4. plant hormones

Question 1

auxins

Answer 1

Synthesis site- Apical meristems, young tissues
Transport- Polar transport via parenchyma cells and phloem

Question 2

Cytokinesis

Answer 2

Synthesis site- Root tips, developing seeds
Transport- xylem

Question 3

gibberellins

Answer 3

Synthesis site- Young leaves, roots, seeds
Transport- phloem and xylem

Question 4

Abscisic acid

Answer 4

Synthesis site- Mature leaves, roots, seeds
Transport- phloem and xylem

Question 5

Ethylene

Answer 5

Synthesis site- Aging tissues, stressed cells
Transport- Diffusion as a gas

Question 6

Brassinosteroids

Answer 6

Synthesis site- Seeds, pollen, shoots
Transport- Local and phloem transport

Question 7

major role of auxin

Answer 7

Controls apical dominance by inhibiting lateral buds
* When a plant’s shoot tip is cut off, no more auxin flows downward, so lateral growth can

Question 8

major role of cytokinesis

Answer 8

used in plant cell tissue culture to promote cell division

Question 9

major role of ethylene

Answer 9

important for fruit ripening
promotes abscission

Question 10

major role of ABA

Answer 10

causes stomata to close
(nothing to do with abscission)

Question 11

major role of gibberellins

Answer 11

can cause bolting (premature seed stalk elongation) when applied to brassicas
seedless grapes
beer malting

Question 12

major role of brassinosteriods

Answer 12

acts as the chemical messenger
controls gene expression

Question 13

How do hormones work at the molecular level?

Answer 13

Hormones work through highly specific interactions with receptors, initiating biochemical pathways that regulate cellular activities and maintain homeostasis