PHOTOSYNTHESIS

Question 1

PHTOOSYNTHESIS EQUATION

Answer 1

6H20 + 6CO2 →(Light energy)→ C6H1206 + 602

Water + Carbon Dioxide →(Light Energy)→ Glucose + Oxygen

Question 2

is photosynthesis exothermic or endothermic and why?

Answer 2

Endothermic because the plants chloroplasts absorb energy to carry out photosynthesis

Question 3

what is an insoluble storage form of glucose?

Answer 3

Starch

Question 4

what is photosynthesis?

Answer 4

when glucose is produced by a plant

Question 5

How is a leaf adapted to it’s functions?

Answer 5

• Broad- large surface area for light to fall on and be absorbed
• Thin- Creates a shorter diffusion pathway for CO2 AND O2
• Chlorophyll- absorbs sunlight - found in chloroplasts and has a green pigment
• Veins- xylem carry water to the cells. Phloem remove water from cells
• Air spaces- allow CO2 to get into the cells and O2 to leave by diffusion easily
• Guard cells & close the stomata to regulate gas exchange

Question 6

How do plants get the carbon dioxide required for photosynthesis?

Answer 6

It diffuses from the air into the leaves via stomata

Question 7

What are the main uses of glucose in plants?

Answer 7

Cellular respiration - break down the glucose to release energy

Make cellulose - which are used to make strong cell walls

Make starch - which are used to store glucose for a later time

Make amino acids - which are used to make proteins

Make lipids - these store the energy as fats or oils for later use

Question 8

What else do plants need to make amino acids?

Answer 8

Nitrate ions

Question 9

What makes starch a useful long term storage molecule?

Answer 9

It can easily be broken down when needed
It is insoluble in water
It is compact
Has no effect of water balance of the plant

Question 10

What is the molecular formula for glucose?

Answer 10

C6H12O6

Question 11

Pondweed Practical

Answer 11

Cut a piece of pondweed 8-10 cm long. Place it in a boiling tube of water
with the cut end uppermost. Add a fixed volume of sodium hydrogen carbonate solution.
2 Use the thermometer to measure the temperature of the water in the
boiling tube.
3 Place the lamp 15 cm from the boiling tube. Place the large beaker of
water between the lamp and the boiling tube.
Leave for 5 mins to allow pondweed to climatise
4 (Wait until there is a steady flow of bubbles from the cut end of the
pondweed. )star stop clock .Count the number of bubbles in 2 minutes. Record this in your
results table.
5 Measure the temperature of the water in the boiling tube again to make
sure it has not changed.
6 Repeat steps 1-5 four more times but in step 3 increase the distance
between the lamp and boiling tube by 2 cm each time.
7 Repeat the whole investigation (steps 1-6) two more times and record
your results.
8 Calculate the mean number of bubbles for each distance, leaving out any
anomalous values from your calculations.
Plot a graph of results

Question 12

Leaf adaptations for photosynthesis / funciton

Answer 12

Broad- large SA for light to fall on
Thin-creates a shorter diffusion pathway
Chlorophyl-absorb sunlight-found in chloroplasts
veins-orylem -carry water to cells of leaves. remote
products (glucose) of photosynthesis in the phloem.
Air spaces-allow co. to get to the cells and Oz to leave by
diffusion
Guard cells-Open + close the stomata to regulate gas exchange.