Bioenergetics Flashcards
Photosynthesis
It is the process that produces ‘food’ in plants
Word equation for photosynthesis
carbon dioxide + water = glucose + oxygen
Chloroplasts
. They contain chlorophyll which is a green pigment that absorbs light.
. It is where photosynthesis takes place
Uses of Glucose
- Respiration
- Making cellulose
- Making amino acids
Glucose : Making cellulose
Glucose is converted into glucose for making strong cell walls which support and strengthen the cells.
Glucose : Making amino acids
.Glucose is combined with nitrate ions, which are absorbed from the soil to make amino acids.
.Amino acids are the building blocks which make up proteins.
.When they are joined together in a specific sequence they make up a particular protein.
Storage of Glucose
1.Lipids - they are stored in seeds
2.Starch - It is stored so that it is ready to be used when photosynthesis isn’t happening as much, like in winter. It is stored in roots, stems, seeds and leaves
Limiting factors in photosynthesis
.light intensity
.volume of carbon dioxide
.temperature
.amount of chlorophyll (sometimes)
Effect of light intensity
as light intensity increases, the rate of photosynthesis increases - but only up to a certain point. Beyond that point it won’t make any difference - as the light intensity increases but the rate will no longer increase.
Effect of carbon dioxide
as the volume of carbon dioxide increases, the rate of photosynthesis increases - but only up to a certain point. Beyond that point it won’t make any difference - as the volume of carbon dioxide increases but the rate will no longer increase.
Effect of temperature
.Enzymes increase the rate of photosynthesis in plant cells. The speed at which enzymes work is affected by temperature
.Enzymes needed for photosynthesis work more slowly at low temperatures.
.But if the temperature gets too hot, the enzymes needed for photosynthesis and its other reactions will be damaged which happens at around 45°C.
Aerobic respiration
Respiration is the process of transferring energy from glucose, which goes on in every cell
Word equation for respiration
glucose+oxygen = carbon dioxide+water
Energy from respiration
.Organisms use energy to build up larger molecules from smaller ones. E.g. proteins from amino acids
.Animals use energy to allow their muscles to contract
.Mammals and birds have the energy to keep their body temperature steady.
Anaerobic respiration
the incomplete breakdown of glucose, making lactic acid
Word equation for anaerobic respiration
glucose -> lactic acid
Oxygen debt
.When you stop exercising, you’ll have an ‘oxygen debt’
.It is the amount of extra oxygen the body needs after exercise to react with the build up of lactic acid and remove it from the cells
Removing lactic acid
. The pulse and breathing rate stay high whilst there are levels of lactic acid and carbon dioxide to deliver more oxygen to the cells and take away the carbon dioxide
. The blood that enters your muscles can also transport the lactic acid to the liver where it is converted back into glucose
Metabolism
the chemical processes that occur within a living organism in order to maintain life
Examples of Metabolism
.Lipid molecules are made up of one molecule of glycerol and 3 fatty acids
.Glucose is broken down in respiration. Respiration transfers energy to power all the reactions in the body that make up molecules.
