Biology · Science General

Cell Biology and Structure

3,062 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

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 statements is/are false?

a. In animal tissues, living tissues are more abundant as compared to dead tissues. b. Impulse is the passage of electrical activity along the axon of a nerve cell. c. Lymph transports excretory products from the tissues to the liver and kidney.

  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
E Correct answer
Explanation

This is the correct option as this statement is false. Blood transports excretory products from the tissues to the liver and kidney.

Multiple choice

Which of the following statements is/are false?

a. Epidermis is one cell thick and is covered with cuticle. b. The cells of cork cambium are rectangular and their protoplasts contain tannins and chloroplasts. c. Each stoma is bounded by a specialised kidney-shaped cell called the guard cell.

  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
E Correct answer
Explanation

This is the correct option as this statement is false. Each stoma is bounded by a pair of specialised kidney-shaped cells called the guard cells.

Multiple choice

Match the following ||| |---|---| |a. Axons|1. They are the single, long cylindrical process of uniform diameter forming fine branches terminally.| |b. Cytons|2. They are short processes arising from the cell body and further branching into dendrites. | |c. Dendrons|3. They contain a central nucleus and cytoplasm with characteristic deeply stained particles called Nissl's granules.|

  1. a - 1, b - 2, c - 3

  2. a - 3, b - 1, c - 2

  3. a - 1, b - 3, c - 2

  4. a - 2, b - 3, c - 1

  5. a - 3, b - 2, c - 1
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct option. Axons are the single, long cylindrical processes of uniform diameter forming fine branches terminally. Cytons contain a central nucleus and cytoplasm with characteristic deeply stained particles called Nissl's granules. Dendrons are short processes arising from the cell body and further branching into dendrites.

Multiple choice

Which of the following structures is found only in the perikaryon of neuron?

  1. Microtubules

  2. Neurofilaments

  3. Mitochondria

  4. Nissl bodies

  5. Golgi apparatus
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The golgi apparatus is a stack of flattened compartments where molecules are packaged for delivery to other cell components or for secretion from the cell. It is present only in the cell body or soma of neuron. It is present close to the nucleus and is absent in axon and dendrites.

Multiple choice

Which of the following glial cells performs its function by the process of phagocytosis?

  1. Neuroglia

  2. Microglia

  3. Macrophages

  4. Oligodendroglia

  5. Astrocytes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Microglia has been regarded as the tissue macrophages of the brain. Microglia is a type of glial cell that are the resident macrophages of the brain and spinal cord and thus act as the first and main form of active immune defense in the central nervous system (CNS). The clearance of dying cells must be fast and efficient and is performed by a resident lineage of professional phagocytes, the microglia. These cells patrol the entire vertebrate brain,  and sense the presence of apoptotic and damaged neurons.

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.