Human Phys 1.3

Question 1

What is diffusion?

Answer 1

Random molecular movement (move on their own)

Question 2

How does diffusion always occur?

Answer 2

Down a concentration gradient (downhill)

Question 3

What is simple diffusion determined by?

Answer 3

Amount of substance available

Velocity of motion

Number of size and openings (permeability)

Question 4

What does facilitated diffusion always require?

Answer 4

Carrier protein

Question 5

What is always true about flow down gradients?

Answer 5

There will always be an energy gradient (supports flow) and a resistance to flow

Question 6

Flow

Answer 6

Movement of substances from one point in the system to another

Question 7

Why does flow occur?

Answer 7

Due to the presence of an energy gradient

Question 8

What can determine the direction of flow?

Answer 8

More than one gradient

Question 9

What will there always be when it comes to flow?

Answer 9

Some form of resistance

Question 10

What is true about resistance in flow?

Answer 10

It can be varied or physiologically controlled

Question 11

Are there multiple gradients during flow?

Answer 11

Yes (working at same time)

Question 12

What is osmosis?

Answer 12

Flow down gradient

Question 13

How do molecules diffuse?

Answer 13

Independently of one another

Question 14

Does the presence of a gradient mean flow will always occur?

Answer 14

No (due to resistance)

Question 15

Chemical gradient

Answer 15

Flow occurs from higher to lower concentration

Question 16

Electrical gradient

Answer 16

Flow occurs based on attraction between + and - charges

Question 17

What is it called when a chemical and electrical gradient are combined?

Answer 17

Electrochemical gradient

Question 18

Pressure gradient

Answer 18

Behaves same as chemical gradient (high to low pressure)

Question 19

Mole

Answer 19

6 x 10^23

Question 20

Equivalent

Answer 20

Used to describe the amount of charged (ionized) solute (moles x valence)

Question 21

Osmole

Answer 21

The number of particles into which a solute dissociates in solution

Question 22

Pores

Answer 22

Always open (non gated)

Question 23

What is selectivity of a pore based on?

Answer 23

Diameter and electrical charge

Question 24

Channel

Answer 24

Closed (gated)

Question 25

What are the types of gates that come with a channel?

Answer 25

Voltage gated Ligand gated Mechanically gated

Question 26

Voltage gated

Answer 26

Opens based on electrical charge

Question 27

Ligand gated

Answer 27

Opens due to molecule binding

Question 28

Mechanically gated

Answer 28

Opens due to change in pressure

Question 29

What limits the maximum rate of facilitated diffusion?

Answer 29

Saturation Speed of conformational change

Question 30

Saturation

Answer 30

All carrier proteins have a limited number of binding sites (and limited number of carrier proteins) (Seats available in boat)

Question 31

Speed of conformational change

Answer 31

The rate of transport can never be greater than the speed of conformational change (how fast the boat can go)

Question 32

What are the factors that affect net diffusion?

Answer 32

Concentration gradient Partition coefficient Diffusion coefficient Thickness of the membrane Surface area

Question 33

Partition coefficient

Answer 33

Decreases the solubility of a solute in oil relative to its solubility in water

Question 34

Diffusion coefficient

Answer 34

Depends on size of molecule and viscosity of the medium

Question 35

Thickness of membrane

Answer 35

The greater the distance of diffusion the lower diffusion rate

Question 36

Surface area

Answer 36

The greater the surface area available the higher rate of diffusion

Question 37

What are two factors that affect net diffusion if the solute is an electrolyte?

Answer 37

Potential difference Diffusion potential

Question 38

When does a diffusion potential occur?

Answer 38

Only if the membrane is permeable to the electrolyte

Question 39

When will negatively charged molecules stop entering a positively charged cell?

Answer 39

When equilibrium is reached between both the chemical and electrical gradient