exercise metabolism and bioenergetics

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 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, carb, and fat

substrates

intermediate forms of nutrients used in metabolic reactions to create adenosine triphosphate

glucose

the simples form of carb 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 carb

where is glycogen stored

liver

what primarily fuels the body when the body is not active

fats

ventilatory threshold 1 (VT1)

the point at which the body uses an equal mix of carb and fat as fuel sources

ventilatory threshold 2 (VT2)

the point where glucose provides nearly all of the energy for the activity

fats

help the body use some vitamins and keep the skin healthy

serve as energy stores for the body

what are the 2 types of fats

unsaturated and saturated

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 ATP

protein

amino acids linked by peptide bonds, the building blocks of body tissues

essential amino acid

amino acid that must be obtained through the diet as the body does not make it; there are 9

how many essential amino acids are there

9

why does the body switch to utilizing glucose during activity

glucose can be used much faster than fat and can be metabolized without o2

can fat be metabolized without o2

no

at what threshold is both fat loss goals and performance goals highest

VT1

what does fat get broken down to in order to be used to produce ATP

fatty acids

if someone is exercising below VT1, what is the fuel source

free fatty acids

how many amino acids are there

20

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 ATP

ketosis

a state of carb depletion where the liver manufactures ketone bodies to meet energy demands that free faty 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 3 molecules make up a ketone

acetone, acetoacetic acids, and betahydroxybutyric acid

can ketone bodies be metabolized without oxygen

yes

if carbohydrate stores run low, what is used for energy

ketones

how increased ketone levels happen

by restricting overall calories to very low levels

by following very low carbohydrate diets

consuming exogenous ketones

lack of insulin

mechanical work

the physical processes that move the body and keep it alive such as muscle contraction

ADP

a high-energy compound occurring in all cells from which adenosine triphosphate is formed

phosphorylation

the addition of phosphate group to a molecule, such as in the transfer of a phosphate group to ADP to create ATP

what are the 3 metabolic pathways

ATP-PC system

glycolytic system (glycolysis)

oxidative system (oxidative phosphorylation)

how does the ATP-PC system work

takes ADP left over from a previous muscle contraction and adds a phosphate taken from a phosphocreatine molecule, rapidly creating available ATP at the site where it needs to be used

what is the downsides to the ATP-PC system

the energy it produces gets used very quickly when there is activity

glycolysis

a metabolic process that occurs in the cytosol of a cell that converts glucose into pyruvate and ATP. Anaerobic glycolysis refers to when this process occurs in the absence of o2

if o2 from glycolysis cant be delivered fast enough, what does it get turned into

lactate

what happens during the Cori cycle

ATP is used to convert lactate in the opposite direction back to pyruvate and subsequently glucose to be released back into the bloodstream to be used again

oxidative phosphorylation

a series of reactions inside the mitochondria that uses oxygen to produce ATP

deamination

the breakdown of amino acids into substrates that can be used for energy metabolism

what three substrates are used in the oxidative system

free fatty acids, pyruvate, amino acids

what happens during the citric acid cycle

reactions that lead to the creation of a few ATP molecules and the waste product of CO

electron transport chain

a series of protein complexes that transfer protons and electrons received from the citric acid cycle through a series of reactions to create ATP

acetyl coenzyme

produced by the breakdown of carbs through glycolysis and by the fatty acids through beta oxidation and is the precursor for these substrates for these substrates to the CAC

beta-oxidation

the first step in the process to break down fats via oxidative phosphorylation

what creates the most ATP

electron transport chain

what happens to someone’s oxidative energy system as cardiorespiratory fitness improves

can support higher intensity levels without having to activate the anaerobic processes

what substance does carbs, fats, and proteins have to be broken down into

acetyl CoA

in what process are FFAs converted to acetyl CoA

beta-oxidation

how does the body respond to EPOC

once the ATP and PC levels have been restored and other physiological processes have returned to normal, o2 consumption returns close to baseline and immediate recovery will be mostly complete

total daily energy expenditure

the total amount of energy expended in one day

resting metabolic rate

the rate at which the body expends energy when fasted and at complete rest,

exercise activity thermogenesis

the calories expended through structure exercise or training

thermic effect of food

the energy required to digest, absorb, and process nutrients that are consumed

nonexercise activity thermogenesis

energy expenditure through ADLs

physical activity level

the total daily energy expenditure divided by resting metabolic expenditure