Lecture 7: Continued from previous lecture

Question 1

Does the movement of molecules impact the change of the cell volume?

Answer 1

YES

Question 2

What is Tonicity?

Answer 2

the effect the solution has on a cells volume

Question 3

What is the determining factor of tonicity?

Answer 3

the concentration of the solution in non-penetrating solutes

Question 4

What are considered non-penetrating solutes?

Answer 4

solutes that cannot pass through the plasma membrane

Question 5

What is isotonic solutions?

Answer 5

solution that result in a constant cell volume

Question 6

What is a hypotonic solution?

Answer 6

solutions that tend to swell the cell

Question 7

What is a hypertonic solutions?

Answer 7

solutions that tend to shrink the cell

Question 8

What is osmolarity?

Answer 8

the measure of solute concentration per unit volume of solvent (includes both non-penetrating and penetrating solutes)

Question 9

What is iso-osmotic?

Answer 9

results in a constant cell volume

Question 10

What is hypo-osmotic?

Answer 10

tens to swell the cell

Question 11

What is hyper-osmotic?

Answer 11

tends to shrink the cell

Question 12

What is the main difference between osmolarity and molarity?

Answer 12

osmolarity could affect cell volume

Question 13

What do we have to remember when counting ions in water?

Answer 13

Ions separate in water therefore when counting non-penetrating ions we have to separate the ion and then count for each of them

Question 14

What are the two types of assisted membrane transport?

Answer 14

type 1 - carrier-mediated transport (small water -soluble molecules)
type 2 - vesicular transport (large molecules and multi particle molecules)

Question 15

What are carrier molecules?

Answer 15

• carrier proteins
• that can change shapes for different binding sites

Question 16

What are the three important characteristics of carrier-mediated transport?

Answer 16

• specificity
• saturation
• competition

Question 17

How do carrier-mediated transport? (2 ways)

Answer 17

1. actively - agaisnt the gradient (RARE)
2. passively - through facilitated diffusion

Question 18

What is an example of a carrier protein transporting a molecule across the membrane passively?

Answer 18

glucose

Question 19

What is the limiting factor od facilitated diffusion?

Answer 19

• the rate is limited by the number of carrier-binding sites there are aka the saturation

Question 20

Why is the rate of simple diffusion going to be at a constant increase rather than carrier-mediated transport? (or facilitated diffusion)

Answer 20

this is due to the fact that with carrier-mediated transport has parameter to follow which include competing molecules