Ch 4 - Metabolism Flashcards
Bioenergetics
study of energy in the body and how it gets transformed into usable forms through chemical reactions
Metabolism
chemical reactions that occur in the body for it to maintain itself; process of nutrients being acquired, transported, used, and disposed of
Exercise metabolism
bioenergetics related to physiologic changes and demands placed on body during exercise
Substrates
material on which enzyme acts; carbohydrates, protein, fat (lipids)
Carbohydrates
top source of energy; eventually becomes glucose; includes sugars and starches
Glucose
simple sugar manufactured by body; end result after digestion of carbs; main source of fuel
Glycogen
form of carbs stored in liver and muscle cells; string of glucose molecules; can be quickly broken into glucose and used as energy
Fat
one of the 3 main substrates; used as energy source in prolonged exercise
Triglycerides
chemical form of fat; how calories that aren’t needed are stored in fat cells
Protein
amino acids linked by peptide bonds; used to build and repair soft tissue; only used as energy in starvation
Gluconeogenesis
formation of glucose from non-carb sources
Adenosine triphosphate (ATP)
energy storage and transfer unit in cells; where source of immediate energy is stored
Adenosine diphosphate (ADP)
compound from which ATP is formed; what’s left behind when ATP bonds are broken to release energy
Rigor
muscle state when ATP is depleted and there’s no energy to break the connection between cross-bridges and active actin sites
ATPase
enzyme that combines with an ATP molecule and splits the last phosphate group away to release free energy
Pi
phosphate molecule remaining along with ADP after the last phosphate group is split away
Phosphorylation
process by which a phosphate group is added back to ADP, so ATP can release energy again
Phosphocreatine
molecule from which a phosphate is transferred to an ADP molecule
Phosphagen
ATP + CP
ATP-PC system
creates new ATP molecule from a PC molecule; simplest and fastest system; anaerobic; for high-intensity, short-duration exercise; always used at onset of activity
Glycolysis
anaerobic process of producing ATP through breakdown of glucose
Pyruvic acid
byproduct of aerobic glycolysis
Lactic acid
byproduct of anaerobic glycolysis
Oxidative system
aerobic progess to generate ATP; made up of aerobic glycolysis, Krebs cycle, electron transport chain; used for sustained exercise and at rest; uses fat; can last an indefinite amount of time
Acetyl CoA
what pyruvic acid converts to in the presence of oxygen
Electron transport chain
hydrogen ions released in glcolysis and Krebs cycle combine with other enzymes and provide energy for oxidative phosphorylation of ADP to form ATP
B-oxidation
first step in oxidation of fat; breakdown of triglycerides to form free fatty acids, which convert into acetyl CoA molecules
Steady-state exercise
performed at constant intensity
Excess post-exercise oxygen consumption
elevation of metabolism after exercise
Recovery
an aerobic event to set ATP-PC back toward normal and eliminate lactic acid
Respiratory quotient
CO2 expired / O2 consumed; 100% carbs at 1.0, 100% fat at 0.85
Fat-burning zone
myth that low-intensity exercise burns more fat because greater energy comes from fat than carbs - but it has lower caloric expenditure, including calories from fat
