transpiration

Question 1

where are most stomata found?

Answer 1

lower epidermis

Question 1

definition of transpiration?r

Answer 1

the loss of water by evaporation from the leaves and surface of the plant

Question 2

how stomata’s open?

Answer 2

-two guard cells either side that control stomata’s actions
-light=guard cells photosynthesise
-increasing water potential so they open
-dark=no photosynthesis, decreasing water potential so water moves in via osmosis
-when full of water they open

Question 3

why do stomata’s need to open?

Answer 3

-so CO2 can diffuse in for photosynthesis
-water loss is an unfortunate consequence-98%
-helps transport mineral ions, cool the leaf as the water evaporates- keeps cells turgid

Question 4

where does water enter the leaves?

Answer 4

-firstly enters from soil into root hair cells
-water gets pulled up by the xylem
-water molecules are sticky, so they stick together and get pulled NOT PUSHED up

Question 5

what are the 5 factors transpiration?

Answer 5

humidity, temperature, wind speed, light intensity, water availability

Question 6

describe how temperature affects transpiration?

Answer 6

hotter temp=faster evaporation as water molecules have more kinetic energy

Question 7

describe how humidity affects transpiration?

Answer 7

very humid air- more water vapour=smaller concentration gradient, so slower transpiration

Question 8

describe how wind speed affects transpiration?

Answer 8

still air- transpiring leaf becomes full of water vapour- transpiration slows down
moving air- water vapour decreases- so transpiration increases

Question 9

describe how light intensity affects transpiration?

Answer 9

daylight causes stomata to open to allow CO2 for photosynthesis
allows more water to diffuse out of leaves into atmosphere

Question 10

describe how water supply affects transpiration?

Answer 10

less water=stomata to close=reduces transpiration and delaying wilting

Question 11

what is the job of root hair cells?

Answer 11

to absorb water from the soil

Question 12

how are root hair cells adapted to their job?

Answer 12

lots of hairs to increase large SA, permeable for osmosis and higher water potential in soil than cells, thin walls- short distance
mineral ions actively transported into root hair cell

Question 13

how to set up a potometer?

Answer 13

-set up under water to prevent air leaks
-cut the shoot
- check for air leaks and cover use patroleum jelly
-put bung in
-measure starting position of air bubble
-measure ending position of air bubble after 5 mins
-find difference and repeat 3x