Bio 304 Exam 2: Sensory Systems And Hormones

Front 1

Hormone

Back 1

An organic compound that is produced in small amounts in one part of a plant and transported to target cells where is it causes a physiological response.

Hint 1

What sort of response does it cause?

Front 2

P fr absorbs what wavelength of light?

Back 2

Red!

Hint 2

This is why it's "active"

Front 3

P r absorbs what wavelength of light?

Back 3

Far-Red!

Hint 3

This is why it's "inactive"

Front 4

Phytochrome

Back 4

A specialized light receptor different from the other pigments involved in photosynthesis. It absorbs light and changes shape.

Front 5

Florigen

Back 5

The hormone involved in flowering

Front 6

Photoperiodism

Back 6

Any response by an organism that is based on photoperiod- the relative lengths of day and night.

Front 7

Phototropism

Back 7

Directed movement in response to light

Front 8

Thigmotropism

Back 8

Directed movement in response to touch (or wind)

Front 9

Gravitropism

Back 9

Directed movement in response to gravity

Front 10

When is the phototrophic response initiated?

Back 10

It's initiated when the PHOT1 protein is phosphorylated.

Front 11

Phototropins

Back 11

Photoreceptors that detect blue light and initiate phototrophic responses

Hint 11

Front 12

The Cholodny-Went Hypothesis

Back 12

Says that auxin moves to the shaded side of the plant, and the asymetric distribution of auxin causes the cells on the shaded side to elongate more

Front 13

What are the three steps of the Acid-Growth Hypothesis?

Back 13

1. Auxin stimulates proton pumps to acidify the cell wall

2. The acidic pH loosens the cell wall

3. Turgor pressure pushes the cell wall out, allowing the cell to elongate

Front 14

Describe the Statolith Hypothesis

Back 14

A change in gravity is sensed in the root cap. Amyloplasts full of starch settle to the bottom of cells and activate pressure receptors that indicate direction for the plant!

Front 15

What's another role that auxin plays in a plant?

Back 15

Auxin also promotes fruit development. Take away a plants seeds, and it won't develop as it should.

Front 16

Ethylene

Back 16

A stress hormone that promotes senescence /aging/death/ripening/etc.

Hint 16

Front 17

Cytokinins

Back 17

Hormones that promote cell division

Hint 17

Think "cytokinesis"

Front 18

Abscisic Acid (ABA)

Back 18

A hormone that promotes stomatal closure due to drought.

Hint 18