Diffusion and facilitated diffusion

Question 1

What are plasma membranes?

Answer 1

semi-permeable

Question 2

What does semi-permeable mean?

Answer 2

that some
substances can pass through and others cannot

Question 3

What is it that determines what substances pass through?

What are examples of substances that can pass through?

Answer 3

The substance has to be very
soluble in the oily phospholipid bilayer.

Steroid hormones, oxygen and
carbon dioxide

Question 4

What does diffusion mean?

Answer 4

The net movement of a substance (liquid or gas) from
an area of higher concentration to an area of lower
concentration.

Question 5

What are the results of diffusion?

Answer 5

1-Particles will continue
to move until they are
distributed evenly.

2- Particles continue to
move and collide, but
concentration does not
change.

Question 6

What type of transport is diffusion?

Answer 6

Passive Transport

Question 7

What does Passive Transport mean ?

Answer 7

A molecule or ion that crosses the membrane by
moving down a concentration gradient and without
expenditure of metabolic energy

Question 8

What factors affect diffusion?

Answer 8

Concentration – the higher the
concentration, the faster diffusion
occurs.

Temperature – the higher the
temperature, the faster diffusion
occurs.

Pressure – the higher the pressure,
the faster diffusion occurs.

Question 9

How do substances that are insoluble in lipid easily cross the membrane?

examples

Answer 9

special transport proteins in the plasma membrane help the transport across the membrane of these insoluble molecules

glucose, amino acids and nucleic acids

Question 10

What does facilitated diffusion mean?

Answer 10

the transport of substances across a biological membrane from an area of higher concentration to an area of lower concentration with the help of a transport molecule

Question 11

What are the carrier proteins called?

Answer 11

facilitators