Photosynthesis

Question 1

Word equation for photosynthesis

Answer 1

Carbon dioxide + water → (light) → glucose + oxygen

6CO2 + 6H2O → (light) → C6H12O6 + 6O2

Question 2

What type of reaction is photosynthesis

Answer 2

Endothermic

Question 3

What does glucose make?

Answer 3

Glucose → lipids
Glucose → joined together → starch
Glucose → +nitrates from soil → amino acids → joined together → proteins
Glucose → many joined together → cellulose

Question 4

What does chlorophyll do?

Answer 4

Absorbs light into leaves

Question 5

How does CO2 enter the plant?

Answer 5

Through stomata when they open

Question 6

Leaf adaptations

Answer 6

Leaves are broad = big surface area
Leaves are thin = short diffusion paths
Contain chlorophyll = absorb light
Have veins = bring water in xylem to cells of leaves, and removes products of photosynthesis in phloem
Air spaces = allow CO2 to get to cells and oxygen to leave by diffusio
Guard cells = regulate gas exchange

Question 7

Factors affecting rate of photosynthesis

Answer 7

Light = lots of photosynthesis can take place, no light = photosynthesis stops, brighter light faster rate
Temperature = photosynthesis controlled by enzymes, temperature gets too high = enzymes denature an rate of photosynthesis will fall
Carbon dioxide concentration = CO2 concentrations rise at night, in the dark a plant respires but does not photosynthesise
Chlorophyll levels = does not get enough minerals → cannot make chlorophyll → plant dies

Question 8

Starch in Plants

Answer 8

Energy transferred in respiration may be used to build smaller molecules into bigger molecules
Glucose → starch & is stored
Lots of glucose stores = affects water balance of plant
Kept in special stored areas in cells of leaves, provides energy store when its dark

Question 9

Testing for starch in plants

Answer 9

!) Boil leaves in ethanol

2) Destroys waxy cuticle and removes colour from chlorophyll (so iodine can get to cells)
3) Rinse leaves in hot water to soften them
4) Add iodine solution to leaves
5) Leaves should turn blue-black

Question 10

Amino acids in plants

Answer 10

Glucose → amino acids
amino acids → (build up into) proteins

Carnivorous plants obtain most nutrients from animals. Plants produce enzymes to digest insects they trap. Use nitrates and other minerals from digested bodies in place of nutrients, that they cannot get from the soil.

Question 11

Lipids in plants

Answer 11

Glucose → fats and oils
Used in cells as energy store
Make cell walls stronger
Used as energy store (in their seeds)
Seeds provide food for new plant to respire as it germinates

Question 12

Garden Greenhouse

Answer 12

Glass = environment is much more controlled than garden or field
Atmosphere is warmer inside than out
Crops grow faster, flower, fruit earlier and crop better

Question 13

What greenhouses can control

Answer 13

You can see how greenhouses limit rate of photosynthesis → morning = light levels and temperature low, as light and temp rises CO2 levels become limiting

Control light levels and CO2 to get fastest possible rates of photosynthesis
Plants grow as quickly as possible
Plants can grow with perfect balance of nutrients in water (grown in water not soil)

Costs lots of money
Profits can be high
Crops are clean and soil-free
No need to plough or prepare the land in these systems 
Crops can be grown where and is poor

Question 14

Greenhouse Economics

Answer 14

Lots of planning
Expensive monitoring equipment = electricity and gas maintaining light and temperatures and CO2 levels
Alarms in place if something goes wrong
Less staff needed
Less time needed for crops to grow
Crop is larger and cleaner
All these factors taken into consideration whether price is high or low