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 biology animal tissue types of neuron nervous tissue neural tissues

The longest cell in the human body is _____________

  1. Muscle cell

  2. Nerve cell

  3. Lung cell

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

The length of the muscle cell is 1-40 micrometers.
Nerve cells possess a cell body and one to many thin, fiber-like axons.
Some nerve cells possess axons as long as 1 meter. Therefore, option B is correct. 

Multiple choice biology animal tissue types of neuron nervous tissue neural tissues

Which cell stops dividing after birth?

  1. Glial cells

  2. Epithelium

  3. Liver

  4. Neuron
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The nerve cells stop dividing after the birth of the child. There are no centrosomes in the neurons. Since there are no centrosomes the formation of the spindle apparatus cannot take place. The spindle fibres are necessary for the cell division to take place because they help in the attachment of the chromosomes

So, the correct answer is 'Neuron'

Multiple choice biology animal tissue types of neuron nervous tissue neural tissues

The longest cell in human body is_______________

  1. Neuron

  2. Muscle fibre

  3. Epithelial cell

  4. Bone cell
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The average length of muscle fibers is of a few centimeters. 
The average size of epithelial cells is of few microns. 
Nerve cells possess a cell body and one to many thin, fiber-like axons.

Some nerve cells possess axons as long as 1 meter. Therefore, option A is correct. 

Multiple choice biology butterfly and honey bee life cycle of a butterfly metamorphosis in frogs the life of a butterfly types of reproduction in animals oviparous and viviparous

Periblastula is found in 

  1. Man

  2. Insects

  3. Sycon

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

Periblastula is the blastula of a centrolecithal egg, which is formed by superficial segmentation. This kind blastula occurs in insects.
Centrolecithal eggs develop to superficial blastula, which consists of a single layer of epithelial cells surrounding the centrally placed yolk and there is no blastocoele.
Thus, the correct answer is option (B).

Multiple choice biology butterfly and honey bee life cycle of a butterfly metamorphosis in frogs the life of a butterfly types of reproduction in animals oviparous and viviparous

A gradual decrease in size of tail during metamorphosis of frog is due to

  1. Cell mecrosis

  2. Pinocytic activity

  3. Programmed cell death

  4. Cell senescence
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A. Cell necrosis - is a form of cell injury which results in the premature death of cells in living tissue by autolysis.

 B. Pinocytic activity - is a mode of endocytosis in which small particles suspended in extracellular fluid are brought into the cell through an invagination of the cell membrane, resulting in a suspension of the particles within a small vesicle

C. Programmed cell death is the death of a cell in any form, mediated by an intracellular program. PCD is carried out in a biological process, which usually confers advantage during an organism's life-cycle.

D. Cell senescence- is a phenomenon by which normal cells cease to divide

So, the correct option is ‘Programmed cell death’.

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Identify the correct statements w.r.t the given cell
A. Concerned with lipid and steroidal hormone synthesis
B. Outer non living rigid structure which gives shape to the cell and protects from mechanical damage and infection.
C. Both lie perpendicular to each other and each has an organisation like the cart wheel'
D. Responsible for trapping light energy for the synthesis of sugar.
E. Present in cells actively involved in protein synthesis and secretion..
F. Spherical structures, rich in hydrolytic enzymes.

  1. A, D & E

  2. B, C & D

  3. A, C & E

  4. A, B, C & F
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Select the wrong statement?

  1. The protein part of the holoenzyme is called the apoenzyme

  2. Thylakoids are arranged one above the other like stack of coins forming a granum

  3. Building blocks of lipid are amino acids

  4. Cross-over occurs at pachytene stage of meiosis I
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cofactor is a nonprotein part of the enzyme. It can be metal ions or the organic chemical. The cofactors which are organic chemicals are known as coenzyme. These are loosely attached to the apoenzyme. The tightly bound coenzymes are prosthetic group. 

