Chapter 8 - Exercise Metabolism and Bioenergetics Flashcards
Adenosine-triphosphate (ATP)
A high-energy molecule that serves as the main form of energy in the human body; known as the energy currency of the body.
Bioenergetics
The study of energy in the human body.
Metabolism
All of the chemical reactions that occur in the body to maintain itself.
Exercise metabolism
The examination of bioenergetics as it relates to the unique physiologic changes and demands placed on the body during exercise.
First law of thermodynamics
Energy cannot be created or destroyed but merely converted from one form to another.
Macronutrients
Food substances required in large amounts to supply energy and include protein, carbohydrate, and fat.
Substrates
Intermediate forms of nutrients used in metabolic reactions to create adenosine triphosphate.
Glucose
The simplest form of carbohydrate used by the body for energy.
Glycogen
Glucose that is deposited and stored in bodily tissues, such as the liver and muscle cells; the storage form of carbohydrate.
Ventilatory threshold 1 (VT1)
The point at which the body uses an equal mix of carbohydrate and fat as fuel sources.
Ventilatory threshold 2 (VT2)
The point where glucose provides nearly all of the energy for the activity.
Fats
One of the three main classes of foods and a source of energy in the body. Fats help the body use some vitamins and keep the skin healthy. They also serve as energy stores for the body. In food, there are two types of fats: saturated and unsaturated.
Triglyceride
The chemical or substrate form in which most fat exists in food as well as in the body.
Free fatty acids
The by-products of the breakdown of stored or consumed fats, metabolized exclusively via the aerobic pathway, which uses oxygen to create adenosine triphosphate.
Protein
Amino acids linked by peptide bonds; the building blocks of body tissues.
Essential amino acid (EAA)
Amino acid that must be obtained through the diet as the body does not make it; there are nine essential amino acids.
Nonessential amino acids
Amino acids that can be synthesized by the body and do not, under normal circumstances, need to be obtained in the diet.
Negative energy balance
When calorie intake is lower than the number of calories expended.
Gluconeogenesis
The formation of glucose from noncarbohydrate sources (proteins and fats).
Ketogenesis
The formation of ketone bodies from nonfat sources, such as certain amino acids.
Ketone bodies
Water-soluble molecules produced in the liver as a result of fatty acid oxidation. They can then be oxidized in the mitochondria to produce adenosine triphosphate.
Ketosis
A state of carbohydrate depletion where the liver manufactures ketone bodies to meet energy demands that free fatty acid oxidation cannot support.
Exogenous ketones
Isolated ketone bodies usually consumed in supplement form.
Insulin resistance
The inability of the cells to respond to insulin; occurs in type 2 diabetes.
Ketoacidosis
Metabolic acidosis induced by very high levels of ketone bodies such as seen in type 1 diabetes or severe insulin resistance.
Mechanical work
The physical processes that move the body and keep it alive, such as muscle contraction.
Adenosine diphosphate (ADP)
A high-energy compound occurring in all cells from which adenosine triphosphate is formed.
Physphorylation
The addition of a phosphate group to a molecule, such as in the transfer of a phosphate group to adenosine diphosphate to create adenosine triphosphate.
ATP-PC System
An energy system that provides energy very rapidly, for approximately 10–15 seconds, via anaerobic metabolism.
Anaerobic
Processes relating to the absence of oxygen.
Glycolysis
A metabolic process that occurs in the cytosol of a cell that converts glucose into pyruvate and adenosine triphosphate. Anaerobic glycolysis refers to when this process occurs in the absence of oxygen.
Oxidative phosphorylation
A series of reactions inside the mitochondria that uses oxygen to produce adenosine triphosphate.
Aerobic
Processes relating to, involving, or requiring oxygen.
Deamination
The breakdown of amino acids into substrates that can be used for energy metabolism.
Mitochondria
The parts of the cell that use nutrients to create energy for the cell; commonly known as the powerhouses of the cell.
Electron transport chain (ETC)
A series of protein complexes that transfer protons and electrons received from the citric acid cycle through a series of reactions to create adenosine triphosphate.
Acetyl coenzyme A
Produced by the breakdown of carbohydrates through glycolysis and by the fatty acids through beta-oxidation and is the precursor for these substrates to the citric acid cycle.
Beta-oxidation
The first step in the process to break down fats via oxidative phosphorylation.
Steady-state aerobic exercise
Aerobic exercise that remains at a relatively constant intensity, including a stable heart rate and oxygen consumption.
Excess postexercise oxygen consumption (EPOC)
The state in which the body’s metabolism is elevated after exercise.
Total daily energy expenditure (TDEE)
The total amount of energy expended in one day.
Kilocalorie (kcal)
One food calorie. Also, the amount of energy needed to raise one kilogram of water by one degree Celsius.
Resting metabolic rate (RMR)
The rate at which the body expends energy (calories) when fasted and at complete rest, such as asleep or lying quietly.
Exercise activity thermogenesis (EAT)
The calories expended through structured exercise or training.
Thermic effect of food (TEF)
The energy required to digest, absorb, and process nutrients that are consumed.
Nonexercise activity thermogenesis (NEAT)
Energy expenditure through daily activities outside of structured exercise, such as walking, completing household chores, and taking the stairs.
Physical activity level (PAL)
The number of calories a person expends through physical activity and structured exercise.
Metabolic equivalent (MET)
A measurement used to describe the energy cost of physical activity as multiples of resting metabolic rate. One MET is 3.5 mL of oxygen consumption per kilogram per minute.
