Cell Biology - Very Short Questions

  Notes of Class 11 biology

 1.       Why is the cell considered as unit of life?

Ø  The cell is considerred as the basic structural and functional unit of life because it carries out all the biological activities which collectively make the organism a living entity.

2.       What do you mean by prokaryotic and eukaryotic cells?*

Ø  Prokaryotic cells are the most primitive cells.They posses primitive nucleus. They lack the major cytoplasmic organelles such as mitochondria, golgi complex, endoplasmic reticulum etc. Eukaryotic cells are the true cells. They consist of definite nucleus and membrane that consists of the major cytoplasmic organelles. Eg.   mitochondria, golgi complex, endoplasmic reticulum etc.

3.       What do you mean by cell inclusions ?

Ø  Cell inclusions are non – living substances present in the cell cytoplasm . They are also known as ergastic substances.

4.       Which organelles is called a “ suicidal bag”.Why is it called so ?

Ø  Lisosomes are called suicidal bag because it consists of hydrolysing enzymes which digests the various cell organelles.

5.       Mention any two functions of golgi bodies.

Ø  The two functions of golgi bodies are as follows :

a.       It forms secretory vesicles which make it the secretory site of the cell.

b.      It also activates the mitochondria to produce ATP(Adenosine Triophosphate).

6.       What are chromoplasts ? Mention their functions.

Ø  Chromoplasts are the coloured plastids, which contain verieties of pigments other than green. They provide colour to the flowers and fruits and make them showy and attractive.

7.       What changes occur during prophase of mitosis ? Write any two.

Ø  This phage is the acutal first phase of mitosis .In this phase of mitosis . In this phase , the cell becomes spherical , refractive and viscous . The nuclear membrane starts degenerating and the chromatids become short and thick.

8.       What is synapsis ?

Ø  Pairing of homologous chromosomes to form bivalents is called synapsis. Crossing over occur after the formation of synapis.

9.       Where do mitosis and meiosis occur in animals and plants ?

Ø  In animals, mitosis occurs in somatic cells and meiosis division occurs in germ cells during gamete formation. In plants, mitosis division occurs in all cells except those which produce spores by meiosis.

10.   Give one diagnostic features of diplotene. * (Note : * indicate that respective question is asked in HSEB examination.)

Ø  Formation of chiasmata.

11.   Name two DNA containing cell organelles.

Ø  Two DNA containing cell organelles are :

a.       Nucleus

b.      Mitochondria

12.   List two characteristics which differ DNA and RNA. *

Ø  The two characteristics which differ DNA and RNA are listed below :

a.       DNA contains deoxyribose sugar while RNA contains ribose sugar.

b.      Nitrogen base thymine which is present in DNA and is replaced by Uracil in RNA.

13.   Give two differences in each of the following pairs : *

Ø  Prophase of Mitosis and Meiosis.

Prophase of mitosis	Prophase of meiosus
Prophase of mitosis occurs in one stage.	Prophase of meiosis occurs in two stages : Prophase I and Prophase II.
Crossing over of homologous chromosomes des not occur.	Crossing over of homologous chromosomes occurs.

14.   Write the functions of mitochondria or chloroplast.**

Ø  Functions of mitochondria :

a.       Mitochondria performs cell respiration.

b.      The energy is produced and stored in the form of ATP(Adenosine Triphosphate) which is an energy rich compound, in the mitochodra.

Functions of chloroplast :

a.       Light (or solar) energy is converted into chemical energy (ATP) Nby photosynthesis in chloroplast.

b.      Chloroplasts also conduct transcription, protein syntheis(produce) like mitochondria.

15.   Mention the change you gind in chromosomes during anaphase stage of mitosis.*

Ø  The changes we find in chromosomes during anaphase stage of mitosis are :

a.       The monads are pulled apart towards the pole due to contraction of spindle fibres.

b.      The two groups of chromatids appear around the centrioles after reaching the pole.

