12 respiration Flashcards
what is aerobic respiration?
requires oxygen and produces CO2 H2O and ATP
what is anaerobic respiration?
takes place where there is an absence of oxygen producing lactate in animals and ethanol and CO2 in plants and fungi
what are the 4 stages of respiration?
glycolysis
link reaction
krebs cycle
oxidative phosphorylation or ETC
where does glycolysis occur?
cytoplasm of cell
overall, what happens in glycolysis?
glucose is converted into pyruvate
give the 3 steps of glycolysis
- glucose is phosphorylated which requires 2 molecules of ATP for energy
- phosphorylated glucose splits into 2 molecules of triose phosphate due to instability
- TP oxidised into pyruvate which requires reduction of NAD and the production of 2 ATP for each pyruvate
what is the net gain of ATP in glycolysis?
2
what is the net gain of NADH2 in glycolysis?
2
what type of phosphorylation creates the ATP in glycolysis?
substrate level phosphorylation
what is pyruvate?
3 carbon long chain
where does the link reaction occur?
mitochondrial matrix
how does the pyruvate get to the mitochondrial matrix?
actively transported from the cytoplasm into the mitochondrial matrix
overall, what happens in the link reaction?
pyruvate is converted into acetylcoenzyme A
give the 2 steps of the link reaction
- pyruvate oxidised into acetate, losing CO2 and 2H (hydrogens accepted by NAD to create reduced NAD)
- 2 carbon acetate combines with coenzyme A to produce acetyl coenzyme A
what is produced in one link reaction?
1x acetyl coenzyme A
1x CO2
1x reduced NAD
where does the krebs cycle take place?
mitochondrial matrix
overall, what is the krebs cycle?
a series of REDOX reactions in the mitochondrial matrix
describe the krebs cycle starting with acetylcoenzyme A
- acetyl coenzyme A reacts with a 4C compound to create a 6C compound
- 6C compound converted to 5C through loss of CO2 and lost H reduce NAD
- 5C converts to 4C again through loss of another CO2 and lost hydrogens reduce 2xNAD and an FAD
- ATP made from 5C to 4C
how is the ATP made in the krebs cycle?
substrate level phosphorylation
what 2 enzymes are used in the krebs cycle?
dehydrogenase and decarboxylase
what are the products of one krebs cycle?
3x reduced NAD
1x reduced FAD
1x ATP
2x CO2
where does oxidative phosphorylation occur?
mitochondrial membranes
describe oxidative phosphorylation
- NAD/FAD converted into NADH/FADH
- ETC on cristae
- electrons passed down electron carriers and series of redox reactions
- energy released from electrons
- protons diffused (facilitated) into intermembrane space
- protons flow back through stalked particles/enzyme
- energy used to synthesise ATP from ADP and phosphate using ATP synthase;
describe how water is formed at the end of aerobic respiration
oxygen acts as a final electron acceptor
and combines with electrons and protons to form water
