3.1 Specialised Exchange Surfaces Flashcards Preview

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

All organisms need to do what?

Exchange with their environment

2

All cells need to take in what?

Oxygen and glucose for aerobic respiration and other metabolic processes

3

Cells also need to excrete what?

Waste products like carbon dioxide and urea

4

The smaller an organism the greater it's what?

Surface area to volume ratio

5

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

Diffusion of gases

6

Why do unicellular organisms not need specialised exchange surfaces?

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

7

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

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

8

What do multicellular organisms need?

Specialised exchange surfaces
E.g. Alveoli in lungs

9

What are the features of an efficient exchange surface?

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

10

Why do most multicellular organisms respire aerobically?

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

11

Give an example of a exchange surface with large sa:

Root hairs
Gives roots large sa increasing water absorption and mineral ions

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