bio chap 9 - nutrition and transport in flowering plants Flashcards

Question

explain how the guard cells control the closing of the stoma

Answer 1

when the leaf loses too much water, the stomata close as excess evaporation causes guard cells to become flaccid this prevents excessive water loss by the leaf

Answer 2

in the daylight, photosynthesis occurs carbon dioxide in leaf is rapidly used up co2 conc in leaf is lower than in the atmospheric air causing a diffusion gradient to exist this causes co2 to diffuse from the surrounding air through stomata into intercellular air spaces in the leaf surfaces of mesophyll cells are always covered by a thin film of water so that co2 can dissolve in it dissolved co2 diffuses into cells

Answer 3

the xylem transportd water and dissolved mineral salts to the leaf from the roots once out the veins, water and mineral salts move from cell to cell through mesophyll and lewf

Answer 4

once the green cells receive the essential raw materials such as co2 and h2o, it manufactures food by photosynthesis phloem transports sugars made in the leaf to other parts of the plant

Answer 5

conducts water and dissolved mineral salts from the roots to the stems and leaves provides mechanical support for the plant xylem tissue consists mainly of xylem vessels made up of many dead cells

Answer 6

the xylem has an empty lumen without cytoplasm or cross walls -> xylem vessels form a long hollow continuous tube which stretches from root to leaf -> lack of cross walls in the xylem vessels reduce resistance to water flowing through the xylem

Answer 7

inner walls of xylem vessels are strengthened by deposits of lignin it is a hard and rigid substance that prevents collapsing of the vessel

Answer 8

all xylem vessels provide mechanical support to the whole plant lignin is deposited in the form of rings or the whole vessel may be lignified except in the regions called pits

Answer 9

conducts manufactured food substances (glucose and amino acids) from the green parts of the plant to other parts of the plant consists mainly of long tubes made up of a row of living cells

Answer 10

each tube stretches form the leaf to other parts of the plant the cross walls separating the cells have a lot of minute pores this allows rapid flow of manufactured food substances through the tube

Answer 11

within a vascular bundle, the xulem is located closer inside the phloem lies outside the xylem with a tissue called the cambium between them the stem is covered by a layer of celle called the epidermis epidermal cells are protected by a waxy and waterproof cuticle and reduces the evaporation of water from the stem

Answer 12

xylem is closer to upper surface of the leaf phloem is closer to the lower surface of the leaf

Answer 13

the process where chlorophyll absorbs the energy from light to make glucose from co2 and water and releases o2

Answer 14

co2 +h2o -> (light up, chlorophyll down) glucose + oxygen

Answer 15

when light intensity increases the rate of photosynthesis increases because more light is supplied to the plant causing an increase in the amount of energy that can be used for photosynthesis after a certain point, rate of photosynthesis remains constant even when light intensity increases

Answer 16

when the conc of co2 increases, the rate of photosynthesis increases because more co2 is available for the plant to carry out photosynthesis and produce more glucose after a certain point the rate of photosynthesis remains constant evej when co2 conc increases

Answer 17

when temperature increases to optimum temperature, the rate of photosynthesis increases beyond the optimum temperature, the rate of photosynthesis decreases rapidly as enzymes involved are being denatured

Answer 18

used immediately in the leaves for cellular respiration provide energy for cellular activities forming cellulose cell walls

Answer 19

conversion between glucose and starch in daylight, excess glucose made is converted to starch for storage in darkness, starch is converted back to glucose

Answer 20

sucrose is transported to other parts kf the plant/storage organs such as seeds and root tubers sucrose is converted into other forms of storage compounds at storage organs sucrose may be converted back to glucose by enzymes for respiration sucrose is a component of nectar in flowers to attract insects for pollination

Answer 21

amino acids form proteins needed to build protoplasm in leaves transported to other parts of the plant for synthesis of new protoplwsm for storage as proteins

Answer 22

glucose is utilised to form fats for storage synthesis of new protoplasm used in cellular respiration

Answer 23

photosynthesis makes chemical energy available for organisms that cannot make their own food during photosynthesis, chlorophyll absorbs energy from light and transfers it to chemical stores of energy in carbs these carbs are converted to fats, proteins and other organic compounds that become food for other organisms plants are producers in food chains and all organisms obtain chemical energy directly or indirectly from them

Answer 24

photosynthesis removes co2 and release o2 o2 allows living things to carry out respiration and release energy for all cell activities this mantains a constant level of oxygen and co2 in the atmosphere

Answer 25

coals are formed from trees when coal is burnt, energy in chemical store of coal is used to drive machinery and transferred to other energy stores

Answer 26

vary the distance, xcm, of light source from the plant for each investigation a shorter distance would give a stronger light intensity co2 conc and temp are kept constant results are obtained by counting number or bubbles releasee per time

Answer 27

use different concs of xm3 of solution sodium hydrogen carbonate is a source for co2 gas constant factors are light intensity and co2 conc results obtained by counting number of bubbles released per time

Answer 28

use dif temperatures, x°c of solution constant factors are light intensity and temp results obtained by counting number of bubbles released per time

Answer 29

when photosynthesis is carried out actively, glucose is formed more quickly than it is used up causing excess glucose converted into starch for storage in the leaf

Answer 30

starch can be formed in the roots/underground storage organs of plants

Answer 31

in darkness, no photosynthesis occurs, enzymes cannot convert starch into sucrose causing no starch to be left in the leaves this ensures that starch is not present in leaves before experiement so that we can assume that all starch present in the leaves after experiment must have been formed during the experiment

