Chapter 4 - Bioenergetics

Question 1

What is photosynthesis

Answer 1

Photosynthesis uses energy to change carbon dioxide and water into glucose and oxygen

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. Energy is transferred to the chloroplasts by light.

Question 3

Is photosynthesis endothermic or exothermic?

Answer 3

It is endothermic which means energy is transferred from environment in the process

Question 4

What is the word equation for photosynthesis

Answer 4

Carbon dioxide + water ➝ glucose + oxygen

Question 5

What are the five main ways that plants use glucose

Answer 5

For respiration - This transfers energy from glucose which enables the plants to convert the rest of the glucose into various other substances

Making Celulose-glucose is converted into cellulose for making strong plant cell walls

Making amino acid-glucose is combined with nitrate irons to make amino acid’s which are then made into proteins

Stored as oil or fat’s-glucose it turned into lipids for storing in seeds

Stored as starch-glucose is Turned into starch and stored in roots stems and leaves ready for use when photosynthesis isn’t happening e.g. in the winter. Starch is insoluble which makes it better for storing them glucose

Question 6

What affects the rate of photosynthesis

Answer 6

Intensity of light
Concentration of CO2
Temperature

These are known as the limiting factors

Chlorophyll can also be a limiting factor. The amount of chlorophyll in a plant can be affected by disease or environmental stress such as lack of nutrients. This means the rate of photosynthesis is reduced because they can’t absorb as much light