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 physiological changes and demands placed in 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 protien, carbs and fat.
All life on earth is?
Carbon based
The “energy” contained in food is located?
Within the molecular bonds
How is carbon removed from the body?
Exhaling co2 is the only way carbon is removed from the body
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.
What primarily fuels the body when it is not active?
Fats
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 the energy for the activity.
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 acids (EAA)
Amino acid that must be obtained through the diet as the body does not make it; there are nine essential amino acids.
Benefits of having fat as a fuel source?
Even relatively lean people still have a large supply stored on their body, which can be broken down into triglycerides and used for energy during prolonged, lower intensity physical activity and exercise.
What is the primary fuel source when an individual is exercising at an intensity below VT1?
Free fatty acids
Before amino acids can be used to make ATP, they are further broken down and then recombined into?
Either glucose through a process called gluconeogenesis or ketone bodies through a process called ketogenesis.
Gluconeogenesis
The formation of glucose from non carbohydrate 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 (ATP)
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.
What three molecules are in a keytone body?
- Acetone
- Acetoacetic acid
- Beta-hydroxybutyric acid
Ketone levels can increase to approximately .5-1.5 millimoles per liter (mmol/L) of blood, which is known as?
Nutritional ketosis
How many calories equal 1 pound of body fat?
3,500
Mechanical work
The physical processes that move the body and keep it alive, such as muscle contraction.
Adenosine disphosphate (ADP)
A high energy compound occurring in all cells from which adenosine triphosphate is formed.
40% if the energy released during metabolism is actually used for?
Cellular work, such as creating more molecules; the remainder is released as heat.
Adenosine triphosphate is made up of?
A nitrogenous base (adenine)
A sugar molecule (ribose)
And three phosphate groups
Phosphorylation
The addition of a phosphate group to a molecule such as 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.
The three main ways that phosphorylation is reached are known as the three metabolic pathways:
- ATP-pc system
- Glycolytic system (glycolysis)
- Oxidative system (oxidative phosphorylation)
Anaerobic
Processes relating to the absence of oxygen.
What is the first of the ATP-generating metabolic pathways?
ATP-PC system, or the phosphagen or the phosphocreatine system. The body naturally creates stores of phosphocreatine by breaking down and converting certain amino acids. *this system is the simplest and fastest way to generate more ATP.
It works by taking ADP left over from a previous muscle contraction and adds a phosphate taken from a phosphocreatine (PC) molecule, rapidly creating available ATP at the site where it needs to be used. This process does NOT require oxygen, ATP-PC is anaerobic
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.
Glycolysis takes place in the?
Cytoplasm of an animal cell.
What are the negatives and positives of glycolysis?
Negative: a bit slower to ramp up to its full ATP production capabilities.
Positive: it lasts longer, with a capacity of apprx 30-60 seconds of duration, which can be increased by several seconds through the use of high intensity styles of training.
Glycolysis can be treated in two different ways depending on whether or not there is oxygen present.
- If oxygen is available -pyruvate is further broken down, enters the oxidative system, and leads to the creation of additional ATP.
- If oxygen cannot be present- pyruvate will be converted into a molecule called lactate, which contributes to the “burn” felt during strenuous exercise as it accumulates in the muscle tissue.
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.
Acidoses
When hydrogen ions contribute to a decrease in muscle pH
Cori cycle
Once Lactate has been removed from soft tissue cells and enters blood stream, instead of being removed from the body, it is processed by the liver (this metabolic process is called cori cycle).
During cori cycle , ATP is used to convert lactate in the opposite direction back to pyruvate and subsequently glucose
Oxidative system (oxidative phosphorylation)
This process uses oxygen to convert food substrates into ATP. Defined as aerobic process because it needs oxygen to complete the reactions.
3 substrates used in oxidative system:
- Fatty acids
- Pyruvate created during glycolysis
- Amino acids that have undergone deamination (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
The rate at which a person can break down fat depends on?
The number of mitochondria in the muscle cell and the amount of oxygen delivered by the blood.
The complete metabolism (anaerobic and aerobic) of a single glucose molecule produces?
Between 35 and 40 ATP
Electron transport chain
Occurs in the inner mitochondrial membrane after the CAC has removed the electrons from acetyl CoA. In the process, protein complexes create a gradient of stored hydrogen ions that allow the electrons freed by the cac to move through them. When the ATP levels fall and ADP levels rise, the hydrogen gradient is “harvested” by a protein called ATP synthase to turn ADP and oxygen into ATP and water. As a result of this efficient handing of the molecules, the ETC can generate a relatively large amount of ATP with minimal waste products.
Steady-state aerobic exercise
Aerobic exercise that remains at a relatively constant intensity, including a stable heart rate and oxygen consumption.
At higher intensities (above VT1), what will provide more of the energy to make ATP?
Carbohydrates (glucose)
Lower intensity activities (below VT1) will rely mostly on to provide ATP?
Fat oxidation
What’s an example of steady-state aerobic exercise?
Running or walking at a steady consistent pace for 1 mile.
Excess post -exercise oxygen consumption (EPOC)
What is its purpose?
The state in which the body’s metabolism is elevated after exercise.
Purpose is to produce additional ATP (above and beyond what is needed for recovery) to help reestablish baseline levels of ATP and PC and to assist with clearing metabolic waste products.
If the prior bout of high-intensity work is less than 1 minute, meaning it was primarily fueled by the ATP-PC system, the recovery period will be?
It will also be about 1 minute or slightly less
If the period of high-intensity work is longer, such as in repeated interval training, the recovery period should have?
1-1 ratio of work-to-rest-time. similar to high-intensity work less than 1 min.
VT1
During vT1 A person needs to take in more air to supply more oxygen to the mitochondria to help support the oxidative metabolism of free fatty acids.
VT2
During vt2 A person is relying primarily on anaerobic metabolism, and the body becomes more focused on exhaling carbon dioxide and trying to recover anaerobically, so expiration becomes more forceful making it difficult to talk.
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.
Non-exercise activity thermogenesis (NEAT)
Energy expenditure through daily activities outside of structured exercise, such as walking. Completing household chores, and taking the stairs.
Steady-state aerobic exercise
Aerobic exercise that remains at a relatively constant intensity, including a stable heart rate and oxygen consumption.
What term is used to describe the number of total calories expended per day divided by the resting metabolic expenditure?
Physical activity level (PAL)
The shift to a larger breathing volume during moderate intensity exercise is known as?
VT1
The point at which carbohydrates and fat contribute equally to energy production
Vt1
VT2
Body becomes more focused on exhaling carbon dioxide.
Glycolysis is a?
Anaerobic process that generates ATP quickly, but not a tremendous amount. The end products of glycolysis are ATP and pyruvate, which can become lactate under anaerobic conditions.
Oxidative phosphorylation
Process that uses oxygen to create ATP from substrate molecules at a relatively slow rate.
Oxidative phosphorylation can use pyruvate (starting with glucose), fatty acids, amino acids, or ketone bodies as substrate molecules. This oxidative metabolism produces carbon dioxide as a by-product, which is then exhaled.
Bioenergetics
The study of the ways in which food is turned into energy
What are the end products of the electron transport chain?
ATP and water
