Efficient Transport And Exchange

Question 1

Which gas do organisms need to take in and which gas do organisms have to remove?

Answer 1

• Taken in: Oxygen (aerobic respiration)
• Taken out: Carbon dioxide (product of aerobic respiration)
• Move between environment and cells by DIFFUSION

Question 2

How is water taken up by cells? Which other substances are also taken up by animals?

Answer 2

• Water us taken up by OSMOSIS

- Dissolved food molecules (eg: glucose and amino acids) and mineral ions diffuse along with it.

Question 3

How is urea transported to be removed from the body?

Answer 3

• Urea = waste product produced by animals from proteins

- Diffuses from cells to blood plasma for removal by kidneys.

Question 4

The larger an organism is, the ? it’s surface area is compared to its volume.

Answer 4

Smaller

Question 5

How is surface area : volume ratio calculated?

Answer 5

Surface area divided by volume

Simplify if necessary

Question 6

What is the unit fir surface area?

Answer 6

Micrometer squared

Question 7

What is the unit for volume?

Answer 7

Micrometer cubed

Question 8

How does transport differ between single cellular organisms and multi cellular organisms?

Answer 8

• Single cellular- gases diffuse directly in and out of cell because of cell membrane (large surface area compared to volume)
• Multi cellular- often have a smaller surface area compared to volume, so this makes it difficult to exchange enough substances for its volume. They require EXCHANGE SURFACES.

Question 9

Which sugar is needed for aerobic respiration?

Answer 9

Glucose

Question 10

What waste product is made by the breakdown of amino acids?

Answer 10

Urea

Question 11

Why does the body need to excrete wastes?

Answer 11

So that they don’t reach a toxic level

Question 12

Lungs have a ? surface area to volume ratio

Answer 12

Large

Question 13

How do alveoli work?

Answer 13

• Blood from the rest of the body enters with a LOW OXYGEN CONC. AND A HIGH CARBON DIOXIDE CONC.
• CARBON DIOXIDE diffuses across the one cell think walls of the alveolus, as the alveolus contains a LOW CONC OF CARBON DIOXIDE
• OXYGEN diffuses out of the alveolus, making the blood have a high conc. of OXYGEN instead

Question 14

What adaptation make the alveoli increase the rate of gas exchange?

Answer 14

• One cell thick walls of alveolus and capillaries = reduce diffusion distance
• It’s shape gives it a large surface area = increase oxygen uptake
• Moist lining = for dissolving gases
• Good blood supply = to maintain concentration gradients for O2 and CO2