Photosynthesis

Question 1

Define photosynthesis.

Answer 1

The process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.

Question 2

What is needed for photosynthesis?

Answer 2

Water, carbondioxide, sunlight, chlorophyll.

Question 3

What does photosynthesis produce?

Answer 3

Glucose and oxygen

Question 4

Does temperature affect the speed of photosynthesis?

Answer 4

Yes. It is faster in higher temperatures.

Question 5

How can we show that sunlight is needed for photosynthesis?

Answer 5

Cover some leafs of the plant in opaque card, to block the sunlight. Cover some in clear tape, as a control. Leave for some time. Do starch test on the leafs. If the one with clear tape has a blue/black color, and the one with opaque card has yellow/brown, sunlight is needed for photosynthesis.

Question 6

What chemical is used for a starch test?

Answer 6

Iodine solution.

Question 7

Do plants get nutrients from the soil?

Answer 7

No. Plants produce their own nutrients. Plants get minerals from the soil.

Question 8

How do we show that carbondioxide is needed for photosynthesis?

Answer 8

Place two plants in two airtight bell jars. Place one with a container containing sodium hydroxide crystals (to absorb the carbondioxide) in one bell jar. And a container containing water in the other. Do starch test on both plants. If postive for the one with the water, and negative for the one with the sodium hydroxide crystals, carbondioxide is needed for photosynthesis.

Question 9

How does a plant store the sugars that it makes?

Answer 9

As starch.