Chapter 4 - Exercise Metabolism and Bioenergetics Flashcards
Metabolism
All of the chemical reactions that occur in the body to maintain itself. Metabolism is the process in which nutrients are acquired, transported, used, and disposed of by the body.
Exercise Metabolism
The examination of bioenergetics as it relates to the unique physiologic changes and demands placed on the body during exercise.
Substrates
The material or substance on which an enzyme acts. Dietary food broken down into smaller by-products. Examples: Proteins, carbohydrates, and lipids (fats) constitute the main substrates used to transfer metabolic energy to be used for all types of cellular activity and life.
Carbohydrates
Organic compounds of carbon, hydrogen, and oxygen, which include starches, cellulose, and sugars, and are an important source of energy. All carbohydrates are eventually broken down in the body to glucose, a simple sugar.
Glucose
A simple sugar manufactured by the body from carbohydrates, fat, an to a lesser extent protein, which serves as the body’s main source of fuel.
Glycogen
The complex carbohydrate molecule used to store carbohydrates in the liver and muscle cells. When carbohydrate energy is needed, glycogen is converted into glucose for use by the muscle cells. A string of glucose molecules that can rapidly be broken down into glucose and used for energy during periods of prolonged or intense exercise.
Fat
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.
Triglycerides
The chemical or substrate form in which most fat exists in food as well as in the body. Triglycerides are derived from fats eaten in foods or made from other energy sources such as carbohydrates.
Protein
Amino acids linked by peptide bonds, which consist of carbon, hydrogen, nitrogen, oxygen, and usually sulfur, and that have several essential biologic compounds. Rarely supplies much energy during hte exercise and in many descriptions is ignored as a significant source of fuel for energy metabolism. When protein becomes a significant source of fuel is starvation.
Gluconeogenesis
The formation of glucose from noncarbohydrate sources, such as amino acids (proteins). During negative energy balance (ie. low-calorie diet), amino acids are used to assist with energy production (usually during starvation).
Bioenergetics
The study of energy how energy is transformed in the human body through various biochemical reactions.
Adenosine Triphosphate (ATP)
A high-energy compound/molecule that stores energy (to be used in cellular and mechanical work including exercise) and is a transfer unit within the cells of the body.
Example: energy released to perform cellular work like a muscle contraction
-only about 40% of the energy release from ATP is actually used for cellular work, remainder is heat.
Adenosine Diphosphate (ADP)
A high-energy compound occurring in all cells from which adenosine triphosphate (ATP) is formed.
What are the three metabolic ways that cells can generate ATP?
- The ATP-PC System
- The glycolytic system (glycolysis)
- The oxidative system (oxidative phosphorylation)
What is the ATP-PC System?
- The process of creating a new ATP molecule from a phosphocreatine molecule.
- The simplest and fastest of energy systems and occurs with t the presence of oxygen (anaerobic).
- Provides energy for primarily high-intensity, short-duration bouts of exercise or activity.
- Approx. 10-15 seconds duration
- Activated at the onset of energy, regardless of intensity, bc of its ability to produce energy very rapidly in comparison with the other systems.
What is glycolysis?
Describe the difference between aerobic glycolysis vs anaerobic glycolysis.
- Another anaerobic means of producing ATP through a chemical breakdown of glucose.
- Approx. 30-50 seconds duration / 8-12 repetitions
- Glucose/Glycogen must be converted to glucose-6-phosphate before glycolysis can occur.
- converting glucose to glucose-6-phosphate uses 1 ATP molecule
- convert glycogen to glucose-6-phosphate does not
- End Result:
- Glucose or Glycogen broken down into Pyruvic Acid (aerobic glycolysis) or Lactic Acid (anaerobic glycolysis)
- 2 ATP for each mole or unit of glucose and 3 ATP from each unit of glycogen
What is the Oxidative System (oxidative phosphorylation)?
-The process in which using substrates with the aid of oxygen to generate ATP
-The most complex of the the energy systems for generating ATP
-
What are the 3 Oxidative/Aerobic Systems? Describe each process.
- Aerobic Glycosis - use of O2 to form Pyruvic Acid
- The Krebs Cycle - Pyruvic Acid converted into Acetyl Coenzyme A (Acetyl CoA) and oxidized to produce 2 units of ATP and by-products CO2 and hydrogen, hydrogen then is combined with other enzymes
- The electron transport chain (ETC) - first two processes then provide energy for the oxidative phosphorylation of ADP to form ATP
B (beta) - Oxidation
The breakdown of triglycerides into smaller subunits called free fatty acids (FFAs) to convert FFAs into acyl-CoA molecules, which then are available to enter the Krebs cycle and ultimately lead to the production of additional ATP.
-requires more oxygen to produce ATP
Excess Postexercise Oxygen Consumption (EPOC)
The state in which the body’s metabolism is elevated after exercise.
What is the Respiratory Quotient (RQ)?
- The amount of carbon dioxide expired divided by the amount of oxygen consumed, measured during rest or at a steady state of exercise using a metabolic analyzer.
- used to estimate fuel contribution during exercise (fats vs carbs)
