Theme 5 Hormones And Reproduction

Question 1

What are auxins

Answer 1

They are delivered from the stem to the root meristem

They promote growth

Question 2

What are gibberelins

Answer 2

They stimulates growth

Mainly elongate stems

Question 3

What are cytokinins

Answer 3

Enhance growth and retard (slow) aging

Question 4

What is ethylene

Answer 4

A gaseous hormone that regulate senescence.

Plants release the hormone as a gas then signals back to the plant for growth

Question 5

What are brassinosteroids

Answer 5

They regulate plant growth responses

A type of steroid hormone

Question 6

What is abscisic acid

Answer 6

Suppresses growth and influences responses to Environmental stresses

Question 7

What are jasmonates

Answer 7

Regulate growth and have roles in plant defence

Question 8

What is the main auxin in plants

Where is it made and what does it do

Answer 8

Indoleacetic acid

It’s made in the shoot apical meristem and young’s stems and leaves

Promotes elongation of cells (allows cell wall expansion)

Controls growth responses to light and gravity

Question 9

How does cell expansion occur

Answer 9

Through the acid growth hypothesis

Auxins make atp for h to be pumped out of the cell (active transport)

Under the now acidic conditions, the protein expansin is activated and breaks the bridges between the cell walls

Then the cell wall expands by cell membrane pushing against it, allows for turgor pressure

Question 10

What are phototrophisms

Answer 10

Growth responses to a directional light source

Putting blue light receptors next to a plant can trigger the auxin transport and can cause differential cell elongation

Elongated on one side so it can bend

Question 11

If light source is in the front of the plant where does the auxin accumulate

Answer 11

On the back (opposite side of the light ) so that the plant can bend towards the light

Question 12

What are the effects of gibberlin/gibberellin acid

Answer 12

Bolting: the development of a flowing (tall) stem
Fruit enlargement

Question 13

What does aspirin do for plants

Answer 13

It’s a chemical deterrent to defend against viruses bacteria fungi worms and parasitic plants

It tells diff parts of the plant that it’s being attacked

Question 14

What is an example of why mono culturing is bad

Answer 14

The potato blight disease where on type of pirates is effected by a pathogen so all of the same type of potato was affects

Only that type of potato was being grown so now all potato’s gone

Question 15

What is a hypersensitive response

Are plants that do this susceptible or resistant

Answer 15

When the plant is infected the uninfected cells around the pathogen kill themselves to contain the spread

The cells strengthen the cell walls and close the stomata. Then they selectively plug the xylem to prevent spread and make anti microbial compounds

Resistant because the whole plant
Isn’t overtaken by the pathogen, the spread is prevented

Question 16

What is systemic aquired resistance

Answer 16

Development of an immune response at a distal site, it’s a signal for defense

One leaf on the same plant is affected then after a week affect the other leaf

The first leafs is affected and doing hypersensitive response. The second leaf isn’t affected at all

If already infected it doesn’t get infected again

Question 17

How do plants attract insects for defense

Answer 17

One plant that’s been damaged tells other undamaged plants to increase tannin levels to make their leaves more bitter (induced tannin level in other plants)

This attracts predatory insects to eat the caterpillar eating the leaves

Question 18

Why do we want plants to reproduce

Answer 18

To get seeds to make more plants

Question 19

What are perfect flowers

Imperfect flowers

Answer 19

They have both stamen and carpels (bisexual)

Have either stamens or carpels, not both (male or female)

Question 20

What happens in mate recognition

Answer 20

The female stigma need to select a genetically diverse mate from its own species

Very important step

Question 21

What does pollination require

Answer 21

Compatible pollen and female tissues

Question 22

What does double fertilization result in

Answer 22

The formation of embryos and endosperm

Question 23

What happens after fertilization

Answer 23

Ovaries develop into fruits that protect seeds and help disperse the seeds

Question 24

How many seeds in one ovule
In 60 ovules

Answer 24

1
60

Question 25

Where does the embryonic sporophyte develop

What happens then

Answer 25

Inside the seed

Seed germinate continues the life cycle

Question 26

What is self incompatibility

Answer 26

If allele of stigma is s1s2 and it gets two pollen of allele s1 and s4, it rejects the s1 pollen allele since it’s the same allele

If both Same both rejected

Question 27

What is non self pollen grain pollinations

Answer 27

If allele of stigma is s1s2 and is gets pollen of s3 allele that allele is accepted and grows into pollen tube