Anita Akweshie-
what is the main respiratory substrate for aerobic respiration in most cells
glucose
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what are other respiratory substrates
lipids
proteins
other carbohydrates
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what is the respiratory substrate that is used as a last resort and why
amino acids because they often have essential functions elsewhere in the cell as proteins
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different substrates release different
amounts of energy
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what is the energy value of carbohydrates when respired
15.8kJ/g
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what is the energy value of lipids when respired
39.4kJ/g
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what is the energy value of proteins when respired
17.0kJ/g
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how can the differences in the energy values be explained
by their molecular composition specifically by the number of hydrogens released from the breakdown
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what is the vital role of hydrogens during respiration
picked up by NAD and FAD molecules and transferred to the inner mitochondrial membrane where they are released to split up into protons and electrons, protons are then pumped into the intermembranal space to set up a proton gradient which is used in chemiosmosis to produce ATP , which are then oxidised to produce water
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what does a substrate having a higher hydrogen content mean
result in a greater proton gradient across the mitochondrial membrane which allows for the formation of more ATP
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which respiratory substrate releases the most energy and why
fatty acids in lipids as they are made up of long hydrocarbon chains with lots of hydrogen atoms
