Which of the following is absent in a prokaryotic cell? MCQ with Answer and Explanation

Which of the following is absent in a prokaryotic cell?
A. Plasma membrane
B. Nuclear membrane
C. Nucleoid
D. Ribosomes
Answer: Option B
Solution (By JKExamLibrary)
Prokaryotes lack a true nucleus and nuclear membrane; their genetic material is concentrated in a nucleoid region. They possess ribosomes (70S), a plasma membrane, and usually a cell wall. The absence of membrane-bound organelles is a defining feature distinguishing them from eukaryotes. Thus, the nuclear membrane is absent.

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Practice More Biology Questions

Question #1
The enzyme pepsin is secreted by which cells of the stomach?
A. Parietal cells
B. Goblet cells
C. G cells
D. Chief cells

Correct Answer: Option D


Explanation:
Chief (peptic) cells secrete pepsinogen, which is activated to pepsin by HCl. Parietal cells secrete HCl and intrinsic factor. Goblet cells secrete mucus.

This question belongs to: Science Biology
Question #2
Consider statements about biotechnology: 1. Agrobacterium tumefaciens is a natural plant genetic engineer. 2. Bt toxin is active in the acidic gut of insects. 3. RNAi is used to silence specific genes. Which are correct?
A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3

Correct Answer: Option C


Explanation:
Agrobacterium tumefaciens is a soil bacterium that naturally transfers a segment of its Ti plasmid into plant cells, making it a natural genetic engineer used to create transgenic plants. RNA interference (RNAi) is a cellular defense mechanism used in biotechnology to silence specific mRNA molecules, preventing gene expression. Bt toxin is inactive in the insect gut until it encounters the alkaline pH, which solubilizes and activates it. Thus, statements 1 and 3 are correct.

This question belongs to: Science Biology
Question #3
The process of mRNA synthesis from DNA is called:
A. Replication
B. Translation
C. Transformation
D. Transcription

Correct Answer: Option D


Explanation:
Transcription, catalyzed by RNA polymerase, copies the genetic information from a DNA template into a complementary mRNA strand. Translation is protein synthesis.

This question belongs to: Science Biology