3.1 Specialised Exchange Surfaces Flashcards Preview

A Level Biology > 3.1 Specialised Exchange Surfaces > Flashcards

Flashcards in 3.1 Specialised Exchange Surfaces Deck (11)
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1
Q

All organisms need to do what?

A

Exchange with their environment

2
Q

All cells need to take in what?

A

Oxygen and glucose for aerobic respiration and other metabolic processes

3
Q

Cells also need to excrete what?

A

Waste products like carbon dioxide and urea

4
Q

The smaller an organism the greater it’s what?

A

Surface area to volume ratio

5
Q

The greater the surface area to volume ratio the greater the efficiency of what?

A

Diffusion of gases

6
Q

Why do unicellular organisms not need specialised exchange surfaces?

A

Substances can diffuse directly in or out of their cell surface membrane
Small diffusion distance
Large sa:v

7
Q

In multicellular organisms why is diffusion across the outer membrane too slow?

A

Large diffusion distance
Small sa:v
High metabolic rate - need constant supply of glucose and O2

8
Q

What do multicellular organisms need?

A

Specialised exchange surfaces

E.g. Alveoli in lungs

9
Q

What are the features of an efficient exchange surface?

A

Large surface area
Thin surface
Concentration gradient (blood supply/ventilation)
Moist surface

10
Q

Why do most multicellular organisms respire aerobically?

A

Higher energy requirements and aerobic provides 19x more ATP than anaerobic

11
Q

Give an example of a exchange surface with large sa:

A

Root hairs

Gives roots large sa increasing water absorption and mineral ions

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