Bioenergetics

Question 1

What is Photosynthesis?

Answer 1

A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy.

Question 2

What is the word equation for photosynthesis?

Answer 2

Carbon Dioxide + Water -> Glucose + Oxygen

6CO2 + 6H2O —> C6H12O6 + 6O2

Question 3

What type of reaction is Photosynthesis?

Answer 3

Endothermic

Question 4

What is a limiting factor?

Answer 4

A factor that slows down photosynthesis.

Question 5

Name 3 limiting factors?

Answer 5

1. At night the lack of sunlight
2. In winter the low temperatures.
3. if its warm/bright enough the C02 can be a limiting factor.

Question 6

Why is Chlorophyll a limiting factor?

Answer 6

Plants in lighting conditions unfavourable for photosynthesis synthesise more chlorophyll, to absorb the light required.

The effects of some plant diseases affect the amount of chlorophyll, and therefore the ability of a plant to photosynthesise

Question 7

How does light Intensity affect the rate of photosynthesis?

Answer 7

As light level increases so does the rate of photosynthesis, until another factor begins to limit it.

Question 8

How does C02 affect the rate of photosynthesis?

Answer 8

Similar to Light intensity, as C02 increases so will the rate of photosynthesis.

Until another factor begins to limit the rate of photosynthesis.

Question 9

How does Temperature affect the rate of photosynthesis?

Answer 9

The temperature will only limit photosynthesis if its to cold.

However it gets to hot then the enzymes will denature and this will destroy the plant.

Question 10

What are greenhouses used for?

Answer 10

To create artificially ideal environments for the plant to grow.

Question 11

Why is heat and light adjusted in a greenhouse?

Answer 11

Heat - The greenhouse traps the Sun’s heat to make sure its not a limiting factor.

Light - Artificial Light is used at night so that there is light 24/7.

Question 12

How do farmers control CO2 and Diseases in Greenhouses?

Answer 12

C02 - They use Paraffin Heaters to produce the C02 so there is always a steady supply.

Diseases - The greenhouse is enclosed which makes it easier to keep the area disease-free

Question 13

What is a negative to the Greenhouses?

Answer 13

It can be very expensive if not managed right.

Question 14

Why is the Pond Weed used?

Answer 14

The rate at which the Canadian Pondweed produces oxygen corresponds with the rate of photosynthesis.

Question 15

What is the factor that is tested in the experiment?

Answer 15

Light intensity

Question 16

How would you carry out the pondweed experiment?

Answer 16

1) Set up a boiling tube containing 45 cm3 of sodium hydrogencarbonate solution (1%).
2) Cut a piece of the pondweed, should be 8 cm long.
3) Use forcepts to place the pondweed in the boiling tube carefully. Make sure no damage is done.
4) Position the boiling tube so that the pondweed is 10 cm away from the light source. Leave the boiling tube to stand for five minutes.
5) Count the number of bubbles emerging from the cut end of the stems in 1 minute and repeat 5 times.
6) Calculate the average number of bubbles produced per minute. Repeat the experiment at varying distances from the source.