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

Mammalian erythrocytes have short life span due to absence of

  1. endoplasmic recticulum

  2. mitochondria

  3. nucleus

  4. golgi complex
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mammalian erythrocytes (red blood cells) lack a nucleus and most organelles, including mitochondria and endoplasmic reticulum. The absence of a nucleus prevents protein synthesis and cellular repair, while the lack of mitochondria means they rely on anaerobic glycolysis. These limitations contribute to their relatively short lifespan of approximately 120 days.

Multiple choice

What are phragmoplasts?

  1. The spindle microtubules formed during cell division which area involved in pulling the chromosomes to the ends of dividing cell.

  2. A set of microtubules formed during cell division to guide the dictyosome vesicles to the site of cell wall formation.

  3. Narrow holds in the cell walls of adjacent cells through which protoplasmic connections are established.

  4. The plastids in ray parenchyma cells of stems that store carbohydrates and other nutrients during dormant periods.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Phragmoplasts are temporary structures formed during telophase of cell division in plant cells. They consist of microtubules and actin filaments that guide vesicles containing cell wall materials to the forming cell plate. This matches option B, which correctly describes them as guiding dictyosome vesicles to the site of cell wall formation. Options A, C, and D describe different cellular structures.

Multiple choice

Callus is defined as

  1. decaying cells

  2. differentiated cells

  3. sterile mass of cells

  4. undifferentiated mass of cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice

In phosphorylation, ATP is synthesised in which of the following parts of cells?

  1. Mitochondria and nucleus

  2. Nucleus and chloroplast

  3. Mitochondria and chloroplast

  4. Golgi apparatus and ribosomes

  5. Ribosomes and chloroplast
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Yes, it is correct. Living organisms have the capability of extracting energy from oxidisable substances and store this in the form of bond energy. ATP, carry this energy in their chemical bonds. In phosphorylation ATP is synthesised by cells in mitochondria and chloroplasts.

Multiple choice

The size of a cell depends upon

  1. its oxygen requirement

  2. its minerals and materials requirement

  3. regulation ability of its nucleus

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The size of a cell depends upon its oxygen requirement, its minerals and materials requirement and the regulation ability of its nucleus.

Multiple choice

_______ can change its shape continuously.

  1. Nerve fibre

  2. White blood cell

  3. Red blood cell

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

White blood cells protect the body against infection, and they can change their shapes continuously.

Multiple choice

The smaller the cell, the

  1. smaller the nucleus

  2. more it will be active metabolically

  3. less it will be active metabolically

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

The smaller the cell, the more it will be active metabolically. For e.g., RBCs which are smaller as compared to other body cells carry the maximum oxygen to body parts.

Multiple choice

Cellular totipotency is demonstrated by

  1. all nucleated eukartyotic cells

  2. bacterial cells

  3. all plant cells

  4. only gymnosperm cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Totipotency is the ability of a single cell to divide and produce all the differentiated cells in an organism, and it is demonstrated by all nucleated eukaryotic cells.

Multiple choice

The lipoprotein, single unit membrane of ER is

  1. thinner than cell membrane

  2. thicker than cell membrane

  3. similar to cell membrane

  4. rich in lipids
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The lipoprotein, single unit membrane of ER is thinner than cell membrane so as to transport proteins and lipids to body parts.