Plants

Question 1

detail the process of the creation of transgenic plants

Answer 1

foreign DNA inserted into plasmid, put into agrobacterium. Put agrobacterium on callus and select for the antibody resistance plants

Question 2

what role do secondary metabolites play for plants

Answer 2

Stored in vacuoles, and are released when predator bites into cell…can either attract pollinators or fend of predators

Question 3

examples of secondary metabolites?

Answer 3

morphine from poppy
cocaine from coca
caffeine from coffee
nicotine from tobacco

Question 4

function of salicylic acid?

Answer 4

a defense molecule produced by willow trees; structurally similar to aspirin with an addition of acetyl group
in plants it acts as a hormone to signal unexposed areas of plants that an infection is either underway or something is eating it

Question 5

function of auxin

Answer 5

promote stem elongation, adventitious root initiation, fruit growth, inhibits lateral bud growth & leaf abscission

Question 6

function of ethylene

Answer 6

promotes fruit ripening & leaf abscission, inhibits stem elongation & gravitropism

Question 7

what does the Triple Response consist of?

Answer 7

Stem thickness, horizontal growth of stem, and slow stem elongation

Question 8

what is an ein mutant?

Answer 8

ethylene insensitivity–> ignores signal for triple response when ethylene is present so it cont to grow tall and straight

Question 9

what is a ctr mutant?

Answer 9

constitutive triple response, undergoes triple response even in absence of ethylene

Question 10

Detail signaling pathway of ethylene when present

Answer 10

when ethylene is present, ETR1 (ethylene receptors) are active, so CTR1 is inactive, so EIN-2 can’t be phosphorylated so it is cleaved; the C-end is soluble so it binds to mRNA that encodes for F box proteins (EBF1/2) and inhibits their txn. Since the F box proteins ubiquinate EIN3 and EIL1 txn factors for the triple response, if F box proteins not made, they are not degraded so –> Triple response

Question 11

Detail signaling pathway of ethylene when absent

Answer 11

The absence of ethylene means inactive ETR1, active CTR1 so EIN-2 is phosphorylated so it’s not cleaved, so txn of EBF1/2 (F box proteins) are not inhibited, so they ubiquinate EIN3 and EIL1 so there is no triple response

Question 12

During phototropism, which side does auxin travel to and what does it do?

Answer 12

The shaded side; stimulates cell elongation

Question 13

During gravitropism, what is auxin’s role in shoots?

Answer 13

in darkness, auxin travels to bottom of leaf and stimulates cell elongation so shoots bend up; done by statolith organelles sinking to the bottom of cells and using Ca+2 signaling to bring auxin to bottom of leaf

Question 14

During gravitropism, what is auxin’s role in roots?

Answer 14

Gets transported down and inhibits growth, so growth occurs faster on top and the root grows down

Question 15

What does auxin release from the cytoplasm into the cell wall space?

Answer 15

H+ and expansin

Question 16

How do expansins work?

Answer 16

are activated by H+ and change H bonding btwn polysaccharides in the plant wall. Turgor pressure presses against this wall and if wall is loose, cell will change shape

Question 17

What orientation do the myofibrils lie and how does this influence direction of cell expansion?

Answer 17

if myofibrils are horizontal, will expand vertically

if myofibrils are vertical, will expand horizontally

Question 18

what is the photoreceptor that initiates phototropism called?

Answer 18

Phototropin (yellow pigment)

- when absorbs blue light, initiates Ca+2 signal