Gas exchange in plants

Question 1

The leaf

Answer 1

Stomata = tiny pores allow gases to enter and leave
Gaurd cells = opening and closing of stomata
Spongy mesophyll = air spaces within the leaf that allow gases to diffuse.

Question 2

Adaptions

Answer 2

Plants that live in dry climates have adaptations to reduce water loss, such as fewer stomata.

Question 3

Fluid mosaic model (7)

Answer 3

Carbohydrate chains
Glycoproteins
Peripheral proteins
Membrane bilayer (hydrophobic core)
Pore (hydrohpillic channel)
Integral proteins
Phospholipid

Question 4

Passive transport mechanisms

Answer 4

Diffusion
Facilitated diffusion
Osmosis

Question 5

Active transport mechanisms

Answer 5

Endocytosis - movement of large mol out of cella through vesicle formation (Requires ATP)
Exocytosis - Movement of large mol out of cells thorugh vesicle formation

Question 6

Osmotic concentrations

Answer 6

Isotonic - same conc of solutes in sol as in cells (flaccid)
Hypotonic - conc of solutes is lower in sol than in cell (turgid)
Hypertonic - conc of solutes is higher in sol than in cell (plasmolysed)

Question 7

How to calculate water potential

Answer 7

Water potential (usually negative) = turgor pressure (usually positive) + osmotic potential (always negative)

Question 8

Gas exchange in insects

Answer 8

spiracles = found along the thorax, entry and exit of respiratory gasses
exoskeleton = support
tracheae = carry air into body for gas exchange, spirals of chitin for support, these are impermeable so little gas exchange takes place
tracheoles = most gas exchange takes place, no rings of chitin