The Fundamental Unit of Life CBSE class 9

Q1.What is protoplasm? Who gave the term protoplasm
Ans. The living material present inside the cell is
 called protoplasm. Nucleus and cytoplasm together form protoplasm.Purkinje’ proposed
the term protoplasm. 

Q2. Differentiate between hypertonic and hypnotonic solution
Ans. Hypertonic solution- if the medium surrounding the cell has higher concentration than the cell then solution is called hypertonic solution

Hypotonic solution: IF the medium surrounding the cell has lower concentration than the cell, then solution is called hypotonic solution

Q3. Explain "A cell is a basic unit of an organism"
Ans. A cell is called basic funtional and structural unit of life. A single cell is able to perform all the essential function of life-respiration, reproduction, excretion etc, hence cell is called the basic unit of an organism


Q4.Write function of plasma membrane

Ans. a. It acts as mechanical barrier between external and internal environment. hence, protect the cell
b. It helps in selective absorption of molecules in and out of the cell,


Q5.Write short notes on- Mitochondria, chloroplast

Q6. Name The cell organelle found in plant cells only. Write its types and function

Ans.Chloroplast in found in plant cells only. It is of three types – 
(a)     Chloroplast – It is the coloured plastids, which provides different colours to
flower, which attracts insects for pollination.  
(b)     Chloroplast – It is the green coloured plastid
 which contain chlorophyll. It
helps in due synthesis of food 
(c)      Leucoplast  –  It  is  the  colorless  plastids.  It
helps  in  the  storage  of
synthesized food. 
Q7.Write the main function of each of the following

a.plasma membrane:It helps in selective absorption of the molecules. 
b. cell wall:It is protective in nature
c. RibosomesIt helps in protein synthesis
d.Lysosome:It  contain  enzymes  which  helps  in  digestion  of  foreign substances. 
e.Nucleolus:It synthesizes ribosome
f.Endoplasmic reticulum:Produces lipids and proteins 

Q8.What are different types of Encoplasmic reticulum

(a) Rough ER – Ribosome are attached on their surface. They synthesize proteins 
(b) Smooth ER – Ribosome are not present on their surface. They synthesize lipids 

Q9.Which organelle is called digestive bag and why
Ans.   Lysosomes  are  called  digestive  bags.  They  contain  digestive  enzymes  which  break
down the organic material present in the cell. 

Q10.How does cell to cell movement of water takes place in plants? 
Ans.  Cell to cell movement of water inside the plant takes place through osmosis. Water
moves from the cell having high concentration to the cell having low concentration. 

Q11. Difference between Cell wall and Cell Membrane
Ans. cell wall is non living. it is made up of cellulose
     Cell membrane is livign and it is made up lipids and proteins

Q12.What is prokaryotic cell? Differentiate between prokaryotic cell & eukaryotic cell?

Ans. Prokaryotic   cells   are   incomplete   cells.   They   do not   have   membrane   bound
organelles. For ex-Bacteria, Mycoplasma
, etc. 


Q10.What is nucleoid? How in is different from the nucleus of eukaryotic cell?  
Ans.In  prokaryotic cell, genetic material in not surrounded by membrane. This undefined
region where genetic material is present, is known as nucleoid 
In eukaryotic cell, genetic material is surrounde by nuclear membrane 

What is ‘division of labour’ in multicellular organisms ? 

   In multicellular organisms every part of an organism performs specific function. For
ex, Heart, pumps blood, stomach digest food, etc hence, all the functions of the body
are divided among different parts of the body. This is known as ‘division of labour’. 

Differentiate between diffusion and osmosis. What is its importance ?

  Diffusion – It is the movement of substances (solid, liquid or gas) from a region   of
higher concentration to the region of lower concentration until they are spread out
evenly. 
  Osmosis  –  Osmosis  in  the  diffusion  of  a  solvent, usually  water,  through  a  semi  –
permeable  membrane  from  a  dilute  or  weaker  solutio into  a  concentrated  or
stronger solution. 
  Importance – diffusion and osmosis are important for the transport of substances
across the cell membrane.

What is ATP? Write its full form.

Ans.Energy rich molecules are called ATP. ATP provide energy to the cell 
ATP – Adenosine – tri – phosphate 

Why lysosomes are called ‘suicidal bags?
Ans.Lysosomes  contain  digestive  enzymes,  they  digest  any  foreign  substance  which enters into the cell. But somehow, if cell is not working properly or become dead, lysosomes burst and digest their own cell in which they are present. Hence, they are called ‘suicidal bag’.

What is cell theory? Who formulated it?

M.J  Schleiden  and  Theoder  Schwann  proposed  cell
  theory.  According  to  cell
theory –
(a) All living organisms, whether plants or anima
ls, are made up of cells. 
(b) Cells are the basic unit of life.

What are cell organelles? Write the names of different cell organelles.
Ans. Cell   organelles   –   organelles   are   the   intracellular   structures   present   in   due
cytoplasm various cell organelles are – 
1.  Mitochondrion – It produces energy 
2.  Endoplasmic reticular – synthesize lipids and proteins 
3.  Golgi apparatus - Storage, packaging and dispatch various substance. 
4.  Lysosomes – Digest intracellular substances 
5.  Ribosomes – Synthesize proteins 
6.  Vacuoles – Provide turgidity and store house of various organic substances 





Q What is difference between Plant cell and Animal Cell
 




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