Answer 32

transport of food, mainly sucrose in the phloem tissue

Answer 33

a ring of bark with phloem is removed from the stem of a woody plant after some time, the stem above the cut region swells immediately this is because when the phloem was removed, food substances from the leaves cannot reach the stem below the cut region food substances accumulate in the region above the cut region and swells up

Answer 34

1. each root hair is a narrow extemsion of epidermal cell it grows between the soil particles, coming into close contact with surrounding soil solution 2. film of liquid, a dilute solution of mineral salts, surrounds each soil particle 3. cell sap in the RHC is a concentrated solution of sugars and salts hence it has a lower water potential than soil solution cell sap and soil solution is separated by ppm of RHC water enters root hair by osmosis 4. entry of water dilutes cell sap cell sap of RHC has a higher water potential than that of the next cell water passes by osmosis from RHC to the inner cell 5. water passes from the inner cell to the next cell of the cortex process continues until the water enters xylem vessels and moves up the plant

Answer 35

when the conc of certain ions in soil solution is higher than in the RHC, and enter the cell by diffusion when conc of ions in soil solution is lower than in the RHC sap, energy used to absorb ions against a conc gradient

Answer 36

RHC has a long and narrow extension which increases the surface area to volume ratio and increases the rate of absorption of water and mineral salts cell membrane of RHC prevents cell sap from leaking out cell sap contains sugars, amino acids, and salts when the cell sap's water potential is lower than the soil solution, water enters roots by osmosis

Answer 37

loss of water vapour from the aerial parts of a plant, mainly through the stomata of the leaves

Answer 38

1. when water moves out the mesophyll cells, it forms a thin layer of moisture over their surfaces, then it evaporates into the intercellular air spaces 2. this causes the concentration of water vapour in the intercellular air spaces to increase and allows it to diffuse out through the stomata this causes a loss of water vapour from the leaves / transpiration 3. thin film of moisture is replenised by more water moving out of mesophyll cells as it evaporates 4. this causes water potential of their cell sap lesser than that of mesophyll cells deep inside the leaf this allows water to move from the inner mesophyll cells to the thin film of moisture via osmosis 5. mesophyll cells deeper inside the leaf extract water from the xylem vessels via osmosis this produces suction force that pulls water upward in the vesells, the transpiration pull

Answer 39

water can be transported to leaves for photosynthesis which keep cells turgid and replace water lost by cells turgid cells enable the leaves to spread out widely to trap light for photosynthesi transpiration pull moves water & mineral salts up the roots to the stems and leaves

Answer 40

a leaf exposed to direct sunlight will absorb heat its temp might increase to a level that would kill the leaf its water evaporating from the leaf helps cool the leaf down

Answer 41

factor: light intensity changed factor: light intensity - place one set up in a sunny area and another in a dark room constant variables: air humidity, wind conditions, temperature 1. record initial weight of apparatus 2. record final weight of the apparatus 3. rate of transpiration = loss in weight/time taken

Answer 42

an instrument used to measure the uptake of water by a plant

Answer 43

water uptake = water loss by transpiration as some water may be used by plants for photosynthesis

Answer 44

when the plant transpires, it absorbs water from the potometer to replace water loss by evaporation through the stomata this causes water in the collumn in the capillary tube to move from x to y

Answer 45

a cm + t second -> a is the length/ volume moved from x to y -> t is time taken for air bubbles to move from x to y

Answer 46

plant must be cut underwater to prevent air being trapped in the xylem cut end is kept immersed in water for a few hours before use this is to allow shoot to adjust to the conditions in the potometer

Answer 47

transpiration will take place more rapidly when the surrounding temperature is higher this is because water from leaves will evaporate more readily at higher temperatures

Answer 48

in still air, air surrounding a leaf becomes saturated with water vapour that diffuses out of it causing less steep concentration gradient of water vapour between leaf and air hence rate of transpiration decreases

Answer 49

light affects the size of stomata in daylight, stomata are open water vapour in the leaves can easily diffuse out into the atmosphere, increasing the rate of transpiration at night, stomata close and transpiration is greatly reduced

Answer 50

intercellular air spaces in a leaf are usually saturated with water creating a water vapour concentration gradient between the leaf and surrounding air the decreasing air humidity causes a lower amount of water vapour in the air this causes a steeper concentration gradient between the leaf and the air increasing the rate of transpiration hence water vapour can diffuse from the leaf into drier or less humid air causing a steeper concentration gradient of water vapour between the leaf and air

Answer 51

sunken stomata that lie in grooves in the upper surface of the leaves have numerous tiny hairs that trap water vapour diffusing out of the stomata this gives rise to increasing humidity around the stomata that helps reduces rate of transpiration

Answer 52

pressure exerted by the fluid, inside the cells of a plant against the cell wall

Answer 53

to support the leaf and keep it firm as it can spread out widely to absorb light for photosynthesis

Answer 54

when rate of transpiration is more than the rate of absorption by the roots in strong light, cells lose their turgor and become flaccid, causing the plant to wilt

Answer 55

their leaves fold up to decrease surface area exposed to sunlight, decreasing exposure of stomata to the atmosphere, causing a decrease in the rate of water loss through stomata guard cells become flaccid and close stomata lowering the rate of transpiration

Answer 56

there is a decrease in the amount of carbon dioxide entering the leaves causing carbon dioxide to be a limiting factor that decreases the rate of photosynthesis in the plant wilting decreases the surface area exposed to light, decreasing the rate of photosynthesis

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bio chap 9 - nutrition and transport in flowering plants Flashcards

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