4.4.1 photosynthesis

Question 2

What is the main limiting factor of photosnthesis during winter.

Answer 2

Temperature

Question 3

What is the equation for photosynthesis?

Answer 3

Question 4

How do plants make Amino acids?

Answer 4

They combine glucose with nitrates.

Question 5

When using a lamp to look at how light intensity affects rate of photosynthesis, how can we increase the light intensity?

Answer 5

Move the lamp closer.

Question 6

What is the symbol for magnesium ions?

Answer 6

Mg²⁺

Question 7

Identify the limiting factor/s at point B

Explain how you know.

Answer 7

CO₂ conc/Temperature/Chlorophyll/Water

Because when light intensity increases past this point rate of photosynthesis does not - so must be one of the other factors.

Question 8

Identify the limiting factor at point A.

Explain how you know.

Answer 8

CO₂ concentration.

because as CO₂ concentration increases so does the rate of photosynthesis

Question 9

What is the symbol for nitrates?

Answer 9

NO₃^-

Question 10

What is meant by a limiting factor of photosynthesis?

Answer 10

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

Question 11

Which type of energy allows carbon dioxide and water to be converted into glucose and oxygen?

Answer 11

Light energy

Question 12

Where do plants get nitrates?

Answer 12

From the soil

Question 13

Why do plants need magnesium ions from soil?

Answer 13

to make chlorophyll

Question 14

What is the symbol equation for photosynthesis?

Answer 14

Question 15

What is the main limiting factor of photosynthesis on a Summer day? Explain your answer.

Answer 15

CO₂ concentration.

Because it is generally warmer in Summer.

Because there is a higher light intensity in Summer.

Atmospheric CO₂ is low (0.03%).

Question 16

What 5 things do plants use glucose for?

Answer 16

1. Oils - energy store
2. Starch - energy store
3. Cellulose - for cell walls
4. Amino acids - for growth and repair
5. Respiration - for energy

OSCAR (wil help you remember!)

Question 17

A plant tha is lacking magnesium will show what symptoms?

Answer 17

Yellow leaves as less chlorophyll.

Poor growth as less photosynthesis happening.

Question 18

What is the main limiting factor of photosynthesis at night time?

Answer 18

The amount of light

Question 19

Starch is insoluble in the cytoplasm of plant cells. Why is this a useful property?

Answer 19

It does not increase the concentration of cytoplasm.

So water does not move into the cell via osmosis which would cause the cell to swell up.

Question 20

What are the limiting factors of photosynthesis?

Answer 20

1. Light
2. CO₂ concentration.
3. Temperature
4. Amount of chlorophyll
5. Water availability

Question 21

How can we calculate the light intensity coming from a lamp that is reaching a plant?

Answer 21

The Inverse Square Law

Light intensity = 1 ÷ Distance of plant from lamp²