Question

Short answer questions:
1. Why is the plasma membrane called a selectively permeable membrane?
2. List the functions of cellwall.
3. Write the consequences when a red blood cells are placed in salt solution.
4. Define osmosis . explain with an experiment.
5. Explain the role of diffusion in gaseous exchange.
6. Write few lines about the discovery of the cell.
7. How does Amoeba consume food?
8. Why does the skin of your fingers shrink,when you eat food for long time?
9. Why is endocytosis found in animals only?
10. Draw the various cells from the human body.​

Answer 1

Answer:

Here are you're answer's...........

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Explanation:

1. Plasma membrane called a selectively permeable membrane because it regulates the movement of substances from within to outside of the cell. This means that the plasma membrane allows the entry of some substances while preventing the movement of some other substance.

2. The cell wall is the protective, semi-permeable outer layer of a plant cell. A major function of the cell wall is to give the cell strength and structure, and to filter molecules that pass in and out of the cell.

3. When RBCs are placed in a hypertonic salt solution, water moves from inside the cell to the outside by osmosis. This causes the cells to shrink. When RBCs are placed in distilled water, a hypotonic solution, water moves from outside of the cell to the inside, causing the cell to swell and rupture.

4. Osmosis is a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one. Experiment to demonstrate osmosis: ... Mark the solution level in the tube and watch the experiment for some time.

5. The carbon dioxide concentration is much greater in your blood than the alveoli. So, by the rule of diffusion, the carbon dioxide moves from the blood to the alveoli, where it can be exhaled through the lungs. The same thing happens with oxygen. ... Oxygen diffuses into the blood from the alveoli.

6. The cell was first discovered and named by Robert Hooke in 1665. He remarked that it looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name. However what Hooke actually saw was the dead cell walls of plant cells (cork) as it appeared under the microscope.

7. An amoeba eats tiny plants and animals present in pond water where it lives. An amoeba takes in food by extending arm-like structures called pseudopodia from any part of its body, since it is shapeless. ... The two pseudopodia then join around the food particle and trap it in a food vacuole with a little water.

8. This type of wrinkling of the skin happens due to digital vasoconstriction, which is a process of narrowing of blood vessels. When the hand is soaked in water, the nerve fiber in the skin shrinks and the body temperature regulator (glomus bodies in the skin) in the hand loses its volume.

9. Endocytosis refers to imagination of a small region of plasma membrane, forming an intercellular membrane-bound vesicle. ... Endocytosis is not shown by plant cells because a rigid cell wall is present over the plasma membrane in them. Thus, this process is found in animals only.

10.

Answer 2

Answer:

1)-- Plasma membrane is also called cell membrane.It is the outermost part of animal cell.It helps in entry & exits of substance according to the requirment of the cell.Due to its structure .It is a colorless plasma fluid like structure.

2)--Cell wall performs various functions like

Structural support to the cell

Protection from external environment

Checks entry of various substances entering and leaving the cell

Maintaining the shape of the cell.

3)--When RBC is placed in high concentration of saline solution they shrink due to Exosmosis (Crenated)

Exosmosis is the net movement of water molecules from cell toward the external environment

4)--Osmosis is the process of passage of water across a semipermeable mambrane(semipermeable mambrane is a mambrane that will allow certain molecules or ions to pass through it by diffusion) from an area where there are more water molecules to an area where there are less.

5)--For the efficient gas exchange, following conditions are required:

1) The surface area through which gases exchange should be large.

2)There must be a good concentration gradient across the membrane.

3)The thickness of the wall, across which diffusion take place should be less.

4)Gases must be dissolved in the fluid.