Question 26:
Which of the following statements are correct?
Choose the correct answer from the options given below:
DNA microarray and differential centrifugation are key techniques in molecular biology, but essential amino acids are misunderstood in option (C). The correct answer is (B) (A), (B) and (D) only.
Correct Answer
Option (B) (A), (B) and (D) only is correct. Statements (A), (B), and (D) accurately describe their concepts, while (C) is false because essential amino acids cannot be synthesized by humans regardless of microbial capability—they must be dietary for humans.
Statement Explanations
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(A) Correct: DNA microarray involves microscopic spots of DNA sequences fixed on a solid surface (e.g., glass slide), enabling hybridization with labeled probes to detect gene expression or sequences.
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(B) Correct: Differential centrifugation separates organelles by spinning samples at increasing speeds and times, exploiting sedimentation rate differences based on size and density.
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(C) Incorrect: Essential amino acids (e.g., leucine, lysine) cannot be synthesized by humans due to lacking enzymes; microbes may produce them, but the definition hinges on human biosynthesis limits.
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(D) Correct: The equilibrium constant (K_eq) is unique to each reaction’s conditions (temperature, pressure), quantifying forward/reverse rate ratios at equilibrium.
Options Comparison
| Option | Includes | Excludes | Why Correct/Incorrect |
|---|---|---|---|
| (A) | A, B, C | D | Wrong: C false |
| (B) | A, B, D | C | Correct: All true |
| (C) | A, C, D | B | Wrong: C false |
| (D) | B, C, D | A | Wrong: C false |
