Term
| 2 rules governing the transfer of energy in biological systems |
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Definition
1) energy is not created nor destroyed, instead it is transferred from one form of energy to another
2)energy trnasfer is ineffiecent, much of the energy during transfer is lost to heat (disorder) |
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Term
| 3 types of work that uses ATP |
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Definition
| mechanical work, chemical work, and transport work |
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Term
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Definition
they are biologic catalysts and facilitate energy conversion.
-reduce required activation energy
-accelerate teh rates of chm reacitons
-reaction rates depend upon pH, temperature, availability of substrates
-used in regulated steps in pathways |
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Term
| Why is maintaing ATP homeostasis crucial and how does it make us fat? |
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Definition
| -you're alive 24 hours but only eat for maybe one of those hours. You have to be able to store the energy you get from that food so you can use it through out your day. This is especially important b/c only 50% of the PE found in our food is extracted by the body. The energy is stored in the phosphate bonds of ATP but ATP storage is very low in muscles. Thus, the ability to conserve what energy we get is crucial. This was especially true in cavemen who didn't eat everyday. This causes problems in modern men who eat way more than they burn causing fat to be built up. |
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Term
| ATP hydrolysis releases how much energy? |
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Definition
7.3 kCal/mol due t oATPase.
ATP + H20 -> ADP + Pi |
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Term
| List the main intermediary molecules for energy transfer |
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Definition
| -ATP, PCr, NAD, NADP, FAD, CoA |
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Term
| Describe the seasaw action of energy transfer? |
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Definition
| -Macromolecules (carbs, fats) are catabolised to form ATP and co2/o2. This atp powers the reaction that combines building block precursors into synthesized end products. This entire breaks down the ATP into ADP that poweres the catabolism. |
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Term
| What are the 3 energy systems that transfer food energy to energy the body can utilize during exercise? |
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Definition
-Phosphogen, Glycolysis, Oxidative phosphorylation/ETC
1) PHOSPHAGEN system
-Immediate (ATP + CP)
-maximal energy capacity: 11.1 kCal
-power events
-Enzyme system: single enzyme
-enzyme location: cytosol
-Fuel storage site: cytosol
-rate of process: immediate, very rapid
-Storage form: ATP, CrP
-Oxygen involved?: No.
2) GLYCOLYSIS
-Anaerobic (non-oxidative)
-max capacity: 15.0 kCal
-type of activity: speed
-duration: 4-50 sec
-100 meter sprints
-enzyme system: 1 complex pathway
-Enzyme location: cytosol
-Fuel storage site: cytosol
-Rate of process: rapid
-storage form: muscle glycogen and glucose
-oxygen involved?: No
3) OXIDATIVE PHSOPHORYLATION/ETC
-aerobic
-max capacity: 2000 kcal
-duration of event: >2 min
-example: marathon
-enzyme system: several complex pathways
-enzyme location: cytosol and mitochondria
-fuel storage site: cytosol, blood, liver, adipose tissue
Rate of process: slower but prolonged
Storage form: muscle and liver glycogen, glucose; muscle, blood, and adipose tissue lipids; muscle, blood, and liver amino acids
-oxygen involved?: yes! |
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Term
| Why isn't ATP stored in high quantities in the muscle? |
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Definition
ATP is too unstable to be stored in pure form
-fat and glycogen are much more stable. |
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Term
| Why isn't ATP stored in high quantities in the muscle? |
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Definition
ATP is too unstable to be stored in pure form
-fat and glycogen are much more stable. |
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Term
| 3 important reactions with the phosphagen system? |
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Definition
1) ATP HYDROLYSIS
-ATP + H20 --> ADP + Pi
-catalyzed by the enzyme ATPase
2) PHOSPHOCREATINE
-higher energy molecule than ATP but resynths ATP
-PCr + ADP + H+ --> ATP + Cr
-Catalyzed by the enzyme creatine kinase
-anaerobic resynthesis of ATP
3) ADENYLATE KINASE
-ADP + ADP --> ATP + AMP
-Catalyzed by enzyme adenylate kinase |
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Term
| Facts about phosphagen storage in skeletal muscle |
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Definition
-phosphagen storage: FT fibers > ST fibers
-Skeletal muscle PCr levels are ~4-5 x greater than ATP
-PCr is the initial replenisher of ATP
--max activation of creatine kinase takes <1 sec
--Rate of ATP regeneration via CK is 1.44 x 10^21 molecules/second (fast!)
