Respiration Flashcards
Describe the process of glycolysis
Aim - glucose to pyruvate
Where - cytoplasm
What:
- glucose phosphorylated by 2ATP to make glucose phosphate
- another phosphate is added to make hexose biosphosphate using energy from ATP
- this unstable so broken down into 2 triose phosphates (lysis)
- both oxidised by NAD (removal of hydrogen) to form reduces NAD
- triose phosphate ( each) converted into glucose releasing 4 ATP (net of 2 ATP)
Where is the link reaction?
Matrix of mitochondria
Aim of link reaction
To produce Acetyl coenzyme
And reduces nad
Also produces carbon dioxide
Process of the link reaction?
- โlinksโ glycolysis to krebs cycle
- pyruvate from glycolysis decarboxylated and dehydrogenated (co2 and h2 removed)
- pyruvate oxidised to make acetate (2C) and co2
- combined with coenzyme A to form acetyl coenzyme A
- process happens 2X
Link reaction equation
Pyruvate + oxidised NAD + CoA
โโโโ-ยปยปยปยป
Acetyl CoA + reduced NAD
What is the aim of Krebs cycle and where does it take place?
- ## produces reduced nap and reduced fad and atp
Process of Krebs cycle
- acetyl coenzyme enters circular pathway from link reaction
- combines with oxaloacetate (4c) to form citrate (6C)
- citrate decarboxylated by losing a carbon as carbon dioxide
- 2 hydrogen also lost forming reduced NAD
- 5 carbon decarboxylated again and dehydrogenated forming 4C (oxaloacetate)
- during this process another carbon is lost
- 6 hydrogens are released producing 1 reduced fad and 2 reduced nad
- overall, 2co2 released, 3 reduced nad, 1 reduced fad
Where and why does oxidative phosphorylation happen?
Where - inner mitochondrial membrane
Aim - produce water and atp
Describe oxidative phosphorylation and the electron transfer chain (chemiosmosis)
- reduced nad and fad release h atoms as they are oxidised
- hydrogen atoms split into protons and electrons
-electrons move down transfer chain losing energy at each carrier - this energy is used during active transport of protons to the intermembrane space from the matrix to create a chemical gradient
- protons then move down gradient through ATP synthase to catalyse synthesis of ATP from adp and inorganic phosphate in the process
- this is chemiosmosis
- protons and electrons them combine to form water
- o2 is final electron acceptor
How many atp in whole process of respiration
32
anaerobic respiration equation
- pyruvate + reduced nad > lactate + nad (oxidised)
Process of anaerobic respiration
- hydrogen from reduced nad added to pyruvate to form lactate
- pyruvate reduce to lactate by lactate dehydrogenase enzyme
- pyruvate is hydrogen acceptor
- nad available to accept electrons and protons ready for glycolysis again
What happens when lacatate is further metabolised?
It can โฆ.
- be oxidised back to pyruvate to Krebs cycle for atp synthesis
- converted into glycogen and stored in liver
- lactate oxidised into pyruvate needs extra oxygen which can cause oxygen debt
Fermentation process of respiration
- pyruvate decarboxylated to ethanol
- produced carbon dioxide
- hydrogen from reduced nad turns ethanAl to ethanOl with enzyme alcohol dehydrogenase as a catalyst
- ethanAl is hydrogen acceptor
- ## ethanol is waste
Fermentation equation
Pyruvate + reduced nad > ethanol + co2 + oxidised nad