Bioenergetics Flashcards
What is the word equation for photosynthesis?
carbon dioxide + water –> glucose + oxygen
What is the balanced symbol equation for photosynthesis?
6CO(2) + 6H(2)O –> C(6)H(12)O(6) + 6O(2)
What type of reaction is photosynthesis?
endothermic
Why is photosynthesis an endothermic reaction?
As the reaction takes heat/energy/sunlight in.
What are factors that can affect the rate of photosynthesis?
temperature, carbon dioxide concentration, light intensity, chlorophyll concentration
If a greater temperature increases the rate of photosynthesis, why does temperature become a limiting factor at some point?
Because the enzymes controlling photosynthesis have been destroyed/denatured due to too much heat.
How does increasing the amount of CO(2) increase the rate of photosynthesis?
As CO(2) is needed in the reaction and therefore more of it would increase the rate of reaction.
What is a limiting factor in relation to photosynthesis?
A factor that may prevent the reaction from going faster.
What is an example of a limiting factor in relation to photosynthesis?
Light intensity: if there is not enough light, the rate of reaction will slow.
Suggest an experiment to determine the effects of light intensity on the rate of photosynthesis using an aquatic organism.
Place your aquatic organism (usually pondweed) in a beaker and shine light onto it from a specific distance away.
Record the number of gas bubbles coming from the plant in a minute.
Repeat this process where the light is at different lengths.
When light intensity is studied, doubling the distance between the light and the pondweed will reduce the light intensity by a quarter. What is this called?
inverse square law
When glucose is produced in photosynthesis, what may the plant convert it into?
insoluble starch (stored in stems, leaves or roots), fat or oil (stored in seeds), cellulose (to strengthen cell walls), proteins (for growth and enzymes)
How does a plant produce proteins from glucose?
It uses nitrate ions, which is absorbs from the soil.
What type of reaction is respiration?
exothermic
Why is respiration an exothermic reaction?
It releases energy from glucose molecules for the body.
What is the word equation for aerobic respiration?
glucose + oxygen –> carbon dioxide + water
What is the balanced symbol equation for aerobic respiration?
C(6)H(12)O(6) + 6O(2) –> 6CO(2) + 6O(2)
Why does anaerobic respiration produce less energy than aerobic respiration?
The glucose is not completely broken down, so less energy is transferred.
What is the product formed in anaerobic respiration in animals?
lactic acid
What is the word equation for anaerobic respiration in plants and yeast
glucose –> ethanol + carbon dioxide
What is anaerobic respiration called in yeast cells?
fermentation
What industry is fermentation important for?
alcohol
Why does the rate of respiration increase during exercise?
More energy is needed to supply oxygen to the muscles.
What causes an oxygen debt?
When anaerobic respiration causes a build-up of lactic acid in the muscles.
How is an oxygen debt ‘repaid’?
The blood flow takes away the lactic acid to the liver, where it is broken down. Once this is removed, the body can replenish its oxygen with aerobic respiration.
What is lactic acid?
Lactic acid is a poison that comes from anaerobic respiration. It builds up in muscles and causes pain and hinders their contraction.
What does metabolism mean?
The sum of all chemical reaction in the body.
What are examples of chemical reactions that happen in the body?
Conversion of glucose to starch/glycogen/cellulose, formation of lipid molecules from glycerol and fatty acids, the use of glucose and nitrate ions to synthesise proteins.