--stores can be exhaused in ~10 seconds |
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Term
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Definition
-non-oxidative/anaerobic
-substrates: glucose and glycogen
--Glycogen is only one stored in muscle in high amounts
-glycolysis occurs in cytosol
-synthesized ATP and high- energy substrates via the breakdown of glucose to pyruvate, then lactate
-Glucose ->-> 2 ATP + 2 lactate + 2 H
-Takes 5 sec to reach maximum rate
-actually produces 4 atp but two are used to help drive reaction. |
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Term
| What are the 2 energy investing steps of glycolysis? |
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Definition
1) HEXOKINASE -1 ATP
-its a preluded reaction and irreversiable in muscle.
-Takes glucose from the muscle and blood, and phosphorelates it.
2) PHOSPHOFUCTOKINASE (PFK) -1 atp
-irreversible and commited step in glycolysis.
-point of no return
-controls how fast reaction occurs.
-Glucokinase is the form of hexo that is found in liver and kignesys
--isn't regulatd by G6P |
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Term
| How many energry harvesting steps are there in glycolysis? |
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Definition
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Term
| Aldolase produces what in glycolysis? |
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Definition
| -2 high energy 3-C molecues by splitting the 6-c molecule. Mass action effect controls this. |
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Term
| What percentage of glucose's potential energey does the two net ATP gained during glycolysis represent? |
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Definition
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Term
| What are the key regulated enzymes in glycolysis? |
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Definition
1) PHOSPHOFRUCTOKINASE (PFK)
-rate limiting step
-ATP inhibits PFK
-Energy state is inversely proportional to PFK activity
2) HEXOKINASE
-regulated by mass action
-inhibited by G6P |
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Term
| How is glucose Transported into the cells? |
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Definition
-glucose enters muscle from blood
-specialized glucose transporters ("glut" proteins)
-Glut 4 is the major transporter in skeletal muscle
-Glut 4 numbers and activity are increased in response to insulin and exercise |
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Term
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Definition
pyruvated is reduced to lactate via lactate dehydrogenase. This is b/c the body can't use pyruvate.
-reaction also regenerates NAD+
=this reaction allows glycolysis to continue during anaerobic metabolism. |
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Term
| What is the energy harvest from glycolysis? |
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Definition
-2 NADH (1 per 3-c)
-4 ATP (2 per 3-c)
Net + 2 atp (2 are used up in the energy investment stages) |
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Term
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Definition
-glycogen is primary form of carb storage in muscle and liver.
-Synthesis is done by glycogen synthase and stimulated by increased G6P |
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Term
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Definition
-the breakdown of glycogen to glucose
-enzyme: glycogen phosphorylase
-inhibited by increase G6P
-Stimulated by epinephrine.
