A-level Biology - 3.3.3 Respiration Part 2
This deck covers key concepts and processes related to respiration, including oxidative phosphorylation, mitochondrial diseases, and the use of various substrates in respiration.
Define oxidative phosphorylation
Key Terms
Describe Oxidative Phosphorylation
Reduced NAD → NAD & reduced FAD → FAD = releases H H atoms split into protons and e− e− move down electron transport chain, losing energy at ea...
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| Term | Definition |
|---|---|
Define oxidative phosphorylation | Process where energy carried by electrons, from reduced coenzymes (reduced NAD and reduced FAD), is used to make ATP Involves electron transport chain and chemiosmosis |
Describe Oxidative Phosphorylation | Reduced NAD → NAD & reduced FAD → FAD = releases H H atoms split into protons and e− e− move down electron transport chain, losing energy at each carrier Energy is used to pump protons from mitochondrial matrix into intermembrane space Conc. of protons is now higher in intermembrane space than in mitochondrial matrix Forms electrochemical gradient Protons move down electrochemical gradient into mitochondrial matrix via ATP synthase Movement drives synthesis of ATP from ADP and P¡ In mitochondrial matrix, at end of transport chain, protons, electrons and O₂ (from blood) combine to form water O₂ = final electron acceptor |
____ ATP are made from each reduced NAD and ___ ATP are made from each reduced FAD | 2.5 ATP are made from each reduced NAD and 1.5 ATP are made from each reduced FAD |
What do mitochondrial diseases affect? | Affect functioning of mitochondria Affect how proteins involved in oxidative phosphorylation or Krebs cycle function = reducing ATP production |
Describe the effect of mitochondrial diseases | May cause anaerobic respiration to increase, to try and make up some of the ATP shortage = lots of lactate being produced, which can cause muscle fatigue and weakness Some lactate will diffuse into bloodstream = high lactate concentrations in blood |
Describe how proteins can be used as respiratory substrates | Amino acids used as respiratory substances Those not used for protein synthesis are deaminated in liver cells Remainder of molecule can be converted into glycogen or fat If there's not enough carbohydrates, muscle proteins can be hydrolysed to amino acids |
Describe how glycerol can be used as a respiratory substrate | Glycerol oxidised and phosphorylated into TP and then enters end of glycolysis |
Describe how fatty acids can be used as a respiratory substrate | Fatty acids are broken down by process known as beta oxidation to produce acetyl CoA when then enters the Krebs cycle |
What is produced a lot in beta oxidation? | Large amounts of FADH2 and NADH |
Fatty acids can only be broken down _______ | aerobically |
Why can fatty acids only be broken down aerobically? | ∵ oxygen will be required as final electron acceptor |
Why do red blood cells only respire glucose? | Have no mitochondria - only respire anaerobically (lipids and proteins require aerobic conditions) |
What is the respiratory quotient | Is the ratio of CO₂ to O₂ in relation to a given respiratory substrate |
Describe how RQ values can be determined experimentally | By measuring O₂ consumption and CO₂ production using a respirometer |
By calculating RQ value, what can you find out? | Substrates being used in respiration by an organism Type of respiration being carried out can be deduced |
State the equation for calculating RQ | |
Work out the RQ for glucose | |
RQ < 1, it’s a ____ or ___ | protein or lipid |
The production of ethanol or lactate regenerates oxidised NAD. Why is this good? | Means glycolysis can continue when there isn't much oxygen around ∴ small amount of ATP can be produced to keep some biological processes going |