Photosynthesis

• Short distance from top>bottom- allows all cells to recieve light
• Broad and Flat - gives large surface area
• Thin Transparent Cuticle- reduces water loss but doesn't affect light entering leaf
• Presence of Chloroplasts- rich in Chlorophyll
• Regular structure of Palisade Mesophyll- Ensures cells rich in chloroplasts aer packed at the top

• Spaces in Spongy Mesophyll- allows Carbon Dioxide to Enter and Oxygen to Leave
• Stomata- Small Pores that allow Carbon Dioxide and Oxygen to Enter and Leave
• Guard Cells- Regulates Opening and Closing of stomata

• When Guard Cells gain Water by Osmosis - curve outward allowing Gases In and Out
• Losing Water Guard Cells - they close Stoppng Gas Movement and Water Loss

• Synthesis: Glucose uses - Cellulose ( for cell walls), Chlorophyll and amino acids to make Protein ( used for growth)
• Storage: In many plants glucose get turned into Insoluble Starch and Oils for Storage
• Respiration : Glucose is used in Respiration to provide Energy

Minerals are taken up at the root hair cells using Active Transport ( the movement of molecules from areas of high>low concentration using energy)

• Nitrates- to make Amino acids which are then to make Protien used for Growth. Plant with nitrate deficiency- Shows Stunted Growth
• Calcium - Used to make cellulose ( important component of the cell wall). Plant with calcium diffieciency - Looks Wilted
• Magnesium - Required to make Chlorophyll ( gives a plant its green colour). Plant with Magnesium difficiency- Has yellow green leaves

• Leave the plant in a dark cupboard/ place for 48hrs. 
• This is to ensure any starch present was produced during the experiment

• Remove leaf from a plant
• Boil in water to kill
• Turn off bunsen burner
• Remove leaf put into a boiling tube of Ethanol . Place boiling tube into hot water for a few minutes
• Dip in warm water ( this is to de-brittle it)
• Spread leaf on white tile and add iodine

    The other product of photosynthesis is oxygen. 

Pondweed was chosen because it's an aquatic plant so it can be used underwater and produce the bubbles we need. The control version of his would be one without pondweed. Test the gas collected with a glowing splint which should relight. You should let  it photosynthesis for 10minutes then multiply by 1hr to know th rate of photosynthesis per hour. 

Inceasing the light intensity increases rate of photosynthesis

For this we need a varigated leaf. This is a leaf with parts of it having chlorophyll and parts of it without.

In our test the green part turned iodine blue/black because they contains chlorophyll needed for photosynthesis. Starch was present

The white part stayed orange/red  because they didn't contain chlorophyll. Starch wasn't present.

We need to use a destarched plant so that we know any starch produced was produced during the experiment

To test if light is needed we need a destarched leaf to have a slip of black stencil covering it. Put it in light for 24hrs and then remove the slip and perform a starch test ( add iodine)

The conclusion was that the covered part stayed orange/red when iodine was added as there was no light produced for photosyntheis to make glucose and that meant no starch was stored

The test for this is simple. Take 2 destarched plants and enclose each with a plastic bag- one with sodium hydroxide ( soda lime) and the other with water. Sodium Hyrdoxide absorbes Carbon dioxide. The one with water is a control experimment to prove that the sodium hydroxide absorbed all the water

Then the starch test should be carriedd out. In which the sodium hydroxide leaf should turn iodine orange/ red as the sodium hydroxide has absorbed the carbon dioxide meaning that there is no photosynthesis. The control on should turn iodine blue/black

Without enough light the plant cannot photosynthesis very quickly, even if there's plently of water and Carbon dioxide. Increasing light intensity wih increase rate of photosythesis

Sometimes photosynthesis is limited by the concentration of carbon dioxide in the air. Even if there's plenty of light a plant cannot photosynthesise without carbon dioxide

If it gets too cold rate of photosynthesis will decrease. Plants cannot photosynthesis when it gets too warm as enzymes which control the reacton will be denatured

• Hydrogencarbonate indicator is sensitive to the change in pH as a result of changes in levels of carbon dioxide. Carbon dioxide is acidic
• Increasing Carbon dioxide - Yellow
• Normal Carbon dioxide - Orange/ red
• Decreasing Carbon dioxide - Purple / blue

This is the point here the rate of respiration and the rate of photosynethesis are equal (e.g at dawn/dusk). The hydrogencarbonate indicator will be orange/red