2E, 2G flowering plants

Question 1

how does a plant make starch?

Answer 1

first it produces glucose, then it is joined together to make starch molecules.
the carbon and oxygen atoms in C6H12O6 (glucose) come together from the carbon dioxide in the air around the plant. the hydrogen atoms come from water

Question 2

what is photosynthesis?

Answer 2

photosynthesis is a chemical process that uses light energy from the sun to create glucose and oxygen from water and carbon dioxide

Question 3

what is the word equation for photosynthesis?

Answer 3

carbon dioxide+water->glucose+oxygen
(on the arrow is light)

Question 4

what is the chemical equation for photosynthesis?

Answer 4

6CO2+ 6H20 -> C6H12O6 +6O2

Question 5

what is the role of chlorophyll?

Answer 5

the green pigment, chlorophyll, is used to absorb light energy needed for the reaction to take place. the products of the reaction (glucose and oxygen) contain more energy than CO2 and H2O because in other words, photosynthesis converts light energy into chemical energy.

Question 6

label a leaf

Answer 6

it must contain:
cuticle, chloroplasts, upper epidermis, palisade cells, spongy cels, mesophyll, xylem, phloem, vein, lower epidermis, guard cell, stoma (pore), air space

Question 7

how is the cuticle adapted to its function?

Answer 7

it s waxy to reduce water loss by evaporation and acts as a barrier to the entry of disease-causing micro-organisms such as fungi and bacteria

Question 8

how is the the upper epidermis adapted to its function?

Answer 8

it is thin and transparent to allow light to enter palisade mesophyll layer underneath it. it also have few chloroplasts

Question 9

how is the lower epidermis adapted to its function?

Answer 9

has many stomata to allow CO2 to diffuse into he leaf to reach photosynthetic tissues. They also allow oxygen and water vapour to diffuse out. It also contains the guard cell which opens and closes the stomata

Question 10

how is the Palisade mesophyll adapted to its function?

Answer 10

Column-shaped (long and thin to increase SA:VOL ratio) cells tightly packed with chloroplasts to absorb more light, maximising photosynthesis. they are also close to the source of light

Question 11

how is the spongy mesophyll adapted to its function?

Answer 11

it is loosely packed, with more rounded cells allowing gases to diffuse. Contains internal air spaces that increase the surface area to volume ratio for the diffusion of gases (mainly carbon dioxide). less chloroplast.

Question 12

how is the guard cell adapted to its function?

Answer 12

changes shape to open and close the stomata to allow carbon dioxide to diffuse in, oxygen to diffuse out

Question 13

how is the stomata adapted to its function?

Answer 13

Where gas exchange takes place: opens during the day, closes during the night. Evaporation of water also takes place from here. In most plants, found in much greater concentration on the underside of the leaf to reduce water loss

Question 14

how is the vascular bundle adapted to its function?

Answer 14

Contains xylem and phloem to transport substances to and from the leaf

Question 15

how is the xylem adapted to its function?

Answer 15

Transports water (from root hair cells to be evaporated in leaf) and mineral ions (magnesium, nitrate, phosphorus) by xylem vessels into the leaf for mesophyll cells to use in photosynthesis and for transpiration from stomata

Question 16

how is the phloem adapted to its function?

Answer 16

Transports sucrose and amino acids around the plant

Question 17

what is translocation?

Answer 17

the movement of food substances from stems to growing tissues and storage

Question 18

what happens when respiration is more common than photosynthesis and why might this happen?

Answer 18

more CO2 is given out. this happens in dim light/when it is dark. this also means that when there is more light intensity, there is less CO2 e.g., in the afternoon there is less CO2 in the atmosphere than when it is dark when it is dark less CO2 being absorbed and respiration is still taking place

Question 19

what is a limiting factor?

Answer 19

something that prevents the rate of reaction from increasing

Question 20

how does Carbon Dioxide affect photosynthesis?

Answer 20

As the concentration of Carbon Dioxide increases, the rate of Photosynthesis will increase
As Carbon Dioxide is a reactant in Photosynthesis, the increase in Carbon Dioxide concentration will allow more Photosynthesis to occur, hence increasing the rate of Photosynthesis
However, as concentration of Carbon Dioxide increases beyond a certain point, rate of Photosynthesis with plateau as another factor will be the limiting factor

Question 21

how does temperature affect photosynthesis?

