module 5 - 18.4 oxidative phosphorylation Flashcards
what is ATP synthase?
- an enzyme that catalyses the formation of ATP using ADP and an inorganic phosphate, Pi
- is a molecular machine
why is the formation of ATP from ADP + Pi energetically unfavourable?
takes in lots of energy
what does ATP ensure for the reaction?
that the reaction goes in a forward direction
what are the sources of energy used to make the reaction move in a forward direction?
- an electrochemical gradient created by the difference in proton or H+ conc. across inner mitochondrial membrane
- the protons diffuse back into the matrix by diffusing through ATP synthase, which supplies energy to reaction of ADP +Pi to make ATP
what is chemiosmosis?
the movement of ions across a semipermeable membrane bound structure, down their electrochemical gradient e.g ATP
what are NAD/FAD?
reduced enzymes
what is the acidity like in the inner membrane of the mitochondria?
very acidic
where is the electron transport chain?
- takes place in the cristae
- oxygen must be present to be able to accept the electrons
what is the mechanism for producing ATP called?
oxidative phosphorylation
how many ATP molecules come from oxidative phosphorylation?
34/38
(2 from krebs cycle, 2 from glycolysis)
what is the electron transport chain?
- electron carrier proteins are in inner mitochondrial membrane
- transport high energy electrons between themselves and pump protons to inter-membrane space of mitochondrion
- creates electrochemical proton gradient across inner mitochondrial membrane
- the high energy electrons come from reduced NAD and reduced FAD
- final low energy electrons accepted by free oxygen forming water
- oxygen is final electron acceptor
what are protons?
hydrogen atoms left on glucose molecules
what are cytochromes?
carriers, conjugated proteins
when can aerobic respiration only occur?
only happens if free oxygen is present in mitochondria
what happens to reduced NAD and reduced FAD during the electron transport chain?
- deliver high energy electrons to electron transport chain
what happens after reduced NAD and reduced FAD deliver high energy electrons to electron transport chain?
as electron is passed through the proteins, energy is used to pump protons into inter membrane space
how is energy generated during electron transport chain?
generated as hydrogen ions (protons) unite to form water, 2 more ATP molecules made
how many ATP molecules are made by one reduced NAD?
3 ATP molecules formed by oxidative phosphorylation
which reactions occur down the length of the chain?
redox reactions
what is oxidative phosphorylation?
ATP synthesis using a flow of protons down a conc. gradient through ATP synthase
what does ATP synthase do?
the protons in the inter-membrane space diffuse down the conc. gradient through ATP synthase by facilitated diffusion
what does the facilitated diffusion produce?
water by condensation reaction
what is FAD?
- carried hydrogen to electron transport chain
- delivers its pairs of hydrogen atoms to a carrier further down the chain than reduced NAD
- generates 2 ATP molecules
what is the net production of ATP?
38
where does the net production of ATP come from?
10 reduced NAD yield 30 ATP
4 reduced FAD yield 2 ATP
