12.3- OXIDATIVE PHOSPHORYLATION Flashcards
What is the hydrogen atoms produced from the Krebs cycle important for?
as potential source of energy
What happens to the hydrogen atoms produced from the Krebs cycle?
carried by coenzymes NAD + FAD into next stage of process, oxidative phosphorylation
What is oxidative phosphorylation?
mechanism by which some of the energy of electrons within hydrogen atoms conserved in formation of adenosine triphosphate (ATP)
What is each mitochondrion bound by?
smooth outer membrane + inner one that’s folded into extensions called cristae
What does the inner space, matrix of the mitochondrion contain?
protein, lipids + traces of DNA
What are mitochondria the site of?
oxidative phosphorylation
What are within the inner folded membrane (cristae) of mitochondria?
enzymes + other proteins involved in oxidative phosphorylation + hence ATP synthesis
Examples of cells mitochondria occur in greater numbers?
muscles, liver + epithelial cells, which carry out active transport
What do the mitochondria in metabolically active cells like?
more densely packed cristae which provide greater SA of membrane incorporating enzymes + other proteins involved in oxidative phosphorylation
What does the synthesis of ATP by oxidative phosphorylation involve?
transfer of electrons down series of electron carrier molecules which together form electron transfer chain
What do the hydrogen atoms produced by glycolysis + Krebs cycle combine with?- electron transfer chain + synthesis of ATP #1
combine with coenzyme NAD + FAD
What do the reduced NAD + FAD do?- electron transfer chain + synthesis of ATP #2
donate electrons of hydrogen atoms they’re carrying to first molecule in electron transfer chain
How do the electrons pass along the chain of electron transfer carrier molecules?- electron transfer chain + synthesis of ATP #3
series of oxidation-reduction reactions
as electrons flow along chain, energy they release causes active transport of protons across inner mitochondrial membrane and into inter-membranal space
Where do the protons accumulate and then what happens?- electron transfer chain + synthesis of ATP #4
accumulate in inner-membranal space before they diffuse back into mitochondrial matrix through ATP synthase channels embedded in inner mitochondrial membrane
What do the electrons do at the end of the chain- electron transfer chain + synthesis of ATP #5
electrons combine with these protons + oxygen to form water
so oxygen is final acceptor of electrons in electron transfer chain
What is the process described in the electron transfer chain + synthesis of ATP?
chemiosmotic theory
What is the importance of oxygen in respiration?
act as final acceptor of hydrogen atoms produced in glycolysis + Krebs cycle
Without the role of oxygen removing hydrogen atoms at the end of the chain in respiration, what will happen?
hydrogen ions (protons) + electrons would ‘back up’ along chain + process of respiration would come to halt
In general, what happens when greater energy is released in a single step?
more of it released as heat + less available for more useful purposes
When energy is released a little at a time, what can more of it be used for?
more of it can be harvested for benefit of organism
For reason that energy released a little at a time being able to be harvested for the benefit of the organism, what happens to the electrons carried by the NAD + FAD?
not transferred in one explosive step
instead passed along series of electron transfer carrier molecules, each of which is it at slightly lower energy level
What can be used as alternative respiratory substrates, other than sugars?
both lipids + proteins can be used as respiratory substrates, without being converted to carbohydrates
Before lipids are respired, what happens?
lipids first hydrolysed to glycerol + fatty acids
What happens to the glycerol? (respiration of lipids)
phosphorylated + converted to triose phosphate which enters glycolysis pathway + subsequently Krebs cycle
