plant responses (better)

Question 1

name the uses of auxin in commercial use

Answer 1

herbicides

cuttings

micropropagation

Question 2

elaborate on the use of auxin in commercial use as a herbicide

Answer 2

stimulates shoot growth (resource using) and inhibits root growth (no resource absorbing) which causes the plant to rapidly grow and exhaust

Question 3

elaborate on the use of auxin in commercial use in micropropagation

Answer 3

removal of meristems from plant and place in growth medium

Question 4

how are cuttings grown

Answer 4

cut at lateral buds

cuttings dipped in rooting powder (auxin)

Question 5

how does auxin herbicide affect narrow-leaf plant

Answer 5

little effect

has little biomass so uses less resouces than broad-leaf plant

Question 6

why do we grow cuttings

Answer 6

able to clone a plant with desirable traits

saves growing from seed

Question 7

why do farmers prefer to kill weeds

Answer 7

prevent competition and increase yield
(weeds take up mineral ions and water)

Question 8

why are synthetic molecules not favourable

Answer 8

not organic and not the exact molecule

Question 9

what are the uses of gibberellins

Answer 9

seed germination

stem growth

delay senescence - synergetic with auxin

improve shape - charge more

Question 10

what are the uses of ethene

Answer 10

speeds up ripening - reduces auxin which stops inhibition of ethene, causing ripening

promote fruit drop

promote female sex expression in cucumbers

promote lateral growth

Question 11

why is lateral growth favourable to farmers

Answer 11

plants sprout more and longer branches, so there will be more flowering buds from which fruit grow

Question 12

what is a con of ethene

Answer 12

gaseous so can’t control its concentration and don’t know if it’s been evenly distributed across a plant

Question 13

what are the uses of cytokinins

Answer 13

prevent yellowing

promote cell division and elongation

Question 14

define synergy

Answer 14

some hormones amplify each other’s effects

Question 15

define a plant hormone

Answer 15

signalling molecule allows plant to respond to stimuli

Question 16

what hormone controls stomata closing

Answer 16

Abscisic acid

Question 17

what is thigmotropism

Answer 17

bend in reponse to touch

Question 18

how are plant hormones transported

Answer 18

diffusion and vascular bundles

Question 19

what is a hormone that produces seedless fruit

Answer 19

auxin + gibberellin

Question 20

what equipment allows a scientist to reduce a gravitropic response

Answer 20

clinostat

Question 21

describe the inhibition and promotion of growth by auxin

Answer 21

lower conc of auxin = promote root growth first
at a certain point = root growth inhibited and shoot growth promoted

Question 22

describe seed germination

Answer 22

1. water enters endosperm through micropyle
2. promotes gibberellin action
3. which promotes the transcription of amylase and proteases
4. starch and protein stored are broken down
5. their products diffuse into the embryo

Question 23

what are the different layers of the seed called starting from the outer most layer

Answer 23

testa

aleurone

endosperm

Question 24

what are the limitations of plants

Answer 24

rooted (immobile)

don’t have rapidly responding nervous system

Question 25

why can't we be sure about the details of plant responses

Answer 25

plant hormones work at very low conc multiple interactions make it difficult to isolate the role of a single chemical

Question 26

what is the difference in the 'cytoplasm' part in dicot and monocot seeds

Answer 26

cotyledon = dicot endosperm = monocot

Question 27

how does auxin affect plant cell elongation

Answer 27

auxin binds to receptors in plant c.m. causing falling in pH 5 optimum for enzyme needed to keep the walls flexibile as cells mature, auxin is destroyed pH rises, out optimum for these enzymes makes cell walls rigid

Question 28

define photoperiodism

Answer 28

plants sensitive to lack of light

Question 29

what is a phytochrome

Answer 29

light-sensitive pigment ratio of Pr and Pfr changes depending on the levels of light

Question 30

how does abcission work

Answer 30

lower light levels = lower auxin leaves produce ethene ethene initiates gene switching in abscission zone producing new enzymes enzymes digest and weaken the cell walls in the outer layer vascular bundles are sealed off + fat is deposited in cells of stem side of separation layer, forming protective layer cells in separation zone respond to hormones by retaining water and swelling, putting more strain on outer layer further abiotic factors lead separation from plant

Question 31

how does plant deal with freezing

Answer 31

cytoplasm + sap in vacuoles have solutes which lower freezing point plants produce sugars and amino acids to prevent freezing (antifreeze)

Question 32

what are tannins

Answer 32

phenols have bitter taste to put off herbivory toxic to insects (binds to digestive enzymes and inactivates them)

Question 33

what are alkaloids

Answer 33

nitrogenous, bitter-tasting compounds affects the metabolism of animals, sometimes poisoning them

Question 34

what are terpenoids

Answer 34

form essential oils but act as toxins to insects and fungi than attack the plant

Question 35

what are pheromones

Answer 35

chemical made by organism which affects social behaviour of other members of the species

Question 36

how do plants use pheromones

Answer 36

when attacked, released and absorbed by leaves to make callose communication

Question 37

define tropism

Answer 37

plant growth response to stimulus from one direction