Photosynthesis

• Photosynthesis is the reaction that converts light energy & Carbon dioxide into Glucose & Oxygen, which takes place in chloroplasts.
• This practical investigates changing a factor that effects the rate of photosynthesis
  • The dependent variable is the production of oxygen
  • The independent variable can change in an exam. It could be the distance to the light source (light intensity), temperature or sometimes Carbon dioxide concentration.
  • The two most common control variables are the temperature which is controlled with a water bath or the concentration of carbon dioxide which is controlled by adding Sodium Bicarbonate
• Forgotten your variables - review them

6CO₂ + 6H₂O --> C₆H₁₂O₆ + 6O₂

Converted to proteins, e.g in beans and legumes

Converted to fats, e.g oils in sunflowers

Converted to Cellulose in cell walls

Converted to Starch and stored, e.g. in Potatoes

Auto means self

Troph means feeding

So autotroph means self feeding - as in plants make their own food.

Animals are heterotrophs - which means 'other feeding' and they need to eat organic molecules from other sources to release energy.