chapter 14

Question 1

what is tropism

Answer 1

a directional growth response to a stimulus in plants

Question 2

positive phototropism ( illumination in one side)

Answer 2

-IAA is produced by cell in the shoot tip
- IAA diffuses down the shoot
- IAA diffuse over to the shaded side
- there’s more cell elongation on the shaded side
- plant bends towards the light
- absorbs more light, which means more photosynthesis

Question 3

positive geotropism

Answer 3

• IAA is produced in the tip of the root
• IAA diffuses down the root
• IAA accumulates on lower side due to gravity
• inhibits cell elongation on the lower side
• upper side grows faster and roots grow downwards

Question 4

what is a reflex

Answer 4

a protective, involuntary, rapid response to a stimulus

Question 5

which type of receptor is a Pacinian corpuscle

Answer 5

a pressure or touch receptor

Question 6

cardiac output equation

Answer 6

heart rate X stroke volume

Question 7

what are synapses

Answer 7

junctions between neurones
chemicals diffuse across a synapse (neurotransmitter)

Question 8

advantage of simple reflex actions

Answer 8

rapid
protect against damage to body tissue
they are automatic
they enable homeostasis control

Question 9

why is it important for heart rate to increase when exercising

Answer 9

• speed up delivery of O2 to the cells and glucose
• to speed up removal of CO2 from the cells
• delays the onset of Ana