Movement Across Membranes

Question 1

What are the four types of movements?

Answer 1

Diffusion
Osmosis
Active transport
Facilitated diffusion

Question 2

What is the definition of diffusion?

Answer 2

Random movement of molecules down the concentration gradient until dynamic equilibrium is reached

Question 3

What is down the concentration gradient?

Answer 3

From a high to a low concentration

Question 4

What is dynamic equilibrium?

Answer 4

When a substance is spread equally within another substance

Question 5

What is the definition of facilitated diffusion?

Answer 5

Movement of molecules down the concentration gradient until a dynamic equilibrium is reached, but with the assistance of a protein

Question 6

What is the definition of osmosis?

Answer 6

Movement of WATER molecules down the WATER concentration gradient through a selectively-permeable membrane until dynamic equilibrium is reached

Question 7

What is the definition of active transport?

Answer 7

Movement of molecules up the concentration gradient until dynamic equilibrium is reached. ATP is needed for this process.

Question 8

What is the definition of a solute?

Answer 8

A substance which has dispersed its molecules throughout a solvent

Question 9

What is the definition of a solution?

Answer 9

A mixture of a solute and a solvent

Question 10

What is the definition of hypertonic?

Answer 10

A substance in which there is a high concentration of solute

Question 11

What is the definition of hypotonic?

Answer 11

A substance in which there is a low concentration of solute

Question 12

What is the definition of isotonic?

Answer 12

A substance which has an equal concentration of water and solute to that of the inside of a cell

Question 13

What is the definition of water potential?

Answer 13

The likelihood of a substance to donate its water particles to another substance

Question 14

What is the definition of concentration gradient?

Answer 14

The process of movement of particles to and from areas of differing concentration

Question 15

What is a hypertonic solution?

Answer 15

A substance in which there is a high concentration of solute and a low concentration of water in comparison with the inside of a cell

Question 16

What is a hypotonic solution?

Answer 16

A substance in which there is a low concentration of solute and a high concentration of water in comparison with the inside of a cell

Question 17

What are free water molecules?

Answer 17

Water molecules that do not have solute to ‘bind’ to

Question 18

What are the five important points to remember when defining osmosis?

Answer 18

Water molecules move
High water potential to
Low water potential
Across a selectively permeable membrane
Until dynamic equilibrium is reached

Question 19

What is the first step when answering osmosis questions?

Answer 19

Identify which substance has a high water potential and which has a low water potential

Question 20

What is the “formula” for answering osmosis questions?

Answer 20

Use the definition and slot in the information given

Question 21

In terms of osmosis, what is dynamic equilibrium?

Answer 21

For every water molecule that crosses over to one side, another water molecule will cross over from that side to the original side

Question 22

Why does diffusion take place?

Answer 22

Every molecule has kinetic energy

Question 23

What affects the rate of diffusion?

Answer 23

The steepness of the concentration gradient

Question 24

What is the concentration gradient?

Answer 24

The difference between the concentration of molecules in different areas

Question 25

What kind of transport is diffusion?

Answer 25

Passive

Question 26

What is water potential?

Answer 26

The ability of a solution to release water given its large number of free water molecules

Question 27

What is the symbol for water potential?

Answer 27

Ψ

Question 28

What substance has the highest water potential?

Answer 28

Pure water