Biomolecules Previous Year Questions — NEET Biology
5 past-year Biomolecules questions from NEET (Biology).
Q96 (2024)
Identify the correct statements about biomolecules.
A. Lipids are generally water soluble.
B. Proteins are polypeptides.
C. Polysaccharides are long chains of sugars.
D. Adenine and guanine are substituted pyrimidines.
E. Almost all enzymes are proteins.
Choose the correct answer from the options given below:
- C, D and E only
- B, C and E only
- B, D and E only
- A, B and C only
### Related Formula
Purines: Adenine & Guanine
Pyrimidines: Cytosine, Thymine, Uracil
Lipids: Insoluble in water
### Core Logic
- A: Lipids are insoluble in water (False).
- B: Proteins are polypeptides composed of amino acid chains (True).
- C: Polysaccharides are polymers of monosaccharide sugar units (True).
- D: Adenine and guanine are purines, not pyrimidines (False).
- E: Almost all enzymes are proteins (True, except ribozymes).
### Step 1: Conclusion
Correct statements are B, C, and E only. This matches Option (2).
### Pattern Recognition
Adenine and Guanine = Purines (D is False). Lipids = Water insoluble (A is False). Correct statements are B, C, E.
### Evaluation Rubric / Model Answer
null
### Chapter Mix
Class 11 Biology: Biomolecules
Q105 (2024)
Alpha-helix is found in which level of protein structure?
- Quaternary structure
- Tertiary structure
- Primary structure
- Secondary structure
### Related Formula
Protein Structures:
Primary = Linear amino acid sequence
Secondary = Alpha-helix and Beta-pleated sheet
Tertiary = 3D folding
Quaternary = Multi-polypeptide complex
### Core Logic
The $\alpha$-helix and $\beta$-pleated sheet conformations represent the secondary level of protein structure, stabilized by hydrogen bonds along the polypeptide backbone.
### Step 1: Selection
Alpha-helix is found in Secondary structure. Option (4) is correct.
### Pattern Recognition
Alpha-helix / Beta-sheet = Secondary structure.
### Evaluation Rubric / Model Answer
null
### Chapter Mix
Class 11 Biology: Biomolecules
Q106 (2024)
Which of the following statements are correct regarding amino acids?
A. They are substituted methanes.
B. Serine is an aromatic amino acid.
C. Valine is a neutral amino acid.
D. Lysine is an acidic amino acid.
Choose the correct answer from the options given below:
- C and D only
- A and B only
- A and C only
- B and C only
### Related Formula
Amino Acid Classification:
Substituted Methanes: Central alpha carbon with $-H$, $-COOH$, $-NH_2$, $-R$
Acidic: Glutamic acid
Basic: Lysine
Neutral: Valine
Aromatic: Tyrosine, Phenylalanine, Tryptophan
Alcoholic: Serine
### Core Logic
- Statement A: Amino acids are substituted methanes (True).
- Statement B: Serine is an alcoholic amino acid, not aromatic (False).
- Statement C: Valine is a neutral amino acid (True).
- Statement D: Lysine is a basic amino acid, not acidic (False).
### Step 1: Conclusion
Statements A and C are correct. Option (3) is correct.
### Pattern Recognition
Lysine = Basic (D false). Serine = Alcoholic, not aromatic (B false). Leaves A and C.
### Evaluation Rubric / Model Answer
null
### Chapter Mix
Class 11 Biology: Biomolecules
Q130 (2024)
Match List I with List II :
<div style="overflow-x: auto; margin: 1rem 0;"><table style="width: 100%; border-collapse: collapse; text-align: left; font-size: 14px;"><thead><tr><th style="border: 1px solid #888; padding: 8px;"></th><th style="border: 1px solid #888; padding: 8px;">List I</th><th style="border: 1px solid #888; padding: 8px;"></th><th style="border: 1px solid #888; padding: 8px;">List II</th></tr></thead><tbody><tr><td style="border: 1px solid #888; padding: 8px;">A.</td><td style="border: 1px solid #888; padding: 8px;">Trypsin</td><td style="border: 1px solid #888; padding: 8px;">I.</td><td style="border: 1px solid #888; padding: 8px;">Intercellular ground substance</td></tr><tr><td style="border: 1px solid #888; padding: 8px;">B.</td><td style="border: 1px solid #888; padding: 8px;">Morphine</td><td style="border: 1px solid #888; padding: 8px;">II.</td><td style="border: 1px solid #888; padding: 8px;">Lectin</td></tr><tr><td style="border: 1px solid #888; padding: 8px;">C.</td><td style="border: 1px solid #888; padding: 8px;">Concanavalin A</td><td style="border: 1px solid #888; padding: 8px;">III.</td><td style="border: 1px solid #888; padding: 8px;">Enzyme</td></tr><tr><td style="border: 1px solid #888; padding: 8px;">D.</td><td style="border: 1px solid #888; padding: 8px;">Collagen</td><td style="border: 1px solid #888; padding: 8px;">IV.</td><td style="border: 1px solid #888; padding: 8px;">Alkaloid</td></tr></tbody></table></div>
Choose the correct answer from the options given below :
- A-III, B-IV, C-II, D-I
- A-I, B-II, C-III, D-IV
- A-III, B-II, C-IV, D-I
- A-IV, B-III, C-II, D-I
### Related Formula
Trypsin = Enzyme
Morphine = Alkaloid
Concanavalin A = Lectin
Collagen = Intercellular ground substance
### Core Logic
- Trypsin: Proteolytic enzyme $\rightarrow$ III
- Morphine: Alkaloid secondary metabolite $\rightarrow$ IV
- Concanavalin A: Lectin $\rightarrow$ II
- Collagen: Structural protein acting as intercellular ground substance $\rightarrow$ I
### Step 1: Match Verification
Sequence: A-III, B-IV, C-II, D-I. Correct option is (1).
### Pattern Recognition
Collagen = Intercellular ground substance (D-I). Concanavalin A = Lectin (C-II). Matches option (1).
### Evaluation Rubric / Model Answer
null
### Chapter Mix
Class 11 Biology: Biomolecules
Q176 (2024)
The following reaction depicts the activity of a particular class of enzymes:
{{IMG1}}
Identify the enzymes class 'E' from the following options:
- Ligases
- Lyases
- Isomerases
- Transferases
### Related Formula
$$\begin{matrix} X & Y \\ | & | \\ C & - & C \end{matrix} \xrightarrow{E} X - Y + C = C$$
### Core Logic
Lyases are enzymes that catalyze the removal of groups from substrates by mechanisms other than hydrolysis, leaving double bonds behind in the product.
### Step 1: Evaluation of Other Classes
* Transferases: Catalyze transfer of a functional group between substrates.
* Isomerases: Catalyze inter-conversion of optical/geometric isomers.
* Ligases: Catalyze joining of two compounds using ATP energy.
### Pattern Recognition
Sees: Chemical reaction showing removal of groups leaving $C=C$ double bond.
Shortcut: Lyases class of enzymes.
### Evaluation Rubric / Model Answer
null
### Chapter Mix
Class 11 Biology: Biomolecules
