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

Nucleus and mitochondria are not found in

  1. WBCs of mammals

  2. Young immature mammalian erythocytes

  3. Mature mammalian erythrocytes

  4. RBCs of frog
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During the development of erythrocytes, mitochondria and nucleus are lost to give extra space for the storage of hemoglobin.

Multiple choice

Which of the following statements are FALSE regarding prokaryotic cell?

  1. Prokaryotic cells are smaller in size than eukaryotic cells.
  2. Site for oxidative phosphorylation is mitochondria.
  3. Ribosomal subunits are 60S and 40S.
  4. Golgi apparatus is absent.

  1. 1 and 2

  2. 1, 2 and 3

  3. 2 and 3

  4. 2, 3 and 4

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mitochondria are not found in prokaryotic cells. Site for oxidative phosphorylation in prokaryotic cells is cell membrane. Cytoplasmic ribosome size of prokaryotic cells is 70S. Ribosomal subunits are 50S and 30S.

Multiple choice

Which of the following is/are not TRUE regarding chloroplasts? P. Single membrane bounded organelles Q. Have their own genetic material R. Electron transport and energy production of chloroplast is located the inner membrane S. Synthesize their own fatty acids, amino acids, and lipid components

  1. P and Q

  2. P and R

  3. Q and R

  4. Q and S

  5. R and S
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chloroplasts are double membrane bounded organelles. Unlike the mitochondria, the electron transport and energy production of chloroplast is located in the thylakoids instead of the inner membrane.

Multiple choice

Assertion (A): Endoplasmic reticulum functions as a system for transporting materials from one part of the cell to another. Reason (R): It is a system of membrane-enclosed channels which extends throughout the cytoplasm of the cell and interconnects with the plasma membrane and the nuclear envelope.

In the following question there are two statements, Assertion (A) and Reason (R), consider both the statements independently and mark your answers as under:
1. If A and R both are correct and R is correct explanation of A.
2. If A and R both are correct and R is not correct explanation of A.
3. If A is correct and R is incorrect.
4. If A is incorrect and R is correct.
5. If A and R both are incorrect.

 

  1. 1

  2. 2

  3. 3

  4. 4

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

Endoplasmic reticulum a system of membrane-enclosed channels which extends throughout the cytoplasm of the cell and interconnects with the plasma membrane and the nuclear envelope. Endoplasmic reticulum has several functions. Such as:

  1. It divides the cytoplasm up into interconnected compartments.
  2. Serves as routes for the transport of materials from one part of the cell to another.
  3. Plays an important role in the synthesis of proteins and some lipids.
  4. Responsible for generating new layers for Golgi bodies.
  5. Expanded regions of the endoplasmic reticulum may serve as storage areas.
Multiple choice

Mesosomes are organelles of bacteria that appear as invagination of the plasma membrane. Functions of mesosomes include -

  1. Increase surface area of plasma membrane
  2. Respiration processes
  3. DNA replication and distribution
  4. Fatty acid synthesis
  5. Transport of materials from one part of the cell to another Select the correct answer.

  1. 1, 2 and 3

  2. 1, 2 and 4

  3. 2, 3 and 4

  4. 2, 3 and 5

  5. 3, 4 and 5
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mesosomes greatly increase the membrane surface of the cell. Mesosomes are site of localization of respiratory enzymes and play important role in aerobic cellular respiration. Mesosome plays an important role in DNA replication, distribution and cell division.

Multiple choice

Match the column – I (Organelle) with column – II (Function) and select the correct option.

 
Column – I Column – II
A. Chloroplasts 1. Digestion of excess or worn-out organelles
B. Golgi complex 2. Contain enzymes that split hydrogen peroxide into water and oxygen
C. Lysosomes 3. Organelles responsible for photosynthesis
D. Peroxisomes 4. Factory for packaging proteins

  1. A - 2, B - 3, C - 4, D - 1

  2. A - 3, B - 4, C - 2, D - 1

  3. A - 3, B - 4, C - 1, D - 2

  4. A - 4, B - 1, C - 3, D - 2

  5. A - 3, B - 1, C - 4, D - 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chloroplasts are the organelles responsible for photosynthesis and function to generate metabolic energy. The Golgi complex is integral in modifying, sorting, and packaging proteins. Lysosomes are small membrane-bound vesicles containing digestive enzymes that digest excess or worn-out organelles, food particles and engulfed bacteria or viruses. Peroxisomes contain enzymes that split hydrogen peroxide into water and oxygen.

Multiple choice

Apoptosis is characterized by

  1. necrosis

  2. programmed cell death

  3. membrane leaky syndrome

  4. cell cycle arrest process
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Apoptosis is a precisely regulated, programmed cell death process characterized by cell shrinkage, chromatin condensation, DNA fragmentation, and formation of apoptotic bodies without inflammation. It is fundamentally different from necrosis (A), which is uncontrolled cell death resulting from injury, causing membrane rupture and inflammation. Cell cycle arrest (D) may precede apoptosis but is not its defining feature. Membrane leaky syndrome (C) is not a standard biological term and does not describe apoptosis. Option B correctly identifies apoptosis as programmed cell death.

Multiple choice

Capsular heteropolysaccharides are polymerised

  1. between the cell wall and membrane

  2. outside the cell wall

  3. inside the cytoplasm

  4. inside the nucleus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The capsular polysaccharides are polymerised outside the cell wall.

Multiple choice

Which of the following is not true about parenchyma?

  1. Cells may be oval, spherical or polygonal.

  2. They are made of dead cells.

  3. They store food and water.

  4. They are present in the stem and roots.

  5. They are thin walled cells with spaces in between them.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sclerenchyma is made of dead cells that are packed together closely. However, parenchyma cells may be oval, spherical or polygonal. The cell wall is thin and there are spaces between the cells. It stores food and water in the roots and stems of the plants.

Multiple choice

The power of regeneration is the lowest in

  1. liver cells

  2. brain cells

  3. muscle cells

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Neurons (brain cells) have extremely limited regenerative capacity in adult mammals because they are post-mitotic cells that have exited the cell cycle. Once damaged, neurons rarely divide or replace themselves, which is why brain and spinal cord injuries are often permanent. In contrast, liver cells (hepatocytes) can regenerate extensively even after significant damage, muscle cells have satellite cells for repair, and some other cell types can divide throughout life.