Exam 2 CH5 Info

Question 1

What factors affect the ability of solutes to pass through a phospholipid bilayer?

Answer 1

Polarity
Charge (like an ion)
Concentration (of inside to outside of the molecule we want to move across)
Size of the molecule

Question 2

Selectively Permeable

Answer 2

A selection to what is allowed across the plasma membrane

Question 3

What can pass through the membrane easy? (highly permeable)

Answer 3

Gasses (very small, uncharged molecules)

Question 4

What molecules are moderately permeable?

Answer 4

Water and Urea

Question 5

What has low permeability?

Answer 5

Polar, organic molecules (too charged to pass through the bilayer) [sugars]

Question 6

What are the two types of passive transport?

Answer 6

Simple and facilitated diffusion

Question 7

Simple diffusion vs Facilitated diffusion

Answer 7

Simple: Substance moves across a membrane by passing directly through the phospholipid bilayer

Facilitated: diffusion of a solute through a membrane with the aid of a transport protein [less permeability molecules]

Question 8

What is Passive transport?

Answer 8

Requires no input of energy
Movement of solutes from high to low concentration (down the concentration gradient) until reaches equilibrium

Question 9

Osmosis

Answer 9

The movement of water across membrane via diffusion
Balance solute concentration with impermeable solutes

Question 10

Outside isotonic

Answer 10

The solute concentration outside the cell is isotonic (or equal) to the inside of the cell

Question 11

Outside hypertonic

Answer 11

The solute concentration outside the cell is hypertonic to the inside of the cell
More solute [sugar concentration] outside than inside
less water outside of the cell than inside the cell (higher concentration of water inside the cell than the concentration of water outside the cell)

Question 12

Outside hypotonic

Answer 12

The solute concentration outside the cell is hypotonic to the inside of the cell
more solute inside than outside
more water outside of the cell than inside (higher concentration of water outside the cell than the concentration inside the cell)

Question 13

Diffusion vs. Osmosis

Answer 13

Diffusion: solUTE molecules move from high to low concentration

Osmosis: solVENT molecules move from low to high concentration

Question 14

Can a solute pass the membrane?

Answer 14

NO
H2O can

Question 15

Why is osmosis important?

Answer 15

it helps maintain the cell shape and integrity of the cell when the environment of the cell changes

Question 16

Describe cell’s shape in an isotonic solution

Answer 16

Cells maintain normal shape

Question 17

Describe cell’s shape in a hypertonic solution

Answer 17

The cells undergo shrinkage (crenation) because water exits the cell

Question 18

Describe the cell’s shape in a hypotonic solution

Answer 18

Cell’s swell up and may undergo osmotic lysis because water is taken into the cell

Question 19

7% red blood cell placed in 100% pure water. What happens?

Answer 19

well there’s 93% water in the cell, and 100% water outside of the cell
Diffusion of water into the cell, causing it to swell

Question 20

7% red blood cell placed in 20% salt solution. What happens?

Answer 20

80% water in the salt solution and 93% inside the cell. The water will leave the cell to create equilibrium, which causes the cell to shrink

Question 21

You drop a raisin into a glass of water. How would you describe the solute concentrations of the raisin compared to the water? What would the raisin look like after 24 hours in the water glass?

Answer 21

Raisin is low water and high solute. Inside of raisin is hypertonic compared to the water in the glass.
The raisin would swell

Question 22

Facilitated diffusion: Transport proteins

Answer 22

Transmembrane proteins [embedded in the membrane]
Provide a passageway for movement of ions and hydrophilic molecules across membranes
two classes based on type of movement (channels and transporters)

Question 23

Channels vs Transporters

Answer 23

Channels: gated
Transporters: conformational change [more specific]

Question 24

Transporter proteins:

Answer 24

change their conformational shape based on the solute binding them
also known as carriers

Question 25

What do channels and carriers both do?

Answer 25

Channels and carriers work to transfer non soluble or non permeable things across the membrane

Question 26

How are molecules moved against the concentration gradient?

Answer 26

Active transport

Question 27

What is active transport?

Answer 27

Requires energy
moving from low to high concentration
primary - uses ATP hydrolysis to pump solutes against gradient
Uses a pump to move protons against gradient

Question 28

Secondary transport

Answer 28

Uses ion gradient to pump solutes against gradient
requires ion gradient created by primary active transport
Using the ion gradient as the energy source