Plants

Question 1

Palisades mesophyll

Answer 1

tightly packed cells containing chloroplasts

Question 2

Spongy mesophyll

Answer 2

loosely arranged cells with lots of intercellular spaces.

Question 3

Stomata

Answer 3

Openings in leaves that lead to air spaces.

Question 4

Transpiration

Answer 4

The loss of water through stomata in plants

Question 5

Guard cells

Answer 5

specialized leaf cells that control the opening and closing of stomata

Question 6

Sunken stomata

Answer 6

Stomata that are sunken in order to decrease the rate of wind-caused transpiration

Question 7

Flowers

Answer 7

Reproductive organs of plants

Question 8

How does gas exchange in plants work?

Answer 8

1. Stomata lets CO2 diffuse into the leaf
2. CO2 diffuses into the water lining the leaf
3. CO2 enters photosynthesizing cells
4. O2 enters through gas pockets in soil, allowing the plant to perform respiration.

Question 9

How do guard cells work?

Answer 9

1. An electrical gradient is established
2. An osmotic gradient is established
3. Water enters the guard cell and the stomata open
4. Water leaves, stomata closes

Question 10

What are the two types of tissue involved in transport of materials in plants?

Answer 10

Xylem and phloem

Question 11

Xylem tissue

Answer 11

Transports water and minerals, and provides mechanical support. Basically columns of cell-wall-ness (the cells are technically dead)

Question 12

Phloem tissue

Answer 12

Transports the products of organic materials, like sugars.

Question 13

How is water’s movement through xylem explained?

Answer 13

Cohesion-tension theory: TACT. Transpiration, Adhesion (attraction between different substances), Cohesion (attraction between the same substance to itself), Tension (which is created as water moves out of the leaf, pulling more water in)

Question 14

Plasmolysis

Answer 14

the contraction of the cell away from the cell wall (In plants). Occurs when not enough water is available.

Question 15

Cell turgor

Answer 15

Rigidity caused by the amount of water in a plant cell

Question 16

What gas causes ripening?

Answer 16

Ethylene. Positive feedback; as the fruit ripens, more ethylene is released.

Question 17

Abiotic

Answer 17

non-living

Question 18

Describe the process of phototropism

Answer 18

Phototropism is plants’ response to light. Auxin is a growth hormone that causes lengthening. When light is unequal on the plant stem, auxin goes to the shady side, causing the plant to bend towards the light

Question 19

What is gravitropism?

Answer 19

Plants’ response to gravity

Question 20

What is thigmotropism?

Answer 20

Plants’ response to touch

Question 21

Dormancy (plants)

Answer 21

Response to unfavourable conditions. Abscission is the loss of leaves or other parts, and Seed Dormancy is a mechanism that allows seeds to delay germination until they have ideal conditions.

Question 22

On what stimuli does seed germination rely?

Answer 22

1. Water
2. Oxygen
3. Temperature (optimal)
4. Fire! Nutrients from burnt stuff, more light for seedlings
5. Hormones

Question 23

Photoperiodism

Answer 23

The response of plants to changes in the photoperiod, the relative length of day vs. night time.

Question 24

Do plants have circadian rhythms?

Answer 24

Yup.

Question 25

How do plants maintain their circadian rhythms?

Answer 25

Two forms of phytochrome that convert from one to the other.

1. P(r) is synthesized in plant cells
2. P(fr) is the active form
3. P(fr) accumulates during the day as P(r) is exposed to 660 nm wavelength light (Red light).
4. P(r) accumulates at night as it’s not converted
5. At daybreak, P(r) is rapidly converted to P(fr)
6. Night length resets the circadian rhythms.

Question 26

When do different plants flower?

Answer 26

1. Long day plants flower when daylight is increasing
2. Short day plants flower in late summer when daylight is decreasing
3. Day neutral plants don’t care. They care about some other stimuli

Question 27

Structural defenses of plants

Answer 27

Stickyness, spines, etc.

Question 28

Chemical defenses of plants

Answer 28

Toxins! (like caffeine or nicotine) that kill insects