Photosynthesis

Question 1

What type of reaction is photosynthesis?

Answer 1

Endothermic

Question 2

Where does photosynthesis occur?

Answer 2

In chloroplasts of green plant cells

Question 3

What is the word equation for photosynthesis?

Answer 3

(Clowns wear light/cool green outfits)

Question 4

What is the symbol equation for photosynthesis?

Answer 4

Question 5

What are 5 main ways that plants use glucose?

Answer 5

•Oils and fats- it is turned to oils and fats for storing in seeds
•Starch- stored as starch in roots, stems and leaves
•Cellulose- converted to cellulose to make strong cell walls
• Amino Acids- combined with nitrate ions to make amino acids for making proteins
•Respiration- this transfers energy from glucose

(OSCAR)

Question 6

What are the limiting factors for photosynthesis?

Answer 6

•light intensity
•temperature
•carbon dioxide concentration

Question 7

When can chlorophyll be a limiting factor for photosynthesis?

Answer 7

When the plant is affected by disease (e.g. TMV) so chloroplasts become damaged and cannot absorb as much light

Question 8

Why is it important that starch is insoluble in the cytoplasm (water) of plant cells?

Answer 8

• starch is insoluble in water
  -therefore the plant can store large amounts of starch for energy store

Question 9

What symptoms would a plant lacking magnesium have?

Answer 9

•yellow leaves as there is less chlorophyll
•poor growth as less photosynthesis occurs

Question 10

Describe this graph

Answer 10

•As carbon dioxide concentration increases, the rate of photosynthesis increases
•eventually the rate of photosynthesis remains constant

Question 11

Explain the shape of the graph at point C

Answer 11

•the rate of photosynthesis is decreasing rapidly past the optimum temperature as enzymes are denaturing
•this changes the shape of the active site so there are fewer successful collisions

Question 12

Identify the limiting factors at point B

Answer 12

Answer: anything other than carbon dioxide concentration

•this is because when the carbon dioxide concentration increases past this point, the rate of photosynthesis does not
•therefore it must be one of the other limiting factors

Question 13

Identify the limiting factor at point A

Answer 13

•light intensity
•because as light intensity increases so does the rate of photosynthesis

Question 14

Why do plants need magnesium ions from soil?

Answer 14

To make chlorophyll

Question 15

Where do plants get nitrates?

Answer 15

from the soil

Question 16

Describe the graph

Answer 16

•as light intensity increases, the rate of photosynthesis increases
•Eventually the rate of photosynthesis remains constant

Question 17

What are meant by the limiting factors of photosynthesis?

Answer 17

Something that slows down the amount of photosynthesis a plant can do

Question 18

What is the symbol for nitrates?

Answer 18

Question 19

Identify the limiting factor at point A

Answer 19

•carbon dioxide concentration
•because as the carbon dioxide concentration increases so does the rate of photosynthesis

Question 20

Identify the limiting factor at point B

Answer 20

Answer: anything other than light intensity

•because as light intensity increases past this point the rate of photosynthesis does not- it must be one of the other factors

Question 21

What is the symbol for magnesium ions?

Answer 21

Question 22

How can you increase light intensity with a lamp?

Answer 22

You can move the lamp closer

Question 23

Describe the graph

Answer 23

•As temperature increases, rate of photosynthesis increases
•A maximum rate is reached
•the rate of photosynthesis decreases rapidly past the optimum and stops at 45 degrees Celsius

Question 24

Describe the shape of the graph at point B

Answer 24

•photosynthesis is happening at it’s optimum rate because enzymes and substrates have maximum kinetic energy
•so there are maximum possible collision

Question 25

Answer 25

Question 26

Answer 26

Question 27

How do farmers optimise conditions for photosynthesis?

Answer 27

They grow plants in a greenhouse

Question 28

Answer 28

Question 29

How do greenhouses optimise photosynthesis?

Answer 29

•artificial light allows photosynthesis to occur at night
•glass allows light to reach crops
•paraffin heater can heat greenhouse to maintain optimum temperature for photosynthesis
•paraffin heater can also increase carbon dioxide concentration
•fertilisers can be used to supply minerals e.g. magnesium
•shades and ventilation can cool things down if it gets too hot
*all of costs a lot of money but If farmers maintain optimal conditions for photosynthesis, plants grow faster and crops can be harvested more frequently, increasing profits. It’s crucial for farmers to provide the right amount of heat, light, etc., enough for optimal growth but not excessive, to avoid wasting money.

Question 30

Answer 30

Inversely proportional

Question 31

What is an endothermic reaction?

Answer 31

A reaction where energy is transferred from the environment

Question 32

What is the experiment to measure photosynthesis in pondweed?

Answer 32

1)Place cut pondweed in a boiling tube containing sodium hydrogen carbonate solution) at a specific distance from the a light source
2)Let the pondweed photosynthesise, collecting oxygen in a capillary tube.
3)Measure the length of the gas bubble in the tube( this indicates the volume of oxygen produced)
4)Repeat the experiment twice with the same light distance and calculate the average oxygen volume.
5)Control variables like temperature and time for reliable results.