16.   What is the basic difference between ribosome and mitochondria ?*

Ø  The basis difference between ribosome and mitochondria is that the ribosomes are responsible for protein systhesis whereas mitochondria synthesize energy rich compound known as adenosine triphosphate or ATP.

17.   Write a change in chromosomes during zygotene stage of meiotic Prophase – I cell division. *

Ø  Pairing of homologous chromosomes i.e. synapsis occurs in zygotene stage of meiotic prophase I cell division.

18.   Why mitochondria is called power house of a cell ?*

Ø  In mitochondria respiration(transformation of chemical energy into utilizable(usable) form ) takes place. The food material is graduallly oxidised and energy generated is stored int he form of ATP (Adenosine Triphosphate). So, mitochondria is called power house of a cell.

19.   Define cell theory.**

Ø  Cell theory states that :

a.       All the living things are made up of cells.

b.      All the cells are produced from the pre – existing cells.

c.       Cells are the hereditary units.

d.      Life passes generation to generation by cell.

20.   What is cristae ? *

Ø  The numerous infolds that found on the inner membrane of the mitochondria which divides mitochondria into different compartments is known as cristae.

21.   Name the full form of ATP and ADP.*

Ø  The full form of ATP and ADP are adenosine tri phosphate and adenosine di phosphate respectively.

22.   Mention the function of lipid.*

Ø  The functin of lipids are :

a.       Lipids are rich sources of energy, yielding twice as many calories as carbohydrate and proteins.

b.      Lipids provide electrical and thermal insulation. They are deposited beneath the skin and other internal organs to lessen the heat loss.

23.   Write the function of cell wall .*

Ø  Cell wall is the outermost , rigid layer found in all plant cells. Its functin is to provide protection to inner contents from mechanical injuries and entry of germs. It also provide mechanical support to aerial parts.

24.   Give two functions of RNA . *

Ø  Two functions of RNA are as follows :

a.       It helps in protein synthesis (translation).

b.      In some organisms it acts as  a hereditarty material eg. Tobacco mossaic virus.

25.   Mention two differences between plant & animal cell.*

Ø  The plant cell differs from animal cell in following ways :

a.       Plant cell is enclosed by a thick , rigid, dead cell wall whereas animal cell lack cell wall.

b.      Plant cell usually possess plastids whereas animal cell lacks plastids.

26.   What are the major chemical constituents of protoplasm ?*

Ø  The major chemical constituents of protoplasm are various inorganic and organic compounds. The inroganic molecules are water, slats of sodium , potassium and other metals . The organic compounds are carbohydrates, lipids , proteins etc.

27.   What is incipient nucleus ? *

Ø  An unorganised nucleus containing naked DNA and lack of nuclear envelope(nuclear membrane) is called incipient nucleus.

28.   What do you mean by cytokiness?*

Ø  Division of cytoplasm is called cytokiness.

29.   Define Cellular totiopotency.*

Ø  The capacity of a living nucleated cell to differentiate into any type of cell and thus form a complete new organism or to generate any part of an organism is called cellular totipotency.

30.   What is plasmodesmata ?*

Ø  Plasmodesmata are intercellular junctions in plant tissue . These are tubular passages through which water and small solute may pass form cell to cell.

31.   Write the functi8on of plasma membrane.*

Ø  Plasma membrane acts as a selectively permeable membrane and allows only selected materials to pass through it.

32.   What is chiasmata ? *

Ø  The chiasmata is a knot like structure which holds the homologous chromosomes during crossing over. The chiasmata mark the sites were crossing over takes place during pachytene of meiotic propase – I.

33.   Define cell wall.*

Ø  Cell wall is the outermost , rigid, protective and supportive layer found in all plant cells , bacteria , cyanobacteria and some protist.

34.   What is cyclosis ?*

Ø  The streaming movement of the cytoplasm/endoplasm is known as cyclosis. This movement is responsible for the movement of food vacuoles in a defineite course.