Photosynthesis

Question 1

Where does it take place?

Answer 1

In the chloroplasts

Question 2

Photosynthesis uses …. to change CO2 and water into…..

Answer 2

Energy

Glucose and oxygen

Question 3

What is are 2 very important molecules that cannot be made without glucose?

Answer 3

Chlorophyll which is essential for photosynthesis (found in the chloroplasts)
Cellulose, (makes up cell walls) .

Question 4

Why do we eat starch and protein?

Answer 4

To provide us with energy and raw materials for growth and repair.

Question 5

How are plant leaves adapted to ensure that photosynthesis is as efficient as possible?

Answer 5

Leaves have a very high SA to volume ratio and therefore can absorb a lot of light and co2 can easily get to all parts of the leaf.

Question 6

Which organelles are where photosynthesis takes place?

Answer 6

Chloroplasts.

Question 7

How does CO2 get into the leaf?

Answer 7

Stomata (tiny holes) under the leaf which open to let gases enter and leave the leaf.

Question 8

How can you measure the rate of photosynthesis?

Answer 8

By working out how fast glucose or oxygen is being produced.

Question 9

What are the 3 factors that alter the rate of photosynthesis?

Answer 9

The concentration of CO2
The light intensity
The temperature.
These are all limiting factors

Question 10

What is a limiting factor?

Answer 10

A limiting factor means that if the value is too low then (photosynthesis) will be slowed even if other factors are high.

Question 11

What practical shows the effect of light intensity on photosynthesis?

Answer 11

A lamp is shone on some pond weed which is in conditions where the O2 can be measured. The volume of O2 produced in a set time is then recorded and the lamp is then moved away a certain distance and the volume is again measured at each distance. The closer the lamp the higher the light intensity (the closer the lamp the more O2 produced).

Question 12

What happens if you continue to increase the light intensity?

Answer 12

You get to a point where the rate of photosynthesis stops rising.

Question 13

Why does temperature effect the rate of photosynthesis?

Answer 13

Temperature effects the rate of photosynthesis as the enzymes are much more efficient at higher temperatures. However if the become too hot the enzymes stop working (denature) and rate will fall.

Question 14

Why doesn’t photosynthesis happen in all plant parts?

Answer 14

As not all plant cells have chloroplasts.

Question 15

What is does Chlorophyll do?

Answer 15

Chlorophyll is a green pigment inside chloroplasts, that absorbs light energy.

Question 16

What is light energy needed for?

Answer 16

Light energy breaks apart compounds which are the raw materials/reactants (co2 and water)

Question 17

The Co2…… around the leaf and can cross both ……. and …… by diffusion.

Answer 17

The Co2 circulates around the leaf and can cross both cell walls and cell membranes by diffusion.

Question 18

What is the hollow pipe like tissue called which carries water up through the plant?

Answer 18

A xylem

Question 19

What is the glucose that is stored converted into?

Answer 19

Glucose which is stored is converted into starch.

Question 20

What is the balanced symbol equation for photosynthesis?

Answer 20

6CO2 + 6H2O ——>C6H12O6 + 6O2

Question 21

How do the plants get the nitrogen they need?

Answer 21

From nitrate ions found in the soil

Question 22

What are symtoms of nitrogen deficiency?

Answer 22

Stunted growth

yellow/pale green leaves.

Question 23

How does the presence of starch show that photosynthesis has taken place?

Answer 23

As starch contains glucose which is a product of photosynthesis.