Facilitated Diffusion

Q. Differentiate between Apoplast and Symplast pathways of water movement. Which of these would need active transport?

Q.

Explain the mechanism of active transport through cell membrane.

Q. Hydrophilic moieties cannot diffuse across the plasma membrane.

1. False

2. True

Q. Select the incorrect statement with respect to facilitated diffusion.

1. Highly selective
2. Uphill transport
3. Requires special membrane proteins
4. Transport saturates

Q. what is meant by aquaporins

Q. In a passive transport across a membrane, when two different molecules move in opposite directions and independent of each other, it is called as

Q.

Differentiate between active transport and diffusion.

Q. How does a gap junction facilitate intercellular communication?

Q. The movement of molecules in the image given below is by

1. facilitated diffusion
2. active transport
3. diffusion
4. both diffusion and active transport

Q. Select the correct statements about facilitated diffusion.

1. There is a specific protein carrier for a specific substance to be transported.
2. The same protein carrier transports all the substance through the membrane.
3. There is no limit to the rate of transport of a substance by facilitated diffusion.
4. The rate of transport is limited by saturation, i.e. when all protein carrier molecules are being used.

Q. The porins are proteins that form large pores, allowing molecules up to the size of small proteins to pass through. They are found in:

1. Membranes of some bacteria
2. Membrane of ribosomes
3. Outer membranes of the mitochondria
4. Outer membranes of the plastids

Q.

A plant cell becomes turgid when placed in

1. 100% water.

2. 10% sugar solution.

3. 10% salt solution.

4. None of the above

Q.

Assertion: Both facilitated diffusion and active transport are mediated through membrane proteins.

Reason: Only active transport is selective in action.

1. if A is true but R is false

2. if both A and R are false.

3. if both A and R are true but R is not the correct explanation of A

4. if both A and R are true and R is the correct explanation of A

Q. The movement of a single molecule across a membrane by carrier protein is called

1. symport
2. all of these
3. antiport
4. uniport

Q. Which of the following undergo conformational change while transporting molecules?

1. Channel proteins
2. Carrier proteins
3. Aquaporins
4. Porins

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

Q.

Which of the following criteria does not pertain to facilitated transport?

1. requirement of special membrane proteins

2. uphill transport

3. high selectivity

4. transport saturation

Q.

Which of the following processes does cause substances to move across membranes without the expenditure of cellular energy?

1. Endocytosis

2. Exocytosis

3. Active transport

4. Diffusion or passive transport

Q. When a freshly collected Spirogyra filament is kept in a 10% potassium nitrate solution, it is observed that the protoplasm shrinks in size:

a. What is this phenomenon called?

When a freshly collected Spirogyra filament is kept in a 10% potassium nitrate solution, it is observed that the protoplasm shrinks in size:

b. What will happen if the filament is replaced in distilled water?

Q.

Give one word for the following:

Shrinking of plant cell due to exosmosis.

Q. Facilitated diffusion requires protein channels to transport molecules across a membrane but does not require a concentrantion gradient.

1. False
2. True

Q.

______ and ________ are reabsorbed by passive transport.

Q. Transport proteins are required for

1. Diffusion
2. Osmosis
3. Facilitated transport
4. Facilitated transport and active transport

Q. Rate of diffusion across cell membrane depends upon

1. Size of the substances
2. Solubility in lipids

3. Both a $\&$ b

4. Living system

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. Rate of diffusion across cell membrane depends upon

1. Size of the substances
2. Solubility in lipids

3. Both a $\&$ b

4. Living system

Q. Fluidity of cell membranes in cold weather is maintained by

1. Increasing concentration of cholesterol in membrane
2. Increasing number of phospholipids with unsaturated hydrocarbon tails
3. Increasing the proportion of integral proteins
4. Increasing the number of phospholipids with saturated hydrocarbon tails

Q.

Transport against the concentration gradient can be done without using energy.

1. True

2. False

Q. Facilitated diffusion

1. Occurs against the concentration gradient
2. Is an active process
3. Needs a carrier protein
4. Needs ATP

Q. The type of diffusion in which substance move across the membrane along their concentration gradient in the presence of certain or transport proteins is called as

1. Simple diffusion
2. Facilitated diffusion
3. Osmosis
4. Active transport