2020 Jan Photosynthesis

Question 1

Photosynthesis

Answer 1

A process in plants in which light energy is trapped by chlorophyll to produce food

Question 2

Endothermic reactions

Answer 2

Reactions that require energy o be absorbed( taken in ) to work

Question 3

Equation for photosynthesis

Answer 3

Light

Carbon dioxide + water === glucose + oxygen

                                    Chlorophyll

Question 4

Balanced symbol equation for photosynthesis

Answer 4

Light

6CO2 + 6H2O === C6H12O6 + 6O2

Chlorophyll

Question 5

Leaf diagram

Answer 5

Palisade mesophyll layer 
Spongy mesophyll 
Lower epidermis 
Upper epidermis 
Waxy cuticle 
Intercellular space 
Stomata ( stoma) 
Guard cells

Question 6

Leaves ( light absorption and gas exchange)

Answer 6

Leaves come in many shoes and sizes but to allow photosynthesis to take place efficiently they are usually highly adapted for light absorption and gas exchange
Leaves are also adapted for defence against disease by the cuticle and cell walls of the epidermis providing a physical barrier
This reduces the entry of disease-causing organisms

Question 7

Light absorption

Answer 7

Short distance
Large surface area
Thin and transparent
Chloroplasts to absorb light energy

Question 8

Gas exchange

Answer 8

Intercellular air spaces
Stomata
Guard cells

Question 9

Path way of molecule carbon dioxide through a leaf

Answer 9

Enters the leaf through stomata 
Moves by diffusion 
Into intercellular air space 
From it goes into mesophyll cells 
Into chloroplasts

Question 10

Respiration ( use of glucose )

Answer 10

The glucose is used in respiration to produce energy

Question 11

Storage ( use of glucose )

Answer 11

In many plants the glucose is converted into starch and oils for storage eg in the roots. The starch is converted back to sugar when needed and transported to other parts of the plants

Question 12

Growth ( use of glucose )

Answer 12

Glucose can be converted into a range of useful products which enable the plant to grow
Cellulose ( for cell walls)
Chlorophyll ( for tapping light for photosynthesis)
Proteins ( for growth and repair )

Question 13

Starch test

Answer 13

Yellow / brown
To blue / black
Iodine

Question 14

What is the chemical solution used in the experiment to show Co2 is necessary

Answer 14

Sodium hydroxide solution

Question 15

Carbon dioxide in pond weed experiment

Answer 15

Piece of pond weed in water with different concentrations of sodium carbonate ( sodium bicarbonate). this provides carbon dioxide

Question 16

Temp in pondweed experiment

Answer 16

Place the pondweed in water of different temperatures (use water bath)

Question 17

Factors affecting rate of photosynthesis

Answer 17

Light intensity
Carbon dioxide
Temperature

Question 18

Limiting factor

Answer 18

An environmental factor that limits the rate of photosynthesis due to that factor being present too small in amount

Question 19

Respiration equation

Answer 19

Glucose + oxygen === carbon dioxide + water + energy

Energy produced

Question 20

Testing for carbon dioxide (purple)

Answer 20

Decreased oxygen CO2 concentration. Due to rate of photosynthesis being higher than rate of respiration eg at day time ( bright light)

Question 21

Testing for CO2 (yellow)

Answer 21

Increased CO2 concentration. Due to respiration producing more than photosynthesis uses up air eg night time (no light)

Question 22

Testing for CO2 (red)

Answer 22

Normal CO2 concentration air (0.04%). Rate of photosynthesis and respiration are equal eg dusk or dawn (low light)