Thylakoids are coin like structure present in the matrix of chloroplast which are stacked to form granum. 
Crossing over in meiosis helps in recombination by exchanging the segments between non homologous chromosomes.
Steroids are the organic molecule which plays an important role in the growth and development of the body. The molecular structure consists of 17 carbon which is arranged in four fused structure. It is found in plants, animals, and fungi. Steroids such as cholesterol form an integral component of the cell membrane and alter the membrane fluidity.
Lipids are nonpolar molecules so they are unable to interact with the polar molecule like water and thus they are insoluble in water. It is a hydrophobic molecule which is formed by ester linkage of the glycerol molecule with three fatty acid molecule. It does not consist amino acids. But the polymer of amino acids is protein.
So, the correct answer is option C.

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

The major site of lipid synthesis in most cells is?

  1. Cytoplasmic ribosome's

  2. Outer membrane of mitochondria

  3. Endoplasmic reticulum

  4. Golgi membranes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The endoplasmic reticulum (specifically the smooth endoplasmic reticulum) is the primary site for the synthesis of most membrane lipids, phospholipids, and cholesterol in eukaryotic cells.

Multiple choice biology transportation in animal and plants blood in humans circulatory system - blood basics of blood and heart

............. in plant cell and ........................ in mannalian cells are non-nucleated in mature stages.

  1. Tracheids, osteocytes

  2. Sieve tubes, RBC

  3. Companion cells, RBC

  4. Parenchyma, bone marrow
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sieve tubes are supporting cells in the conducting tissue of the plant and are characterised by the absence of a nucleus. 

The RBC in the blood does not have a nucleus so as to carry enough oxygen.
So, the correct option is 'Sieve tubes, RBC'.

Multiple choice evs transportation in living organisms blood in humans circulatory system - blood basics of blood and heart

Correct statement regarding Mitochondria and Chloroplast
A. ATP synthesis is seen in both
B. Outer membrane has more surface in both
C. Circular naked DNA, RNA and 70 ribosomes are seen in both
D. Oxidative phosphorylation occurs in both

  1. A and B

  2. B and C

  3. A and C

  4. A and D
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chloroplasts are very similar to mitochondria but are found only in the cells of plants and some algae.ATP synthesis is present in both Mitochondria and Chloroplast and the outer membrane has not more surface in both.

So, the correct option is 'A and C'.

Multiple choice biology transport in plants transport of food, water and minerals theories of translocation transport in the phloem of plants

Active transport from outside to inside of molecules across a membrane requires

  1. Cyclic AMP

  2. ATP

  3. Phloroglucinol

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

The active transport of substances require energy and hence they use up ATP which is the energy currency of the cell.

Acetly choline and Cyclic AMP are involved in cell signalled.
Phloroglucinol is a stain used to observe lignin.
So the correct answer is 'ATP'.

Multiple choice biology transport in plants transport of food, water and minerals theories of translocation transport in the phloem of plants

On which surface of cell, Donnan equilibrium occurs

  1. Cell wall

  2. Plasma membrane

  3. Transport

  4. Nuclear membrane
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Donnan equilibrium is the equilibrium reached between two ionic solutions separated by a semipermeable membrane when one or more of the kinds of ion cannot pass through the membrane. The result is a difference in osmotic pressure and electrical potential between the solution.
So the correct answer is 'Plasma membrane'.
Multiple choice botany root - external morphology morphology of the root root system in plants root

Root cap regenerates$/$ dead torn cells of root cap are replaced by the activity of

  1. Plerome

  2. Dermatogen

  3. Calyptrogen

  4. Periblem
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • At the terminal region of the root tip is a cup-like or a thimble-like structure called the root cap which is formed from calyptrogen (specialized internal meristematic cells).
  • The root apex is protected by this root cap.
  • The root cap is formed by a specialized internal meristematic which is part of the histogen and is called calyptrogen.
  • The calyptrogen continuously divide to form the root cap and also helps in the regeneration of root cap in case of injury.
  • So, the correct answer is 'Calyptrogen'.