responses

Question 1

name and define the 2 types of reflex

Answer 1

cranial= nerves from brain
spinal= nerves from spine

Question 2

define neurogenic and myogenic

Answer 2

neurogeic= contractions triggered by nerve impulses
myogenic= contractions initiated in heart

Question 3

what happens when plant embryos are activated (by water)

Answer 3

begins producing gibberellins
stimulate production of enzymes that break down food stores in seed
food stores produce ATP to break through seed

Question 4

name 2 plant hormones and their function

Answer 4

auxins
-control cell elongation
-involved in tropisms
-prevent leaf fall
gibberellins
-cause stem elongation

Question 5

what is the effect of auxins and how is it caused

Answer 5

effects plasticity of walls
make walls stretch more easily
auxin mol.s bind to specific receptor site on plasma membrane
pH falls to about 5
optimum pH for enzymes that keep wall flexible

Question 6

what are the apical and lateral shoots

Answer 6

apical= roots

lateral=shoots

Question 7

how do high concentrations of auxins affect the apical and lateral shoots

Answer 7

suppress growth of lateral shoot

promote growth of apical shoot

Question 8

define synergism

Answer 8

hormones work together
complement each other
create greater response

Question 9

define antagonism

Answer 9

substrates have opposite effects

balance between them determines response of plant

Question 10

name and describe some chemical defenders of plants

Answer 10

tannins- bitter taste + toxic to insects
alkaloids- bitter, effect metabolism of animals
terpenoids- interfere with nervous system of insects
pheremones

Question 11

how do gibberellins cause stem elongation

Answer 11

affect effect length of internodes (section between leaves on stem

Question 12

what is meant by unilateral light and what is its effect

Answer 12

plants partly shaded
side exposed to light contains less auxin
auxin moves across to unshaded side
stimulates cell growth on unshaded side
once facing light plant grows straight

Question 13

what is meant by climatic fruit

Answer 13

continue ripening after being harvested
hormone these involved
stimulates ripening of other fruits

Question 14

name some commercial uses or plant hormones

Answer 14

ripped fruit/ fruit dropping plants
gibberellins delay ripening
auxins in production of seedless fruits