Q.52 Zoology ⭐ 360° Option Elimination Active

NEET 2020 Zoology Question 52 Solution

Topic: Cell Cycle and Cell Division · Official NTA Booklet Code E1

Question

Match the following with respect to meiosis: (a) Zygotene (i) Terminalization (b) Pachytene (ii) Chiasmata (c) Diplotene (iii) Crossing over (d) Diakinesis (iv) Synapsis Select the correct option from the following: (a) (b) (c) (d)

(1)(iii) (iv) (i) (ii)
(2)(iv) (iii) (ii) (i)
(3)(i) (ii) (iv) (iii)
(4)(ii) (iv) (iii) (i)

✓

Verified Against NTA Final Answer Key

Option (2) : (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

📚 Cell Cycle and Cell Division Easy

📋 Given Parameters & Problem Setup

Column I (Sub-stages) (a) Zygotene, (b) Pachytene, (c) Diplotene, (d) Diakinesis

Column II (Hallmarks) (i) Terminalization, (ii) Chiasmata, (iii) Crossing over, (iv) Synapsis

⚡

The 30-Second Exam Hall Shortcut: ⚡ "Zygotene = Synapsis; Pachytene = Crossing Over; Diplotene = Chiasmata; Diakinesis = Terminalization"

⏱️ 30 seconds

Zygotene forms synaptonemal complex (Synapsis, a->iv). Pachytene features recombinase-mediated Crossing Over (b->iii). Diplotene shows X-shaped Chiasmata (c->ii). Diakinesis culminates in Terminalization of chiasmata (d->i). Combination is (iv), (iii), (ii), (i) -> Option 2 in 10 seconds!

1 Zygotene -> Synapsis of homologous chromosomes (iv).

2 Pachytene -> Crossing over between non-sister chromatids (iii).

3 Diplotene -> Dissolution of synaptonemal complex, revealing Chiasmata (ii).

4 Diakinesis -> Terminalization of chiasmata (i).

5 Mapping: (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i) -> Option 2.

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Cell Cycle and Cell Division (Meiosis I: Prophase I Sub-stages)

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Zygotene (a) -> Synapsis (iv)

During Zygotene, chromosomes start pairing together through a process called synapsis, facilitated by the formation of a proteinaceous synaptonemal complex forming bivalents.

Step 2

Pachytene (b) -> Crossing Over (iii)

During Pachytene, four chromatids of each bivalent chromosome become distinct as tetrads. Crossing over occurs between non-sister chromatids of homologous chromosomes, mediated by enzyme recombinase.

Step 3

Diplotene (c) -> Chiasmata (ii)

The beginning of Diplotene is recognized by the dissolution of the synaptonemal complex and tendency of homologous chromosomes to separate, except at sites of crossovers, creating X-shaped structures called chiasmata.

Step 4

Diakinesis (d) -> Terminalization (i)

The final stage of meiotic prophase I is Diakinesis, which is marked by the terminalization of chiasmata as chromosomes fully condense and nucleolus disappears.

⭐

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; mispairs Zygotene with crossing over (crossing over occurs in pachytene).

⚠️

Student Fallacy (Why candidates pick this trap): Confusing the chronological order of synapsis and crossing over.

2 B

✓ 100% Correct

Verdict & Scientific Reason:

Accurate pairing across all four substages of Meiosis Prophase I.

💡

Why this is airtight: None; standard meiotic stages sequence.

3 C

✗ Incorrect

Verdict & Scientific Reason:

Incorrect; inverts terminalization and synapsis.

⚠️

Student Fallacy (Why candidates pick this trap): Reversing early prophase with late prophase events.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect; chiasmata do not become visible in Zygotene.

⚠️

Student Fallacy (Why candidates pick this trap): Failing to remember that chiasmata appear only in diplotene.

⚠️

NTA Trap Alert: Pachytene vs Diplotene vs Diakinesis

Pachytene = Crossing over happens. Diplotene = Chiasmata first appear (X-shape). Diakinesis = Chiasmata terminate (Terminalization).

🛡️ How to avoid the -1 mark: Mnemonic: "Z-Syn, P-Cross, Dip-Chias, Dia-Term" (Zygotene-Synapsis, Pachytene-Crossing over, Diplotene-Chiasmata, Diakinesis-Terminalization).

📖

Core NEET Syllabus Standard

Zoology · Cell Cycle and Cell Division Standard Benchmark

Core Scientific Principle Tested:

Syllabus Focus: Prophase I Sub-stages and Hallmark Events: Zygotene, Pachytene, Diplotene, Diakinesis

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2020 Zoology Question 52 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ "Zygotene = Synapsis; Pachytene = Crossing Over; Diplotene = Chiasmata; Diakinesis = Terminalization"

Step-by-Step Rigorous Workflow & Mathematical Proof

Zygotene (a) -> Synapsis (iv)

Pachytene (b) -> Crossing Over (iii)

Diplotene (c) -> Chiasmata (ii)

Diakinesis (d) -> Terminalization (i)

360° Option Elimination Engine Key Feature

NTA Trap Alert: Pachytene vs Diplotene vs Diakinesis

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Cell Cycle and Cell Division

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