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

Ubish granules containing sporopollenin are produced by

  1. endothelium

  2. middle layers

  3. tapetum

  4. epithelium

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The tapetum is the innermost layer of the anther wall. It is responsible for secreting sporopollenin, which forms the Ubisch granules that contribute to the outer exine layer of pollen grains.

Multiple choice

Which of the following facts are true about stem cells?

  1. They are manufactured in a laboratory.
  2. They can reproduce any kind of tissue in the body.
  3. They are an essential part of the repair system of a body.

  1. 1 and 2

  2. 2 and 3

  3. 1 and 3

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Stem cells are biological cells found in all multi-cellular organisms that can divide (through mitosis) and differentiate into diverse specialised cell types and can self-renew to produce more stem cells. Hence, fact 1 is incorrect.

Multiple choice

Which of the following can act as a source of adult stem cells for transplantation in humans?

  1. Bone marrow
  2. Adipose tissue
  3. Blood

  1. 1 and 2

  2. 2 and 3

  3. 1 and 3

  4. All of the above

  5. None of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

There are three accessible sources of autologous adult stem cells in humans:

Bone marrow, which requires extraction by harvesting, i.e. drilling into bone (typically the femur or iliac crest)

Adipose tissue (lipid cells), which requires extraction by liposuction, and
Blood, which requires extraction through pheresis, wherein blood is drawn from the donor (similar to a blood donation) and passed through a machine that extracts the stem cells and returns other portions of the blood to the donor. Stem cells can also be taken from umbilical cord blood just after birth.

Multiple choice

To what does the term stroma refer?

  1. The double membrane of the chloroplasts

  2. A flattened disk or sac in the chloroplast

  3. A central fluid filled space in the chloroplast

  4. The cytochrome system in the membranes of the thylakoids

  5. A stack of thylakoid membrane structures

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The stroma is the fluid-filled space within the chloroplast that surrounds the thylakoid membranes, where the Calvin cycle occurs.

Multiple choice

To what does the term granum refer?

  1. A stack of thylakoid membrane structures

  2. A central fluid filled space in the chloroplast

  3. A flattened disk or sac in the chloroplast

  4. The double membrane of the chloroplasts

  5. The cytochrome system in the membranes of the thylakoids
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A granum is a stack of thylakoid disks within the chloroplast, functioning as the site for the light-dependent reactions.

Multiple choice

Restorer gene for fertility is present in the ______.

  1. ribosome

  2. nucleus

  3. endoplasmic reticulum

  4. polyribosome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Restorer genes are nuclear genes that suppress the effects of cytoplasmic male sterility, allowing the plant to produce functional pollen. Therefore, they are located in the nucleus.

Multiple choice

Which of the following statements is/are false?

a. Some animals like sponges, corals and sea anemones do not move from place to place. b. The movement of a plant or its part towards the soil is called as geotropic movement. c. The period during which bacteria complete their life cycle is very long.

  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

The period during which a bacterium completes its life cycle is very short. It is not more than 20 minutes.

Multiple choice

Which of the following sentences about epithelial tissue is false?

  1. Cells are densely packed together with minimal amount of intercellular substance.

  2. It is avascular.

  3. It is richly supplied with nerve fibres.

  4. It gets nutrients by absorption from underlying connective tissue.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

It gets nutrition by diffusion from underlying connective tissue. Thus, it is the answer as it is a false statement about epithelial tissue.