Bioenergetics Flashcards
Substrates:
fuel sources from which we make energy (ATP); carbohydrate, fat, protein
Bioenergetics
process of converting subtsrates into energy
metabolism
highly integrated network of chemical reactions essential to viability of living organisms
Measuring energy release
calories or kilocalorie
Calorie (cal)
amount of heat energy needed to raise 1g of water 1 degree celcius
Kilocalorie
equals 1,000 calories
Endergonic reactions
require energy to be added to the reactants before the reaction will proceed
Exergonic reactions
reactions that give off energy as a result of chemical processes
3 primary sources of energy:
carbohydrates (CHO), fats, proteins
Energy is released when chemical bonds are:
broken
During short activity, more __; during longer activity,
CHO; CHO, Fat
Carbohydrates provide:
4kcal/g ~ 2500 kcal stored in body (very little)
All CHO is converted into:
glucose
CHO is transported to:
all body tissues
Extra glucose is stored as ___ in the liver and muscles
glycogen
Glycogen is converted back to glucose when:
more ATP is needed
Glycogen stores are:
limited, rely on dietary CHO to replenish
Fat provides:
~9kcal/g
fat is an ___ substrate, with ___ storage
efficient, efficient
Fat is stored in the form of:
triglycerides (TGs)
TGs must be broken down by a process called
lipolysis
only FFA’s are used to form:
ATP
Phospholipids are used to build:
cell membranes
More glycogen is stored in ___ than ___
muscle than liver
Not a lot of glucose is stored in:
body fluids (blood)
Not a lot of fat is stored in ___
muscle
Protein provides:
4kcal/g (similar to carbs)
Protein must first be converted to ___ before it can be used
glucose
Gluconeogenesis:
Converting protein and fat into glucose
lipogenesis
converting protein and CHO into FFAs
Protein can provide ___% of energy during prolonged exercise
5-10
use of protein is usually during:
fast/starvation states or ultra marathons
Enzymes
to NOT start chemical reactions or set ATP yield, do facilitate reactions, lower activation energy for chemical reaction, end with suffix -ase
ATP is broken down by:
ATPase (Adenosine Tyriphosphatase)
Enzymes will be impacted by increases in :
body temperature
warm-ups help with enzyme ____
activity
Types of work in the body:
transport, chemical, mechanical
Transport work:
active transport, resets membrane
chemical work
glucose glycogen; glycerol + FA > Triaclygycerol; amino acids > protein
mechanical work
contractile cells; muscle contraction; protein filaments convert chemical energy to mechanical energy
Breakdown of ATP to release energy
Hydrolysis: ATP + Water + ATPase > ADP + Pi + energy
How many kcal per mole of ATP is produced during hydrolysis
~7.3
Synthesis of ATP from by-products:
ADP + Pi + energy > ATP (via phosphorylation)
Oxidative Phosphorylation:
generates largest amount of ATP; aerobic
Substrate-level phosphorylation:
anaerobic
Body must constantly synthesize new:
ATP
If we are exercising in a hot environment (air temp > skin temp) which is the primary factor of heat loss?
evaporation
If it’s humid outside, what is the primary factor of heat loss?
convection because it’s harder to sweat, so you would rely on wind more to cool down
Bioenergetic outline in order that they would be utilized
metabolism, creatine phosphate or ATP-PC system, glycolysis, citric acid cycle, oxidative phosphorylation
Immediate energy systems
stored ATP, Phosphocreatine (creatine phosphate)
How much ATP is stored in the body?
very small amounts
stored ATP is the primary supplier of energy for the first ___ seconds of intense exercise
1-3
Creatine Phosphate reaction is catalyzed by
creatine kinase
Creatine Phosphate is most useful for:
short high-intensity exercise
Is oxygen required for creatine phosphate to take place?
it can occur in the presence of oxygen, but it is not required, it is anaerobic
Creatine phosphate keys:
rapidly available
very limited supply
used during high-intensity activity
anaerobic
How much creatine phosphate is stored in the muscle?
enough for about 10-20 seconds of exercise (more than stored ATP)
As ATP is used, CP reforms more:
ATP from ADP
Creatine Kinase (CK) controls rate of __ production
ATP
When ATP levels increase, CK activity __
decreases
Levels of ATP maintained early during sprinting exercise by ___ breakdown
PCr
When PCr is depleted, ATP ___
declines
Creatine Phosphate system is limited, what are some ways to increase CP stores?
eat animal meat or take creatine supplements
Anaerobic Glycolysis is called onto when doing more ___ exercise
long-term
Anaerobic Glycolysis
metabolism of glucose molecules to produce energy
How long does Anaerobic Glycolysis last?
15 seconds - 2 mins
How many ATP does Anaerobic Glycolysis yield?
2 ATP molecules per 1 molecule substrate
Intramuscular glycogen supplies most of the energy for ATP resynthesize at first:
then we increasingly use blood glucose which is replenished from glycogen stores in the liver
Which stores are used first, intramuscular, or liver glycogen?
intramuscular
What is the only macronutrient whose stored energy can be used to generate ATP anaerobically?
