Week 11 - Plant Leaves

Question 1

Explain guard cells

Answer 1

Size of the stoma is determined by turgidity of the guard cells. Sucrose is the solute that keeps them open

Question 2

Explain signalling molecules

Answer 2

Guard cells produce molecule diffusing in cells peoventing them from becoming guard cells

Question 3

What is photorespiration?

Answer 3

Binds with oxygen and uses ATP to generate CO2 instead of sugar

Question 4

Explain C3 plants

Answer 4

CO2 is taken up by ribusco, makes the three carbon molecule

Ruler shape on the inside

Question 5

Explain C4 plants

Answer 5

Circle shape on the inside
Have air chambers that have low CO2 concentration. When stomata open, co2 comes in way faster

Fix CO2 into malate which goes into the bundle sheath cells

Much less carbon overall can be fixed.

Question 6

Explain CAM plants

Answer 6

Stomata only open at night

In desert environments

Fix very little carbon. Can get into osmotic shock

Question 7

What is phyllotaxy?

Answer 7

Placement of leaves on a stem to reduce self-shading

Question 8

What is fibonacci’s number sequence

Answer 8

1,2,3,5,8,13,etc

Question 9

How many spirals do leaves have?

Answer 9

A fibonacci number

Question 10

What is LAI

Answer 10

Leaf area index

Ratio of surface area (view from above) of leaves divided by the area of land on which it grows

If LAI is more than 1, some branches must die

Question 11

What are sunflecks?

Answer 11

Light that reaches the ground through shifting leaves. LIFELINE for forest understory

Question 12

How hot can leaves get without wind?

Answer 12

20-30°C HOTTER than environment

Question 13

What is fenestration?

Answer 13

1. Reduces thermal stress
2. Permits sunflecks to cross
3. Reduces the amount of drag

Holes in leaves