Year 1 spec topic 3 - Organisms exchange substances with their environment

Question 1

3.3.1 surface area to volume ratio

Answer 1

Surface area to volume ratio relationship to size of organism
Exchange is facilitated by mass transport systems in larger organisms who have a small SA: Vol ratio

Question 2

3.3.2 Gas exchange

Answer 2

In insects, plants, xerophytes (balance exchange with water loss)
and fish
Ventilation in humans: alveoli etc
Lung disease

Question 3

3.3.3 Digestion and absorption

Answer 3

Digestion of carbs, protein, fats
By enzymes
Absorption into blood by co transport, simple diffusion, micelles etc

Question 4

3.3.4.1 Mass transport in animals

Answer 4

Haemoglobin
Structure of heart + blood vessels
Cardiac cycle
Tissue fluid

Question 5

3.3.4.2Mass transport in plants

Answer 5

Xylem - cohesion tension
Phloem - translocation
Evidence for mass flow hypothesis of phloem