The method of separating proteins based on their size using an electric field is: MCQ with Answer and Explanation

The method of separating proteins based on their size using an electric field is:
A. PCR
B. DNA sequencing
C. ELISA
D. SDS-PAGE
Answer: Option D
Solution (By JKSSB Mock Tests)
SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) denatures proteins and coats them with negative charge, allowing separation by molecular weight in an electric field. PCR amplifies DNA, sequencing determines base order, ELISA detects antigens/antibodies. SDS-PAGE is a fundamental biochemistry technique.

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Practice More Biology Questions

Question #1
Which of the following is an example of a genetically engineered insulin-producing bacterium?
A. Escherichia coli
B. Saccharomyces cerevisiae
C. Pseudomonas aeruginosa
D. Bacillus subtilis

Correct Answer: Option A


Explanation:
Recombinant human insulin (Humulin) is produced by genetically engineered Escherichia coli (or yeast) carrying the human insulin gene. Before this, insulin from animal sources was used. The A and B chains of insulin are produced separately and then combined. This was the first genetically engineered pharmaceutical approved for human use (1982).

This question belongs to: Science Biology
Question #2
Which of the following hormones is responsible for the closure of stomata during water stress?
A. Abscisic acid (ABA)
B. Cytokinin
C. Auxin
D. Gibberellin

Correct Answer: Option A


Explanation:
Abscisic acid (ABA) is a stress hormone that induces stomatal closure by causing efflux of K⁺ ions from guard cells, leading to loss of turgor, thereby reducing water loss during drought. Auxin and cytokinin promote growth, gibberellin stimulates stem elongation and seed germination. ABA also promotes seed dormancy and leaf senescence.

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Question #3
The enzyme that converts angiotensinogen to angiotensin I is:
A. Pepsin
B. Renin
C. Trypsin
D. ACE (angiotensin-converting enzyme)

Correct Answer: Option B


Explanation:
Renin, released by juxtaglomerular cells of the kidney when blood pressure drops, cleaves angiotensinogen (from liver) to angiotensin I. ACE then converts angiotensin I to the active angiotensin II, a potent vasoconstrictor and stimulator of aldosterone. Pepsin and trypsin are digestive proteases.

This question belongs to: Science Biology