transport in plants- Uplearn

Question 1

in dicotyledonous plants what are substances transported in

Answer 1

xylem
phloem

Question 2

what is transported in the xylem

Answer 2

Water/minerals

Question 3

what is transported in the phloem

Answer 3

organic substances

Question 4

why do plants require specialized transport systems

Answer 4

-meet high metabolic demands
-ensure nutrients reach all tissues
-Overcome low surface area to volume ratio
-Allows diffusion over long distances

Question 5

where does gas exchange take place

Answer 5

in the leaves via the stomata.

Question 6

how is the stomata open and closed

Answer 6

by guard cells

Question 7

what happens during the day with plants

Answer 7

stomata is open and photosynthesis and respiration occur.

Question 8

What happens during the night with plants

Answer 8

Stomata is closed and only respiration takes place

Question 9

what is transpiration

Answer 9

loss of water vapor through stomata via Evaporation/Diffusion

Question 10

what factors increase transpiration

Answer 10

-Light
-Wind
-Humidity
-Temperature

Question 11

how does more light increase transpiration

Answer 11

more open stomata

Question 12

how does higher temp increase transpiration

Answer 12

increase kinetic energy of water molecules so faster evaporation

Question 13

How does increased wind and decreased humidity increase transpiration

Answer 13

less water vapor outside leaf so increase water potential gradient.

Question 14

what two pathways can water take from roots to reach xylem

Answer 14

symplast pathway
apoplast pathway

Question 15

how is water transferred via the symplast pathway

Answer 15

passes through cytoplasm of cells which are connected via plasmodesmata.

Question 16

how is water transfered via the apoplast pathway

Answer 16

travels through cell walls till it reaches casparian strip and then is forced into cell and travels down symplast pathway to xylem.

Question 17

what is the casparian strip

Answer 17

part of apoplast pathway and is impermeable to water

Question 18

what does the cohesion tension theory explain

Answer 18

How water travels up the xylem

Question 19

how the cohesion tension theory work

Answer 19

-evaporation of water lowers water potential in mesophyll cells (in leaf).
-water moves along water potential gradient + pull column of water with it.#
-This makes xylem experience tension, negative pressure within it
-water molecules adhere to the xylem walls being stuck together by H bonds (Cohesion)