Photosynthesis and Limiting Factos

Question 1

What is photosynthesis?

Answer 1

The process by which plants use sunlight (light energy) to change carbon dioxide and water into glucose and oxygen (chemical energy).

Question 2

Where does photosynthesis take place?

Answer 2

It takes place in chloroplasts in green plant cells. They contain pigments like chlorophyll that absorb light.

Question 3

How energy is transfered to the chloroplasts?

Answer 3

Energy is transfered to the chloroplasts from the environment by light.

Question 4

Photosynthesis is endothermic. What does this means?

Answer 4

This means energy is transferred from the environement to chloroplasts by light in the process.

Question 5

What is the word equation for photosynthesis?

Answer 5

Carbon dioxide + Water → (light) → Glucose + Oxygen

Question 6

What is the symbol equation for photosynthesis?

Answer 6

6CO₂ + 6H₂o → (light) → C₆H₁₂O₆ + 6O₂

Question 7

What are the five main ways that plants use glucose?

Answer 7

1. For respiration.
2. Making cellulose.
3. Making amino acids.
4. Stored as oil or fats.
5. Stored as starch.

Question 8

How does plants use glucose for respiration?

Answer 8

By transfering energy from glucose which enables the plants to convert the rest of the glucose into various other useful substances.

Question 9

Why does plants use glucose to make cellulose?

Answer 9

Glucose is converted into cellulose for making strong plant cell walls.

Question 10

How and why does plants use glucose to make amino acids?

Answer 10

When glucose is combined with nitrate ions (which are absorbed from the soil) to make amino acids, which are then made into proteins.

Question 11

Why does plants use glucose to be stored as oils or fats?

Answer 11

The glucose is turned into lipids (fats and oils) for storing in seeds.

Question 12

How does plants use glucose to be stored as starch?

Answer 12

The glucose is turned into stach and stored in roots, steems and leaves.

Question 13

Why does plants use glucose to be stored as starch?

Answer 13

To be ready when photosynthesis isn’t happening, like in the winter. Because the starch is insoluble, it is much better for storing than glucose.

Question 14

Why is it that an cell which is insoluble better for storing than glucose?

Answer 14

Because a cell with lots of glucose in would draw in loads of water and swell up.

Question 15

What affects the rate photosynthesis?

Answer 15

The intensity of light, concentration of CO₂ and temperature.

Question 16

What is a limiting factor and what are those for photosynthesis?

Answer 16

A limiting factor means that it’s stopping photosynthesis from happening any faster. Those are the intensity of light, concentration of CO₂ and temperature.

Question 17

Why does the limiting factors depends on the environmental conditions?

Answer 17

The limiting factors have a combined effect. So, the limiting factors could be:
⋇the time; if it’s night, it is pretty obvious that light is the limiting factor.
⋇the season; in winter, the limiting factor is often the temperature.
⋇ if it’s wam and bright enough, the amount of CO₂ is usually the limiting factor.

Question 18

How can chlorophyll be a limiting factor?

Answer 18

Some factors (such as a disease or environmental stress) can cause chloroplasts to become damaged or not make enough chlorophyll. This means the rate of photosynthesis is reduced because hey can’t absorb as much light.