Transport Across The Membrane

Question 1

Mention all the ways substances are transported across the membrane

Answer 1

• Simple diffusion
• Facilitated diffusion
• Active transport
• Secondary active transport
• Endocytosis
• Exocytosis
• Osmosis
• Solvent drag

Question 2

What is simple diffusion

Answer 2

Simple diffusion is the movement of the molecule of a substance from a region of higher concentration to a region of lower concentration till all the molecules are evenly dispersed.

Question 3

Characteristics of simple diffusion

Answer 3

• Continues till all the molecules are evenly distributed
• Passive transport (doesn’t require energy)
• Moves substances down their concentration gradient
• Does not display inhibition either competitive or not.
• It is not saturable

Question 4

Sodium-potassium pump consists of a carrier protein which is a complex of two separate globular proteins

T/ F

Answer 4

T

Question 5

What is the molecular weight of the larger globular protein in the sodium-potassium pump?

Answer 5

100,000

Question 6

What is the molecular weight of the smaller globular protein in the sodium-potassium pump?

Answer 6

45,000

Question 7

The specific features needed by the sodium-potassium pump is found on which of the globular protein?

Answer 7

The larger globular protein

Question 8

Characteristics of active transport

Answer 8

• Requires energy
• Expresses inhibition, either competitive or not
• Can be saturated
• Carries substance against their concentration gradient
• Example is the sodium-potassium pump
• It is carrier mediated
• It is saturable
• Energy used is gotten from hydrolysis of adenosine triphosphate (ATP)

Question 9

Example of symport

Answer 9

Carrier protein in the intestinal mucosa that co-transports sodium ion and glucose from the intestinal mucosa into the mucosa cells.