Chapter 38- Transport in plants

Question 1

How does water enter/exit a plant

Answer 1

enters roots from soil

• moves to xylem
• leaves through stomata

Question 2

how does water move through a plant? (3 things)

Answer 2

1. root pressure-pushing of water entering roots
2. capillary action (xylem)-push/pull due to cohesion/adhesion
3. transpiration(leaves)-a sort of pull

Question 3

how do substances other than water enter a plant?

Answer 3

active transport through protein transporters

-facilitated diffusion or active transport

Question 4

what enhances osmosis in plants?

Answer 4

aquaporins speed up osmosis but do not change the direction of water movement

Question 5

what are the 3 transport routes of water

Answer 5

1. apoplast route-movement through cell walls and space btwn the cells
2. symplast route-cytoplasm contiuum between cells connected by plasmodesmata
3. transmembrane route-membrane transport between cells and across the membranes of vacuoles within cells

Question 6

How do ions accumulate in root cells

Answer 6

active transport because mineral ion concentration in the soil is much lower than the plant

Question 7

What are essential minerals to plants

Answer 7

phosphorus, potassium, nitrogen, and calcium

Question 8

what regulates transpiration in plants

Answer 8

guard cells

Question 9

how do guard cells open

Answer 9

they are hypertonic to surrounding cells, so water flows into them and turgor pressure opens them up

Question 10

explain how water and co2 entry can be controlled

Answer 10

stomates are usually open during the day (take in co2) and closed at night (prevent water loss)

• can open at night for low co2 levels
• can close during day to prevent water loss

Question 11

how does the transpiration rate increase?

Answer 11

increases with temperature and wind velocity

Question 12

how does transpiration rate decrease?

Answer 12

decreases with increasing atmospheric humidity due to more water vapor in atmosphere

Question 13

How do plants limit water loss in drought conditions

Answer 13

dormancy

• loss of leaves
• reducing number of stomata

Question 14

what are the negative effects of flooding on a plant

Answer 14

abnormal growth

-oxygen deprivation

Question 15

How do plants deal with salty environments (3 ways)

Answer 15

-supply oxygen to submerged roots and control salt balance
-secrete salt
-leaves with large amounts of water to dilute salts
pneumatophores-long air filled roots that emerge above mud to give oxygen to submerged roots

Question 16

What does the Phloem do

Answer 16

transports mono and disaccharides to rest of plant for energy needs and storage
-transports hormones, mRNA, and other molecules

Question 17

what is translocation

Answer 17

in the phloem, it provides building blocks for actively growing regions of the plant

Question 18

What is the pressure flow theory

Answer 18

model describing the movement of carbohydrates in phloem
-dissolved carbohydrates flow from a source (tissues) and are released at a sink (developing fruit, growing root and stem tips)