Topic 3 - Plant Nutrition & Transport

Question 1

Leaves

Answer 1

site of photosynthesis

Question 2

How is water transported to the leaves

Answer 2

through the roots and xylem vessels

Question 3

waxy cuticle

Answer 3

prevents water loss by evaporation

Question 4

upper epidermis

Answer 4

transparent, light is able to reach chloroplasts in palisade mesophyll

Question 5

palisade mesophyll

Answer 5

tightly packed with chloroplasts, maximising light absorption for photosynthesis

Question 6

spongy mesophyll

Answer 6

air spaces for gas exchange, makes cells more permeable

Question 7

lower epidermis

Answer 7

contains guard cells and stomata

Question 8

guard cells

Answer 8

absorb water from surroundings to regulate gas exchange

by opening + closing stomata

Question 9

water diffusing into the guard cells by osmosis

Answer 9

guard cells become turgid ++ stomata open

Question 10

water diffusing out of the guard cells by osmosis

Answer 10

guard cells become flaccid + stomata close

Question 11

stomata

Answer 11

holes in the bottom of the lead which open and close to allow water and gases to enter and exit

Question 12

vascular bundle

Answer 12

contains xylem and phloem vessels

Question 13

phloem vessel

Answer 13

carries food (amino acids, glucose)

Question 14

xylem vessel

Answer 14

carries water and mineral salts

Question 15

guard cells at night

Answer 15

they close as photosynthesis isnt taking place

Question 16

why are stomata at the bottom of the leaf

Answer 16

because the lower surface is cooler and more shaded -> less water evaporates

Question 17

plant form of stem cells

Answer 17

meristem tissue

found at growing roots and shoots of plants, differentiate into different cell types

Question 18

photosynthesis

Answer 18

the conversion of light energy into chemical energy in plants

ENDOTHERMIC reaction

Question 19

chlorophyll

Answer 19

green pigment found in chloroplasts

absorbs light from the sun and converts it into chemical energy

Question 20

photosynthesis word equation

Answer 20

carbon dioxide + water —> glucose + oxygen

Question 21

photosynthesis symbol equation

Answer 21

6CO2 + 6H2O —> C6H12O6 + 6O2

Question 22

glucose is the main product wanted in photosynthesis

what is it needed for?

Answer 22

• cellular respiration
• to make cellulose + strenghten cell walls
• can combine to make starch
• good store of starch

Question 23

factors affecting photosynthesis

Answer 23

light intensity
- because it requires light energy from sun, more light intensity = more photosynthesis

temperature
- temperatures close to optimum = more photosynthesis due to optimum enzyme acticity

carbon dioxide concentration
- because it is a reactant, more carbon dioxide = more photosynthesis

chlorophyll
- because it requires chlorophyll, more chlorophyll = more photosynthesis
- not enough chlorophyll = tobacco mosaic virus

all of these factors will eventually plateau as another factor becomes limiting

Question 24

mineral ions

Answer 24

naturally charged particles found in the soil

Question 25

how do plants obtain mineral ions in the soil

Answer 25

by active transport through root hair cells

Question 26

# mineral ions use of magnesium

Answer 26

to produce chlorophyll

Question 27

# mineral ions if magnesium is deficient...

Answer 27

yellow leaves stunted growth

Question 28

# mineral ions use of nitrates

Answer 28

to make amino acids (proteins)

Question 29

# mineral ions if nitrates are deficient...

Answer 29

yellow leaves and stunted growth

Question 30

transpiration

Answer 30

evaporation of water from the leaves of plants occurs in xylem vessels

Question 31

how are the xylem vessels adapted for transpiration?

Answer 31

- walls strenghtened by lignin - are able to suck water upwards due to cohesive and adhesive qualities

Question 32

transpiration stream

Answer 32

chain of water evaporating out of leaves

Question 33

translocation

Answer 33

movement of cell sap (sugar+water) up and down the plant

Question 34

how does temperature affect transpiration rate

Answer 34

warmer = higher rate of transpiration because water particles have more kinetic energy more likely to evaporate + diffuse out of stomata

Question 35

how does light intensity affect transpiration rate

Answer 35

bright light intensity = more photosynthesis this causes stomata to open for carbon dioxide to enter therefore more water can evaporate out of stomata = more transpiration

Question 36

how does air flow affect transpiration rate?

Answer 36

high air flow (e.g. wind) = more transpiration because wind can blow water molecules in surrounding air away this steepens the concentration gradient = more transpiration

Question 37

how does humidity affect transpiration rate?

Answer 37

high humidity = less transpiration because humidity means more water vapour in air more water in air = shallow concentration gradient = less transpiration