CHO
Glycolysis
uses glucose or glycogen as its substrate
glycolysis must convert:
glucose-6-phosphate
Costs _ ATP for glucose, _ ATP for glycogen
1, 0
Glycolysis pathway starts with glucose-6-phosphate, ends with:
pyruvic acid (PA)
All steps of glycolysis occur in the:
cytoplasm
In glycolysis, glucose is transported into the cell by:
mediated transport
Since glucose needs to be concentrated in the cell and trapped, it is converted into a form of glucose that will stay in the cell:
glucose-6-phosphate
Glucose > glucose-6-phosphate is helped by which enzyme?
hexokinase
If using glycogen first, does glucose need to be converted into glucose-6-phosphate?
no
Second (or first) step of glycolysis
Glucose-6-phosphate gets turned into Fructose-6-phosphate (F6P) then with the help of PFK is turned into Fructose 1,6-biphosphate
Rate limiting steps in glycolysis
adding phosphate to glucose required ATP and hexokinase; adding phosphate to already phosphorylated fructose compound requires ATP and PFK
the anaerobic breakdown requires _ ATP and gains _ ATP
2, 4
if there’s not enough O2 present, and pyruvic acid starts to pile up, it will become:
lactate as a buffer
Due to 2 rate limiting steps, _ ATP is consumed during glycolysis
2
in glycolysis, there are _ ATP producing steps
2
in glycolysis, there are _ gross ATP produced, resulting in _ net ATP produced
4, 2
Explain the level of involvement of the respiratory and renal systems in Acid-Base regulation during exercise
rely on respiratory more because blood flow is reduced to renal system
Describe the energy investment phase of glycolysis
2 steps for glucose (costs 2 ATP), and 1 step for glycogen (1 ATP), adding phosphate to glucose requires ATP and Hexokinase, adding phosphate to already phosphorylated fructose compound requires ATP and PFK
End product of glycolysis:
pyruvate
Under aerobic conditions, pyruvate:
goes to citric acid acycle via acetyl CoA molecule; when it is completely combusted, more ATP is produced, so you won’t tire as quickly
under anaerobic conditions, pyruvate:
becomes lactate; hits a dead end and no more ATP is produced if lactate is accumulated
lactate may be converted back to:
pyruvate if pyruvate levels are lowered
You can reduce lactate concentration by:
cooling down after a workout
H+ removed from reaction are accepted by:
NAD to form NADH
NADH + O2 >
shuttled H+ into mitochondria
NADH + no O2 >
H+ to pyruvic acid to form lactate
Electron carriers
carriers of electrons which has high energy potentials: NAD and FAD
NADH
only one active in glycolysis; carrier of electrons; donates electrons in production of 2.5-3 ATP; derived from vitamin Niacin
FADH2
active in kreb’s cycle; electron carrier; donates electron in production of 1.5-2 ATP; riboflavin is associated with the B2 vitamin
If conditions are right, electron carriers help generate:
a lot of ATP
Acetyl CoA enters:
Citric Acid cycle
citric acid cycle allows for the complete oxidation of
Acetyl CoA
Citric acid cycle has:
1 molecule of glucose, 2 pyruvate, 2 acetyl CoA
Citric acid cycle is responsible for:
oxidation of CHO, fat, and proteins
products of the citric acid cycle include:
water, CO2, NADH, H+, FADH2, GTP
Citric acid cycle occurs in the:
mitochondria
glycolysis in the citric acid cycle takes _ pyruvate per 1 molecule of glucose
2
pyruvate undergoes pyruvate decarboxylation to become:
acetyl-CoA before entering citric acid cycle
During beta-oxidation (fat breakdown)
several acetyl-CoA enter the citric acid cycle
protein catabolism (protein breakdown)
contributes minimally to bioenergetics; can be converted to glucose or pyruvate, some to acetyl-CoA and other citric acid intermediates
NADH produces _ ATP
15
FADH produces _ ATP
3
GTP produces _ ATP
2
How many ATP are produced from 2 turns of the krebs cycle?
20
12 ATP is added to the krebs cycle from:
glycolysis and pyruvate becoming Acetyl CoA
What is the total ATP produced from 1 glucose molecule in the krebs cycle?
32
oxidative phosphorylation is also known as:
electron transport chain
Where does oxidative phosphorylation occur?
mitochondria
In oxidative phosphorylation, NADH carries __ ATP, and FADH2 carries:
2.5 ATP, 1.5 ATP
Main controllers of energy systems
creatine phosphate or ATP-PC system, glycolysis, citric acid cycle, oxidative phosphorylation, glycogen breakdown: phosphorylase
Aerobic exercise training increases aerobic capacity by:
increasing number of mitochondria, and increasing capillary density. Also increases use of fatty acids and reduces H+ production
Why do we care about reducing the carbohydrates we use, and increasing metabolism of fats during exercise?
because it is glucose sparing, maintains pH, and maintains lactate for longer exercise at a higher intensity
What are the primary fuel source for muscle during low-intensity exercise?
fats
What are the dominant substrate during high-intensity exercise?
CHO
During prolonged, low-intensity exercise, there is a shift from:
carbohydrate metabolism toward fat metabolism
