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Question 545
Biochemistry → General
Classification
Question
SSBAQuestion Header
A cytoskeletal defect simultaneously disrupts intracellular transport, ciliary structure and chromosome separation during cell division. Which structural abnormality best accounts for this combination?
Question Stem
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Options
A
Loss of keratin intermediate filaments
B
Loss of actin-containing microfilaments
C
Failure of alpha- and beta-tubulin microtubules
D
Loss of desmin intermediate filaments
E
Failure of DNA–histone association
Explanation
Microtubules are composed of alpha- and beta-tubulin and participate in intracellular transport, cell shape and strength, centrioles, cilia and the spindle involved in chromosome movement.
Option Validity
A) Keratin is an intermediate-filament constituent and does not account for the full combination described.
B) Microfilaments contain actin and myosin but are not the structure linking cilia, intracellular transport and the mitotic spindle.
D) Desmin is an intermediate-filament constituent rather than a microtubular protein.
E) DNA–histone association forms chromatin and does not provide the cytoskeletal functions described.
Further Reading
Saxena - MRCOG-1 Basic Sciences - Biochemistry, printed p.128.