Photosynthesis and plant cells

1. Photosynthesis and plant cells W. Richards Worthing High School

2. Photosynthesis A definition: Photosynthesis is the process a plant uses to make food and grow.

3. Four things are needed for photosynthesis: SUNLIGHT Gives the plant energy CHLOROPHYLL The green stuff where the chemical reactions happen WATER Travels up from the roots CARBON DIOXIDE Enters the leaf through small holes on the underneath

4. The word and chemical equations for photosynthesis: Sunlight Carbon dioxide + water glucose + oxygen 6CO2 + 6H20 C6H12O6 + 6O2 Chlorophyll Sunlight Chlorophyll

5. Four factors affect photosynthesis: • Light – if there is more light photosynthesis happens faster • Water – if there is not enough water photosynthesis slows down • Temperature – the best temperature is about 300C – anything above 400C will slow photosynthesis right down • CO2– if there is more carbon dioxide photosynthesis will happen quicker

6. Palisade cells Photosynthesis happens in the “palisade” cells in the leaf:

7. Close up on a palisade cell: Cell wall Cell membrane Chloroplasts (containing chlorophyll) Large vacuole Nucleus Cytoplasm

8. Plant cells have three “extra” things than animal cells: Only plant cells have these: Both types of cell have these: Cell wall – provides support 4) Cytoplasm - this is where the reactions happen 1) Nucleus – The “brain” of the cell 2) 5) Chloroplasts – contain chlorophyll Cell Membrane – holds the cell together 3) Large Vacuole – contains sap 6)

9. Plant growth Plants grow using food they make through photosynthesis. So what else do they need? Plants also need three important minerals to keep healthy. They absorb these through their roots.

10. Plant roots are made of “root hair cells” which have a large surface area and a thin cell membrane to help absorb the minerals: Root hair cells Thin cell membrane Large surface area

11. The three main types of nutrient are: • Nitrates – used to make proteins • Phosphates – used to provide phosphorus to help photosynthesis and respiration • Potassium – helps the enzymes that are needed for photosynthesis and respiration

12. Lack of the three minerals would lead to a “Deficiency Symptom”: Lack of nitrates: Small plant, yellow leaves Lack of phosphates: Small roots and purple leaves Lack of potassium: Yellow leaves with dead bits