CARB ENERGY Flashcards
energy
dynamic state i.e. mech work, chem, electrical
ability to produce energy determines exercise capacity
metabolism
sum of all chem rxns in body…breakdown and syntehsis
caratbolism vs anabolism
catabolism: molecule breakdown
anabolism: molecule synthesis
bioenergenics
converting food into usable energy
ATP
adenine and ribose
- adenosine triphosphate
lots of energy held w/in bonds
supplied by anabolic metabolism
why don’t we store much ATP
normal ATP storage is 80-100g when we produce 25kg/day
cannot sustainably gain/lose the weight
limited stores bcs extremely heavy
enzymes
protein molecules that catalyze rxns
SPEED up not cause
in metabolism, regulate the catabolism/breakdown of compounds to produce energy
oxidation vs reduction
oxidation: lose electron, more positive
reduction: gain electron
factors that effect enzyme effectiveness
- cofactor: inorganic non-protein component i.e. Mg
- called coenzyme if organic ie. NAD - substrate concentration: amt and available…can become saturated
- modulator: stim or inhibits i.e. hormones
- temperature: falls apart when too high away from ideal
- ph: lose function away from optimal…acidity more impact
- enzyme concentration: more enzyme = faster
types of enzyme competition
competitive: molecules compete for binding sites
- prevent desired rxn from happening
non-competitive: molecule binds to non-binding site and causes conformational change
feedback inhibition: the products of the rxn inhibit production
- says to slow down
enzyme activity: how likely enzyme is to catalyze rxn
oxidase
catalyzes oxidation-reduction rxns involving o2
kinase
transfers phosphate group
phosphorylation
phosphorylase
adds Pi
dehydrogenase
removes H
phosphatase
removes phosphate group
2 factors impacting energy production
- total energy demand
- rate of demand
these factors are coupled
PCr
aka phosphagen system
- does NOT require o2
- only lasts seconds, strong but brief bursts
- initiation of exercise and workload transition
PCr + ADP –> ATP + Cr
immediately produces 1 ATP/unit of substrate
- limited process to amount of PCr
- low production capacity
how is ATP made in emergency
i.e. ADP + AMP
- when run out of PCr and need FAST
adenylate kinase: catalyzes conversion of various adenosine phosphates
glycogen vs glucose
glucose: single monomer
glycogen: polymer of glucose (many molecules) to store carvs
glycogenesis vs gluconeogenesis
glycogenesis: glycogen to glucose
- so glycolysis may occur, bcs we do NOT store much glucose
gluconeogenesis: formation of glucose from non-carb sources i.e. fat, protein
- occurs during exercise in liver
glycolysis
produces pyruvate
- fate of pyruvate determined by o2 availability…becomes lactate when anaerobic, becomes acetyl coa w o2
glycolysis = anaerobic state
energy investment phase of glycolysis
glucose –> G6P by adding Pi
- break down an ATP to add Pi
- via hexokinase
molecule is rearranged, then 2nd ATP used to change into fructose 1,6 biphosphate
- via phosphofructokinase/PFK
- then splits into 2 G3P (end product)
blood glucose vs musc glycogen energy investment
blood glucose –> G6P via hexokinase
musc glycogen does NOT need ATP
- glycogen phosphorylase cleaves glucose from glycogen and adds Pi
- a mutase changes it to G6P
how much ATP used in energy investment phase
1 or 2
1 for glycogen
2 for blood glucose
energy generation phase glycolysis
occurs TWICE, one per G3P
G3P is oxidized then phosphorylated
- produces NAD –> NADH (2 total)
- prods 2 ATP (4 total)
- prods 2 pyruvate
NADH goes to ETC
some H produced, which goes to aerobic energy system or to create lactic acid
glycolysis energy tally
blood glucose:
- 4 ATP
- 2 ATP invested
- net 2 ATP
glycogen
- 4 ATP
- 1 ATP invested
- net 3 ATP
lactic acid vs lactate
lactate is the salt of lactic acid
dissociation causes H and lactate
lactate uses and at rest
at rest, some lactate produced even w adequate o2
law of mass action: if available, will be used
- LDH -> lactic acid
lactate generation allows the REGENERATION OF NAD from NADH
- allows NAD to be used at G3P
- without this, glycolysis couldn’t move past G3P…no ATP production
sources of carb during exercise
muscle glucose: primary source in high intensity, supplies most in the first hour
blood glucose: primary source when low intensity, long duration
the oxidative system
aka oxidative phosphorylation, aerobic metabolism
most complex energy system because uses both carb and FAT
where do TCA and ETC take place
both w/in mitochondria
ETC w/in mitochondrial membrane
TCA w/in inner membrane space
how does pyruvate become acetyl coa
in presence of o2, pyruvate dehydrogenase turns pyruvate to acetyl coa
- causes to lose a carbon
acetyl coa: major substrate in oxidative metabolism
TCA cycle
aka tricarboxylic acid cycle, aka krebs
- complete oxidation of food stuff/H removal
- H maintains potential energy
acetyl coa –> co2 and H
acetyl coa combines w oxaloacetate to make citrate, starting the cycle
- cycle bcs start w citrate, ends w oxaloacetate
- comb w acetyl coa to start again
citrate synthase: increases w aerobic metabolism
important krebs steps/draw TCA
- citrate –> isocitrate
- isocitrate –> a-ketoglutarate
- removes co2 and makes NADH - a-keto to succinyl coa
- makes NADH and CO2 - one direct ATP made from succinyl coa to succinate
- via GDP + Pi –> GTP
- makes ADP –> ATP - succinate –> fumarate
- makes FADH2 - malate to oxaloacetate
- makes NADH
krebs cycle tally
ONE acetyl coa makes:
- net 3 NADH
- net 1 FADH2
- net 1 direct ATP
= (3 x 2.5) + (1 x 1.5) + 1
= 10 ATP per acetyl coa
= 20 ATP total
why do NADH and FADH2 produce different energy
energy is also used to transport ATP out of the mitochondria
ETC
electron transport chain
- uses potential energy of H carriers NADH and FADH2 to rephosphorylate ADP to ATP
- electrochem grad gives energy for ATP phosphorylation
cytochromes: e- carriers…e- removed then passed thru cytochromes
- like magnets, o2 pulls e- thru
- order of protons is important, get stronger as go
ETC is same as oxidative phosphorylation
- krebs is NOT oxidative p
chemiosmosis
mechanism explaining aerobic formation of ATP
movement of H ions across inner mito memb
- causes H gradient across memb
energy released forms ATP, and H ions diffuse back in
accumulation of H creates potential energy
cytochrome oxidase
the complex that turns o2 and h to h2o
ETS is series of oxidation-reduction rxns
- electrochemical grad made when H is pumped from inner memb to intermembrane space
when 2 H return, cytochrome oxidase transfers them to 1/2 o2 molecule and makes water
total ATP from all carb systems
glycolysis
- 2/3 direct ATP
- 5 ATP from 2 NADH
PDH rxn (pyruvate to acetyl coa)
- 5 ATP from 2 NADH
Krebs/ETC
- 2 direct ATP
- 18 from 6 NADH and 2 FADH2
total = 32-33 ATP
