Bioenergetics Flashcards
What do plants use as a source of energy?
Light from the sun
What is the name of the reaction that traps energy for plants
Photosynthesis
What type of reaction is photosynthesis?
Endothermic because it takes in energy
Where does photosynthesis take place in?
The leaf
How does photosynthesis occur?
Plant takes in carbon dioxide and water
The chlorophyll in chloroplasts absorb light energy
Light energy used in reaction to concert CO2 and H2O into glucose and oxygen
Photosynthesis word equation
Carbon dioxide + water ——> Glucose + Oxygen
Photosynthesis symbol equation (unbalanced)
CO₂ + H₂O ——> C₆H₁₂O₆ + O₂
Limiting factor in photosynthesis
When a factor lowers the rate of photosynthesis
So if you increase it the rate of photosynthesis will increase
But eventually rate stops increasing as something else becomes limiting factor
What could be a limiting factor?
Light intensity
Carbon dioxide level
Amount of chlorophyll
Temperature
Amount of chlorophyll as a limiting factor
The leaf will trap less light if there are low levels of chlorophyll in the leaf
Making it a limiting factor
How are limiting factors shown on a graph for photosynthesis
(CO2, chlorophyll, light intensity)?
The rate will increase as the factor increases showing it couldn’t have increased before as there wasn’t enough
It straightens off when it no longer is a limiting factor
Temperature as a limiting factor
Increasing it will increase rate of reaction
But if you increase it over the enzymes optimum it will denature and rate will fall
How is temperature limiting factor graph shown?
Rate increase as temperature increases
But falls to 0 as it reaches optimum temperature
What can plants use glucose from photosynthesis for?
For respiration to release energy
Starch
Fats and oils
Cellulose
Amino acids
Why do plants store glucose as starch?
It is insoluble
So can be stored and then converted back into glucose if they need it for respiration
Because at night time they cannot make more glucose with no photosynthesis so they can use the stored starch instead
Why do plants convert glucose to fats and oils?
As a storage form of energy
Why do plants make cellulose from glucose?
Because it strengthens the cell wall which keeps it from bursting
Why do plants make amino acids from glucose?
Amino acids are needed for protein synthesis
How do plants make amino acids from glucose?
From nitrate ions
How can we determine what the limiting factor is?
Increase the amount of another factor and record the rate of photosynthesis
If the rate increases then that was the limiting factor
If not repeat with another factor