aerobic metabolism (carb) Flashcards
where is the greatest concen of glycogen and glucose
muscle glycogen > liver glycogen > blood glucose
500g > 80g > 5g
why is the mito the powerhouse of the cell
produces ATP and has all the enzymes needed to do so
what can be stored in the muscle (4-10% mito)
carbs and fat
- can’t store protein
what parts occur in the mito
TCA
ETC
ATP synthase (inside ETC)
what happens to pyruvate in the mito
goes into the mito matrix (doesn’t need to convert during low intensity exercise)
pyruvate —PDH—> acetyl coa + CO2
- loss of a carbon atom from pyruvate
- electrons transferred to NAD+ to produce NADH (used in the cell to produce ATP)
what is the function of pyruvate dehydrogenase (PDH) - rate limiting enzyme
reduces the level of lactate
controls the rate fo carb entry into the mito
irreversible - traps acetyl coa in the mito (can’t leave)
what activates and inhibits PDH
activated by Ca2+
inibited by acetyl coa, ATP, and NADH
where does the released carbon from pyruvate breakdown go
creates CO2
where does the NADH go
into the TCA cycle - no redox reaction yet
what is a coenzyme
a non protein substance that is requried for an enzyme to catalyse a reaction
- not all enzymes need coenzymes but coenzymes need enzymes to work (can’t catalyse by themselves)
what is the function of oxaloacetate
needs to be there for TCA cycle to work
- always there
- isn’t produced, converted, or destroyed
- reformed each cycle
what are the inputs and outputs of the TCA cycle
inputs = acetyl coa
outputs = ATP, NADH, FADH2, CO2
what activates the TCA cycle
Ca2+, ADP, and NAD+
- shows that ATP has been hydrolysed and muscle knows that more has to be resynthesised
when are the ATP and NADH/FADH2 produced from TCA cycle used
ATP - used immediately
NADH/FADH2 - carry electrons from TCA cycle to ETC
which protein in the ETC doesn’t transport any electrons
protein 2
which protein does FADH not give electrons to
protein 1
(continues on pathway after the first protein)
where are the protein complexes involved in ETC
inner mitochondrial membrane
what happens when the gradient of protons (H+) increases inside the intermembrane space
H+ moves through ATP synthase back into the matrix
what is the final electron acceptor
oxygen
how many protons does it take to produce 1 ATP from ATP synthase
4 protons
where can ATP and water produced from the ETC be used
ATP - leaves the cell and can be used directly or to replicate PCr
water - can be used by the cell
which enzymes remove electrons from hydrogens in NADH and FADH2
dehydrogenase enzymes
what is the function of ATP synthase
catalyses formation of ATP from ADP and Pi
- driven by influx of H+ into matrix along its gradient
how many ATP are made from one NADH
2.5 ATP
(10 H+ pumped through)
how many ATP are made from one FADH2
1.5 ATP
(6 H+ pumped through)
should we adopt a low carb diet
athletes - need carbs for high intensity exercise, can be fine for low intensity
gen pop - sure, don’t need lots of carbs for little exercise
context specific
what is the fuel perspective on carbs
- carbs make you obese
- carbs enhance athletic perf
what is the signalling perspective on carbs
- carbs produce signalling cascade
- gene expression for signalling pathways
- mitochondrial biogenesis (caused when there are no carbs - increases volume and size of mito)
- lose enyzmes that regulate carb utilisation during low carb
what is the health perspective on carbs
needed regardless to a certain level
- support immune system
what are the 3 Ts of carb periodisation
time, type, and total
what is the best option for carb periodisation
sleeping low carb
training low carb
competing high carb
what is the benefit of training low carb and competing high carb
able to do well at high intensity with increased carb storage
low carb after training is good for mito biogenesis
what are the consequences of continued low carb diet
can impair high intensity exercise performance if it continues for multiple days
what are the carb values in different carb diets
ketogenic <50d/day
low carb ~150-200g/day
moderate carb diet ~200-400g/day
high carb diet >400g/day
