2.8 Flashcards
What is respiration?
the controlled release of energy from organic compounds in cells to form ATP
Why do we need cell respiration
used In many processes & for ATP
- active transport
- muscle contraction
- protein synthesis
- vesicle transcport
- cell signalling
- DNA/RNA replication
What do all processes release?
- heat bc not all reactions are 100% efficient processes
- heat can be initially used to raise the temp of an organism but is eventually all heat is lost to the environment & cannot be used for metabolic processes
How is the release of energy controlled?
- by enzymes; metabolic pathways & cycles
- cells control the rate of enzyme catalysed pathways + cycles by end product inhibition
What type of cell would have a lot of mitochondria
muscle cells
What are respirometers used for?
to calculate the rate of respiration by measuring the consumption of oxygen
Filter paper wicks
increase the efficiency of CO2 absorption
respiring organism in respirometer
- need to be at a certain stage of germination
- suitable living organism that respires aerobically
Potassium hydroxide
- alkali solution
- absorbs CO2 in the air
- ensures that they are not absorbing CO2 in the respirometer itself
Capillary tube containing oil
movement in the oil per minute toward the tube B measures the rate of oxygen consumption
- if the diameter pf the capillary tube is known, then a volume can be calculates
- quantitate & measure the changes –> links to rate of oxygen consumption
Syringe
used to reset the position of coloured oil
Rubber bungs seal tubes
closes the system to prevent changes changes in air volume not due to respiration
Hoffman clip
seals the respirometer & can be opened to reset it after the volume has been reduced by oxygen consumption
Temp controlled in respirometer
the respirometer is immersed in a water bath to prevent temp affecting the pressure & hence the volume in the apparatus
Tube A
acts as a control to ensure that changes in the levels 0f coloured oil are due to respiration & not the reaction of alkali w atmospheric gases
How does yeast respire?
aerobically & anaerobically, but when oxygen in the dough is used up so the yeast is forced to respire anaerobically
What is bioethanol?
ethanol produced by organisms
- bioethanol is a renewable energy source
- most bioethanol is produced from sugar cane & maize, using yeast
Why are fermenters used?
to keep the yeast in optimum temps
Which respiration generates a greater yield of ATP?
aerobic respiration
Which respiration can supply ATP very rapidly?
anaerobic respiration
- this is because oxygen is not required
What does rapid generation of ATP enable us to do?
maximise the power of muscle contractions
What limits how much or how long anaerobic respiration can be done for?
the fact that anaerobic respiration produces lactate
- there is a limit to the concentration that the body can tolerate
What is oxygen debt?
when a process involves the use of oxygen
- the demand for oxygen that builds up during a period of anaerobic respiration
What are the 2 main types of cell respiration?
anaerobic respiration
aerobic respiration
What does anaerobic respiration involve?
the breakdown of glucose in the cytosol for a small yield of ATP
What does aerobic respiration utilise?
oxygen to completely break down glucose in the mitochondria for a larger ATP yield
What does ATP contain?
1 molecule of ATP contains 3 covalently linked phosphate groups - which store potential energy in their bonds
What happens when ATP is hydrolysed (to for ADP +Pi)?
the energy stored in the phosphate bond is released to be used by the cell
Where does aerobic respiration take place?
inside the mitochondrion
In yeasts, what does fermentation cause?
the production of ethanol & carbon dioxide
In respirometers, what does an increase in CO2 levels indicate?
an increase in respiration
- this is because CO2 is a product of aerobic respiration
In respirometers, what does a decrease in O2 indicate?
increase in respiration
-this is because O2 is a product of respiration
