B8 Photosynthesis

Question 1

what do all organisms need

Answer 1

food for respiration

Question 2

how do plants make their own food

Answer 2

by respiration

Question 3

how does photosynthesis produce gluocse

Answer 3

by using light

Question 4

where does photosyntheis take place

Answer 4

in the green parts of plants (especially the leaves)

Question 6

the cells in algae and plants leaves are full of what

Answer 6

small green parts called chloroplasts
-contain a green substance called chlorophyll

Question 7

explain the process of photosynthesis

Answer 7

energy is transferred from the environement to the chloroplasts by light
-this energy is then transferred to convert carbon dioxide from the air plus water

Question 8

what type of reaction is photosynthesis

Answer 8

an endothermic reaction
-also needs an input of energy from the environment

Question 9

whats the equation for photosynthesis

Answer 9

light
carbon dioxide + water —– glucose + oxygen

Question 10

for photosynthesis to be successful, what do plants need

Answer 10

-carbon dioxide
-light
-water

Question 11

state the 5ways plants use glucose for

Answer 11

-for respiration
-making cellulose
-making amino acids
-stored as oils or fats
-stored as fats

Question 12

what do limiting factors do

Answer 12

affect the rate of photosynthesis

Question 13

how is the rate of photosynthesis affected

Answer 13

-by the intensity of light
-concentration of CO2
-temperature

Question 14

explain how the following are limiting factors depending on environmental conditions

-by the intensity of light
-concentration of CO2
-temperature

Answer 14

-at night the light is a limiting factor

-in winter, the temperature

-if its warm and bright enough, the amount of CO2 is limiting

Question 15

how is chlorophyll a limiting factor of photosynthesis

Answer 15

the amount of chlorophyll in a plant is affected by disease or environmental conditions

Question 16

state the 3 important graphs for rate of photosynthesis

Answer 16

-not enough light slows down the rate of photosynthesis
-too little carbon dioxide also slows it down
-the temperature has to be just right

Question 17

state the most common way to artificially create the ideal environment for plants to grow

Answer 17

a greenhouse
-they trap the suns heat and make sure the temperature doesn’t become limiting
-in winter a farmer may use a heater
-in summer it may get too hot so they use shades and ventiliation to cool things down

Question 18

state what farmers use in a greenhouse

Answer 18

-artificial light, so after the sun goes down to give their plants more quality photosynthesis time

-increase the level of carbon dioxide in the greenhouse, e,g a paraffin heater

-keep plants enclosed, to free them from pests and diseases, also adding fertilisers to the soil

Question 20

explain how plants are adapted for photosyntheis

Answer 20

-most leaves are broad, giving them a big surface area for light to fall on
-most leaves are thin= diffusion distances for gases is short
-contain chlorophyll in chloroplasts=absorb light
-have veins
-air spaces= allow carbon dioxide to get into the cells and oxygen to leave by diffusion

Question 21

how do guard cells allow the process of photosynthesis

Answer 21

they have guard cells that open and close the stomata to regulate gas exchange

Question 22

what is needed for photosyntheis to take place

Answer 22

light

Question 23

how does algae photosynthesis

Answer 23

as they’re aquatic, they are adapted to photosynthesising in water

-they have a large surface area and absorb carbon dioxide dissolved in water around them

Question 24

during photosythesis energys transferred

Answer 24

from the environment to the chloroplast by light.

Question 25

why do plants grow in summer

Answer 25

as they need light, warmth and carbon dioxide which theres more of in summer

Question 26

name a factor that affects the rate of photosynthesis

Answer 26

light intensity
-more light means more photosynthesis can take place
-if theres little or no light, photosynthesis qill stop