-Can't produce AND breakdown glycogen at the same time. |
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Term
| Why is glycolysis important? |
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Definition
Cons: Its very inefficient (30% of PE is conserved)
-only good for short periods of energy needs like a sprint at the end of a mile run
Pros:
Produces lactate. Keeps pyruvate from building up and messing up glycolysis. |
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Term
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Definition
2nd phase of glucose metabolism
-Oxygen isn't used in TCA cycle
-Primary function is to generate NADH and FADH2
-occurs in matrix of mitochondria
-pyruvate enters mitochondria, combines with CoA to produce Acetyl-CoA + CO2 + NADH via pyruvate Dehydrogenase (PDH)
-PDH is stimulated by pyruvate and NAD and is inhibited by acetyl-CoA and NADH
-1 acetyle-CoA --> 3 NADH + H and 1 FADH2
-glycolysis produces 2 pyruvate(acetyle-coA)/ glucose
-produces 6 NADH, 2 FADH2, 2 ATP |
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Term
| How much ATP does NADH and FADH2 produce in ETC? |
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Definition
NADH = 3 ATP
FADH2 = 2 ATP |
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Term
| the availability of O2 is the ______________ of oxidative metabolism |
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Definition
| single most important regulator |
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Term
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Definition
-fat represents the body's largeest source of stored PE
-two storage depots: adipose tissue and intramuscular triglycerides
-Lypolysis - utilization of lipids is oxidative
1) Mobilized
2) activated (requires 2 ATP)
3) tranported into the mitochondria
4) oxidized (Beta oxidation) |
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Term
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Definition
1) FADH2 is produced
2) NADH is produced
3) Fadh2 and nadh go straight into etc
4) CoA added. enzyme cleaves 2 carbons. the result is acetyl=CoA. This goes straight into kreb's cycle |
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Term
| Energy yield of lipid oxidation |
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Definition
-each cycle of B-oxiday produces 1 NADH + 1 FADH2 + acetyl-CoA
-Cycles of B-oxidation = (# of C/2) - 1
-Palmitate: 16 c fatty acid
-(16/2)-1 = 7 cycles
--7 FADH2 = 14 ATP
7 NADH = 21 ATP
8 acetyle-CoA = 8 x 12 ATP = 96 ATP
With 3 fatty acids in the one triglyceride the complete oxidation of palmitate = 131-2=129 ATP
(-2 ATP for activation) |
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Term
| Details behind the Crossover Concept |
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Definition
At rest, our body uses lipids as the predominate fuel (2/3 are fat oxidation)
As exercise increase, the proportion of CHO that is oxidized increases while the % of lipids decreases.
-with training, the curve adn the crossover shift to hte right (occuring at 75-80% of max.)
-ex traini9ng allows you to rely on fat utilization longer and save your CHO longer. |
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Term
| What is the difference b/t RER and RQ? |
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Definition
VCO2/VO2: CO2 produced divided by O2 consumed
-RER = respiratory exchange ratio
--measured at the mouth and represents whole body substrate utlization.
--at rest RER = 0.7
--with ex, RER increases from 0.7 to 1.0 and can exceeded 1.0
-RQ = respiratory quotient
--measured at cellular level and represents cellular substarte utilization. |
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Term
| What are the mitochondrial adaptation to exercise training? |
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Definition
1)-Aerobic exercise training increases the number and size of mitochondria via doubling of mitochondria area and greater capacity to oxidize lipids.
2) Increased mitochondrial enzyme activity because there is an increase in total enzyme content. |
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Term
| Overall, what metabolic enzymes are measured to assess if training adaptations have occur? |
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Definition
TCA CYCLE: succinate dehydrogenase (SDH) and Citrate synthase (CS)
ETC: Cytochrome c oxidase
B-OXIDATION: 3-hydroxacyl CoA dehydrogenase (HAD)
GLYCOLYSIS: phosphofructokinase (PFK) and Lactate dehydrogenase (LDH)
-all of theses enzymes concentratiosn increase with ex training. This is one of the reasons why exercise gets easier. These gains are lost very rapidly once exercise is stopped. |
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Term
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Definition
-AMP-activated protein kinase
-master metabolic swithch that is activated when cells undergo energy depletion stress and increase AMP:ATP ratios.
-Increases fluxh through energy producing pathways and decreases flux through energy consuming pathways.
-Effects on gene expression:
Stimulates: glucose transport, Vegf and glute 4, glycolysis, fatty acid oxidation.
Inhibits: fatty acid synthesis, glycogen synthesis, and protein synthesis. |
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Term
| 3 things that exercise helps induce mitochondrial biogenesis |
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Definition
1) AMPK
2) Calcium/Calmodulin-dependent kinase (CaMK)
3) p38 MAPK
-all 3 activate PGC-1 alpha which is a transcription factor that stimulates mitochondrial biogenesis. |
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