LESSON 4 - bioenergetics of muscle metabolism in the cycle Flashcards
different forms of activity require different levels of energy which is supplies in the form of ____
ATP
are cellular levels of ATP minuscule or large ?
minuscule
what is the energy donor fr muscle contraction ?
ATP
what are the three types of work energy is used for?
- chemical
- mechanically
- transport
what is chemical work ?
synthesis of cellular molecules (everything to do with cells)
what is mechanical work ?
muscle contraction (acting and myosin)
what is transport work?
maintain concentration of substances in intracellular and extracellular fluids (bringing Ca back to SR)
give an example of chemical work
from and conserve ATP from food
give an example of mechanical work
power stroke
give an example of transport work
action potentials, Ca uptake
what are the two broad classes we can divide metabolic pathways into ?
catabolic and anabolic
what is catabolic ?
those that convert substrates (fuel) int energy
what is anabolic ?
those that use energy to produce substrate
what are the two parts of a reaction ?
substrate and product
define substrate …
starting material of chemical reaction
define product …
compound obtained at completion of reaction
if we have more glucose what does that mean for energy ?
more energy
what are the two controlling rates of energy production ?
- mass action effect
- enzyme effect
what is mass action effect ?
more substrate = faster rate ; more product = slower rate
what is enzyme effect ?
lowers activation energy for a chemical reaction
more enzyme or increased enzyme activity =
faster rate of product formation
chemical reactions occurs only when …
they have sufficient initial energy (activation energy)
what is an enzyme ?
biological catalyst
what do enzymes do ?
speed up metabolism or the chemical reactions in our bodies
what are energy substrates ?
fuel sources that we can convert to energy through cellular process
what are the three ways the body stores fuel ?
carbs, fats and protein
when do we break down protein ?
case of extreme starvation / very sick
which macro form of fuel is the easiest / most accessible ?
carbs
what are some examples of substrates that the macros that provide energy to resynthesize ATP provide ?
pyruvate, acetyl coA and coenzymes
what is the most effective form of storage ?
fats
define fats ?
- efficient substrate
- efficient storage
- slow rate of energy production
how many kcal/g of fat ?
9.4
whats the more healthy type of fat ?
unsaturated (double bond)
whats the more unhealthy type of fat ?
saturated (single bond)
what are the two main macros we focus on ?
carbs and fats
between fats and carbs which activation is higher ?
carbs
define carbs ?
- less efficient substrate
- less efficient storage
- high rate of energy production
how many kcal/g is a carb ?
4.1 kcal/g
what is the worst type of fat ?
trans
what does the breakdown of ATP provide ?
the required energy needed for all muscle cell functions
what is the term used for when chemical bonds of the molecule are broken through the addition of water ?
hydrolysis
what does the breaking of these chemical bonds release ?
energy
what are the the consumers of ATP within the muscle fiber ?
- myosin ATPases
- Ca ATPases
- Na-K ATPases
what does ATP break down into to initiate powerstroke ?
ADP and Pi
what do the capillaries do in regards to the overall muscle fiber ?
brings nutrients in and getting waste out
what is the ATP store ?
6 mol ATP/kg wet muscle
what are the three exercise types ?
- heavy aerobic exercise
- severe aerobic exercise
- “all-out” sprint
what is the ATP breakdown rate of a heavy aerobic exercise ?
0.4 mol/kg/sec
what is the ATP breakdown rate of a severe aerobic exercise ?
1.0 mol/kg/sec
what is the ATP breakdown rate of a “all-out sprint” ?
3.7 mol/kg/sec
what is the time to complete ATP depletion of heavy aerobic exercises ?
15 seconds
what is the time to complete ATP depletion of severe aerobic exercise ?
6 seconds (cannot move muscle)
what is the time to complete ATP depletion of “all-out sprint” exercise ?
< 2 seconds
what would happen if we only relied on stored ATP ?
we would be exhausted in seconds
what are the two ways we resynthesize ATP ?
non oxidative and oxidative energy sources
what are the two non oxidative energy sources ?
phosphocreatine and glycolysis/glycogenolysis
what are the two oxidative energy sources ?
citric acid cycle/electron transport and fatty acids from beta-oxidation
what is glycolysis ?
glucose breakdown
what is glycogenlysis ?
breakdown of glycogen
what does non oxidative mean ?
we dont need oxygen for it
what does oxidative mean ?
oxygen is present
where is non oxidative found ?
in the cytoplasm
where is oxidative found ?
in the mitochondria
ATP resynthesized through non-oxidative processes are referred to as …
“substrate-level” phosphorylation
ATP resynthesized through oxidative processes are referred to as …
oxidative phosphorylation
how many ATP do non-oxidative energy sources produce ?
2-3 ATP
how many ATP do oxidative energy sources produce ?
36 ATP
what are the three non-oxidative contributors to energy supply ?
- stored ATP
- stored PCr (phosphocreatine)
- glycolysis/glycogenolysis (glycolysis)
what can phosphocreatine do in regards to ATP ?
resupply ATP
what does lactic acid buildup cause ?
causes pain
what happens when ATP levels decrease ?
ADP increases and CK (creatine kinase) decreases
what happens when ATP levels increase ?
CK (creatine kinase) decreased
what does creatine kinase break down ?
phosphocreatine breaks into creatine by creatine kinase
describe how long creatine lasts during your workout ..
creatine only lasts for a little but of your workout then goes to ATP
if we only relied on stored ATP and PCr we would be exhausted in ______
20 seconds or less
what does glycolysis and glycogenolysis use as its substrate ?
glucose and glycogen
costs how many ATP for glucose ?
1
costs how many ATP for glycogen
0
the pathway of glycolysis and glycogenolysis starts with …
glucose-6- phosphate
the pathway of glycolysis and glycogenolysis ends with …
pyruvate
what is the ATP yield for glycolysis and glycogenolysis ?
glucose = 2
glycogen = 3
where is glycogen and glycogenelysis stored ?
glucose and glycogen
what do glucose and glycogen become ?
G-6-P
glucose and glycogen to G-6-P eventually turn into…
pyruvate
what happens if too much pyruvate is created during glycolysis and glycogenolysis ?
whole process will stop
what is NADH in the process of glycolysis ?
a substrate
why do we convert pyruvate to lactate ?
to prevent inhibition of glycolytic flux by accumulation of pyruvate
name two importances of lactate…
helps us produce energy and gives us NAD
what does lactate dehydrogenase do ?
LDH catalyzes the conversion of pyruvate to lactate and back
FILL IN THE BLANK
_________ contributes to ATP resynthesis requirements but as a low ATP yield
glycolysis/glycogenlysis
between ATP, PCr and Glycolysis which do we use immediately ?
ATP
between ATP, PCr and Glycolysis which do we use quickly and run out of in seconds ?
PCr
between ATP, PCr and Glycolysis which do we use for way longer before hitting exhaustion ?
glycolysis
what allows us to exercise for longer ?
oxygen
if we only relied on ATP, PCr and Glycolysis we would be exhausted within about ________
2 minutes or less
what are the four contributors to energy supply ?
- stores ATP
- stored PCr
- glycolysis/glycogenolysis
- oxidative phosphorylation
which form of energy supply leads to no exhaustion ?
oxidative phosphorylation
what is the main energetic system we use in our day to day life ?
oxidative phosphorylation
FILL IN THE BLANK
____________ can sustain ATP resynthesis requirements indefinitely
oxidative phosphorylation
