Photosynthesis and Respiration Flashcards
What is photosynthesis?
A biochemical process that uses light energy to synthesise organic compounds.
What type of reaction is photosynthesis?
Anabolic, but has some catabolic processes.
What is the chemical equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
Where does photosynthesis occur?
Chloroplast
Draw a diagram of a chloroplast labelling the stages of photosynthesis and the reactants/products.
See book.
What organisms does photosynthesis occur in?
Plants and other autotrophs.
What are the stages of photosynthesis?
Light dependent and light-independent (Calvin cycle).
Where does the light dependent stage occur?
Thylakoid membrane.
Where does the light independent/Calvin cycle
occur?
Stoma
What occurs in the light dependent stage?
Photosystems 2 (photo-excitation), cytochrome complex, ATP synthase, photosystems 1 and NADP+ reductase.
Describe what happens in the light dependent stage of photosynthesis.
See book.
What occurs in the light independent stage?
Carbon fixation, reduction and regeneration.
Describe what happen in the light independent stage of photosynthesis.
See book.
What are the factors that effect photosynthesis?
- Light intensity.
- Temperature.
- Carbon dioxide concentration.
How does light intensity effect photosynthesis?
Light fuels the reaction that transforms CO2 and H2O to O2 and C6H12O6. Increasing the light intensity will increase the rate of photosynthesis until the chlorophyll becomes saturated with light at which point the rate of photosynthesis plateaus. Decreasing light intensity will decrease photosynthesis rate as there is no light to fuel the reaction.
How does temperature effect photosynthesis?
Enzymes are required at multiple stages of photosynthesis. Enzymes have an optimum temperature range where their activity is maximised. At low temperatures energy is lower and less collisions occur between enzyme and substrate. At high temps enzymes denature.
How does carbon dioxide concentrations effect photosynthesis?
Carbon dioxide availability can limit photosynthesis as it is one of the reactants required for the reaction. Increasing CO2 increases the rate of photosynthesis until the process reaches saturation and the rate plateaus.
Draw graphs to illustrate the factors that affect photosynthesis.
See book.
What are the optimum factors for photosynthesis?
- Light intensity = ~ 38%.
- Temperature = ~ 25ºC - 35ºC.
- Carbon dioxide concentration = ~0.1%.
What is respiration?
A biochemical process that occurs in the cytosol and mitochondria, and metabolises organic compounds (glucose), anaerobically or aerobically, to release usable energy in the form of ATP.
What type of reaction is respiration?
Catabolic
What is the chemical equation for respiration?
C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
Where does respiration occur?
- Glycolysis: cytosol.
- Krebs cycle/electron transport chain: matrix of mitochondria.
- Anaerobic: cytosol.
Draw a diagram of a mitochondria labelling the stages of respiration and the reactants/products.
See book.
