Topic 5 (Respiration) Flashcards
What is the definition of oxidation?
loss of e-s or H2
What is the definition of reduction?
gain of e-s or H2
What is cristae?
fold of inner membrane in mitochondria
Draw a labelled diagram of mitochondria (should include 7 labels)
- cristae
- matrix
- inner membrane
- outer membrane
- intermembrane space
- ribosomes
- mitochondrial DNA
What are the 4 main stages of aerobic respiration?
- glycolysis
- Link reaction
- Kreb’s cycle
- Oxidative phosphorylation
What does Pi stand for?
Inorganic phosphate
what is glycolysis?
lysis of glucose
where does glycolysis take place?
cytoplasm
what are the products of glycolysis?
2x Pyruvate (3C) molecules
Net gain 2 ATP
2 reduced NAD
Why is the net gain of 2 ATP in glycolysis?
2 ATP used in phosphorylation
4 ATP made in oxidation/dephosphorolation
What are the steps of glycolysis?
Glucose (6C) → 2x Glycerate-3-phosphate
while 2 ATP → 2 (ADP +Pi)
Glycerate-3-phosphate → 2x pyruvate (3C)
while 4 (ADP+Pi) → 4ATP
and 2NAD + e- + H+ → Reduced NAD
What is used for link reaction?
Pyruvate (+ coenzyme A)
What is the product of link reaction?
Acetyl-CoA
How many ATPs are made in total using one glucose in respiration?
38
Draw glycolysis
Draw link reaction
Draw krebs cycle
Draw oxidative phosphorylation
What is the whole point of respiration
Produce as much energy possible in the form of ATP
Breaking
ATP ->
ADP ->
using…
ATP -> ADP + Pi
(Di-phosphate)
ADP -> AMP + Pi
(Mono phosphate)
Hydrolyse using water, via hydrolysis
Aka dephosphorylation
What are 2 ways of ATP production
- Substrate level phosphorylation
- Oxidative phosphorylation
4 steps of aerobic respiration and where they occur
- Glycolysis - cytoplasm
- Link reaction - matrix
- Krebs cycle - matrix
- Oxidative phosphorylation - inner membrane
What is substrate level phosphorylation?
Simply
ADP + Pi -> ATP
How many ATPs do oxidation and substrate level phosphorylation make?
34
4
Respectively
so total 38 in aerobic respiration
Oxygen acts as… in respiration
FINAL ELECTRON ACCEPTOR
What’s the word when a CO2 is released when making a 5C compound from 6C?
Decarboxylation
For each glucose, link reaction and kerbs cycle happens how many times?
Twice
What are the net products per glucose in anaerobic respiration?
2 red FAD
6 red NAD
4 CO2
2 ATP
What are the net products in link reaction per glucose?
2 red NAD
2 CO2
as 2x link reaction per glucose
What would happen if e- carrier is inhibited (e.g. consuming cyanide)?
Red CoA cannot be reoxidised
So red NAD cannot become NAD
ETC cannot function
Cells cannot respire aerobically
So can only respire anaerobically but cannot be sustained for too long
Hence fatal
How many ATP are made in oxidative phosphorylation?
34
Describe oxidative phosphorylation in great detail
Takes place in inner membrane
Red NAD and red FAD oxidised into FAD, NAD + H+ + e-
H+ ions are actively transported from matrix to inter membrane space
e- carriers are reduced by accepting e-s and passing down the e- transport chain
H+ undergo chemiosmosis, thru ATP synthase, via facilitated diffusion down the electrochemical gradient
O2 IS THE FINAL E- ACCEPTOR
Why does anaerobic respiration happen?
Lack of O2
As O2 is a final e- acceptor
E-s cannot be accepted into e- transport chain
So red NAD & FAD cannot be reoxidised
So link and Krebs cannot happen
How many ATPs are made in anaerobic respiration?
2
From glycolysis only
Better than 0!
What happens to pyruvates in anaerobic respiration?
Pyruvate -> lactate
While red NAD (oxidises into) -> NAD (reused in glycolysis)
Enzyme involved: lactate dehydrogenase
Why can’t humans use anaerobic respiration forever?
