2.1 Nutrition in flowering plants
***Photosynthesis equation:
carbon dioxide + water → glucose + oxygen
6CO2 + 6H2O → C6H12O6 + 6O2
● When light energy is absorbed by chloroplast, chlorophyll traps energy, using energy
to split water molecules
● Enzymes catalyze photosynthetic reactions (light energy → chemical energy)
● Glucose stored as starch, ***usages:
○ Respiration (again broken down from glucose)
○ Build cellulose cell walls
○ ***Converted into lipids for long-term energy storage
○ Converted into amino acids by using nitrate/ammonium ions from soil to
synthesize proteins
Factors affecting rate of photosynthesis (limiting factors - limit
each other)
● Light intensity
○ Light intensity ↑, rate of photosynthesis ↑
○ If no light, no photosynthesis, turns to respiration
● Temperature
○ Temperature ↑, rate of photosynthesis ↑
○ If cold, slow activity of photosynthetic enzymes
○ If too hot, photosynthetic enzymes denature, rate of photosynthesis ↓
● Carbon dioxide concentration
○ Carbon dioxide concentration in air ↑, rate of photosynthesis ↑
○ Insufficient carbon dioxide for photosynthetic reaction(s)
● ***As any factor increases further, there comes a point at which there is no
corresponding increase in rate of photosynthesis, due to another factor being
rate-limiting (limiting factor)
Adaptations of plants leaves for photosynthesis
● Larger surface area
○ Lots of light energy is collected
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***Photosynthesis equation:
carbon dioxide + water → glucose + oxygen
6CO2 + 6H2O → C6H12O6 + 6O2
● When light energy is absorbed by chloroplast, chlorophyll traps energy, using energy
to split water molecules
● Enzymes catalyze photosynthetic reactions (light energy → chemical energy)
● Glucose stored as starch, ***usages:
○ Respiration (again broken down from glucose)
○ Build cellulose cell walls
○ ***Converted into lipids for long-term energy storage
○ Converted into amino acids by using nitrate/ammonium ions from soil to
synthesize proteins
Factors affecting rate of photosynthesis (limiting factors - limit
each other)
● Light intensity
○ Light intensity ↑, rate of photosynthesis ↑
○ If no light, no photosynthesis, turns to respiration
● Temperature
○ Temperature ↑, rate of photosynthesis ↑
○ If cold, slow activity of photosynthetic enzymes
○ If too hot, photosynthetic enzymes denature, rate of photosynthesis ↓
● Carbon dioxide concentration
○ Carbon dioxide concentration in air ↑, rate of photosynthesis ↑
○ Insufficient carbon dioxide for photosynthetic reaction(s)
● ***As any factor increases further, there comes a point at which there is no
corresponding increase in rate of photosynthesis, due to another factor being
rate-limiting (limiting factor)
Adaptations of plants leaves for photosynthesis
● Larger surface area
○ Lots of light energy is collected
1
