[FMS] NAM - aerobic metabolism Flashcards
what is another name for aerobic metabolism
Krebs cycle
Citric acid cycle
Tricarboxylic acid cycle
Common terminal pathway
where does aerobic metabolism occur
mitochondrial matrix
what happens in aerobic metabolism
oxidation of acetyl CoA to CO2 and water
what tissues aerobically metabolise? and which ones do not?
all tissues that have mitochondria
not RBC or white muscle fibres
- what are the functions of aerobic metabolism?
- energy trapping
- biosynthesis of intermediates
- how many decarboxylations occur in TCA?
2 (decarboxylation = when co2 is removed which happens 2 times in TCA cycle)
draw out the TCA cycle including enzymes and where the following are made: H, GTP, CO2, and FADH2
what is the link reaction
reaction for conversion pyruvate to Acetyl CoA, prep for TCA
what kind of reaction is link reaction
decarboxylation
what are the other cofactors involved in aerobic respiration (link reaction)
- thiamine pyrophosphate (thiamine VitB1)
- lipoic acid
- FAD (riboflavin: vitB2)
- Coenzyme A (panthothenic acid: vitB5)
- what does coenzyme A form?
thioester bonds with carboxylic acids
- where is the electron transport chain?
inner mitchondrial matrix
what does the Electron Transport chain contain?
metal ions that undergo electron transfer reactions
what do metal ions in the ETC prevent?
leakage of electrons
what is the function of the ETC
to get:
NADH –>NAD+
FADH2 –> FAD
ADP –> ATP
how does the ETC generate ATP
via the re-oxidation of NADH to NAD+ and FADH2 to FAD
how many of the following enzyme reaction are there in the TCA cycle:
- enzyme reactions that produce NADH and H+
- enzyme reactions that produce FADH2
- enzyme reactions that produce GTP
3 enzyme reactions produce NADH and H+
1 enzyme reaction produces FADH 2
1 enzyme reaction produces GTP
what is the ATP yield of TCA
10(new)/12 ATP (old)
which 3 enzyme steps in TCA cycle are highly exergonic & irreversible:
- citrate synthase
- isocitrate dehydrogenase
- α-ketoglutarate dehydrogenase
what is the definition of oxidative phosphorylation
process for the transfer of H atoms to oxygen
where does oxidative phosphorylation take place
inner compartments of mitochondria
which tissue does oxidative phosphorylation take place in, which cell does it NOT take place in
most tissues & cell types
(not red blood cells)
what the function of oxidative phosphorylation
‘energy trapping’ direct phosphorylation of ADP to produce ATP
What do we need oxygen for in oxidative phosphorylation
Oxygen is the terminal electron acceptor to generate ATP.
what are 2 components of the electron transport chain
H pair acceptors:
Flavin cofactors
Coenzyme Q CoQ
Electron acceptors:
Iron sulphur proteins
Cytochrome proteins
what are the steps in the electron transport chain?
what is redox potential
Redox potential, E’0, is a measure of the electron affinity of a molecule.
what does a more positive or more negative redox potential mean
The more negative E’0, the more likely a molecule is to pass on electrons (reduce another molecule).
Alternatively, the more positive E’0, the more readily a molecule will accept electrons (be reduced).
how are H+ (protons) transferred from matrix to inter-membrane space
Energy released by electron transport is used to transfer protons (H+) from the matrix to the inter-membrane space
what is the mechanism of ATP synthesis in oxidative phosphorylation (aerobic respiration)
- This pump is called the F1 ATP synthase.
- The protons are going to fit inside of it and they’re going to spin it around - as it rotates around it forms ATP.
- However in order to do that, you have to input adenosine diphosphate (ADP) and Pi, and that will yield ATP.
- The protons go from the intermembrane space, back across the inner membrane into the matrix.
what is the ATP yield in oxidative phosphorylation when NADH is reoxidised and when FADH2 produced
NADH reoxidised - 2.5 ATP
FADH2 - 1.5 ATP
What is the relationship between ADP/ATP concentration and O2 uptake in oxidative phosphorylation?
Increased [ADP] signals higher energy demand, promoting increased O2 uptake as the electron transport chain is more active in generating ATP.
Conversely, increased [ATP] signals reduced energy demand, leading to decreased O2 uptake to prevent unnecessary oxygen consumption.
what are the inhibitors and uncouplers of oxidative phosphorylation?
- Inhibitors (of the electron transport chain):
CN-, rotenone, CO - Uncouplers: dinitrophenol (DNP), thermogenin which is a protein in brown adipose tissue
What is the total ATP production from complete oxidation of 1 molecule of glucose?
30/32 ATP
When metabolism takes place in aerobic tissues O2 utilisation results mainly from:
A. Its carboxylation to CO2 in the TCA cycle.
B. Its reduction to H2O by cytochrome oxidase.
C. Its reduction to H2O2 by cytochrome oxidase.
D. Its reduction to H2O in the TCA cycle.
E. Oxygenation of haemoglobin.
B
In the TCA cycle, how many reactions produce NADH + H+ from NAD+?:
A. None
B. One
C. Two
D. Three
E. Four
D
Oxidation of the NADH and FADH2 produced in the TCA cycle occurs:
A. in the cytosol.
B. on the inner mitochondrial membrane.
C. in the mitochondrial intermembrane space.
D. in the mitochondrial matrix.
E. in the nucleus.
B
The electron transport chain is made up of a chain of electron carriers with:
A. decreasing electron affinity and decreasing redox potential.
B. decreasing electron affinity and increasing redox potential.
C. increasing electron affinity and decreasing redox potential.
D. increasing electron affinity and equal redox potential.
E. increasing electron affinity and increasing redox potential.
E
If cells were exposed to an agent that causes the inner mitochondrial membrane to become freely permeable to protons, which of the following effects would you expect to observe?
A. Cells would be completely unable to synthesize ATP.
B. NADH would build up.
C. Carbon dioxide production would cease.
D. Consumption of oxygen would fall.
E. The ratio of ATP to ADP in the cytosol would fall.
E
NOT A BECUASE while ATP synthesis would be impaired, it wouldn’t be completely abolished because there are other mechanisms for ATP synthesis, such as substrate-level phosphorylation.
what are the 3 main products of the ETC
ATP
H2O
NAD+ and FAD
