Chapter 4 Flashcards
Bioenergetics
The study of energy in the human body
Metabolism
All the chemical reactions that occur in the body to maintain itself. It is the process in which nutrients are acquired, transported, used & disposed of by the body
- main source of chemical energy are carbohydrates, fats & protein
Exercise metabolism
The examination of bioenergectics as it relates to the unique physiologic changes & demands placed on the body during exercise
Substrates
The matter or substance on which an enzyme acts
MAIN SUBSTRATES
- proteins
- carbs
- lipids (fats)
Carbohydrates
Fuel & energy for all day activity; organic compounds of carbon, hydrogen & oxygen, which include starches, cellulose, and sugars and are an important source of energy
- All carbodhydrates are eventually broken down in the body to glucose (a simple sugar)
Glucose
A simple sugar manufactured by the body from carbohydrates, fat, and to a lesser extent, protein, which serves as the body’s main source of fuel
Glycogen
The complex carbohydrate molecules used to store carbs in the liver & muscle cells. When carbohydrate energy is needed, glycogen is converted into glucose for use by the muscle cells
- it is store IN liver & muscle cells
Fat
1 of the 3 main classes of foods & a source of energy in the body. Fats help the body use some vitamins & keep the skin healthy. They also serve as energy stores for the body
- In food there are 2 types of fat
1. Saturated
2. Unsaturated
Triglycerides
The chemical or substrate form in which most fat exists in food as well as in the body
Protein
Amino acids linked by peptide bonds, which consist of carbon, hydrogen, nitrogen, oxygen & usually sulfur and that have several essential biologic compounds
- Significant fuel during starvation
- Rarely supplies much energy during exercise & is ignored as significant fuel for energy metabolism
Gluceoneogenisis
The formation of glucose from non-carbohydrate sources such as amino acids
Adenosine Triphosphate
Energy storage & transfer unit within the cell of the body
Adenosine Diphosphate
A high-energy compound occurring in all cells from which adenosine triphosphate (ATP) is formed
What are the 3 metabolic pathways in which cells can generate ATP?
- ATP-PC System
- The glycolytic system (glycolysis)
- The oxidative system (oxidative phosphorylation)
ATP - PC System
“The Phosphagen System”; ATP + PC = Phosphagens
The process of creating a new ATP molecule from a phosphocreatine (PC) molecule (ATP-PC System) is the simplest and fastest of the energy systems and occurs without the presence of oxygen (anaerobic)
- provides energy for primarily high-intensity, short-duration bouts of exercise or activity; seen in power & strength forms of training
- this system is activated at the onset of activity, regardless of intensity, because of its ability to produce energy very rapidly in comparison with the other systems
Glycolysis
The process of glycolysis does not begin until either glucose or glycogen is broken down into glucose-6-phosphate
The end result of glycolysis in which glucose or glycogen is broken down to either pyruvic acid (aerobic glycolysis) or lactic acid (anaerobic glycolysis) is 2 ATP for each molecule or unit of glucose and 2 ATP from each unit of glycogen
This system produces a significantly greater amount of energy than the ATP-PC system, but it too is limited to approx. 30 - 50 seconds of duration. Most workout will place a greater stress on this system than others because typical repetition range of 8 - 12 reps falls within this time frame
The Oxidative System
The most complex of the 3 energy systems; it uses substrates with the aid of oxygen to generate ATP; the 3 oxidative (aerobic) processes are:
- Aerobic glycolysis
- The Krebs cycle
- The electron transport chain (ETC)
Without oxygen during glycolysis, what is the end product?
Lactic acid
With oxygen during glycolysis, what is the end product?
Pyruvic acid
In the presence of oxygen, pyruvic acid is converted into an important molecule in metabolism called acetyl coenzyme A (acetyl CoA). This is an important molecule because it contributes substrates for use in the 2nd process of oxidative production of ATP, called the Krebs cycle
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 & ultimately lead to the production of additional ATP
Excess Post Exercise Oxygen Consumption (EPOC)
The state in which the body’s metabolism is elevated after exercise
When would energy be mostly derived from anaerobic metabolism?
When an athlete begins an activity
What usually happens after 90 minutes of exercise?
The majority of muscle glycogen stores are depleted
