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Q.53 Zoology ⭐ 360° Option Elimination Active
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NEET 2020 Zoology Question 53 Solution

Topic: Plant Kingdom · Official NTA Booklet Code E1
NEET 2020 Zoology Question 53: Unicellular Algae Rich in Proteins: Chlorella and Spirulina

Question

Which of the following pairs is of unicellular algae?

  1. (1)Laminaria and Sargassum
  2. (2)Gelidium and Gracilaria
  3. (3)Anabaena and Volvox
  4. (4)Chlorella and Spirulina
✓
Verified Against NTA Final Answer Key
Option (4) : Chlorella and Spirulina
📚 Plant Kingdom Easy
📋 Given Parameters & Problem Setup
Criterion Pair of unicellular algae
Candidate Pairs Laminaria & Sargassum, Gelidium & Gracilaria, Anabaena & Volvox, Chlorella & Spirulina
⚡

The 30-Second Exam Hall Shortcut: ⚡ "Chlorella and Spirulina = Unicellular Single Cell Protein Algae!"

⏱️ 20 seconds

Chlorella (unicellular chlorophyte) and Spirulina (unicellular cyanobacterium/blue-green alga) are rich in proteins and used as food supplements even by space travelers. Laminaria/Sargassum are giant multicellular brown kelps; Gelidium/Gracilaria are multicellular red algae. Mark Option (4) in 5 seconds!

1 Laminaria & Sargassum = Multicellular brown algae (kelps).
2 Gelidium & Gracilaria = Multicellular red algae producing agar.
3 Volvox = Colonial green alga (not unicellular).
4 Chlorella and Spirulina are unicellular organisms rich in proteins.
5 Select Option (4).
🛡️
Why You Can 100% Trust This Shortcut: NCERT Biology · Plant Kingdom (Algae: Unicellular Algae & Single Cell Protein)
📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Identify Unicellular Algae in NCERT

NCERT explicitly highlights: "Chlorella and Spirulina are unicellular algae rich in proteins and are used as food supplements even by space travellers."

Step 2

Evaluate Laminaria and Sargassum

Laminaria and Sargassum belong to Phaeophyceae (brown algae); they possess complex multicellular thalli (kelps reaching up to 100 meters) differentiated into holdfast, stipe, and frond.

Step 3

Evaluate Gelidium and Gracilaria

Gelidium and Gracilaria are multicellular Rhodophyceae (red algae) harvested commercially for extraction of agar-agar.

Step 4

Evaluate Volvox and Anabaena

Volvox is a colonial green alga (coenobium of thousands of cells connected by cytoplasmic strands), not a unicellular organism.

⭐

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; both are massive, multicellular brown algae (kelps).

⚠️
Student Fallacy (Why candidates pick this trap): Confusing brown seaweed macroalgae with unicellular algae.
2 B
✗ Incorrect
Verdict & Scientific Reason:

Incorrect; both are multicellular red algae used for commercial agar extraction.

⚠️
Student Fallacy (Why candidates pick this trap): Thinking agar-producing red algae are unicellular.
3 C
✗ Incorrect
Verdict & Scientific Reason:

Incorrect; Volvox is a colonial alga (coenobium), not unicellular.

⚠️
Student Fallacy (Why candidates pick this trap): Assuming colonial algae count as unicellular.
4 D
✓ 100% Correct
Verdict & Scientific Reason:

Factually exact; both are single-celled organisms cited in NCERT as unicellular algae utilized for single-cell protein.

💡
Why this is airtight: None; textbook verbatim example.
⚠️

NTA Trap Alert: Colonial vs Unicellular

Volvox is COLONIAL (consisting of 500 to 60,000 cells arranged in a hollow sphere called a coenobium). Only Chlorella and Spirulina are UNICELLULAR.

🛡️ How to avoid the -1 mark: Remember: Volvox = Colony; Chlorella & Spirulina = Unicellular single cell protein!
📖

Core NEET Syllabus Standard

Zoology · Plant Kingdom Standard Benchmark
Core Scientific Principle Tested:

""

Syllabus Focus: Unicellular Algae Rich in Proteins: Chlorella and Spirulina
✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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