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Question 535
Biochemistry → General
Classification
Question
SSBAQuestion Header
A cytoskeletal structure measures approximately 10 nm in diameter. Which constituent is most consistent with this structure?
Question Stem
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Options
A
Desmin
B
Alpha- and beta-tubulin
C
Actin and myosin only
D
DNA and histone
E
RNA and ribosomal protein
Explanation
Intermediate filaments measure approximately 10 nm in diameter and include proteins such as keratin, glial filaments, neurofilaments, vimentin and desmin. Microtubules are larger at approximately 20–30 nm, while microfilaments measure approximately 4–12 nm.
Option Validity
B) Alpha- and beta-tubulin form microtubules, which measure approximately 20–30 nm.
C) Actin and myosin are associated with microfilaments rather than intermediate filaments.
D) DNA and histone form chromatin and are not cytoskeletal intermediate-filament constituents.
E) RNA and protein are components of ribosomes rather than intermediate filaments.
Further Reading
Richa Saxena. Textbook for MRCOG-1: Basic Sciences in Obstetrics & Gynaecology. Biochemistry and Nutrition — Biochemistry — Cytoskeleton. Printed page 128.