Human Bio Unit 1 - Diffusion, Active Transport and Osmosis

Question 0

Define diffusion

Answer 0

Substances moving along a concentration gradient from high to low until the to concentrations are equal

Question 1

What is transported by diffusion in and out of cells?

Answer 1

CO2

H2O

Question 2

What is used in facilitated diffusion?

Answer 2

Channel proteins

Question 3

Is facilitated diffusion passive (doesn’t require ATP) or not?

Answer 3

Yes

Question 4

What way does facilitated diffusion go on a concentration gradient?

Answer 4

From high to low

Question 5

Where does the energy for diffusion come from?

Answer 5

The kinetic energy of moving particles

Question 6

When does diffusion stop?

Answer 6

When there is equilibrium

Question 7

What increases the rate of diffusion?

Answer 7

Surface area (larger increases)

Thickness (thinner)

Difference in concentration (larger)

Question 8

Define facilitated diffusion

Answer 8

Transmembrane proteins that form a water filled ion channel to transport larger molecules into cells

Question 9

Facilitated diffusion - define semi-permeable

Answer 9

Not all molecules can fit through

Question 10

What is transported by facilitated diffusion?

Answer 10

Sugars

Potassium ions

Sodium ions

Question 11

How does facilitated diffusion work?

Answer 11

Substrate (molecule to move across the membrane) binds to carrier protein

Molecule changes shape

Release of the molecule (product) at the other side of the membrane

Question 12

Define osmosis

Answer 12

The diffusion of water across the semi-permeable membrane of a cell

Question 13

Define water potential

Answer 13

Measurement of the ability or tendency of water molecules to move

Question 14

Water potential scale

Answer 14

Pure water is 0

the more stuff in it the more negative the number becomes

Question 15

What is water potential measured in?

Answer 15

kPa (kilo pascals) - pressure

Question 16

Hypotonic

Answer 16

Solution is more dilute outside cell

Gains water by osmosis

Cell swells

Question 17

Hypertonic

Answer 17

Solution with higher concentration of solutes outside the cell

Cell loses water by osmosis

Cell shrinks

Question 18

Isotonic

Answer 18

Same solution inside the cell and outside

Cells don’t change their shape

Question 19

Define active transport

Answer 19

Movement of solutes against the concentration gradient from low to high

Question 20

How do solutes move along the concentration gradient in active transport?

Answer 20

Against it

From low to high

Question 21

What is transported by active transport?

Answer 21

Materials that will not move directly through the phospholipid bilayer

Question 22

Two types of active transport?

Answer 22

Direct

Indirect

Question 23

Where does the energy for direct active transport come from?

Answer 23

Hydrolysis

Question 24

Where does the energy for indirect active transport come from?

Answer 24

Stored energy

Question 25

What do the molecules bind to in active transport?

Answer 25

Carrier proteins/intrinsic proteins

Question 26

Does active transport require ATP?

Answer 26

Yes

Question 27

Endocytosis

Answer 27

Part of the plasma membrane sinks into the cell

Forms a vesicle with substances from outside

Seals back onto the plasma membrane again

Question 28

Exocytosis

Answer 28

Vesicle is formed in the cytoplasm or from an edge of the Golgi apparatus

Moves towards plasma membrane and fuses with plasma membrane

Contents are pushed outside cell