Biology · Science General

Cell Biology and Structure

3,221 Questions

Cell biology focuses on the structure and function of cellular organelles. Key topics include cellular respiration, DNA inheritance, and energy production. These fundamental biology concepts are crucial for medical entrance and state service examinations.

Cell organelles functionsCellular respiration sitesDNA and ribosomesAnimal cell structurePlant cell components

Cell Biology and Structure Questions

Multiple choice

Cell surface receptors may be any of the following, exceptAll the following are cell surface receptors, except

  1. G protein linked

  2. enzymatic receptors

  3. transcription factors

  4. ligand gated ion channels
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cell surface receptors include G protein-coupled receptors, enzymatic receptors (like receptor tyrosine kinases), and ligand-gated ion channels. Transcription factors are intracellular nuclear proteins that bind DNA - not cell surface receptors.

Multiple choice

Which statement is not true for gap junctions?

  1. They allow the passage of proteins between cells.

  2. They are essential for metabolic cooperation between cells.

  3. They occur in the developing embryo.

  4. They synchronise the beating rate of heart muscle cells.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gap junctions are intercellular channels that allow the passage of small molecules and ions between adjacent cells, but NOT proteins or larger macromolecules. They are crucial for metabolic cooperation, electrical coupling in heart muscle, and embryonic development. Option A incorrectly claims they allow protein passage.

Multiple choice

Choose the mismatched pair(s).

 
Cell organelle Marker molecule
(A) lysosomes acid phosphatase
(B) peroxisomes catalase
(C) mitochondria cytochrome oxidase
(D) SER amino acid permease

  1. Only A

  2. Only B and C

  3. Only D

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lysosomes are correctly marked by acid phosphatase, peroxisomes by catalase, and mitochondria by cytochrome oxidase. However, SER (smooth endoplasmic reticulum) is associated with detoxification enzymes and lipid synthesis, not amino acid permease, which is a plasma membrane transport protein. Therefore, only pair D is mismatched.

Multiple choice

Which of the following are absent in a prokaryotic cell?

  1. Mitochondria and nucleus

  2. Mitochondria and ribosome

  3. Nucleus and ribosome

  4. Plasma membrane and chromosome

  5. Plasma membrane and ribosome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option. Mitochondria and nucleus are absent in a prokaryotic cell.

Multiple choice

Which of the following statements about the cell wall is/are false?

a. The major function of the cell wall is to provide protection and strength to the cell. b. The cell wall is formed of lipids and proteins and a small number of carbohydrates. c. The cell wall is quite thick in plant cells and lies outside the cells.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct option as this statement about the cell wall is false.