B3-Food & Ecosystems Flashcards
What factors affect the rate of reaction
Temperature
pH
Substrate Conc.
How do I change the temperature to increase the rate of reaction
Increase it
Why does increasing the temp. increase the rate of reaction
There are more collisions between the active site of the enzyme and the substrate
What are Enzymes
Enzymes are biological catalysts
What do Enzymes do
Speed up reactions
What has happened to an enzyme when a substrate does not fit into it’s active site
It has denatured
What happens if the pH of the environment surrounding an enzyme is too high or too low
It affects the bonds holding the active site together, the enzyme eventually denatures
What is the optimum pH for MOST enzymes
It is neutral 7
What happens if I increase the substrate conc.
The reaction begins to get faster
what is the name of the model which describes the substrate fitting into the active site
Lock and key model
what is respiration
Process of transferring energy from a molecule such as glucose
How do animals produce energy
Animals consume glucose by breaking down the bio mass of organisms they eat
What kind of reaction is respiration
Its exothermic
what is exothermic
exothermic is the release of energy in a reaction
Is respiration 1 or several chemical reactions
It is several chemical reactions
What is ATP
ATP is a store of energy from respiration
why do we have ATP
The energy from respiration cant be used directly by cells
what is energy used for
Contracting muscles. making new molecules, breaking molecules and active transport
what are the processors need for organism staying alive
Contracting muscles. making new molecules, breaking molecules and active transport
where and when does respiration happen
All cells all the time
what does aerobic respiration produce
it produces lots of ATP
where does respiration happen in the prokaryotic cell happen
It happens in the cytoplasm
where does respiration happen in the eukaryotic cell
It happens in the Cytoplasm and the Mitochondria
When do human cells perform anaerobic respiration
During exercise . The body can’t meet the demand of oxygen from muscles so the muscles respire anaerobically. Produces lactic acid as a result
When do plant root cells anaerobically respire
When the soil becomes waterlogged, there is no oxygen .
When do bacterial cells respire anaerobically
When under the skin. There is very little oxygen, only bacteria, respiring anearobically survive
Why is anaerobic respiration not as good as aerobic
It produces less energy per glucose molecule
What is glucose anaerobically respired to make in humans
Glucose= Lactic acid . It is partially broken down glucose , so not all of the energy from the bonds in glucose are released
What do plants and some micro organisms produce during anaerobic respiration
Glucose = Ethanol + CO2. Again Glucose is only partially broken down.
how much Atp is produced in anerobic respiration
2 ATP is produced
What does the enzyme catalase break down
Hydrogen Peroxide (H2O2)
What does catalase make
Water and Oxygen
What can you collect in the reaction metabolised by catalase
Oxygen
How can you investigate the affect of temperature(or any factor) on enzyme activity
You can either measure how fast a product appears
OR
You can measure how fast a substrate disappears
Why is the reaction catalysed by Catalase important
We can collect the O2 and measure how much is produced in a set time ie. we can measure how fast the reaction happens
How do we measure the speed of the catalase reaction
1) Pipette X amount of H2O2 into a boiling tube .
2) Put the tube in the water bath at Y temperature (for 5 minutes so the tube is at the right temperature)
3) Set up the rest of the appartus so that water is in an upturned measuring cylinder in a tub of water. The measuring cylinder has a delivery tube in it and is attached to a bung.
4) Put some catalase in the H2O2 solution in the boiling tube and quickly attach the bung with the delivery tube.
5) Record how much oxygen is produced in the first minute , repeat three times until the reaction seems to stop producing oxygen (which will be in the upside down measuring cylinder)
6) Repeat at different temperatures
When measuring a reaction w hat must you control
Any other variables e.g. when measuring the affect of temperature on a reaction you must measure other factors including; pH, potato(source of catalase)
How do you calculate the rate of reaction
You calculate the mean volume of oxygen produced each minute (Volume/Time) Units will be cm3/second .
