Muscle energetics Flashcards
(32 cards)
What are the sources of energy for the myosin head?
ATP ONLY
What components of the muscle require ATP?
Calcium pumps in ER
Myosin
Na/K pump to maintain ion gradients
Can ATP be transferred between cells?
No, each cell makes it’s own ATP
What is the [ATP]?
5-8µM
How much contraction can the intramuscular ATP store power?
2 seconds
8 contractions
Where does PCr provide energy?
Vertebrate skeletal muscle
cytoplasm
Is intracellular [ATP] constant?
Yes
Where is PCr created?
Liver
What is the Lowman reaction?
PCr + ADP → Cr + ATP
What enzyme catalyses PCr breakdown?
Creatine Kinase
What are the advantages of PCr supply?
Immediate
High rate
No osmotic/charge imbalances
No effect of end products
What are the disadvantages of PCr supply?
28µM concentration can only sustain 10-15 seconds
Rapidly depleted
What substrates does glycolysis consume?
Glucose
Glycogen (enters at G6P)
What are the net products of glycolysis?
2ATP
2NADH
2H2O
What are the advantages of glycolysis?
Faster rate than CHO
Larger yield than PCr
What are the disadvantages of glycolysis?
NAD must be recycled Lower ATP yield than CHO Takes ~5 seconds to activate Pyruvate acts as product inhibition Glycogen stores are depleted Low release of energy Lactate build up affects pH
What range of lactate changes can be buffered?
20x increase buffered to 1pH unit change
How much energy is released from lactate?
5%
What are the 2 main regulatory points of glycolysis?
Phosphofructokinase
Hexokinase
What organelles produce CHO?
Mitochondria
What are the TCA products?
3 NADH
1 FADH2
1 GTP
2 CO2
What are the substrates of TCA?
Fatty Acids
Pyruvate
Amino acids
How much energy does TCA generate?
FA: 14ATP
CH: 15ATP
How much energy does ETC generate per electron pair?
3ATP
