How ATP provides energy for biological processes
- ATP is hydrolysed, ATP –> ADP + Pi
Describe the role of the electron transport chain of mitochondria in the synthesis of ATP
- rNAD/rFAD release hydrogen and are oxidised
- hydrogen splits into electrons and H+
- the electron passes from one carrier to the next
- moving from a higher energy level to a lower energy level
- the redox reactions release energy (electrons release energy)
- this energy is used to move H+ ions into the intermembrane space from the matrix - creating an electrochemical gradient
- as H+ move down gradient back into matrix, they move through staled particles, passing ATPase located on the stalked particle, which catalyses the synthesis of ATP
- the electron then combine with H+ and combines with oxygen to form water, oxygen is the final electron acceptor
Explain the fate of lactate produced by anaerobic respiration
- the lactate formed when pyruvate is reduced and rNAD is oxidised (to regenerate NAD) is converted back into pyruvate
- lactate is oxidised to CO2 and H2O, releasing energy to synthesise ATP
- oxygen debt
- some lactate converted into glycogen and stored in the muscle or liver
Explain what happens to the hydrogen is produced during the krebs cycle
- the hydrogen is picked up by NAD/FAD and moved to the ETC
- the hydrogen splits up into H+ and e-
- electrons pass along electron carriers
- from a higher energy level to a lower energy level
- redox reactions release energy
- energy used to move H+ into the intermembrane space, creating electrochemical gradient
- H+ moves back into matrix down gradient through stalked particles, passing ATPase which catalyses the synthesis of ATP
- H+ combines with e- and then combines with oxygen to form water, oxygen is the final electron acceptor
Explain why oxygen concentration drops while mitochondria respire
- oxygen concentration decreasing
- greatest decrease when ADP is added
- oxygen used to convert ADP to ATP in respiration
- oxygen is need for respiration
- oxidative phosphorylation, hydrogen combine with oxygen to form water
Name an electron donor used in the ETC in mitochondria
- rNAD/rFAD
State the location of the ETC in mitochondria
- inner mitochondrial membrane
Describe how ATP is synthesised in the ETC
- rNAD/rFAD is oxidised
- hydrogen breaks up into H+ and e-
- electrons pass down electron carriers
- from a high energy level to a lower energy level
- redox reactions release energy
- this energy is used to move H+ from matrix to intermembrane space, creating electrochemical/concentration gradient
- H+ moves down electrochemical/concentration gradient into matrix through stalked particles, where ATPase is located
- ATPase catalyses the synthesis of ATP by oxidative phosphorylation
- oxygen is the final electron acceptor
- water is formed
Explain what happens to lactate built up after fast movement
- lactate removed from muscle and diffuses into blood
- the lactate formed (by pyruvate is reduced and rNAD is oxidised) is converted back into pyruvate
- lactate is oxidised to form CO2 and H2O
- energy released used to synthesise ATP
- higher oxygen consumption, greater oxygen debt
- some lactate converted to glycogen to be stored in the liver or muscle cells
Suggest reasons for absorbing CO2 in respiration apparatus
- CO2 produced in respiration
- affects volume and pressure of gas
- allows measurement of oxygen used
Suggest why a valid comparison cannot be made between the mean rates of respiration of the germinating seeds in air and the insects and suggest a modification that would allow a valid comparison
- mass of organism may differ, use same mass
- temperature changes, control temperature using a water bath
- pressure may affect volume of gas, use of control with no organisms, at same time
Enzyme involved in chemiosmosis
- ATPase
Explain how a high concentration of H+ ions is maintained in the intermembrane space
- hydrogen from rNAD split into H+ and e-
- energy lost when electrons move from one carrier to the next, ETC on innermembrane
- energy used to pump H+ ions into intermembrane space (active transport)
Describe the role of hydrogen ion concentration gradient in making available an accessible supply of energy
- H+ ions move back into matrix down concentration (and electrochemical) gradient
- this causes an energy change and makes energy available
- ATP is formed
- this occurs on stalked particles where ATPase is located
- ATP is energy source for biological processes
Names the process that produces pyruvic acid (pyruvate)
- glycolysis
Names the process that produces pyruvic acid (pyruvate)
- glycolysis
During the Krebs cycle, what is lost/formed when citrate (6C) is converted to a 5C compound
- CO2 removed
- hydrogen is removed
- NAD reduced
During the Krebs cycle, what is lost/formed when citrate (6C) is converted to a 5C compound
- CO2 removed
- hydrogen is removed
- NAD reduced
Suggest a reason for the rapid oxygen uptake in a medium containing lactic acid
- lactate can be converted to pyruvate
- lactate oxidised to form CO2 and H2O
- increases oxygen requirement, oxygen debt
- can make most of reduced coenzyme as NAD is regenerated
Suggest a reason for the rapid oxygen uptake in a medium containing lactic acid
- lactate can be converted to pyruvate
- lactate oxidised to form CO2 and H2O
- increases oxygen requirement, oxygen debt
- can make most of reduced coenzyme as NAD is regenerated
What could cause a fall in pH in living muscle
- anaerobic respiration
