Bioenergetics Flashcards
What is bioenergetics?
Flow of energy in a biological system: macronutrients into biologically useable energy. (food/chemical energy into muscle contraction/mechanical energy)
Exergonic vs. endergonic reactions
Exergonic: releases energy; usually catabolic
Endergonic: requires energy; usually endergonic
3 basic biological energy systems
1) phosphagen
2) glycolysis
3) oxidative systems
Anaerobic process
Do not require the presence of oxygen
Aerobic process
Process that depends on oxygen
Kreb cycle, electron transport chain, and rest of the oxidative system
Aerobic mechanisms that occur in the mitochondria
Which macronutrients are essential to anaerobic metabolism and why?
Carbohydrates: metabolized for energy with out oxygen involvement
Creatine phosphate
High energy molecule involved in the phosphagen system. Hydrolysis of this molecule provides a phosphate group to combine with ADP
Law of mass action or mass action effect
The concentration of reactants and/ or products in solution will drive the direction of the reaction
Glycolysis
The break down of carbohydrates; anaerobic. Less rapid than creatine kinase but higher capacity of ATP
What 2 things can happen with pyruvate?
1) fast glycolysis: converted to lactate and used for anaerobic ATP resynthesis
2) taken to mitochondria and undergoes the keen cycle (slower and used for longer duration)
Gluconeogenesis
The formation of glucose from noncarbohydrate sources- during extended exercise and recovery
true or false: the process of pyruvate to lactate results in the formation of lactic acid.
False.
lactate production increases with…
increased exercise and type II muscle fibers
Lactate clearance
3 ways: lactate can be oxidized in the muscle it was produced in or transported by the blood to another muscle to be oxidized OR taken to liver where it is converted into glucose
Cori Cycle
cycle of: blood glucose taken to the muscle- lactate in muscle- blood transports lactate to liver - converted to glucose in the liver- taken back by way of the blood to muscle
Phosphorylation
process of adding an inorganic phosphate to another molecule. (ADP+P=ATP)
Oxidative Phosphorylation
resynthesis of ATP in the electron transport chain
Substrate Level Phosphorylation
direct resynthesis of ATP from ADP during a single reaction in the metabolic pathways.
What are the 2 primary mechanisms for ATP resynthesis during metabolism
Substrate-level phosphorylation and
Oxidative phosphorylation
What is the net gain of glycolysis (using blood glucose)? Explain
2 ATP are required to power glycolysis and 4 are resynthesized: net gain of 2
What is the net gain of glycolysis (using muscle glycogen)? Explain
1 ATP is required to power glycolysis and 4 are resunthesized: net gain of 3
What factors stimulate glycolysis?
High concentrations of ADP, decrease in pH levels and AMP
What must be the conditions for pyruvate to be transported to the mitochondria? What happens next?
If oxygen levels are high enough (exercise intensity is low enough/ athlete is conditioned) then pyruvate is converted to Acetyl CoA and undergoes the Kreb cycle.
the oxidative system is the primary system when…
the body is at rest or at low intensity, long endurance exercise
What is oxygen deficit?
up to the first 4 minutes of exercise the body’s energy systems require a higher oxygen level then the body is able to provide. Oxygen uptake increases rapidly during this time until the body reaches steady state
name 3 important glycolytic enzymes
hexokinase
phosphofructokinase
pyruvate kinase
Energy
capacity to perform work
Catabolic reactions
breakdown of large protein/fat/carbohydrate molecules into smaller products “yielding energy release”
Anabolic reactions
The formation of large molecules from small protein/fat/carbohydrate substrates requiring energy
Why can’t we sprint indefinitely?
The processes required for different activities differ in duration. Fast powerful activity requires ATP at a higher rate then slower longer duration activities (Anaerobic vs. aerobic). Anaerobic processes cannot last as long as long
Metabolism
the total of all the reactions that take place in the cells of the body
coupled reactions
the energy given off by exergonic reactions powers an endergonic reaction
ATP
bioenergy currency of all cells
Energy
capacity to perform work
Catabolic reactions
breakdown of large protein/fat/carbohydrate molecules into smaller products “yielding energy release”
Anabolic reactions
The formation of large molecules from small protein/fat/carbohydrate substrates requiring energy
Why can’t we sprint indefinitely?
The processes required for different activities differ in duration. Fast powerful activity requires ATP at a higher rate then slower longer duration activities (Anaerobic vs. aerobic). Anaerobic processes cannot last as long as long
Metabolism
the total of all the reactions that take place in the cells of the body
blood lactate concentrations reflect…
lactate production and clearance
ATP
bioenergy currency of all cells
energy is stored between the …
2nd and 3rd phosphate groups
true or false: all energy systems are always active but in different proportions.
true
which muscles contain the highest concentrations of creatine kinase?
IIx
what determines the fate of pyruvate?
presence or absence of oxygen
Lactate Dehydrogenase
enzyme the catalyzes the formation of lactate
blood lactate concentrations reflect…
lactate production and clearance
How does H+ effect muscle contraction?
3 Mechanisms:
- enzyme activity
- actin/myosin binding affinity
- O2 carrying capacity for hemoglobin
OBLA
Onset of Blood Lactate Accumulation: when the blood lactate concentration reaches 4 mmol/L
What does OBLA reflect
body’s clearance capacity
LT
Lactate Threshold
What is LT?
point when lactate levels abruptly rise above baseline concentration (body must be working anaerobically. high lactate concentration reflect and perpetuate glycolysis)
What determines oxidative capacity?
1) oxidative enzyme levels
2) muscle fiber type composition
3) oxygen availability
Cardiorespiratory Endurance
Ability of whole body to sustain prolonged exercise
where does the phosphagen system take place?
sarcoplasm of the muscle cell
where does the kreb cycle take place?
mitochondria
where does glycolysis take place?
sarcoplasm of the cell
Define VO2 Max
The maximum capacity of an individual’s body to transport and use oxygen during exercise. Also called maximum aerobic capacity
