Facilitated Diffusion

Q.

Proteins that form huge pores in the membrane of the certain organelles and bacteria are called as

1. Flaccid

2. Porins

3. Pressure gradient

4. Enzymes

Q.

What is meant by facilitated diffusion?

Q.

Consider the following statements and choose the correct answer.

I. Carrier proteins are needed by both facilitated diffusion and active transport and are sensitive to inhibitors that react with protein side chain.

II. Different types of proteins present in the membrane play a major role in both active as well as passive transport.

III. The carrier proteins needed by facilitated and active transport are specific.

IV. There is no need of energy to pump molecule against a concentration gradient in active transport.

V. Transport rate reaches to saturation point, when all the active proteins are used.

1. I, II, III, IV and V

2. I, II and III

3. V, IV and I

4. I, II, III and V.

Q.

How many types of aquaporins are recorded?

1. 12 types

2. 5 types

3. 8 types

4. 4 types

Q. Porins are the proteins that form huge pores in the membranes

1. True

2. False

Q. Select the correct option for the table given below.
$\begin{array}{ccc}& \text{Facilitated diffusion}& \text{Active transport}\\ \text{Transport saturates}& \text{yes}& \text{(1)}\\ \text{Uphill transport}& \text{(2)}& \text{yes}\end{array}$

1. (1) is yes and (2) is no
2. (1) is no and (2) is yes
3. (1) is yes and (2) is yes
4. (1) is no and (2) is no

Q. Identify the incorrect statement related to facilitated diffusion.

1. Substances are transported without the use of ATP.
2. Causes net transport of molecules from low to high concentration
3. Transport rate reaches saturation.
4. Very specific and selective to substances

Q.

What characterstics is shared by simple diffusion and facilitated diffusion?

1. Both require cellular energy for the transport of substances.

2. Both involve the movement of water across a semipremeable membrane.

3. Both require a special carrier molecule to move substances across the membrane.

4. Both involve the movement of a substance from regions of a higher concentration to lower concentration without cellular energy.