sakshi ROLL NO. 12 -fundamental unit of life -cell

THE FUNDAMENTAL UNIT OF LIFE - CELL

Date: 21/04/16

    QUESTION:   why does water come out FROM 

                           cucumber  when we add salt to it ?

   ANSWER:   water come out from cucumber when we add

                              salt to it because the content of salt IN

                            cucumber is less where as the salt in its 

                            surrounding has high salt content , so to 

                          get balance salt drawn from the  cucumber .

EXERCISE 

DATE: 7/05/16

Q. Make a comparison and write down ways in which plant cell are different from animal cell.

Plant cell	Animal cell
Plant cell have cell wall.	Animal cell don’t cell wall.
They contain chloroplast.	They don’t have chloroplast.
Vacuole is large and present in centre of the cell.	Vacuole is small.
Nucleus is present in the side of the plant cell.	Nucleus is present in the centre of animal cell.

Q. How is prokaryotic cell is different from eukaryotic cell?

Prokaryotic cell	Eukaryotic cell
Size of prokaryotic cell is generally small (1-10 um)	Size of eukaryotic cell is generally large(5-100 um)
Nuclear region is poorly defined due to absence of a nuclear membrane and known as nucleoid	Nuclear region is well defined and surrounded by a nuclear.
Membrane bound cell organelles absent.	Membrane bound organelles are present.
There is a single chromosome.	There are more than one chromosome.

Q. What would happen if the plasma membrane ruptures or break down?

Ans. If plasma membrane ruptures or break down then molecules of some substance will freely move in and out.

Q. What would happen to the life of a cell if there were no Golgi apparatus?

Golgi apparatus has the function of storage, modification and packaging of the products in vesicles. If there were no Golgi apparatus and dispatching of material synthesized by the cell will be stocked.

Q. Which organelle is known as powerhouse of the cell? Why?  

Ans. Mitochondria is known as powerhouse of the cell because it release the energy required for different activities of life.

Q. where do the lipids and protein constituting the cell membrane get synthesized?

Ans .Lipids and protein are synthesized in ER (SER).

Q. How does Amoeba obtain it’s food?

Ans. Amoeba take it’s food by the cell membrane which form the food vacuole.

   Endocytosis  in amoeba

Q. What is osmosis?

Osmosis is the process of movement of water molecule from a region to higher concentration to the region of lower concentration through a semi –permeable membrane.

Q. Carry out the following osmosis experiment: take four peeled potato cups, one of these potato cups should, be made from a boiled potato .Put each potato cup in a trough containing water.

Now,

     a) Keep cup A empty

     b) Put one teaspoon

    c) Put one teaspoon salt in cup C

    d) Put one teaspoon sugar in boiled potato cup D

Keep these for two hours. Then observe the four potato cups and answer the following:

Explain why water gathers in the hollowed portion of B and C.

Why is potato A, necessary for this experiment?

Explain why water does not gather in the hollowed out portion A and D.

Ans.

Water gather in B and C  because in both the situation there is difference in the concentration of water in the trough and water in  the cup of potato .Hence, osmosis takes  places cells act as a semi-permeable membrane.

Potato A is necessary for this experiment for comparison, it acts as a control.

Water does not gather in the hollowed out portion of A and D .As cup of A does not have change in the concentration for water to flow. For osmosis to occur one of the concentrations should be higher than the other. In cup D , the cells are dead and hence the semi-permeable membrane does not exist for the flow of water and no osmosis take place.