Answer 21

As temperature increases towards optimum, the rate of Photosynthesis will increase
This is because the increase in temperature towards optimum will allow optimum enzyme activity for Photosynthesis-related enzymes, hence increasing the rate of photosynthesis
However, as temperature increases above optimum, enzymes involved in Photosynthesis will denature, therefore causing the rate of Photosynthesis to decrease

Question 22

how does light intensity affect photosynthesis?

Answer 22

As light intensity increases, the rate of Photosynthesis will increase
As Photosynthesis can only occur under the presence of light, the increase in light intensity will therefore allow more Photosynthesis to occur, increasing the rate of Photosynthesis
However, as light intensity increases beyond a certain point, the rate of Photosynthesis will plateau as another factor is the limiting factor

Question 23

what happens to glucose in a plant

Answer 23

most glucose is made into starch for storage, however glucose can also be converted into fructose, disaccharide sucrose (main sugar carried in the phloem), and cellulose (plant cell walls). plant cells can also convert glucose into lipids which are needed in the membranes of all cells, and are also an energy store for many seeds and fruits e.g., peanuts, sunflower seeds, olives

Question 24

what is a monosaccharide?

Answer 24

a single sugar unit e.g., glucose, fructose

Question 25

what else is needed apart from glucose from photosynthesis of a plant for energy?

Answer 25

energy provided form the respiration of glucose

Question 26

name all the mineral ions needed from plants

Answer 26

nitrate, phosphate, potassium, magnesium

Question 26

what is nitrate used for? what happens if a plant is deficient in it (symptoms)?

Answer 26

• making amino acids, proteins, chlorophyll, DNA and many other compounds
• limited growth of plant, older leaves turn yellow

Question 27

what is phosphate used for? what happens if a plant is deficient in it (symptoms)?

Answer 27

• making DNA and many other compounds; part od cell membranes
• poor root growth; younger leaves turn purple

Question 28

what is potassium used for? what happens if a plant is deficient in it (symptoms)?

Answer 28

• needed for enzymes of respiration and photosynthesis to work
• leaves turn yellow with dead spots

Question 29

what is magnesium used for? what happens if a plant is deficient in it (symptoms)?

Answer 29

-part of chlorophyll molecule
-leaves turn yellow

Question 30

how is diffusion used in gas exchange in plants?

Answer 30

CO2 and O2 diffuse in an out of the leave without he stomata. the stomata also allow water vapour to escape during transpiration

Question 31

how is the structure of the leaf adapted for photosynthesis?

Answer 31

stomata and guard cells, part of the lower epidermis, allow for gas exchange via diffusion (co2 and o2)
the spongy mesophyll is losely packed so the gasses can diffuse with a high SA:VOL ratio
the palisade mesophyll has column-shaped cells tightly packed with chloroplasts to absorb more light, maximising photosynthesis
the upper epidermis is thin and transparent to allow light to enter palisade mesophyll layer underneath it to allow for photosynthesis

Question 32

how is the structure of the leaf adapted to gas exchange?

Answer 32

it has stomata which allows gases in and out of the leaf (diffusion)
the spongy mesophyll contains internal air spaces that increase the surface area to volume ratio for the diffusion of gases (mainly carbon dioxide)
the guard cells absorbs and loses water to open and close the stomata

Question 33

what is the role of the stomata in gas exchange?

Answer 33

Stomata are tiny pores in the underside of leaves that allow plants to exchange gases with the environment and control water loss
Gas exchange-Stomata allow carbon dioxide to enter the plant and oxygen to exit through diffusion. This movement of gases in opposite directions is called gas exchange.
Water loss- Stomata also allow water vapor to escape the plant through transpiration. Plants regulate the size of the stomatal pores to control water loss.
Guard cells-Each stoma is surrounded by a pair of guard cells that control the opening and closing of the stoma.

Question 34

what affects the opening and closing of the stomata?

Answer 34

Environmental stimuli- The opening and closing of stomata is affected by environmental stimuli such as light intensity, relative humidity, and CO2 concentration. For example, in bright light, the guard cells take in water and become turgid, causing the stomata to open. In low light, the guard cells lose water and become flaccid, causing the stomata to close

Question 35

how does intensity of light affect net movement of CO2 and O2?

Answer 35

less light means less photosynthesis but respiration continues regardless so net movement of CO2 out of plant is higher when it is dark

Question 36

what happens in gas exchange in relation to respiration and photosynthesis?

Answer 36

respiration is uptake of oxygen and release of co2 whereas photosynthesis is the uptake of CO2 and release of oxygen (gas exchange)