Q.108 Botany ⭐ 360° Option Elimination Active

Vault ↗

NEET 2021 Botany Question 108 Solution

Topic: Cell: The Unit of Life · Official NTA Booklet Code M1

Question

Which of the following is an incorrect statement?

(1)Mature sieve tube elements possess a conspicuous nucleus and usual cytoplasmic organelles.
(2)Microbodies are present both in plant and animal cells.
(3)The perinuclear space forms a barrier between the materials present inside the nucleus and that of the cytoplasm.
(4)Nuclear pores act as passages for proteins and RNA molecules in both directions between nucleus and cytoplasm.

✓

Verified Against NTA Final Answer Key

Option (1) : Mature sieve tube elements possess a conspicuous nucleus and usual cytoplasmic organelles.

📚 Cell: The Unit of Life Easy

📋 Given Parameters & Problem Setup

Target Identify the INCORRECT statement among the four choices

⚡

The 30-Second Exam Hall Shortcut: ⚡ Sieve Tubes are Enucleated at Maturity (Controlled by Companion Cell)!

⏱️ Save ~25 seconds

A mature sieve tube element lacks a nucleus and has only peripheral cytoplasm and a large central vacuole! Its functions are governed by the nucleus of the adjacent companion cell. Claiming it possesses a "conspicuous nucleus" is false and thus the right answer! Match Option (1)!

1 Check Statement (1): "Mature sieve tube elements possess a conspicuous nucleus..." — Factually FALSE; sieve tube elements lose their nucleus upon functional maturation.

2 Check Statement (2): Microbodies (peroxisomes, glyoxysomes) are membrane-bound vesicles present in both plant and animal cells — TRUE.

3 Check Statement (3): Perinuclear space (

10-50\text{ nm}

) acts as a barrier between nucleoplasm and cytoplasm — TRUE.

4 Check Statement (4): Nuclear pores facilitate bidirectional transport of RNA and proteins — TRUE.

5 The incorrect statement is (1).

🛡️

Why You Can 100% Trust This Shortcut: Canonical NCERT Cell Biology & Plant Anatomy on Sieve Elements.

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Cytological Specialization of Sieve Tube Elements

Sieve tube elements are elongated, conducting cells of the phloem in angiosperms. To minimize resistance to the bulk flow of organic sap (sucrose), they undergo selective autophagy during differentiation:

Step 2

Organelle Loss and Enucleation

At functional maturity: - They lack a nucleus (enucleated). - They possess a thin peripheral layer of cytoplasm and a large central vacuole. - Their metabolic functions and pressure gradients are controlled by the prominent nucleus of adjacent companion cells connected via plasmodesmata.

\text{Mature Sieve Element} \implies \begin{cases} \text{Nucleus:} & \mathbf{\text{Absent (enucleated)}} \\[3pt] \text{Cytoplasm:} & \text{Peripheral parietal layer} \\[3pt] \text{Control:} & \text{Maintained by companion cell nucleus} \end{cases}

Step 3

Verification of Valid Statements

Evaluating statements 2, 3, and 4 confirms they are all textbook-accurate statements: - Microbodies occur in both plants and animals. - The space between the two nuclear membranes is the perinuclear space ( $10-50\text{ nm}$ ). - Nuclear pores are octagonal protein complexes providing bidirectional movement of macromolecules.

⭐

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 1

✓ 100% Correct

Verdict & Scientific Reason:

This statement is FALSE (and hence the correct answer). Mature sieve tube elements lack a nucleus and most standard organelles.

💡

Why this is airtight: None. Directly flags the glaring textbook contradiction.

2 2

✗ Incorrect

Verdict & Scientific Reason:

This statement is TRUE. Microbodies are ubiquitous membrane-bound vesicular structures containing enzymes present in both plant and animal cells.

⚠️

Student Fallacy (Why candidates pick this trap): Thinking microbodies are unique to plants (confusing them with glyoxysomes exclusively).

3 3

✗ Incorrect

Verdict & Scientific Reason:

This statement is TRUE. The lumen between the outer and inner nuclear membranes acts as an isolating physical barrier.

⚠️

Student Fallacy (Why candidates pick this trap): Over-scrutinizing the word "barrier" and assuming it implies complete impermeability.

4 4

✗ Incorrect

Verdict & Scientific Reason:

This statement is TRUE. Nuclear pore complexes mediate bidirectional nucleocytoplasmic transport.

⚠️

Student Fallacy (Why candidates pick this trap): Assuming nuclear export is unidirectional (only RNA out, never proteins in).

⚠️

NTA Trap Alert: Confusing Sieve Tube Element with Companion Cell

Companion cells have dense cytoplasm and a conspicuous nucleus, whereas sieve tube elements are enucleated. Students often attribute companion cell cytology to sieve tube elements.

🛡️ How to avoid the -1 mark: Remember: Mature mammalian RBCs and mature angiosperm sieve tube elements are the two famous living enucleated cells in the NCERT syllabus!

📖

Core NEET Syllabus Standard

NEET / NCERT Biology · Cell: The Unit of Life Standard Benchmark

Core Scientific Principle Tested:

"A mature sieve tube element possesses a peripheral cytoplasm and a large vacuole but lacks a nucleus."

Syllabus Focus: Nucleus, Cell Organelles, and Vascular Tissue Anatomy

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Ready to attempt under real exam pressure?

Test your speed and accuracy in the authentic 200-minute timed NTA simulator.

Launch NEET 2021 CBT Test →

← Previous (Q.107) All Botany Questions Grid Next (Q.109) →

Organellar Membrane Specializations: Cristae, Cisternae, Thylakoids, Phospholipids

View Solution →

Spotted a mistake in this solution? Report an error ([email protected])

⚖️ Legal & Fair Dealing Notice: Sourced from publicly released NEET 2021 question papers and NEET answer keys for private study, research, and non-commercial educational practice under Fair Dealing (Section 52(1)(a) of the Indian Copyright Act, 1957). Not affiliated with or endorsed by NTA or NMC.

NEET 2021 Botany Question 108 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Sieve Tubes are Enucleated at Maturity (Controlled by Companion Cell)!

Step-by-Step Rigorous Workflow & Mathematical Proof

Cytological Specialization of Sieve Tube Elements

Organelle Loss and Enucleation

Verification of Valid Statements

360° Option Elimination Engine Key Feature

NTA Trap Alert: Confusing Sieve Tube Element with Companion Cell

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Cell: The Unit of Life

Historical Formulation of the Cell Theory

Structural and Organellar Characteristics of Prokaryotic Cells

Mitochondrial Compartmentalization & The Matrix

Organellar Membrane Specializations: Cristae, Cisternae, Thylakoids, Phospholipids

Solve 4 NEET Questions a Day — One per Subject