Photosynthesis

Question 1

photosynthesis

Answer 1

this is the process by which plants manufacture carbohydrates from new materials using energy from light

Question 2

where does the plant get water + co2 from?

Answer 2

carbon dioxide = through stomata

water = soil from roots, up thru xylem tubes

Question 3

what does chlorophyll do?

Answer 3

chlorophyll is a green pigment tbat transfers light energy into chemical energy in molecules, for the synthesis of carbohaydrates

Question 4

chemical eqution

Answer 4

carbon dioxide + water makes glucose and oxygen

Question 5

factors necessary for photosynthesis

Answer 5

carbon dioxide

water

chlorophyll

sunlight

suitable temperature

Question 6

what is glucose used for?

Answer 6

• used in respiration to provide energy
• converted into other sugars such as fructose for fruit and sucrose which is transported to other parts if the plant in phloem tissue as a source of energy
• used to make cellulose for new cell walls
• used to make amino acids for building proteins
• used to make fatty acids and glycerol to build lipids
• transferred into vacuoles to form cell sap which helps support the cell by turgor pressure
• excess is stored as starch

Question 7

what is oxygen used for

Answer 7

used by plant for aerobic respiration

excess oxygen is excreted through the stomata

Question 8

what do plants need nitrate ions for

Answer 8

making amino acids and proteins

Question 9

what do they need magnesium ions for

Answer 9

for making chlorophyll

Question 10

a deficiency of nitrate ions

Answer 10

means the plant is not able to make protein which results in stunted growth, weak stem and yellow leaves

Question 11

a deficency of magnesium ions

Answer 11

the plant is not able to make chlorphyll which results in the yellowing of leaves leading to reduced photosynthesis and stunted growth

Question 12

why is the leaf greener on the upper surface

Answer 12

higher concentration of chlorphyll as that is where rhe light intesity is

Question 13

how are leaves adapted

Answer 13

• broad: large surface area
• the xylem tissue in the veins gives support (it has lignin in it‘s walls) so that it can be flat and absorb as much light as possible
• palisade cells are near the upper surface of the lead, so light can reach chloroplasts easily as it only needs to pass through the transparent upper epidermis
• stomata on lower surface for gas exchange. reduce water loss by transpiration
• air spaces between spongy mesophyll so that co2 can diffuse easily up to the palisade mesophyll and o2 can diffuse out easily
• phloem to transport sucrose and amino acids

Question 14

why do plants store carbohydrates as starch ratjer than sugar?

Answer 14

starch is insoluble and does not affect the water concentration