class 9 biology practice worksheet
(1) Give the chemical nature of the plasma membrane.
(2) Why the plasma membrane is called selectively permeable?
(3) State one difference between diffusion and osmosis.
(4) Why does the skin of your finger shrink when you wash clothes for a long time?
(5) With the help of a well labeled diagram, describe the structure of the nucleus.
(6) On what basis are eukaryotes different than the prokaryotes?
(7) Differentiate between RER and SER.
(8) What would happen to the life of a cell if there was no Golgi apparatus?
(9) Define biogenesis.
(10) Why are lysosomes known as “suicide bags” of a cell?
Answers
Answer:-
1) The main components of the plasma membrane are lipids, proteins, and carbohydrate groups that are attached to some of the lipids and proteins.
2) Plasma membrane is called as a selectively permeable membrane because it regulates the flow of substances from and within the outside of the cell. And it allows only selected particles to enter inside the cell.
3) Diffusion:- It is the process where two mixtures or solutions are separated by inter mixing of particles. It can take place in any medium.
Osmosis:- It is the movement of water across the membrane. And it occurs only in semi permeable membrane.
4) It is because, soap solution is hypertonic and it is more concentrate than our skin. So, due to this reason it keads to shrinkage of skin over fingers.
5) Look into the attechment for your diagram.
6) Eukaryotes are membrane bounded organelles and they contain nucleus. Whereas prokaryotes does not contain any nucleus and they're not membrane bounded organelles.
7) RER is the presence of ribosomes whereas SER do not have any ribosomes.
8) If there are no golgi bodies, then protein cells would float around without any direction. And other cell bodies would not function properly.
9) Biogenesis is the synthesis of substance by new living organisms.
10) Lysosomes are called as suicidal bags of the cell because when the cell gets damaged, lysosomes release enzymes which can digest their own cell. So, due to this reason they are called suicide bags of the cell.
