acid

  4. It can be either glucogenic or ketogenic in nature

Answer: (b)

14. Among the 20 standard proteins which coding amino acids, which of the following occurs the least number of times in proteins?

  1. Glycine

  2. Alanine

  3. Tryptophan

  4. Methionine

Answer: (c)

15. Which of these is the first amino acid in a polypeptide chain?

  1. Serine

  2. Valine

  3. Alanine

  4. Methionine

Answer: (d)

16. Which of the following are sulfur containing amino acids?

  1. Cysteine and methionine

  2. Methionine and threonine

  3. Cysteine and threonine

  4. Cysteine and serine

Answer: (a)

17. Which of the following are positively charged basic amino acids?

  1. Lysine and arginine

  2. Lysine and asparagine

  3. Glutamine and arginine

  4. Lysine and glutamine

Answer: (a)

18. Out of theses, the acidic amino acids are-

  1. Arginine and glutamate

  2. Aspartate and asparagine

  3. Aspartate and lysine

  4. Aspartate and glutamate

Answer: (d)

19. The 21st amino acid is

  1. Hydroxy lysine

  2. Hydroxyproline

  3. Selenocysteine

  4. citrulline

Answer: (c)

20. Out of the following, amino acids with hydroxyl groups are-

  1. Serine and alanine

  2. Alanine and Valine

  3. Serine and threonine

  4. Valine and Isoleucine

Answer: (c)