Chapter 11: Plants Flashcards Preview

Barron's AP Biology > Chapter 11: Plants > Flashcards

Flashcards in Chapter 11: Plants Deck (22):
1

Plants

Multicellular, eukaryotic, photosynthetic autotrophs.

2

What Allowed Plants to Move to Land?

1. Cell walls
2. Roots and root hairs
3. Cutins
4. Stomates
5. Xylem and Phloem
6. Seeds and pollen

3

The Leaf

Maximizes sugar production while minimizing water loss.
Has a palisade layer (tightly packed) and spongy mesophyll (to allow easy transfer of gases).

4

Guard cells

Epidermal cells that contain chloroplasts, stomates, and are photosynthetic.

5

Stomates

The openings where plants lose water by transpiration. When the stomata cells absorb water and become turgid they curve and open the stomate, and the stomate closes when the cells lose water and become flaccid.

6

Short Distance Transport

- Diffusion
- Osmosis
- Aquaporins (Osmosis of water)
- Cell swelling (Stomates)

7

Long Distance Transport

- Bulk flow: movement from high to lower pressure.
- Phloem: transports sugars from photosynthesis.
- Transpirational pull: Fluid in the xylem can be pulled upwards.
- Root pressure: fluid in the xylem can be pushed down.

8

Transpiration

The evaporation of water from the leaves.

9

Cohesion

The attraction of water to water. Makes it possible to pull a column of water from above within the xylem.

10

Transpirational Pull-Cohesion Tension Theory

For every molecule that is evaporated at the leaf through transpiration, another is pulled in at the root to replace it.

11

Factors that Affect the Rate of Transpiration

1. High humidity will slow down transpiration, and vice versa.
2. Strong winds can reduce humidity, thus increasing transpiration.
3. Increased light intensity can increase transpiration.
4. Closed stomates will stop transpiration.

12

Plant Hormones

Can affect the growth, development, and responses to environmental stimuli. Hormones usually do not depend on the raw amount given, but on the relative amounts. Examples include auxin, gibberellins, abscisic acid, cytokinins and ethylene gas.

13

Signal Transduction Pathways

Can amplify the hormonal signal.

14

Tropism

Growth of a plant towards or away from a stimulus. Toward a stimulus is a positive tropism, and away is a negative tropism.

15

Phototropisms

Result from an unequal distribution of auxins on once side of plant away from the light. Since auxins cause growth, the cells on the shady side enlarge, which cause the plant to move toward the light.

16

Geotropism

The interaction of auxins and statoliths.

17

Photoperiodism

The psychological response to a photoperiod.

18

Photoperiod

The environmental stimulus that lets the plant know of the season and time of day.

19

Circadian Rhythm

Most plants have this, which is a 24 hour biological clock.

20

Long Day Plants

Will only flower when the light period is longer than a certain number of hours.

21

Day Neutral

Will flower regardless of the length of day.

22

Phytochrome

The photoreceptor responsible for keeping track of the length of day and night.