Q.14 Choose the option that shows the correct pairing of the cellular components with their corresponding function.

P. Dynein i. Movement of organelles
Q. Desmosome ii. Membrane vesicle
R. Endosome iii. Beating of flagella
S. Kinesin iv. Attachment of cells together

(A) P-iv, Q-i, R-ii, S-iii
(B) P-iii, Q-iv, R-ii, S-i
(C) P-iii, Q-i, R-ii, S-iv
(D) P-ii, Q-i, R-iv, S-iii

The correct answer is option (B): P-iii, Q-iv, R-ii, S-i.​

Dynein powers the beating of flagella through ATP-driven microtubule sliding in axonemes. Desmosomes anchor adjacent cells via cadherin proteins linked to intermediate filaments. Endosomes act as membrane-bound vesicles that sort internalized materials during endocytosis. Kinesin drives anterograde movement of organelles along microtubules toward the plus end.​

Option Analysis

Each option pairs cellular components (P-Dynein, Q-Desmosome, R-Endosome, S-Kinesin) with functions (i-Movement of organelles, ii-Membrane vesicle, iii-Beating of flagella, iv-Attachment of cells together).​

• (A) P-iv, Q-i, R-ii, S-iii: Incorrect. Dynein does not attach cells (desmosomes do). Desmosomes lack motility roles. Kinesin handles organelle transport, not flagellar beating (dynein does).​

• (B) P-iii, Q-iv, R-ii, S-i: Correct. Matches dynein to flagella, desmosomes to adhesion, endosomes to vesicles, kinesin to organelles.​

• (C) P-iii, Q-i, R-ii, S-iv: Incorrect. Desmosomes do not move organelles (kinesin does). Kinesin does not attach cells.​

• (D) P-ii, Q-i, R-iv, S-iii: Incorrect. Dynein is a motor protein, not a vesicle. Endosomes are not for cell attachment. Kinesin moves organelles, not flagella.​

Dynein desmosome endosome kinesin functions form a key topic in CSIR NET Life Sciences, testing cellular organization knowledge. This guide details their roles—dynein in flagella beating, desmosomes in cell attachment, endosomes as membrane vesicles, kinesin in organelle movement—with the correct pairing P-iii, Q-iv, R-ii, S-i (option B).​

Dynein: Flagellar Beating Motor

Dynein drives microtubule sliding for flagella and cilia beating in eukaryotic cells, essential for motility. Cytoplasmic dynein also aids mitosis and transport, but axonemal dynein matches “beating of flagella” (iii).​

Desmosome: Cell Adhesion Junction

Desmosomes link cytoskeletons between cells via cadherins and plakins, resisting shear stress in tissues like skin and heart. They enable “attachment of cells together” (iv), distinct from gap junctions.​

Endosome: Membrane Vesicle Sorting Hub

Endosomes are membrane vesicles in endocytosis, sorting receptors and cargo to lysosomes or recycling. Early endosomes fuse with incoming vesicles, fitting “membrane vesicle” (ii) precisely.​

Kinesin: Organelle Transport Protein

Kinesin moves organelles like vesicles toward microtubule plus ends (anterograde transport), opposite dynein’s minus-end direction. This matches “movement of organelles” (i).​

CSIR NET Exam Insights

For competitive exams like CSIR NET, distinguish motors (dynein/kinesin) from junctions (desmosomes) and compartments (endosomes). Mnemonics: “Dynein Down flagella,” “Kinesin Keeps organelles.” Practice pairings to score in Unit 2 Cellular Organization.​