B8

Question 1

What is photosynthesis?

Answer 1

The process by making soluble foods from carbon dioxide and water

Question 2

Where does photosynthesis occur

Answer 2

Takes place in chloroplast in green plant cells- they contain pigments like chlorophyll that absorb light

Question 3

Is photosynthesis exothermic or endothermic and explain what it means

Answer 3

Endothermic - meaning energy is transferred from the envrionment in the process

Question 4

Word equation for photosynthesis

Answer 4

Light
CARBON DIOXIDE + WATER —–> glucose + oxygen

Question 5

Symbol equation for photosynthesis

Answer 5

6CO2 + 6H2O ——> C6H1206 + 602

Question 6

Plants use glucose in 5 different ways:

Answer 6

FOR RESPIRATION: transfers energy from glucose which enables the plants to convert the rest of the glucose into various pther useful substances.
STORED AS OILS OR FATS: glucose is turned into lipid for storing in seeds.
STORED AS STARCH: glucose turned into starch, stored in roots, stems, leaves. Ready for photosynthesis is not happening. Starch - insoluble, better for storing than glucose. A cell with lots of glucose in would draw in loads of water and swell up.
MAKING CELLULOSE: Glucose converted into cellulose for making strong plant cell walls.
MAKING AMINO ACIDS: glucose combined with nitrate ions to make amino acids, then into proteins

Question 7

Limiting factors of photosynthesis:

Answer 7

At night, light is limiting.
In winter, temp is limiting.
Chlorophyll can be limiting as the amount of it can be affected by disease or environmental stress, such as a lack of nutrients. Causing chloroplast to be damaged or not make enough chlorophyll

Question 8

What is the inverse square law

Answer 8

Light intensity is proportional to 1 / DISTANCE 2

Question 9

Explain how light slows down the rate of photosynthesis

Answer 9

-As light level increases, rate of photo increases steadily up to a point
- beyond that, it wont make a difference- as light increases, the rate won’t because now temp or co2 level is the limiting factor

Question 10

Explain how carbon dioxide slows down the rate of photosynthesis

Answer 10

• the amount of CO2 will only increase the rate of photosynthesis up to a point then something else is the limiting factor

Question 11

Explain how temp has to be just right in terms of rate of photosynthesis

Answer 11

If temp is limiting factor, then its usually because its too low- enzymes work slower at lower temp.
- if too hot, enzyme is damaged

Question 12

How do greenhouses help with farming

Answer 12

Greenhouses increases rate of photosynthesis because by the heat inside meaning plants grow, flower and fruit quicker. Also, they protect them from pests.