B4 Bioenergetics Flashcards
What is photosynthesis?
A chemical reaction in which energy is transferred as the environment as light from the sun to leaves of a plant. This is an endothermic reaction.
What are chlorophyll?
Green pigment in chloroplasts in the leaves which absorbs light energy. Leaves are well adapted to increase rates of photosynthesis.
What is a limiting factor?
Anything that limits the rate of a reaction when it is in short supply.
What are the limiting factors of photosynthesis?
Temperature
Carbon dioxide concentration
Light intensity
Amount of chlorophyll
How does less chlorophyll reduce rate of reaction?
Less chlorophyll in leaves reduces light absorbed for photosynthesis.
What is the word and balanced symbol equation for photosynthesis?
Carbon dioxide + water –> glucose + oxygen
6CO2 + 6H2O –> C6H12O6 + 6O2
How does temperature affect photosynthesis?
Low temperatures, rate of photosynthesis is low because the reactant molecules have less kinetic energy
Photosynthesis is an enzyme controlled reaction so at high temperatures the enzymes are denatured and the rate quickly decreases
How does carbon dioxide concentration affect photosynthesis?
Carbon dioxide is used up in photosynthesis so increasing concentration increases rate of photosynthesis
At a certain point another factor becomes limiting
Carbon dioxide is often the limiting factor
How does light intensity affect photosynthesis?
Light energy is needed for photosynthesis so higher intensity increases rate of photosynthesis
At a certain point another factor becomes limiting
Photosynthesis will stop if there is little or no light
How do limiting factors interact?
Any one may limit photosynthesis
Rate increases until another factor becomes limiting
What is the inverse square law?
As the distance from a light source increases, the light intensity decreases at the same rate.
If you double distance, light intensity halves
What are greenhouse economics?
Commercial greenhouses control limiting factors to get the highest possible rates of photosynthesis so they can grow plants as quickly as possible or produce the highest yields, whilst still making profit.
What are uses for glucose?
Converted into insoluble starch for storage
Produce fats or oils for storage
Produce amino acids for protein synthesis using nitrate ions
Produce cellulose to strengthen cell walls
Produce energy from cellular respiration
