Chapter 9 Nutrition and Transport in Flowering Plants

Question 1

why does a leaf blade have a large flat surface?

Answer 1

-so that it can obtain the maximum amount of light for photosynthesis
- its thin so that carbon dioxide can rapidly reach the inner cells

Question 2

what is the upper epidermis made of?

Answer 2

single layer of closely packed cells covered by a waxy and transparent cuticle

Question 3

why is there a cuticle covering the cells?

Answer 3

to prevent evaporation of water vapour

Question 4

what’s the difference between palisade and spongy mesophyll in shape

Answer 4

the cells in palisade mesophyll is more elongated while spongy is more irregular

Question 5

which part of the leaf has the most chloroplast

Answer 5

palisade mesophyll

Question 6

where is the main site of photosynthesis

Answer 6

palisade mesophyll as it has the more chloroplast

Question 7

which part of the leaf contains transport tissue (xylem and phleom)

Answer 7

spongy mesophyll

Question 8

what are the intercellular air spaces for ?

Answer 8

gas exchange and evaporation

Question 9

what is the function of stomata

Answer 9

it opens in the presence of light, allows carbon dioxide to diffuse in and oxygen to diffuse out

Question 10

how does carbon dioxide enter the leaf

Answer 10

1.carbon dioxide diffuses in from surrounding air through stomata into the intercellular air spaces
2. it dissolves in the thin film of moisture covering the cells
3. diffuses into the cells

Question 11

what is the function of xylem

Answer 11

1.transport water and mineral salts from the roots to the leaves
2. provide mechanical support

Question 12

what are the adaptations of xylem

Answer 12

1. long hollow continuous tube without cytoplasm or cross walls-> reduces resistance to water flowing through
2. inner walls with lignin (hard substance) -> prevents collapse

Question 13

what the function of phloem

Answer 13

transport food from leaves to other parts of the plant( translocation)

Question 14

whats the adaptation of phloem

Answer 14

made of long tubes, with rows of living cells with cross walls separating the cells –> allow rapid flow of food substances

Question 15

what’s in a vascular bundle?

Answer 15

from the inside,
xylem, cambium, phloem

Question 16

what’s the word equation of photosynthesis?

Answer 16

carbon dioxide+water —-light and chlorophyll— –> glucose +oxygen

Question 17

what does alcohol do to the leaf

Answer 17

it removes the green pigment chlorophyll

Question 18

what does sode lime and potassium hydroxide do

Answer 18

it absorbs co2

Question 19

what are factors affecting rate of photosynthesis

Answer 19

light intensity, amount of carbon dioxide, temperature

Question 20

how does light affect rate of photosynthesis?

Answer 20

as light intensity increases, the rate of photosynthesis increases

Question 21

how does concentration of carbon dioxide affect rate of photosynthesis

Answer 21

as carbon dioxide increases, the rate of photosynthesis increases

Question 22

how does temperature affect rate of photosynthesis

Answer 22

as temperature increases to the optimum temperature, the rate of photosynthesis increases.

Question 23

what happens if temperature is above the optimum temperature

Answer 23

the rate of photosynthesis decreases as enzymes would denature

Question 24

what happens to excess glucose during the day

Answer 24

it is converted to starch

Question 25

what happens to glucose in darkness

Answer 25

as photosynthesis stops, the glucose that was converted to starch during the day is converted back to glucose by enzymes

Question 26

what is translocation

Answer 26

the transport of food, sucrose and amino acids in the phleom tissue

Question 27

why does a tree grow downwards and sideways

Answer 27

downwards: can reach mineral salts and water
sideways: to provide stability for the plant

Question 28

how does water enter the plant

Answer 28

as the cell has a higher water potential than the next cell, it enters by osmosis

Question 29

how is the root hair cell adapted?

Answer 29

1.long and narrow extension –> increases surface area to volume ratio –> increases rate of adsorption
2. cell membrane prevents cell sap from leaking out –> lower water potential than soil solution –> water entering the roots by osmosis

Question 30

what’s is transpiration

Answer 30

the loss of water vapour from the leaves and stems of plant through stomata of leaves

Question 31

what is transpiration pull

Answer 31

the suction force which pulls water and mineral salts up the plant

Question 32

how does water move inside the leaf?

Answer 32

1. water evaporates from the thin film of moisture surrounding the mesophyll cells, forming water vapour in the intercellular air spaces
2. water vapour diffuses through stomata
3. the water moves out to replenish the mesophyll cells
4. water moves out by osmosis as the water potential in the mesophyll is lower

Question 33

why is transpiration important

Answer 33

1. it draws water and mineral salts from the roots to other parts of plant
2. evaporation of water cools the plant, prevent it from being scorched

Question 34

what are factors affecting the rate of transpiration

Answer 34

HWLT
wind, temperature, light intensity, humidity

Question 35

how does wind affect rate of transpiration

Answer 35

when there is wind
1. water vapour outside is blown away
2. concentration gradient from water inside and outside is steep
the stronger the wind, steeper the concentration gradient, higher the rate of transpiration

Question 36

how does temperature affect rate of transpiration?

Answer 36

as temperature rises:
1. rate of evaporation increases
2. concentration gradient inside and outside the leaf steeper
higher the temperature, higher the rate of transpiration

Question 37

how does light intensity affect rate of transpiration

Answer 37

in bright light:
1. stomata opens and becomes wider
2. more water is lost from leaf
as light intensity increases, rate of transpiration

Question 38

how does humidity affect rate of transpiration

Answer 38

when more humid
1. concentration gradient between leaf and surrounding air is less steep
as humidity increases, concentration gradient less steeper, lower rate of transpiration

Question 39

what is wilting

Answer 39

when rate of transpiration exceeds rate of absorption of water, the plant will become flaccid and the plant wilts

Question 40

what are advantages of wilting

Answer 40

the leaf folds up:
1. surface area exposed to light reduced –> reduce exposure of stomata –> reduce rate of water loss –> cause guard cells to be flaccid –> rate of transpiration is reduced

Question 41

what is disadvantages of wilting

Answer 41

as stomata closed –> carbon dioxide entering reduced –> decreased rate of photosynthesis
reduces surface area exposed to light –> reduce rate of photosynthesis