Movement of molecules in and out of cells

Question 1

Dissolved substances can move how?

Answer 1

By diffusion and active transport.

Question 2

Water moves across boundaries by…

Answer 2

…osmosis.

Question 3

Osmosis is what?

Answer 3

The diffusion of water down the concentration gradient through a partially permeable membrane.

Question 4

What causes osmosis?

Answer 4

Differences in concentration inside and outside of a cell.

Question 5

Most soft drinks contain what?

Answer 5

Water, sugar and ions.

Question 6

Sports drinks contain sugars to what?

Answer 6

Replace sugars used in exercise.

Question 7

Sports drinks contain water and ions to what?

Answer 7

To replace water and ions lots during sweating.

Question 8

What happens if water and ions aren’t replaced?

Answer 8

The body’s water/ion balance is disturbed and the cells do not work as efficiently.

Question 9

What is active transport?

Answer 9

The absorption of material against the concentration gradient. It requires energy from respiration.

Question 10

Active transport allows cells to absorb what from dilute solutions?

Answer 10

Ions.

Question 11

Effectiveness of exchange surfaces is increased by…

Answer 11

…a larger surface area.
…being thin (shorter distance).
…efficient blood supply (animals).
…ventilated (animals for gaseous exchange).

Question 12

Gas and solute exchange surfaces are adapted for what?

Answer 12

To provide maximum effectiveness.

Question 13

Difficulty of exchanging of materials is increased with what?

Answer 13

size and complexity of the organism.

Question 14

In humans the surface area of the lungs is increased by…

Answer 14

…the alveoli.

Question 15

In humans the surface area of the small intestine is increased by…

Answer 15

…the villi.

Question 16

What do villi do?

Answer 16

Provide a large surface area with an extensive network of capillaries to absorb products of digestion by diffusion and active transport.

Question 17

The breathing systems are in the body, why?

Answer 17

So that oxygen from the air can diffuse into the bloodstream and carbon dioxide can diffuse out of the bloodstream into the air.

Question 18

How does air move into the lungs?

Answer 18

The ribcage moves out and the diaphragm downwards which increases the volume of the lungs. This decreases the pressure and air from the higher pressure surroundings moves in.

Question 19

How does air move out of the lungs?

Answer 19

The ribcage contracts and the diaphragm relaxes causing a decrease in volume in the lungs. This means the pressure is increased and air moves to the lower pressured surroundings.

Question 20

The action of breathing in and out is known as what?

Answer 20

Ventilation.

Question 21

Plants obtain carbon dioxide how?

Answer 21

Through diffusion in their leaves.

Question 22

Plants absorb water and mineral ions mostly through what?

Answer 22

Their roots.

Question 23

How is the surface area of roots increased?

Answer 23

With root hair cells.

Question 24

How is the surface area of leaves increased?

Answer 24

With internal air spaces and flattened shape.

Question 25

Plants have stomata, why?

Answer 25

To obtain carbon dioxide from the atmosphere and remove oxygen produced in photosynthesis.

Question 26

Where does most water loss in plants take place?

Answer 26

In the leaves through the stomata.

Question 27

Evaporation is more rapid in what conditions?

Answer 27

Hot, dry and windy conditions.

Question 28

What happens when plants lose water quicker than it is being replaced by the roots?

Answer 28

The stomata close to prevent wilting.

Question 29

What controls the size of stomata?

Answer 29

The guard cells surrounding them.