plant structures and their functions

Question 1

where does photosynthesis take place

Answer 1

the leaves, more specifically the chloroplasts

Question 2

what is the job of chloroplasts

Answer 2

they contain a pigment called chlorophyll that absorbs light, making plants green

Question 3

how do chlorophyll perform photosynthesis

Answer 3

they absorb light in little packets of energy and uses the energy to convert carbon dioxide and water

Question 4

what is the word equation for photosynthesis

Answer 4

carbon dioxide + water —(light)— glucose + oxygen

Question 5

what is the symbol equation for photosynthesis

Answer 5

6CO2 + 6H2O → C6H12O6 + 6O2.

Question 6

what type of reaction is photosynthesis and why

Answer 6

endothermic as energy is taken from the surroundings by chloroplasts

Question 7

what are the 5 things plants need glucose for

Answer 7

• cellular respiration
• make cellulose
• make starch
• making amino acids
• make oils/fats

Question 8

what is cellulose

Answer 8

a complex carbohydrate made by glucose to strengthen cell walls

Question 9

what is starch and why do plants need it

Answer 9

a compact version of glucose, used as a long term energy source for when photosynthesis is not happening, its good because its insoluble so will not draw in water

Question 10

why do plants need to make amino acids from glucose

Answer 10

they combine glucose and nitrate ions to make proteins

Question 10

what are the 4 factors affecting photosynthesis

Answer 10

• light intensity
• temperature
• carbon dioxide
• chlorophyll

Question 11

how does chlorophyll affect the rate of photosynthesis

Answer 11

chlorophyll is a pigment that absorbs light energy and different amounts of chlorophyll means the plant cannot absorb the required amount

Question 12

what does the term plateaued mean on a graph

Answer 12

the rate stops increasing as another factor is in affect

Question 13

how does temperature affect the rate of photosynthesis

Answer 13

it initially rises as enzymes can work quickly and molecules move faster, but past the optimum temperature, the enzymes begin to denature and the rate begins to drop

Question 14

how can farmers artificially make light intensity, co2 and temperature

Answer 14

• in cold climates, they put crops in light houses to trap sun’s heat to increase temperature or lamps
• they might pump co2 into the greenhouse or use a paraffin heater which makes heat and co2
• fertiliser to ensure correct minerals
• pesticides to kill unwanted bugs

Question 15

what is translocation

Answer 15

the movement of sugars around a plant

Question 16

what are phloem tubes

Answer 16

long stacks of phloem cells sugars pass through

Question 17

what direction can phloem cells transport materials

Answer 17

up or down

Question 18

what are the pores in a phloem cell

Answer 18

gaps which enable to movement of cell sap

Question 19

what are xylem tubes

Answer 19

long columns of xylems, which don’t have ends, effectively making one long hollow tube

Question 20

what material are xylem cells strengthened by

Answer 20

lignin

Question 21

what do xylem tubes do

Answer 21

transport water and mineral ions from the roots up the stem into the leaves

Question 22

how does water constantly move up the plant

Answer 22

there is constantly water molecules in the xylem column, and when water is evaporated in the leaves (TRANSPIRATION), one moves up into its place (TRANSPIRATION STREAM)

Question 23

what is transpiration

Answer 23

water in the leaves evaporating

Question 24

what is the transpiration stream

Answer 24

the constant stream of water molecules up a xylem tube

Question 25

what are the 4 factors affecting the rate of transpiration

Answer 25

• light intensity
• temperature
• air flow
• humidity

Question 26

how does light intensity affect the rate of transpiration

Answer 26

the brighter the light intensity, the more photosynthesis taking place meaning stomata are open, leading more water to evaporate and a higher rate

Question 27

how does temperature affect the rate of transpiration

Answer 27

when it is warm, the water molecules have more energy so more likely to evaporate, increasing the rate

Question 28

how does air flow affect the rate of transpiration

Answer 28

because of the constant flow of water inside the leaf, the concentration gradient will be larger in the leaf than outside, so it is easy for the water to leave the leaf, when the air flow is high (windy) the water will quickly be blown away, keeping the concentration gradient high, increasing the rate

Question 29

what is humidity

Answer 29

a measure of how much water vapour is in the air

Question 30

how does humidity affect the rate of transpiration

Answer 30

the more humid it is, the lower the rate as there is a decrease in the concentration gradient, as there is a lot of water outside the plant, meaning less water will diffuse out and the rate will decrease