CAROUSEL MUST LEARN ALL FOR TEST TODAY

Question 1

guard cells role

Answer 1

guard cells control the opening and closing of stomata and therefore control gas exchange and water loss

Question 2

process of guard cells

Answer 2

1- high rate of photosynthesis causes potassium ions to move into the guard cells
2- this increases the concentration of the solution inside the guard cells
3- water moves into the guard cells by osmosis
4- cell swells unevenly, because the thicker inner edge of the wall is less flexible than the thinner outer edge
5- stomata opens

Question 3

xylem cells vs phloem cells

Answer 3

xylem cells are adapted for transport of water and mineral ions in the transpiration stream

phloem cells are adapted for transport of dissolved sugars (translocation and bidirectionally)

Question 4

describe and explain the effect of temperature on rate of photosynthesis

Answer 4

photosynthesis is controlled by enzymes. at temperatures below optimum there is less kinetic energy, so the enzymes and substrates are less likely to collide, reducing the rate. at temperatures above optimum the enzyme denatures. this means the active site cannot change shape and the substrate cannot bind, reducing the rate

Question 5

explain how structure of root hair cells are adapted to their function

Answer 5

root hair cells have an extension providing a large surface area, to increase the rate of water absorption by osmosis, many mitochondria, to release energy for active transport of mineral ions, and a thin cell wall to reduce diffusion distance for absorption

Question 6

describe the location and role of meristem tissue

Answer 6

meristem tissues is found at the growing tips of shoots and roots. they contain plant stem cells to allow new cells to be produced for grlwth and differentiation to form new plant organs

Question 7

describe and explain effect of light intensity on rate of photosynthesis

Answer 7

the higher the light intensity, the more light can be absorbed by the chlorophyll in the chloroplasts. this means more energy is transferred from the environment, and so the rate increases. at high light intensities there is no further increase in rate of photosynthesis as another factor is limiting it

Question 8

describe how structure of spongy mesophyll is related to its function

Answer 8

the spongy mesophyll contains many irregular-shaped cells, which increases the surface area for carbon dioxide absoprtion. there are many air spaces between the cells, which allow carbon dioxide and oxygen to diffuse quickly through the spongy mesophyll

Question 9

explain how structure of the xylem in a leaf is related to its function

Answer 9

the xylem contain columns of dead cells that are adapted to transport water and dissolved minerals from roots to leaves. they are adapted by being dead cells with a lumen (hollow center) to allow water and minerals to flow through the tubes, and having walls reinforced with waterproof lignin to make the xylem tubes strong and prevent water loss

Question 10

method to investigate effect of light intensirt on rate of photosynthesis of pondweed

Answer 10

1- place the pondweed in a solution of sodium hydrogen carbonate
2- place the pondweed at 5cm from an LED source and leave to equilibriate
3- measure the rate of photosynthesis by eiyher counting the bubbles or collecting and measuring the volume of oxygen released in 5 minutes
4- repeat steps 1-3 at different distances from the lamp
5- draw a graph of oxygen production against distance from lamp and draw a cruved line or best fit

Question 11

economic importance of understanding limiting factors of photosynthesis

Answer 11

limiting factors are important in the economics of enhancing the conditions in greenhouses to gain the maximum rate of photosynthesis while still maintaining a profit. (e.g. burning fuel to increase the temp and carbon dioxide concentration)

Question 12

describe and explain effect of amount of chlorophyll on rate of photosynthesis

Answer 12

choraphyll absorbs light to transfer the energy required for photosynthesis. the more chloraphyll that is present, the more light is absorbed. the increase in energy transfer, increases the rate. at high levels of chloraphyll there is no further increase in rate of photosynthesis as another facotr is limiting it

Question 13

chlorophyll

Answer 13

CHLOROPHYLL

Question 14

three uses of the glucose produced in photosynthesis

Answer 14

1- used in respiration
2- converted to insoluble starch for strorage, this is because starch is insoluvle so if much better four storage than glucose- cell filled with glucose would draw in a lot of warer by osmosis and swell up
3- used to produced cellulose which strengthens the cell walls
4- combined with nitrate ions absorbed from the soil to produce amino acids to make proteins

Question 15

structure of upper epidermis related to func

Answer 15

the upper epidermis is thin and transparent to allow light to pass to the palisade mesophyll

Question 16

why sodim hydrodgen carbonate when measuring photosynthedsis in aquatic plant

Answer 16

sodium hydrodgen carbonate provides carbon dioxide for the plant, controlling its concentration

Question 17

structure of palisade mesophyll of a leaf is related to its func

Answer 17

palisade mesophyll is formed og box shaped cells, stacked together that contain lots of chloroplast. this allows the maximum absorption of light

Question 18

describe how plants use the oxygen produced in photosynthesis

Answer 18

oxygen is used for aerobic resp

Question 19

why bubble coutning photosynthesis is more reproducible

Answer 19

collect the oxygen gas released in a set amount of time, using a measuring cylinder

Question 20

structure of phloem tissue related to func

Answer 20

the phloem contains columns of elongated livign cells that are adapted to transport dissolved sugars from the leaves to rest of plant for immediate use or storage
they are adadpted by containing a little cytoplasm and no nucleus, to allow more efficient transport of food substances, seperated by sieve plates (end walls) that have small pores, to allow movement of sap between phloem cells, and being paired with compainion cells that contain mitochondria to release energy for transport in the phloem

Question 21

structure of guard cells is related to func

Answer 21

guard cells and stomata control gas exchange and water loss. pairs of guard cells have thicker cellulose cell walls on their inner edge. this means that when they absorb water by osmosis and become turgid the cells bend away from each other and open the stomata (pore) between them

Question 22

endothermic reaction

Answer 22

a reaction that transfers energy from environment

Question 23

effect of carbon dioxide conc on rate of photosynthesis

Answer 23

carbon dioxide is a reaction in photosynthesis. the higher the conc of co2, the more likely the molecules will collide with the enzymes, increasing the rate. at high concentrations of carbon dioxide there is no further increase in rate of photosynthesis as another factors is limiting it

Question 24

photosynthesis

Answer 24

an endothermic reaction in which energy is transferred from the environment to the chloraplasts by light

Question 25

why LED bulb of have bottle of water vetween lamp and pondweed

Answer 25

to prevent the pondweed getting hot and so control the variable of temp

Question 26

structure of lower epidermis related to func

Answer 26

lower epidermis contains many pairs of guard cells, which control the opening and closing of stomata to control gsa exchange between the leaf and the atmosphere

Question 27

inverse square law light intensity

Answer 27

as distance dubles, light inteensity qjuarters/ divided by four

Question 28

role of chloroplasts in photosynthesis

Answer 28

chloraplasts are sib cellular structurtes containing chlorophyll to absorb light during photosynthesis