Lactic acids produced
Acids = lots of H+
Denatures enzymes
As R group bonds in tertiary structure breaks
( H bonds, disulphide, ionic, hydrophobic/philic)
So enzymes don’t work as well
So less effective glycolysis
Causing fatigue
When oxygen debt is paid , lactate can be..
Converted back to pyruvate to enter link reaction for respiration again
How do plants anaerobically respire?
Pyruvate -> ethanal -> ethanol
\CO2. red NAD /\NAD
Decarboxylation. Oxidation of red NAD
enzyme used: pyruvate Decarboxylate
Describe what happens to oxygen at the end of the electron transport chain. (2 marks) (in respiration)
Oxygen is the final electron acceptor
Forms water
Describe how glucose is converted to pyruvate in glycolysis. (3 marks)
(- draw it out!)
- glucose is phosphorylated using ATP
- product is converted into glycerate-3-phosphate
- GP converted to pyruvate producing red NAD and ATP
Detergents dissolve lipids.
Explain how detergents inhibit the functioning of electron carriers in chloroplasts. (3 marks)
- e- carrier components are on chloroplast membranes
- detergents distrupt phospholipid bilayer
- so electrons can no longer move along chain
Some cancer cells depend on oxidative phosphorylation for ATP production.
Explain why the antibiotics that inhibit the production of ribosomes prevent oxphos when used to treat cancer cells. (2 marks)
- ribosomes prevented from synthesising enzymes/ATP synthase
- so protein not made
(nothing to do with cells)
Waterlogged soil lacks oxygen.
Explain why a lack of oxygen in waterlogged soil could reduce the growth of a plant. (4 marks)
- aerobic respiration inhibited
- so ETC inhibited, except glycolysis
- less ATP synthesis and Red NAD
- less GP/GALP/spindle fibre contraction/protein synthesis
how many CO2 molecules are released in anaerobic respiration?
ZERO
Describe the role of oxygen in the formation of ATP during aerobic respiration. (3 marks)
- is the final electron acceptor
- allows e-s to pass down ETC
- so FAD & NAD can be replaced
- H+ ions move through ATP synthase
Describe how water is formed from respiration. (2 marks)
- electron transport chain
- oxygen is the final e- acceptor
Human activity causes pollution in water, reducing the oxygen concentration in water.
Explain why the pH in tadpoles’ blood will decrease. (2 marks)
Anaerobic respiration
So lactate and lactic acid produced
As pyruvate is reduced
Some people with leigh syndrome have mutations that affect proteins involve in the electron transport chain.
Explain why these mutations lead to a build-up of lactate. (3 marks)
Mutations may prevent e-s passing down ETC/ ATPase working properly
So no red NAD oxidised
So pyruvate will produce lactate
But Lactate produced at a faster rate than it can be removed
Explain the role of Krebs cycle. (4 marks)
- completely oxidised acytl CoA
- to release as much energy as possible
- generate ATP
- produce reduced NAD and FAD
- so ATP can be produced in oxidative phosphorylation
Describe what happens to oxygen at the end of the electron transport chain. (2 marks)
- final electron acceptor (becomes reduced)
- forms water
Explain why a low oxygen concentration in water would lower the pH of the blood of tadpole. (3marks)
- anaerobic respiration takes place
- lactate produced
- because pyruvate reduced
Explain how a mutation in ATP synthase (an enzyme) can affect oxidative phosphorylation. (3 marks)
- it will change the amino acid sequence of ATP synthase
- active site would be a different structure, ADP won’t be able to bind as well
- ATP synthase will be the wrong shape, so hydrogen ions cannot pass through as well
- less ATP made
Some people with Leigh syndrome have mutations that affect proteins in the electron transport chain.
Explain why these mutations lead to a build up of lactate. (3 marks)
- mutations prevents electrons being passed down the electron transport chain properly
- so reduced NAD cannot be oxidised
- so pyruvate and reduced NAD will produce lactate
- lactate produced at a quicker rate than it can be removed
Is carbon dioxide produced in anaerobic respiration?
Yes in plants
No in animals
Succinate ——> Fumarate
FAD—>FADH2
What is being oxidised and reduced?
Succinate loses 2H+ and e- so oxidised
FAD gains 2H+ and 2e- so is being reduced
When gaining H+, they gain e-s too to balance charge
