Respiration Flashcards
Stages of aerobic respiration
1) glycolysis
2) link reaction
3) krebs cycle
4) oxidative phosphorylation
Location of glycolysis
Cytoplasm
Glycolysis
Substrate level phosphorylation
- 2 ATP molecules add 2 phosphate groups to glucose
glucose phosphate splits into two triose phosphate (3C) molecules
both TP molecules are oxidised
(reducing NAD) to form 2 pyruvate molecules (3C)
releases 4 ATP molecules
Coenzymes
A molecule which aids / assists an enzyme
NAD and FAD in respiration both
gain hydrogen to form reduced
NAD and reduced FAD
NADP in photosynthesis gains
hydrogen to form reduced NADP
Coenzymes
A molecule which aids / assists an enzyme
NAD and FAD in respiration both
gain hydrogen to form reduced
NAD and reduced FAD
NADP in photosynthesis gains
hydrogen to form reduced NADP
Products of glycolysis
Net gain of 2 ATP
2 reduced NAD
2 pyruvate
Location of link reaction
Mitochondrial matrix
Link reaction
Reduced NAD and pyruvate are actively transported to matrix
pyruvate is oxidised to acetate (forming reduced NAD)
carbon removed and CO2 forms
acetate combines with coenzyme A to form acetylcoenzyme A (2C)
Products of link reaction
2 acetylcoenzyme A molecules
2 carbon dioxide molecules released
2 reduced NAD molecules
Location of krebs cycle
Mitochondrial matrix
Krebs cycle
Acetylcoenzyme A combines with 4C molecule to produce a 6C molecule - enters cycle
oxidation-reduction reactions
Products of Krebs cycle
8 reduced coenzymes:
6 reduced NAD
2 reduced FAD
2 ATP
4 carbon dioxide
Location of oxidative phosphorylation
Cristae of mitochondria
Mitochondria structure
Double membrane with inner membrane folded into cristae enzymes in matrix
Role of reduced coenzyme in oxidative phosphorylation
Accumulate in mitochondrial matrix, where they release their protons and electrons
regenerate NAD and FAD to be used in glycolysis/ link reaction / Krebs cycle
Role of electrons in oxidative phosphorylation
Electrons pass down series of
electron carrier proteins, losing energy as they move energy released actively transports H+ from
mitochondrial matrix to inter membrane space
electrochemical gradient
generated
How is atp made in oxidative phosphorylation
Protons move down electrochemical gradient back into matrix via ATP synthase
ATP created movement of H+ is chemiosmosis
Role of oxygen in oxidative phosphorylation
Oxygen is the final electron acceptor in electron transport chain
oxygen combines with protons and electrons to form water
enables the electron transport chain to continue
How would lack of oxygen effect respiration
Electrons can’t be passed along the electron transport chain
the Krebs cycle and link reaction stop because NAD and FAD cannot be produced
Oxidation
Loss of electrons
when a molecule loses hydrogen
Reduction
Gain of electrons
A reaction where a molecule gains a hydrogen
Location of anaerobic respiration
Cytoplasm
glycolysis only source of ATP
Anaerobic respiration in plants and microbes
Pyruvate produced in glycolysis is reduced to form ethanol and CO2
pyruvate gains hydrogen from reduced NAD
reduced NAD oxidised to NAD so can be reused in glycolysis
2 ATP produced
Anaerobic respiration in animals
Pyruvate produced in glycolysis is reduced to form lactate
pyruvate gains hydrogen from reduced NAD
reduced NAD oxidised to NAD so can be reused in glycolysis
2 ATP produced
Other respiratory substances
Fatty acids and amino acids can enter the kreb cycle for continued atp synthesis
Lipids as respiratory substances
Glycerol from lipid hydrolysis
converted to acetylcoenzyme A
can enter the Krebs cycle
Proteins as respiratory substances
Amino acids from protein hydrolysis can be converted to intermediates within Krebs cycle
