Lesson 14: Bioenergetics of Exercises + Fuel Use During Physical Activity Flashcards
ATP is stored within muscles but where does the majority of ATP used for muscle contraction come from?
the food we eat
What is ATP?
The immediate chemical energy needed for all cellular function
What does ATP stand for?
Adenosine Triphosphate
What is ATP the combination of?
Adenosine and 3 phosphate groups
Carbs/proteins/fats are digested down to their simplest forms and absorbed into the blood before transporting to metabolically active cells, from here, what/where do they go?
They either immediately enter the metabolic pathway for ATP Production or are stored for later use.
The protein we eat is usually used for growth and repair of cellular structures or excreted as waste, but can amino acids be converted to and used in?
Glucose in the liver through gluconeogenesis and used in the nerves/muscles.
In a state of starvation, what happens to protein?
It is catabolized and converted to glucose in the liver.
Why is energy released from ATP?
ATP is adenosine and 3 phosphate groups, there is special high-energy bonds between the phosphate groups that when broken, releases energy to the cell that can directly use it to perform cellular function.
If there is no ATP present in a muscle looking to contract, what will happen?
It won’t be able to contract until there is a source of ATP
Why is our human physiology organized to provide uninterrupted sources of ATP?
Due to our ancestors need to exercise in order to procure food, pursure mates and escape predators.
Why must ATP be continuosly resynthesized in one of the three energy systems?
Because although it can be stored in a cell, the amount of ATP that is stored and immediately available (for muscular contraction) is very limited and will only provide seconds of energy.
What two compounds are referred to as phosphagens when combined?
ATP and Creatine Phosphate
What is another high-energy phosphate compound found within muscle cells? (Not ATP)
Creatine Phosphate
When ATP is broken down for muscular contraction, what is it re-synthesized from?
the breakdown of creatine phosphate
The energy released from breaking the Creatine Phosphate’s bone is used to reconstitute ATP from what? (2)
Adenosine Diphosphate (ADP) and P.
Why can Creatine Phosphate levels drop very low in comparison to ATP Levels?
Due to CP constantly reconstructing ATP.
During heavy exercise, what combines to make ATP and AMP?
x2 ADP (adenosine diphosphate)
why is it important that ADP combines to make ATP and AMP?
it results as another pathway for rapid re-synthesization of ATP and because AMP is an important signalling molecule that tells your body to adapt to training in a way that increases production of ATP.
How many seconds of energy will the total of ATP and CP stored in a muscle provide during all-out exertion exercise when ATP is no continuosly resynthesized?
10 seconds
What is anaerobic glycolysis?
the anaerobic production of ATP from carbohydrates
How does anaerobic glycolysis make ATP?
it uses the energy contained in glucose
Anaerboic Glyoclysis provides a convenient intermediate/halfway energy system between the __________ system and ________ ________ of ATP.
phosphagen
aerobic production
When is anaerobic glycolysis required?
when energy is needed to perform activities that require large bursts of energy over a longer period of time than the phosphagen system will allow (around 1-3 mins)
Anaerobic glycolysis occurs within the _______1 of the ____2 and involves the incomplete breakdown of _______3 or _________4 to a simpler substance, _________5 to be used in the mitochondria by the aerobic energy system.
1 cytoplasm 2 cell 3 glucose 4 glycogen 5 pyruvate
What is pyruvate?
pyruvate is a key intermediate compound in several metabolic pathways throughout the cell
If energy is very high and there are little amounts of oxygen available, what can pyruvate be converted into and transported to do?
Pyruvate will be converted into lactate and will transport out of the active cell to be used for energy by other cells in the body.
What does continuous production of pyruvate via anaerobic glycolysis result in?
a steady stream of ATP
What is lactate accumulation attributed to changes in?
muscle pH (acidity)
What does changes in muscle pH contribute to?
muscle fatigue
If the circulatory system and other inactive structures cannot maintain a good ratio of lactate in the muscle, what will occur?
Muscle fatigue will occur and therefore painful symptoms like ‘the burn’
Is it aerobic or anaerobic glycolysis that provides the main source of ATP during high-intensity exercise?
anaerobic
Can anaerobic glycolysis be used continusly or only for a specified amount of time during sustained activity?
sustained amount of time
What is the aerobic production of ATP used for?
activities that require a sustained amount of energy production
Aerobic metabolic pathways need a continous supply of oxygen delivered by the circulatory system, without oxygen, they cannot produce ATP - why?
because the metabolic fuels (carbs and fats) are burned in the presence of oxygen and the energy produced from burning these is what provides ATP.
What is the efficiency of cellular respiration? And what is most of it wasted as?
25%, most of it is wasted as heat.
Where does Aerobic Glycolysis/Oxidative Glycolysis occur and why?
in the mitochondria because they contain oxidative enzymes that are needed by the cell to utilize oxygen.
What is Aerobic/Oxidative Glycolysis limited by?
the capacity of the cardiorespiratory system to deliver oxygen to the active cells.
When sufficient oxygen is available, what is pyruvate converted into?
acetyl-CoA
In Aerobic/Oxidative Glycolysis, once pyruvate is converted to acetyl-CoA, what happens next?
the acetyl-CoA enters the Kreb’s cycle and electron-transport system to then produce ATP, CO2 and H2O.
What are fatty acid oxidation and beta oxidation?
they are metabolic pathways that occur within the mitochondria and require a continuous supply of oxygen to produce ATP.
Why is fat such an excellent source of stored energy?
because the aerobic metabolism of fat produces a large amount of ATP.
at rest, what does the body use for energy production?
glucose and fatty acids (via aerobic pathways)
During exercise and as intensity increases, does the body utilize glucose or fat more and why?
It utilizes glucose more for energy production as glucose metabolism requires less oxygen than fatty-acid metabolism.
What is the Respiratory Exchange Ratio (RER)?
a marker of the proportion of fat or carbohydrates that is being used for fuel at different exercise intensities.
How is Respiratory Exchange Ratio measured?
By evaluating both concentrations of CO2 produced and O2 consumed in expired air during steady state exercises.
What is the Respiratory Exchange Ratio formula?
RER = Co2 divided by O2 consumed
When the Respiratory Exchange Ratio value is at 1, the source of fuel is 100% ?
carbohydrates
when the Respiratory Exchange Ratio value is 0.7, the source of fuel is primarily 100 ?
fat
At rest, the Respiratory Exchange Ratio averages at 0.75, what percent of fat and carbohydrates are used here for fuel?
85% fat
15% carbs
As exercise intensity increases so does the Respiratory Exchange Ratio, what shift is reflected in this increase?
A shift from primarily fat metabolism to primarily carbohydrate metabolism
When is protein broken down for energy ue?
In extreme, sustained exercise events such as ultramarathons or in a clinical condition such as diabetes.
Why is assessing an individuals oxygen consumption a great measure of their ability to perform sustained endurance exercises?
Because the primary mechanism for creating energy is from the OXIDATION of glucose and fatty acids.
The more O2 taken in, transported and utilized = the more physical work can be done.
How can O2 consumption be determined?
by measuring the volume of air that an individual is breathing and the concentrations of O2 and Co2 exhaled.