Exchanging Substances

Question 1

Do single-celled organisms have a (large Surface Area : volume ratio) or (small surface area : volume ratio)

Answer 1

large Surface Area : volume ratio

Question 2

Why is having a large Surface Area : volume ratio good?

Answer 2

enough substances can pass across the outer surface to meet the needs of the organism

Question 3

Does a multicellular organism have a (large Surface Area : volume ratio) or a (small surface area : volume ratio)

Answer 3

small surface area : volume ratio

Question 4

What is the downside to having a small surface area : volume ratio

Answer 4

Many cells are too far away from the outer surface to get substances in and out this way

Question 5

With a small surface area : volume ratio, ________ surfaces and ________ systems are needed so the _____ of every cell can be ___.

Answer 5

With a small surface area : volume ratio, exchange surfaces and transport systems are needed so the needs of every cell can be met

Question 6

What four things do exchange surfaces usually have?

Answer 6

• a large surface area (so lots can diffuse at once)
• A thin membrane (for a short diffusion distance)
• an efficient blood supply (in animals)
• ventilation (in gas exchange in animals)

Question 7

Name four organs (plant and animals) that are adapted for exchange.

Answer 7

• Leaves
• Gills
• Small intestine
• Alveoli

Question 8

How are leaves adapted for exchange?

Answer 8

• Large surface area
• flat shape
• stomata lets gases in and out

Question 9

How are gills adapted for exchange?

Answer 9

• Large surface area
• efficient blood supply
• Lamellae have a thin surface layer of cells and lots of capillaries

Question 10

How is the small intestine adapted for exchange?

Answer 10

• single layer of surface cells
• large surface area, covered in villi
• capillary network

Question 11

How are the alveoli in lungs adapted for exchange?

Answer 11

• Large surface area
• air moves in and out
• alveoli have thin walls
• capillary network