Chapter 2: Quiz 2 Flashcards
ATP-PCr/ Phosphagen System
high energy molecule in muscle used to reform ATP
SOURCES: food:red meat/meat. Fish (best source) Body manufactures creatine in live and kidney
- Anaerobic
- Cytoplasm
- Simplest (one reaction/ one enzyme)
- Quickest
- Provides energy at the onset of exercise and yo sustain high-intensity muscular activity for - 10 sec.
create phosphocreatine until you are in recovery
100 M dash or anything shorter
Recreating ATP with PCr
PCr + ADP —-(CK)—- Cr + ATP
ATP - PCr System
-limitation-muscle cells store only small amounts of PCr.
need ATP to form PCr
- can’t do until recovery
- 50-70% restored in 30 sec
- full recovery in 10-30 min
creatine supplementation
- quicker recovery
- most studies show more work when exercise is repeated
- muscle swell=water
Control of ATP-PCr System Creatine Kinase (CK)
-PCr breakdown catalyzed by CK
CK controls rate of ATP production
- Negative feedback system
- When ATP levels decrease (ADP increase), CK activity increases
- When ATP levels increase, CK activity decrease
Glycolytic System
- anaerobic
- cytoplasm
- ATP yield: 2 to 3 mol ATP/ 1 mol substrate
- duration: 15 s to 2 min
*400m Dash
Anaerobic Glycolysis
When a decrease in O2, pyruvic acid —> Lactic Acid
*PURPOSE -to reform NAD+ to allow glycolysis to continue
LIMITATION: lactic acid dissociates to lactate–> decrease in pH===> FATIGUE
High Intensity Exercise=15 sec-2min
Energy Yield from Anaerobic Glycolysis starting from Glucose
invest: -2 ATP
payoff: +4 ATP
net: 2 ATP
Energy Yield from Anaerobic Glycolusis starting from G1P
invest: -1 ATP
payoff: +3 ATP
net: 3 ATP
Lactate Threshold and Endurance Performance
- LT, when expressed as % VO2max, is one of best determinants of athletes pace in endurance events
- Untrained LT: ~50% to 60% of their VO2max
- Trained LT: ~70% to 80% VO2max
Fates of Lactate
- Heart has LDH-h which takes lactate and makes pyruvate
- Oxidized to pyruvate to go Krebs. Can happen within the cell. Slow twitch muscle fibers can oxidize lactate to pyruvate better than fast twitch muscle fibers, so sometimes lactate is transported from fast twitch fibers to slow twitch fibers to be utilized
- Can enter Cori cycle where blood lactate goes to the liver to be changed to liver glycogen or glucose which may be sent back through glycolysis
Energy Sources for Early Minutes of Intense Workout
- Combined actions of ATP-PCr and glycolytic systems allow muscles to generate force in the absence of O2
- These two energy systems are the major energy contributors during the early minutes of high-intensity exercise
Glycolytic System (PFK)
- phosphofructokinase )PFK)
- rate liminting enzyme
- decrease ATP. increase ADP. increase PFK activity
- increase ATP, decrease PFK activity
-also regulated by products of Krebs Cycle
Oxidative (Aerobic) Systems
- Mitochondria
- Large # ATP
- Limited by availibility
- Activity of long duration
- CHO, fat, and pro
- CO2
4 Parts of CHO Oxidative Metabolism
- Glycolysis
- PA shuttled into mitochondrion - PA ==> Acetyl CoA (ACoA)
- Krebs Cycle
- Electron Transport Chain (ETC)
PA to A CoA & Krebs Cycle
- Each time 1 PA is converted to 1 A CoA, 1 NADH + H+ is made
- A CoA turns Kreb’s Cucle
- 1 turn of Krebs=1 ATP, 1 FADH2, 3 NADH + H
