Chapter 3 - Bioenergetics Flashcards
Catabolic and anabolic
Breaking down and building up
ATP
Composed of
Adenine
Ribose
3 phosphate groups
1 phosphate removed makes ADP then another AMP
High energy
ATP is replenished by
Phosphagen system (anaerobic)
Glycolysis (anaerobic)
Oxidative (aerobic)
Only carbs can be used for energy without oxygen
Phosphagen system
High-intensity activities
But used at start of all activities
Relies on ATP and creatine phosphate
Using ATPase and creatine kinase enzymes
Myosin ATPase increases rate of breakdown of ATP to form ADP and P and energy (catabolic)
Creatine kinase increases rate of synthesis of ATP from CP and ADP by supplying P group (anabolic)
do type 2 fibers contain more phosphagens than type 1?
yes
what does creatine kinase primarily regulate?
breakdown of CP
increase in muscle cell concentration of ADP promotes creatine kinase activity
increase in ATP concentration inhibits it
how does ATP work?
ATP broken down to ADP, releasing energy for actions
increase in ADP concentration activates creatine kinase to promote formation of ATP from breakdown of CP
increase in ATP decreases creatine kinase activity
how does glycolysis work?
ATP provided by glycolysis supplements phosphagen system initially then becomes primary source of ATP for high-intensity activity lasting 2 minutes
where are enzymes for glycolysis located?
in cytoplasm of cells
difference between fast and slow glycolysis?
anaerobic and aerobic
during fast, final product pyruvate is converted to lactate, providing energy at faster rate
during slow, pyruvate is transported to mitochondria for energy production through oxidative system
fast glycolysis is faster rate
what other byproduct is created?
nicotinamide adenine dinucleotide (NADH), which goes to electron transport system for further ATP production
what is formula for fast glycolysis?
Glucose + 2P + 2ADP -> 2lactate + 2ATP + H20
what is formula for slow glycolysis?
Glucose + 2P + 2ADP + 2NAD -> 2pyruvate + 2ATP + 2NADH + 2H20
why are three ATPs created if glycogen is used instead of glucose (2 ATPs)?
reaction of phosphorylating glucose, which requires one ATP, is bypassed
what is the rate limiting step during glycolysis?
conversion of fructose-6-phosphate to fructose-1,6-biphosphate. activity of PFK is primary factor in regulation of rate of glycolysis
how is lactate made?
fast glycolysis when oxygen is low. converts to lactic acid causing fatigue but fatigue is more likely result of decreased tissue pH
what happens when pH decreases?
inhibits glycolytic reactions and interferes with muscle action, by inhibiting calcium binding to troponin or interfering with actin-myosin cross-bridge formation
where is lactate used?
energy substrate in type 1 and cardiac muscle
in gluconeogenesis during exercise
where is lactate oxydized?
in muscle where it was produced or transported by blood to other muscles, or converted to glucose in liver
what is Cori cycle?
conversion of lactate to glucose in liver
what is normal concentration of lactate in blood?
0.5 to 2.2 mmol/L at rest
what is lactate threshold?
relative intensity of exercise at which blood lactate begins increase above baseline concentration
typically begins at 50% to 60% of max oxygen uptake in untrained subjects and 70% to 80% in trained
what is onset of blood lactate accumulation?
second increase in rate of lactate accumulation
occurs when concentration of blood lactate near 4 mmol/L
how does oxydative aerobic system work?
uses fats and carbs
protein not used before 90 minutes
at rest, 70% of ATP produced is derived from fats, 30% carbs
if oxygen is present, pyruvate is not converted to lactate but transported to mitochondria and converts to acetyl-CoA, where it enters Krebs cycle again
Krebs produces two ATPs from GTP for each glucose
for each glucose 6 NADH and 2 FADH2 produced
what is electron transport chain?
produces ATP from ADP
uses NADH and FADH2 to rephosphorylate ADP to ATP
hydrogen bonds with oxygen at end to make water
how much ATP can NADH and FADH2 make?
one NADH can make 3 ATP
one FADH2 makes 2 ATP
how much ATP does the oxydative system make?
38
how is fat oxidized?
fats enter mitochondria, where they undergo beta oxidation, forming acetyl-CoA and H
Acetyl-CoA enters Krebs cycle, H carried by NADH and FADH2 to ETC
what is the rate-limiting step in Krebs cycle?
conversion of isocitrate to alpha-ketoglutarate
energy production and capacity
weightlifting and tennis rely on phosphagen system
low-intensity but long duration use oxydative
move to glycolysis and oxidative as slows down
inverse relationship between rate and amount of ATP
fatigue during activities usually due to phosphagen depletion
what disappears first?
phosphagens first as a result of high-intensity anaerobic exercise moreso than aerobic
CP disappears 50-70% during first 30 seconds of high-intensity exercise
muscle ATP not burned more than 60% even during intense exercise
isometric moves use fewer phosphagens
how fast is ATP and CP repletion?
3 to 5 minutes after exercise, 8 for CP
how much glycogen is available?
300-400g in muscle, 70-100g in liver
liver is more important in low-intensity exercise
how optimally is muscle glycogen repleted?
if 0.7 to 3.0 g carbs per kilo ingested every 2 hours following exercise
how is oxygen uptaken during aerobic and anaerobic exercise?
oxygen uptake increases until steady state of uptake reached
at start, some energy must be supplied through anaerobic
what is oxygen deficit?
anaerobic contribution to total energy cost of exercise
what is oxygen debt?
postexercise oxygen uptake when rate remains ab ove preexericse levels
when are anaerobics used?
when intensity is above max oxygen uptake a person can attain, like if you’re not used to it
