ex phys 2026 metabolism and bioenergetics

what are the 3 energy sources?

carbs, fats, and protein

in regards to carbs, glucose is what?

blood sugar

what form of glucose is the only form of CHOS that can be directly metabolized to obtain energy?

glucose

what form of glucose is the stored form of CHOS in the mm and liver and is formed by the process known as glycogenesis?

glycogen

what is is called when glyogen is broken down?

glycogenolysis

what is the primary function of carbs?

to supply energy for cellular work

true or false? glycolysis can be either anaerobic or aerobic?

true

in order to burn a fat, you need what?

a carb

what is nutrient fatigue?

when you have an abundance of fats, but not enough carbs, you cant break down fat

during light to moderate aerobic exercise the bodies energy requirement comes from what?

½ CHOS, ½ fats

what is the only source of energy that can be used during anaerobic glycolysis?

CHOS

with maximaal exercise the intensity is so high the only fuel that can be used is?

CHOS

anaerobic means

no oxygen needed

aerobic means

oxygen needed

true or false; the citric acid cycle needs oxygen

true

the citric acid cycle and electron transport chain is the breakdown of what?

carbs

slide 9

enzymes _______ a chemical reaction.

regulate

what is the bodys most plentiful source of potential energy?

stored fat

there are fats stored where?

intramuscluar, in fat cells, and circulating

what is the name of the stored form of carbs?

glycogen

what is the name of the stored forms of fats?

triglycerides (3fatty acids and glycerol)

at rest, you’re burning…

fats

light to moderate exercise you’re buring…

CHOS

true or false; you can make a protein into a carb

true

whenever protein and carbs that are not used are stored as what?

fats

discuss the role of phosphocreatine (PCr) in the formation of ATP

phosphocreatine can combine w ADP with creatinine kinace as the enzyme which then forms ATP

what are the 3 components of aerobic metabolism?

citric acid cycle, electron transport chain, and oxidative phosphorylation

**how much of ATP synthesis takes place in the electron transport chain?

90%

during strenous exercise, if there is inadequate oxygen, the atp can not be made in the electron transport chain. the electrons have to go somewhere or else they will change the pH. what binds to them that produces lactic acid?

pyruvate

during exercise, where does the glucose come from in order

first the body uses glucose, the blood sugar. then it turns the glycogen stored in the mm into glucose and uses that. then if more is needed, the body takes from the liver

what is the only fuel source that can be used to make atp anaerobically?

carbs

in the citric acid cycle, carbs do what?

go through glycolysis to be used as fuel

in the citric acid cycle, fats do what?

go through beta oxidation (converted to acetyl-coA) to be used as fuel

in the citric acid cycle, proteins do what?

go through deamination to be used as fuel

pyruvate is converted to what?

acetyl-coa and then it can go into CAC

what is the primary function of the citric acid cycle?

the generate electrons for passage into the electron transport chain. you do get some atp but that is not its main function

fats are stored as triglycerides in the body (3 fatty acids and 1 glycerol), when we want to use them as fuel, they are broken down in a process called lipolysis. the fatty acid is converted to acetyl-coA via beta oxidation and the glycerol goes where?

to the liver to be changed into glucose which can then be used

fats are stored as triglycerides in the body (3 fatty acids and 1 glycerol), when we want to use them as fuel, they are broken down in a process called lipolysis. the fatty acid is converted into what? via beta oxidation and the glycerol goes to the liver to be changed into glucose which then can be used

acetyl-coA

lipolysis is stimulated by what?

hormones such as epinephrine, norepinephrins ect

during exercise, the concentration of hormones increase or decreases? why?

increases bc hormones stimulate lipolysis. the body is trying to break down fats bc we cant deplete our carbs fully

***what does it mean when we say “fats burn in a carbohydrate flame”?

in order for a fat to be burnt, the fatty acids have to go through beta oxidation to be turned into acetyl-coA then go into the citric acid cycle. in order to be turned into acetyl-coA we need oxaloacetate to allow it into the CAC which comes from pyruvate during the breakdown of carbs.

***with training the mms capacity to oxidize carbs increase due to what 3 things?

1. increase oxygen delivery to mm

2. increase utilization by the mms

3. increase glycogen storage

why are carbs the most important fuel for exercise?

makes energy that we can use during exercise quickly and uses the least amount of oxygen

You have been walking your dog for 10 minutes what energy systems have you used?

all three but eventually aerobic glycolysis at steady state

when does lactate happen

when there is a lack of oxygen

***why is lactate formed during intense exercise?

bc there is less oxygen, thus a greater predominace of anaerobic glycolysis

what does OBLA stand for?

onset of blood lactate accumulation or blood lactate threshold

what is the definition of OBLA?

the exercise intensity (or oxygen consumption) at which a specific blood lactate level concentration is reached

what are the 3 reasons why lactate acid is formed during exercise?

1. lack of oxygen

2. recruitment of fast-twitch fibers→ LDH enzyme →which favors the conversion of pyruvic acid to lactate

3. rate of lactate removal in the blood

in an untrained personnel, when does lactic acid builds up?

at 50-60% of their aerobic capacity

in a trained personnel, when does lactic acid builds up?

at 55-90% of their aerobic capacity

***why can a trained individual generate higher blood lactate levels?

1. improved motivation (trained so will push through the burn)

2. increased intra mm glycogen stores as a result of training so increase contribution of energy from anaerobic glycolysis

3. increase in enzyme’s that regulate glycolysis

what is the definition of steady state?

the balance btwn what the body requires for said activity and the amount of atp being produced.

true or false? during steady state, there is buildup of lactic acid.

false, no buildup of lactic acid bc what the activity requires, youre making

***a trained individual can last a long time in steady state because of what 3 things?

1. increased capillaries→ increased ability to deliver oxygen

2. improved ability by cell to use oxygen→ increased # and size of mitochondria

3. increased concentration of exzymes and transfer agents (NAD and FAD)

what is “temporary lag/oxygen deficit” ?

the time that occurs btwn the energy systems that do not require oxygen (atp-pcr and anaerobic glycolysis) before they hit steady state

why do trained individuals reach steady state faster than an untrained person

they have a lower oxygen deficit bc they are more efficient

what is maximal oxygen consumption (vo2max)

when you increase the workload but oxygen consumption plateaus

this happens past steady state

any work after vo2max happens anaerobic

***true of false? a steady rate of oxygen uptake is similar during light/medium exercise for both trained and untrained individuals

true however the trained person reaches steady state quicker

***what happens during oxygen consumption in recovery?

after exercise, your body continues breathing in extra oxygen to get the body back down to resting level

what is EPOC?

the extra oxygen your body uses after exercise to return the body to is resting state

what does EPOC stand for?

excess post-exercise oxygen consumption

in regards to EPOC and breathing, who will recover to normal faster, a trained or untrained person

a trained person will recover faster, therefore less EPOC

recovery and getting back to resting state depends on what?

wether the person is trained vs untrained and intensity and duration of exercise

what are the 2 phases of EPOC?

1. rapid component

2. slow component

during exercise, mm glycogen is depleted and replenishing depends on what 2 major factors?

-type of exercise (low intensity long duration or high intensity short duration

-amount of dietary carbs consumed during recovery

mm glycogen is replenished when after continuous endurance activities?

very little recovery 1-2 hrs after

complete recovery w high dietary intake 46 hrs

mm glycogen is replenished when after short endurance activities?

significant amount replenished within 30mins to 2 hrs

complete recovery does not require greater than normal intake of carbs