Photosynthesis

Question 1

What is photosynthesis?

Answer 1

The process of glucose production in plants and algae.

Question 2

Where does photosynthesis take place in a plant cell?

Answer 2

In the chloroplasts.

Question 3

What in the chloroplasts enables them to photosynthesise?

Answer 3

Chlorophyll

Question 4

What is the equation for photosynthesis?

Answer 4

Carbon Dioxide + Water –(Light)–> glucose + oxygen

Question 5

What is a method of investigating the rate of photosynthesis?

Answer 5

Keeping pondweed in a flask with a gas syringe to collect the oxygen produced. You would then set a certain amount of oxygen you want to be produced and time how long it takes for that amount to be produced.

Question 6

What are the three limiting factors of photosynthesis?

Answer 6

• Light intensity
• Carbon Dioxide concentration
• Temperature

Question 7

What is the effect of light intensity on the rate of photosynthesis?

Answer 7

As light intensity increases so does rate of photosynthesis - but only to a point. Beyond that, it won’t make a difference because either carbon dioxide concentration or temperature is acting as the limiting factor.

Question 8

What is the effect of carbon dioxide concentration on the rate of photosynthesis?

Answer 8

As carbon dioxide concentration increases so does the rate of photosynthesis- but only to a point. After this the graph flattens out.

Question 9

What is the effect of temperature on the rate of photosynthesis?

Answer 9

The enzymes used in photosynthesis work slowly at low temperatures but denature completely at 45 degrees. 37 degrees is generally the best temperature.

Question 10

How can using a greenhouse stop temperature becoming a limiting factor?

Answer 10

By trapping the Sun’s heat. Heaters and ventilators can also be used depending on the season.

Question 11

How can using a greenhouse stop light intensity becoming a limiting factor?

Answer 11

By providing artificial light when the Sun goes down.

Question 12

How can using a greenhouse stop carbon dioxide concentration becoming a limiting factor?

Answer 12

A greenhouse can have a paraffin burner that releases carbon dioxide.

Question 13

How can using a greenhouse help the general health of plants?

Answer 13

• Keep out pests and disease

* Fertilisers and mineral supplements

Question 14

How can plants and algae use glucose?

Answer 14

• Respiration
• Conversion into cellulose for making cell walls
• Combination with nitrate ions from the soil to make amino acids

Question 15

How can plants and algae store glucose?

Answer 15

• They can be converted into lipids which are kept in plant seeds or as droplets in algae cells
• It can be converted into starch which is kept in the roots, stems, seeds and leaves.