Chapter 6 Part from uni 2

Question 1

What are the two primary factors that will affect how solutes move across a membrane?

Answer 1

• Is the membrane permeable to the solute

- is the solute moving in a thermodynamicly favored direction.

Question 2

What effects thermodynamics of movement across membranes?

Answer 2

Entropy,

• if the two sides of the membrane have equally ordered sides than it has a high entropy.
• if the two sides of the membrane have a concentration difference between sides of the membrane than it has a low entropy.

Question 3

What are the two thermodynamically-driven processes that work to equalize the concentration differences?

Answer 3

• Diffusion

- Osmosis

Question 4

What is Diffusion?

Answer 4

Membrane is permeable to the solute.
Thus, the solute is favored to cross the membrane and move from a high to low concentration, therefor toward a maximus entropy state.

Question 5

What is Osmosis?

Answer 5

• Occurs when the membrane is impermeable to the solute.

- Therefor, water moves from the low solute side to the high solute side.

Question 6

What direction does water move in a osmotic permeable based membrane?

Answer 6

hypotonic to the hypertonic side

Question 7

What consequences can osmosis have on a cell?

Answer 7

cell shrinkage or cell bursting.

- depends whether the inside or the outside of the cell is hypo/hyper tonic

Question 8

Isotonic?

Answer 8

Same concentration of dissolved particles.

Question 9

If the solute is charged, then we also have to consider more than just the concentration gradient of that cell. Why?

Answer 9

undermost conditions cells contain a net charge difference across their cell membrane.

• Inside of the cell has a negative net charge
• outside of the cell has a positive net charge
• Therefore, there is already an electrochemical gradient.

Question 10

What are things you need to considered when thinking about a solute moving across a membrane?

Answer 10

• Is the solute a charged particle.

- Is that ion moving against or with the electrochemical gradient

Question 11

What is DELTA:G(sub c)?

Answer 11

change is free energy associated with movement of the solute relative to it’s concentration gradient

Question 12

What is DELTA:G(sub m)?

Answer 12

Change in free energy associated with the movement of a charged solute relative to the electrical gradient across the membrane.

Question 13

• If the membrane permeable to the solute
  -if the solute moving in a thermodynamic favored direction.
  IF THE ASWER IS YES TO BOTH QUESTIONS, WHAT IS OCCURING?

Answer 13

Simple diffusion

Question 14

-if the solute moving in a thermodynamic favored direction. (only this)
IF THE ASWER IS YES TO just this QUESTION, WHAT IS OCCURING?

Answer 14

facilitated diffusion

Question 15

• If the membrane permeable to the solute
  -if the solute moving in a thermodynamic favored direction.
  IF THE ASWER IS NO TO BOTH QUESTIONS, WHAT IS OCCURING?

Answer 15

active transport

Question 16

What is the function of channel proteins?

Answer 16

Create an open channel through the membrane that allows for the movement of ions.
- Key for facilitated diffusion

Question 17

t/f most channel proteins are highly accepting of all ions?

Answer 17

false, most are highly selective.

Question 18

t/f most channel proteins are gated?

Answer 18

True, they can open and close depending upon what is the circumstances are. ex voltage gated channel proteins

Question 19

What is function of carrier proteins?

Answer 19

• involved in facilitated diffusion
• ## ex: Glut 1. moves glucose from high-low concentrations

Question 20

What determines the directionality of movement in carrier proteins?

Answer 20

Thermodynamics, the carrier protein just serves as a functioning pathway.

Question 21

What is active transport?

Answer 21

energy is required to move the charged particles in un-energetically favored direction.
- Requires membrane proteins

Question 22

What is the difference between primary and secondary active transport?

Answer 22

Primary: (direct active transport), energy comes from the hydrolysis of ATP
Secondary: (indirect active transport), energy comes from coupling an energetically unfavorable transport process to an energetically favorable transport process.

Question 23

What is the best-studied example of active transport:

Answer 23

(Na+/K+/ATPase) pump

Question 24

What is the function of a symporter?

Answer 24

movement of two molecules in the same direction.