Classification of amino acid and MCQ for based on amino acids for NEET, UPSC, GPAT, SSC, GATE, CSIR NET Exams
Classification of Amino Acids
Amino acids are classified based on various criteria such as structure, polarity, nutritional requirement, and metabolic fate. Below is a detailed classification with a chart and multiple-choice questions (MCQs).
1.Classification Based on Structure (R-group)
| Type | Examples |
|---|---|
| Aliphatic (Non-polar) | Glycine, Alanine, Valine, Leucine, Isoleucine |
| Aromatic | Phenylalanine, Tyrosine, Tryptophan |
| Sulfur-containing | Cysteine, Methionine |
| Hydroxy-containing | Serine, Threonine |
| Acidic (Negatively Charged) | Aspartic acid, Glutamic acid |
| Basic (Positively Charged) | Lysine, Arginine, Histidine |
| Amide-containing | Asparagine, Glutamine |
2. Classification Based on Polarity
| Type | Examples |
|---|---|
| Non-Polar (Hydrophobic) | Glycine, Alanine, Valine, Leucine, Isoleucine, Phenylalanine, Methionine, Proline, Tryptophan |
| Polar (Uncharged) | Serine, Threonine, Asparagine, Glutamine, Tyrosine, Cysteine |
| Polar (Charged, Acidic) | Aspartic acid, Glutamic acid |
| Polar (Charged, Basic) | Lysine, Arginine, Histidine |
3. Classification Based on Nutritional Requirement
| Type | Examples |
|---|---|
| Essential Amino Acids (Cannot be synthesized by the body) | Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine |
| Non-Essential Amino Acids (Synthesized by the body) | Alanine, Asparagine, Aspartic acid, Glutamic acid |
| Conditionally Essential Amino Acids (Essential under certain conditions) | Arginine, Cysteine, Glutamine, Glycine, Proline, Tyrosine |
4. Classification Based on Metabolic Fate
| Type | Examples |
|---|---|
| Ketogenic (Forms ketone bodies) | Leucine, Lysine |
| Glucogenic (Forms glucose) | Alanine, Arginine, Aspartate, Cysteine, Glutamate, Glutamine, Glycine, Histidine, Methionine, Proline, Serine, Valine |
| Both Glucogenic & Ketogenic | Isoleucine, Phenylalanine, Threonine, Tryptophan, Tyrosine |
Amino Acid Classification
┌────────────────────────┬────────────────────────────┬───────────────────┐
│ Structure │ Polarity │ Metabolic │
│ (R-group) │ │ Fate │
├────────────────────────┼────────────────────────────┼───────────────────┤
│ Aliphatic (Gly, Ala, │ Non-polar (Gly, Ala, │ Glucogenic (Ala, │
│ Val, Leu, Ile) │ Val, Leu, Ile, Phe) │ Arg, Asp, Cys…) │
│ Aromatic (Phe, Tyr, │ Polar Uncharged (Ser, Thr,│ Ketogenic (Leu, │
│ Trp) │ Asn, Gln, Tyr, Cys) │ Lys) │
│ Sulfur-containing │ Polar Acidic (Asp, Glu) │ Both (Ile, Phe, │
│ (Cys, Met) │ Polar Basic (Lys, Arg, His) │ Thr, Trp, Tyr) │
└────────────────────────┴────────────────────────────┴───────────────────┘
MCQs on Amino Acid Classification
1. Which of the following amino acids is sulfur-containing?
a) Serine
b) Methionine
c) Histidine
d) Valine
Answer: b) Methionine
2. Which amino acid is both glucogenic and ketogenic?
a) Valine
b) Leucine
c) Isoleucine
d) Arginine
Answer: c) Isoleucine
3. Which of the following amino acids is essential?
a) Glycine
b) Proline
c) Leucine
d) Aspartic acid
Answer: c) Leucine
4. Which amino acid is classified as an aromatic amino acid?
a) Alanine
b) Cysteine
c) Phenylalanine
d) Serine
Answer: c) Phenylalanine
5. Which of the following is a non-polar amino acid?
a) Serine
b) Asparagine
c) Leucine
d) Glutamine
Answer: c) Leucine