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Biology
Photosynthesis (Section 3)
Question | Answer |
---|---|
Plants are autotrophs. What does that mean? | They can make complex molecules (glucose) from simple molecules (carbon dioxide and water) |
What is the word equation for photosynthesis? | carbon dioxide + water ----> glucose + oxygen |
What is the chemical equation for photosynthesis? | 6CO2 + 6H20 ------> C6H12O6 + 6O2 |
Photosynthesis converts ________ energy to _________ energy | light, chemical |
What 3 main factors limit the rate of photosynthesis? | 1. Light intensity 2. Temperature 3. Carbon dioxide concentration |
Where does photosynthesis take place? | In the chloroplasts |
What pigment in chloroplasts absorbs sunlight? | Chlorophyll |
What are 3 causes of a decreased amount of chlorophyll in a plant? | 1. Diseases 2. Lack of nutrients 3. Loss of leaves |
Name 3 adaptations a plant has for photosynthesis | 1. Large surface area - for CO2 and light 2. Thin - for CO2 diffusion 3. Transparent epidermis - allows more light to reach palisade cells |
What does the waxy cuticle do in a leaf? | Prevents water from evaporating |
Is photosynthesis and endothermic or exothermic reaction? | Endothermic (it requires energy from the sun) |
What are 5 of the main uses of glucose in plants? | 1. To make cellulose 2. To make starch 3. To make amino acids 4. To make lipids 5. For cellular respiration |
What is a limiting factor? | Anything that stops photosynthesis happening any faster |
Why do plants store carbohydrates as starch rather than glucose? | Starch is insoluble, so does not diffuse out of cells |
When testing for starch in a leaf, why do we dunk the leaf in boiling water? | To stop any chemical reactions from happening |
When testing for starch in a leaf, why do we place the leaf in a boiling tube and heat it with ethanol? | To get rid of any chlorophyll |
After removing a leaf from ethanol, what colour will it be? | Colourless |
Explain a safety precaution when testing a leaf for starch | Use a water bath instead of Bunsen Burner to heat ethanol, as it is highly flammable |