HNES 465 Quiz 3

Chapters 5 &6

Immediate energy system

Adenosine Triphosphate, ATP-Phosphocreatine energy system

Short term energy system

Fast glycolysis

First law of thermodynamics

energy cannot be created or destroyed, but only transformed from one state to another without being depleted

conservation of energy

chemical energy stored within the bonds of macronutrients does not immediately dissipate as heat during energy metabolism

large portion remains as chemical energy, which musculoskeletal system then changes into mechanical energy

exergonic

any physical or chemical process that releases energy to its surroundings

endergonic

chemical processes store or absorb energy

Second law of thermodynamics

tendency of potential energy to convert to kinetic energy of motion with lower capacity for work

biologic work takes one of three forms

mechanical work

chemical work

transport work

enzymes

highly specific, large protein catalysts that accelerate forward and reverse rates of chemical reactions without being consumed or changed

reaction rates

operation rate of enzymes

mode of action

how an enzyme interacts with its specific substrate

coenzymes

complex nonprotein substances facilitate enzyme action by binding a substrate with its specific enzyme

adenosine triphosphate

provides the required energy for all cellular functions

Each mole ATP degraded to ADP liberates 7.3 kcal _____ ______ for biologic work

free energy

limited currency

body stores only 80 to 10000 g ATP

glycolysis

carbohydrate breakdown

anaerobic (fast)

relatively rapid but limited ATP production produces the end product lactate

aerobic (slow)

relatively slower process resulting in substantial ATP formation

energy release from glucose

rapid anaerobic glycolysis

phosphofructokinase (PFK)

rate limiting enzyme reaction for fast glycolysis

NET = _____ in fast glycolysis

2 ATPs

In slow glycolysis lactate _____ formed.

IS NOT

what is the end product of slow glycolysis?

2 pyruvate and 2 NADH

long term energy system

pyruvate metabolism in TCA cycle, FAT oxidation

Phase 1 of aerobic metabolism

In mitochondria, the citric acid cycle generates H+ during acetyl-CoA breakdown

Phase 2 of aerobic metabolism

significant ATP regenerates when H+ oxidizes via electron transport oxidative phosphorylation

stored fat

most plentiful source of potential energy

three specific energy sources for fat catabolism

triacylglycerols stored directly within a muscle fiber in close proximity to mitochondria

circulating triacylglycerols in lipoprotein complexes become hydrolyzed on surface of a tissue’s capillary endothelium

adipose tissue provides circulating free fatty acids mobilized from triacylglycerols in adipose tissue

breakdown of triacylglycerol molecule yields about _____ molecules

460 ATP

activation

epinephrine, nor-epinephrine, glucagon, and growth hormone trigger hormone sensitive lipase

transport

circulation bound to albumin

uptake

brought into skeletal muscle and to mitochondria

utilization

beta oxidation - 2 carbon acyl CoA

OIL

Oxidation Involves Loss

RIG

Reduction Involves Gain

Six macronutrient fuel sources supply substrate for oxidation and subsequent ATP regeneration

Triacylglycerol, blood glucose, free fatty acids, amino acids, anaerobic reactions, phosphorylation

deamination

removal of amine group ammonia

transamination

transfers an amino acid group to ketoacid

Immediate energy

ATP-PCr

Short-term energy

Lactate system (anaerobic/fast glycolysis)

Long-term energy

aerobic system (aerobic/slow glycolysis and fat oxidation)

Peak power (Wingate Test)

highest mechanical power generated during any 3 to 5 sec period

Relative power (Wingate Test)

represents peak power / body mass

Anaerobic fatigue

percentage decline in power output

Anaerobic capacity

total work accomplished over 30 sec

Rate of fatigue

corresponds to decline in power relative to peak power

Short-term glycolytic (lactate-forming) system

performances of short duration high intensity require rapid energy transfer that exceeds phosphagen supply (400m sprint, 100m swim, multi-spring sports)

Blood lactate threshold

blood lactate begins to increase exponentially (occurs at ~55% of max capacity for aerobic metabolism)

OBLA

Onset of blood lactate - 4mmol

OBLA 4 mmol

defined cut point where muscle fatigue has been demonstrated

lactate threshold

intensity where clearance no longer outweighs production

Three mechanisms explain training response

improved motivation with training, increased intramuscular glycogen stores with training allow greater contribution of energy via anaerobic glycolysis, training-induced increase in glycolytic-related enzymes particularly phosphofructokinase

The aerobic system

aerobic metabolic reactions provide the greatest portion of energy transfer when exercise duration exceeds 2 to 3 min

VO_2max

how well person can maintain intense activity for longer than 4 to 5 minutes

Fast-twitch, type II muscle fibers

possess rapid contraction speed and high capacity for glycolytic, anaerobic ATP production

Slow-twitch or type I muscle fibers

primarily generates energy aerobically, activated during slow contraction speeds, used during continuous activities

What two factors determine energy system and metabolic mixture that predominate during exercise

intensity and duration

sound approach to training

first analyze exercise for specific energy components and then establishes task-specific training regimen focusing on energy systems

EPOC fundamentals (fast component)

in low-intensity, primarily aerobic exercise, half of EPOC occurs within 30 sec; complete recovery requires several minutes

EPOC fundamentals (slow component)

second slower phase occurs in recovery from more strenuous exercise, depending on intensity and duration; may require 24 h or more to re-establish pre-activity VO₂

Possible EPOC causes

resynthesis of ATP and PCr; resynthesis of blood lactate to glycogen; oxidation of blood lactate in energy metabolism; restoration of O₂ to blood, tissue fluids, and myoglobin; thermogenic effects of elevated core temperature; thermogenic effects of hormone, particularly catecholamines; increased pulmonary and circulatory dynamics and other elevated levels of physiologic function

What does EPOC stand for?

excess post-exercise oxygen consumption