M2 L5 Flashcards
Three ways to increase ATP demand. One is high energy phosphate system.
* speed?
* what does it use? 2 things
- fast acting
- uses phosphocreatine (PCr) which has a high energy phosphate to convert ADP to ATP
- also uses creatine phosphokinase to catalyze the PCr reaction
Three ways to increase ATP demand. One is anaerobic metabolism
* does it need o2?
* what does it rely on?
* speed?
* is it efficient?
* color?
- does not need o2
- relies on gylcolysis to create ATP
- fast way to replenish ATP but its a brief process bc glucose depleats
- its infieicent, takes 1 glucose to make 2 ATP
- white fibers
Three ways to increase ATP demand. One is aerobic metabolism
* does it need o2?
* what does it rely on?
* speed?
* is it efficient?
* what does it have a high concentration of
* what are two o2 binding molecules?
* color?
- needs o2
- relies on oxidative phosphorylation
- slow process
- efficient, 1 glucose makes 36 ATP
- lots of mitochondria bc it occurs there
- hemoglobin or myoglobin
- red due to iron
Why does aerobic have a small fiber diameter?
A small diameter cuts down the diffusion distance. Aerobic needs oxygen so cutting down the diameter gets it faster.
Why is anerobic more fatiguable than aerobic?
Anaerobic is fatiguable because once the glycogen runs out it’s over. Aerobic is good as long as there’s o2.
what is intermediate oxidative glycolytic metabolism?
a blend of anaerobic and aerobic metabolic processes. relatively fast
What two things do you consider to determine fiber types?
- Metabolism (oxidative or glycolytic)
- Contractility (slow or fast myosin)
Why are there differences in contractility of fiber types?
Attributable to differences in myosin heavy chain gene expression which leads to different MHC isoforms (slow or fast isoforms)
List the 3 fiber types. Categorize as slow or fast.
Slow fibers: made from slow MHC isoforms
* Type I fibers - slow, oxidative
Fast fibers: made from fast MHC isoforms
* Type IIa fibers - fast, oxidative/glycolytic
* Type IIb fibers - fast, glycolytic
Explain why type I is slow rise, long-lasting force
- Low myosin ATPase activity → Slow ATP hydrolysis → Slower cross-bridge cycling → Slower force development.
- High mitochondria & capillary density → Efficient oxidative phosphorylation, providing sustained ATP supply.
- Fatigue-resistant, suited for endurance activities (e.g., marathon running).
Explain why type 2a is fast force, more fatigue-resistant
- Faster myosin ATPase activity → Quicker force production.
- Uses both oxidative phosphorylation & glycolysis, balancing power and endurance.
- More fatigue-resistant than Type IIb, but not as much as Type I
Explain why type 2b is quick force, fatigues fast
- Highest myosin ATPase activity → Rapid force generation.
- Relies mostly on glycolysis → Quick ATP but limited supply → Fatigues rapidly.
- Suited for short bursts of power (e.g., sprinting, weightlifting).
Discuss the graph of twitch force of the three fibers
Type I fiber: slow, oxidative
* Takes 2x longer to get to peak twitch
tension
* Lower peak
Type IIa: fast, oxidative/glycolytic
Type IIb: fast, glycolytic
Discuss the graph of fatigue of the three fibers
● Type I (oxidative fibers): slow rise, generates force for longer time
● Type IIa (oxidative/glycolytic fibers): fast force generation, more resistant to fatigue
● Type IIb (glycolytic fibers): quick force generation, fatigues quickly
Answer slow, high, or low
Type 1:
* vmax (myosin isoform type):
* oxidative phos:
* glycolysis:
* vasculature (blood vessel networks):
* mitochondria conc:
* fiber diameter:
* conc of Ca2+:
- slow (Contracts slowly, built for endurance)
- high (Uses oxygen efficiently to generate sustained ATP)
- low (Relies on oxidative metabolism)
- high (to supply o2)
- high (o2 phos occurs in the mitochondria)
- small (allows for better diffusion)
- low (Contracts slowly, so it doesn’t need as much rapid Ca²⁺ release)
Answer slow, high, or low
Type 2a:
* vmax (myosin isoform type):
* oxidative phos:
* glycolysis:
* vasculature (blood vessel networks):
* mitochondria conc:
* fiber diameter:
* conc of Ca2+:
*fast ( Faster myosin ATPase, meaning ATP is broken down faster → Faster contraction speed)
- medium ( Uses both oxidative and glycolytic metabolism)
- medium ^
- medium
- medium
- medium
- medium
Answer slow, high, or low
Type 2b:
* vmax (myosin isoform type):
* oxidative phos:
* glycolysis:
* vasculature (blood vessel networks):
* mitochondria conc:
* fiber diameter:
* conc of Ca2+:
- fast (Fastest myosin ATPase → Very rapid contraction, producing maximum speed and force)
- low (Relies more on anaerobic glycolysis)
- high
- low (doesn’t need o2)
- low (Relies mostly on glycolysis, which happens in the cytoplasm (not mitochondria). This means fewer mitochondria but fast energy production, leading to quick fatigue)
- large (The biggest fibers → Max force production)
- Contracts extremely fast → Needs rapid Ca²⁺ release and uptake
what kind of exercise is type 1 best for
endurance - it is fatigue resistance but low power
what kind of exercise is type 2a best for
versatile activities - Used for activities needing both endurance and power, like middle-distance running, cycling, swimming.
Moderate fatigue resistance and good force output.
what kind of exercise is type 2b best for
max strength and speed - Used for explosive movements like sprinting, jumping, weightlifting.
High force but fatigues quickly.
