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NEET 2026 Botany Question 123 Solution

Topic: Cell: The Unit of Life · Official NTA Booklet Code 50

Question

Smooth endoplasmic reticulum

(1)has ribosomes attached to its surface
(2)is the major site for the synthesis of lipids
(3)is actively involved in protein synthesis
(4)is a site for the synthesis of carbohydrates

✓

Verified Against NTA Final Answer Key

Option (2) : is the major site for the synthesis of lipids

📚 Cell: The Unit of Life Easy

📋 Given Parameters & Problem Setup

Organelle Smooth Endoplasmic Reticulum (SER)

Morphology Agranular membrane network devoid of ribosomes

⚡

The 30-Second Exam Hall Shortcut: ⚡ SER vs RER Golden Distinction

⏱️ Save ~40 seconds

RER = Ribosomes = Protein synthesis; SER = Smooth = Lipid & Steroid synthesis!

1 Recall canonical roles from NCERT Cell Biology:

2 Rough ER (RER) has ribosomes on its surface -> active in protein synthesis and secretion.

3 Smooth ER (SER) lacks ribosomes -> major site for lipid synthesis (and lipid-like steroid hormones).

4 Option (2) states: "is the major site for the synthesis of lipids".

5 Mark Option (2) in 3 seconds!

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Cell: The Unit of Life (Endoplasmic Reticulum: Smooth ER is the primary site for lipid and steroidal hormone synthesis).

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Morphological Distinction of Endoplasmic Reticulum

The endoplasmic reticulum (ER) forms an extensive interconnected network of branching tubules and flattened cisternae in the eukaryotic cytoplasm. When ribosomes are studded along the cytoplasmic surface, it is termed Rough ER (RER); when ribosomes are absent, it is termed Smooth ER (SER).

\text{SER} = \text{Agranular ER (Lacks attached ribosomes)}

• Continuous with the outer nuclear membrane via RER.

Step 2

Physiological Function of SER

The biochemical machinery embedded within SER membranes catalyzes phospholipid, cholesterol, and fatty acid biosynthesis. In animal endocrine cells (e.g. adrenal cortex, gonads), SER synthesizes lipid-like steroid hormones (androgens, estrogens, progesterone). Furthermore, in liver hepatocytes, SER mediates xenobiotic detoxification.

\text{SER} \xrightarrow{\text{Biochemical function}} \mathbf{Major\text{ site for the synthesis of lipids and steroidal hormones}}

• NCERT verbatim: "The smooth endoplasmic reticulum is the major site for synthesis of lipid. In animal cells lipid-like steroidal hormones are synthesised in SER."

Step 3

Evaluate Options

Option (1) describes RER. Option (2) accurately describes SER. Option (3) describes RER. Option (4) is incorrect (carbohydrate polymers are synthesized in Golgi or plastids). Option (2) is correct.

\text{Correct Option} = \text{Option (2)}

• Matches official NTA final answer key Option B / (2).

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan

1 A

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Ribosomes are attached to Rough ER (RER), not Smooth ER.

⚠️

Student Fallacy (Why candidates pick this trap): Swapping RER with SER.

2 B

✓ 100% Correct

Verdict & Scientific Reason:

100% accurate. Canonical NCERT text describing SER function.

💡

Why this is airtight: None; standard direct recall.

3 C

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Protein synthesis is carried out on ribosomes of RER and free cytosolic polyribosomes.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing protein synthesis with lipid synthesis.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Complex polysaccharide synthesis and glycosylation primarily occur in the Golgi apparatus or chloroplasts.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing lipid synthesis with carbohydrate production.

⚠️

NTA Trap Alert: Overlooking Steroid Hormones in SER

Questions sometimes ask where testosterone, estrogen, or cortisol are synthesized. Because they are steroids (lipids), they are synthesized in the SER!

🛡️ How to avoid the -1 mark: Remember: Smooth = Slippery Lipids and Steroid Hormones.

📖

Core NEET Syllabus Standard

NEET Biology Core Syllabus · Cell: The Unit of Life Standard Benchmark

Core Scientific Principle Tested:

"Smooth endoplasmic reticulum (SER) is devoid of ribosomes and acts as the major cellular site for the synthesis of lipids and steroidal hormones."

Syllabus Focus: Endoplasmic Reticulum

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

RER has Ribosomes for Ribonucleic Protein; SER is Smooth for Steroids and Lipid sheen!

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NEET 2026 Botany Question 123 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ SER vs RER Golden Distinction

Step-by-Step Rigorous Workflow & Mathematical Proof

Morphological Distinction of Endoplasmic Reticulum

Physiological Function of SER

Evaluate Options

360° Option Elimination Engine Key Feature

NTA Trap Alert: Overlooking Steroid Hormones in SER

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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