Respiration Flashcards
🔴️Anaerobic respiration in animals
- Pyruvate is converted to Lactate
- NADH releases H to Pyruvate
- NAD reformed
- NAD can be reused to oxidise more respiratory substrate, so glycolysis can continue
🔴️Similarities in anaerobic respiration in yeast and muscle cells
- ATP formation
- Glycolysis is involved in both
- Pyruvate is reduced in both
- NAD reformed
🔴️Differences in anaerobic respiration in yeast and muscle cells
- Ethanol made in yeast whereas lactate is made by muscle cell
- CO2 is released by yeast but not by muscle cell
🔴️How ATP is generated by reactions in the mitochondria
- ATP made in Krebs cycle
- NADH made in Krebs and Link reaction
- NADH and FADH release H+ and e-‘s
- Electrons passed to the ETC, located in the inner membrane (cristae)
- Electron carrier arranged in order of decreasing energy level
- Energy is lost by movement along ETC
- Energy is used to AT H+ into intermembranal space
- Protons diffuse through ATP synthase into matrix, leading to ADP + Pi→ ATP
🔴️Explain why the CO2 production will be higher when Apple decomposes in pure Nitrogen
- Anaerobic respiration occurs
- This is less efficient as less ATP is produced
- More respiratory substrate must be respired to make the same amount ATP, so more CO2 is made
🔴️Why do humans need to make loads of ATP daily?
- ATP is unstable
- It can’t be stored as it is an immediate source of energy
- Used for active transport and muscle contraction etc
- ATP releases energy in small chunks
Explain why respiration produces more ATP per molecule of glucose under aerobic conditions
- Only glycolysis occurs without oxygen as there is no Krebs or ETC
- Only 2 ATP are made per glucose
- krebs cycle and the Electron transport chain produces ATP
- Oxygen is final electron acceptor as it combines with electrons and protons to make water
Explain why glucose can’t be used as a respiratory substrate for mitochondria.
- Glucose cannot cross mitochondrial membrane but pyruvate can.
- This means Glucose has to be broken down during glycolysis in cytoplasm;
3 ways ATP can be formed?
- photophosphorylation: light dependent stage of photosynthesis
- substrate-level phosphorylation: glycolysis and krebs cycle of respiration
- oxidative phosphorylation: electron transport chain of respiration
Glycolysis
- Glucose is phosporylated as 2 ATP molecules are hydrolysed
- Phosphorylated glucose is split into 2 Triose Phosphate
- The 2 TP molecules are oxidised as the NAD molecules accepts a H.The NADH goes to the ETC
- Enzyme-controlled reactions convert the oxidated TP into Pyruvate which enters link reaction
- All of this occurs in the cytoplasm
- 1 glucose makes 2 ATP, 2 Pyruvate, 2 NADH
Link reaction
- Pyruvate is dehydrogenated and decarboxylated. NAD accepts the H, then goes to ETC
- The acetyl groups reacts with CoA, forming acetyl coenzyme A
- Acetylcoenzyme A used in krebs cycle
- CO2 released as waste
Krebs Cycle
- Acetyl coenzyme A, reacts with a 4-C oxaloacetate, forming a 6-C Citrate
- Citrate releases 2 CO2 and H, reforming a oxaloacetate which recombines with the acetyl
- The H are accepted by NAD and FAD, forming FADH,FADH2 , NADH
- ATP is made
- CO2 given off as waste
How does converting pyruvate to lactate allows continued production of ATP during anaerobic respiration
- Pyruvate accepts H from NADH
- NAD Regenerated
- NAD is used to accept H from TP in glycolysis
When there’s sufficient O2 , why is lactate converted to pyruvate in the muscles.
- Lactic acid causes muscle fatigue
- Pyruvate can enter link reaction and continue aerobic respiration
Describe how water is formed at the end of aerobic respiration.
- oxygen is the final acceptor of electrons ;
- O2 combines with electron and hydrogen, forming water
How many molecules of ATP are produced from each glucose molecule in anaerobic respiration ?
2
Things produced from anaerobic respiration in muscle
- lactate
- ATP;
Explain why most of the energy provided is by anaerobic respiration rather than aerobic respiration during a 100m sprint
- energy demand is very high so high respiration rate;
- insufficent oxygen supplied to muscles
- insufficient time for oxygen to reach muscles
Why do athletes pant after a race
- oxidise lactate;
- converting it to pyruvate,
- aerobic respiration can now occur so CO2 + H2O made
Benefits of having many cristae
- larger surface area for oxidative phosphorylation;
- more ATP can be made
- which is needed to supply the energy for muscle contraction, AT etc;
If glycolysis is inhibited how will this affect the ATP production in the electron transfer chain
- No NADH released
- So no pyruvate formed, so no link reaction or Krebs cycle ;
- Movement of electrons down the chain stops;
- No energy is released for protons to be AT across membrane
- No energy is released to phosphorylate ADP
How does lactic acid production lead to muscle fatigue during anaerobic resp
- Lactic acid lowers pH
- It increases conc of H+ by dissociating to produce lactate and H+;
- This decrease enzyme activity and stops muscle proteins working effectively
Difference between how ATP is made in glycolysis and the ETC
- In glycolysis no oxygen required (substrate level phosphorylation)
- oxidative phosphorylation in ETC
Uses of ATP in cells
- Active transport;
- Synthesis of: glycogen/ protein
Explain how ATP is useful in biological processes
- Releases energy in small suitable chunks
- Broken down in a one step (single bond broken)
- Immediate energy source so energy rapidly available
- Can Phosphorylate molecules
- Makes phosphorylated substances (e.g glucose) more reactive
- Rapidly reformed during glycolysis
Benefits of carb loading for marathon
- More glycogen stored in the liver/muscles
- Releases many glucose
- Glucose can be respired so energy is released
Explain why respiration produces less ATP in the absence of oxygen
- Incomplete breakdown of glucose in glycolysis;
- No Krebs cycle;
- No electron transport chain
- As oxygen is terminal electron acceptor;
- Most ATP formed along electron transfer chain
Explain how carbon dioxide is produced during aerobic respiration.
- Decarboxylation during link reaction
- Conversion of pyruvate to acetylcoenzyme A
- During the Krebs cycle;
- Conversion of 6C (citrate) 5C
- Conversion of 5C to 4C
Describe what happens to this lactate made in muscle
- Passes into the blood;
- Transported to the liver
- Some is converted to pyruvate;
- Which undergoes aerobic respiration
- To form carbon dioxide and water;
Why should all respiration experiments be done at the same temperature?
- respiration involves enzymes (2m)
