Lesson 4: Cell Membrane Permeability

Question 1

Passive Transport

Answer 1

The diffusion of a substance across a membrane which does not require energy (spontaneous).

Question 2

For passive transport, substances must be:

Answer 2

small, uncharged and soluble.

Question 3

Diffusion is the tendency for molecules to:

Answer 3

spread out evenly into the space available.

Question 4

Diffusion is when molcules move from a…

Answer 4

high concentration to a low concentration.

Question 5

Facilitated Diffusion

Answer 5

The passive movement of molecules across the cell membrane via the aid of a transport protein.

Question 6

Each protein (in facilitated diffusion) is specific to the substance it moves. There are two types of proteins, which are:

Answer 6

those that act like carriers, and those that form channel across the membrane.

Question 7

Osmosis

Answer 7

The passive movement of water (solvent) through a semipermeable membrane.

Question 8

Isotonic solutions

Answer 8

Same solute concentration

Question 9

Hypotonic solutions

Answer 9

External solition has low solute concentration

Question 10

Hypertonic solutions

Answer 10

External solution has high solute concentration

Question 11

Factors that can affect the rate of diffusion include:

Answer 11

size and polarity (solubility) of molecules being transported; temperature of the system; concentration gradients.

Question 12

Active Transport occurs when…

Answer 12

energy (ATP) is required to move solutions/ions across a membrane.

Question 13

Active Transport involves moving solutions…

Answer 13

against their concentration gradient using membrane proteins.