Plant Responses (only key points so refer to notes) Flashcards Preview

Biology A Level > Plant Responses (only key points so refer to notes) > Flashcards

Flashcards in Plant Responses (only key points so refer to notes) Deck (16)
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1
Q

tannins

A
toxic to MOs/herbivores
found in upper epidermis
leaf taste bad
prevent pathogens entering root
in cell vacuoles or surface wax on plants
2
Q

alkaloids

A

derived from amino acids
taste bitter
in tips, flowers
peripheral cell layers of stems and roots

3
Q

pheromones

A

affect behaviour/physiology of other individuals

4
Q

tropism

A

directional growth response

5
Q

thigmotropism

A

shoot of climbing plants wind around other plants/structures for support

6
Q

nastic response

A

non-directional response

7
Q

thigmonasty

A

respond to touch like fold leaf

8
Q

cytokinins

to do with bud growth

A

promote cell division
delay leaf senescence
overcome apical dominance
promote cell expansion

promote bud growth
override apical dominance if applied to bud
high auxin make shoot apex, sink for cytokinins produced in root
apex removed - cytokinins spread through plant

9
Q

abscisic acid

info to do with bud growth

A

inhibits seed germination and growth
stomatal closure when plant has low water availability

inhibits bud growth
high auxin in shoot keeps levels of acid high in bud
tip removed - abscisic levels drop so bud grows

10
Q

auxins

A

promote cell elongation
inhibit growth of side-shoots
inhibit leaf abscission (leaf fall)

11
Q

gibberellins

A

promote seed germination and elongation

growth of stems

12
Q

ethene

A

promote fruit ripening

promote lateral growth

13
Q

apical dominance

A

auxins from apical bud at tip of shoot prevent lateral buds from growing

14
Q

seed germination

A

seed absorbs water
embryo releases gibberellin
travels to aleurone layer in endosperm region of seed
enables production of amylase which breaks donw starch to glucose
substrate for respiration for embryo as grows

15
Q

auxin’s effect

A

increase stretchiness of cell wall
promote active transport of H ions by ATPase on plasma membrane to cell wall so low pH optimum for wall-loosening enzymes
break bonds within cellulose and H ions break H bonds
less rigid walls so expand as cell takes in water

16
Q

herbicides

A

man made auxin that kills weeds because difficult to break down so acts in plant longer leading to too much shoot growth, stem can’t support and dies