Diffusion is very important to plants since:

1. The cells have a permeable cell wall

2. It is the only means for gaseous movement within the plant body.

3. Plants cannot transport material by active transport.

4. They are unable to move towards the source of the nutrients.

Substances that enter the living cells by facilitated diffusion are:

1. generally polar in nature

2. transported in the direction of the concentration gradient 

3. transported with the help of carrier proteins 

4. all of the above

The incorrect statement for facilitated diffusion is:

1. Special proteins help move substances across membranes without the expenditure of energy.

2. Can cause net transport of molecules from a low to a high concentration.

3. It is very specific, it allows cells to select substances for uptake.

4. Transport rate reaches a maximum when all of the protein transporters are being used.

Substances which are soluble in lipids…….a…...But which have a hydrophilic moiety……..b……

1. a- move slowly

2. a- move similarly as that of others

3. b- move faster

4. a- move faster

Rate of diffusion of substances is affected by all, except

1. Gradient of concentration

2. Temperature but not pressure

3. Density

4. Both temperature and pressure

Which one of the following is incorrect regarding faciliated diffusion :-

(1) Selective nature

(2) Dependent on energy

(3) Transport Saturation

(4) Requirement of protein

Main factor deciding rate of diffusion is :-

1. Pressure/concentration gradient

2. Solubility of gases

3. Thickness of diffusion membrane

4. Posture of body 

When a plant undergoes senescence, the nutrients may be

1.  accumulated

2.  bound to cell wall

3.  translocated

4.  None of these

What do A, B, C and D represent in the following figure?

(1) A : carrier protein, B : symport, C : uniport, D : antiport

(2) A : carrier protein, B : uniport, C : antiport, D : symport

(3) A : carrier protein, B : antiport, C : symport, D : uniport

(4) A : carrier protein, B : uniport, C : symport, D : antiport

What is correct about the movement of substances across the membrane in facilitated diffusion?

1. It is an active transport.

2. It causes the transport of molecules from low concentration to high concentration.

3. It is insensitive to inhibitors.

4. It is a very specific transport.