Plant responses

Question 1

Ethene

Answer 1

Causes food ripening and promotes abscission

Question 2

Auxins

Answer 2

Control cell elongation, prevent abscission, maintain apical dominance, involved in tropisms, stimulate the release of ethene

Question 3

Giberellins

Answer 3

Causes stem elongation, triggers food stores mobilisation during germination, sitmulate pollen tube growth in fertilisation

Question 4

Tannins

Answer 4

Phenols that are bitter to animals and toxic to insects, where they will bind to digestive enzymes and deactivate them (insects)

Question 5

Alkaloids

Answer 5

Nitrogenous compounds that taste bitter and affect metabolism by acting like drugs ie caffeine, nicotine, morphine and cocaine

Question 6

Pheromones

Answer 6

(Not all plants produce these)

Chemicals that can affect social behaviour of neighbouring plants of the same species

Question 7

Volatile Organic Compounds

Answer 7

Chemicals that can be used by plants to communicate with other plants or animals, especially animals to eat the herbivore eating it

Question 8

Terpenoids

Answer 8

Normally act as essential oils, but can act as toxins to insects and fungi. Example: Pyrethrin

Question 9

Abscisic Acid (ABA)

Answer 9

Maintains dormancy of seeds and buds, stimulates cold protective responses ie antifreeze production and stomatal closing