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41 Cards in this Set
- Front
- Back
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bioenergetics
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the study or energy transformations in all living organisms.
the energy for all activity is supplied by the synthesis and degradation of energy-containing substances. |
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energy
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the capability of performing work or generating heat.
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biological energy cycle
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solar energy---> energy stored in plants--->transferred to animals
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calorie
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1 Kcal (Cal)= 1000 calories
calorie is the amount of heat required to raise the temperature of 1 gram of H2O 1 degree |
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chemical energy
mechanical energy |
energy stored in the cells (ATP)
movement force |
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biological thermodynamics
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1. energy is neither created nor destroyed=
carbs--->ATP--->muscle contraction. 2. concentration of energy= all reactions go in the direction of increased entropy (randomness) in energy exchanges some energy will escape carbs--(lose some as heat)-->ATP--(" ")---> entropy |
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gibbs free energy "G"
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what energy you can use to do work.
often in energy transfers (as above) there is a change in energy form = triangle G how much free energy release if influenced by pH, temp, substrate and product concentration and pressure |
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1. - delta G
2. +delta G |
1. exergonic
losing energy within the reaction, giving to the environment catabolic (breakdown) 2. endergonic within the reaction it is gaining energy (taking from the environment) anabolic (building) |
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ATP
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atp formed in reactions that release more than 14kcal of free energy
the free energy is then stored in the atp molecules. the free energy released from ATP breakdown (making adp) can make an endergonic reaction exergonic. |
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phosphate hydrolysis
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breaking ATP to release the stored energy that can be used as mechanical work
ATP--(ATPase)--> ADP + Pi+ energy ATPase is the enzyme used to catalyze the reaction |
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ATP's unique role
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it can give or take energy
need energy to build something; when you break it apart you get something (energy) atp is phosphorilating the ones below it. ATP is the primary high energy compound that supplies energy for most cellular processes. |
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coupled reactions
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endergonic and exergonic reactions working together.
they are very common. an exergonic reaction is used to drive an endergonic reaction. |
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energy metabolism
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how our bodies convert food into ATP
ATP is formed and used through this process what is metabolism? -the sum of all chemical reactions and changes 2 types: "catabolic" breakdown of molecules "anabolic" synthesis or building of molecules |
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food sources are broken down (catabolized) into=
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metabolic substrates for use by our cells
what are metabolic substrates? molecules that directly act on enzymes (from your food so cells can use it) |
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energy nutrients (3 food fuels)
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- carbs (CHO)
major energy fuel for exercise (GLUCOSE!) 4 kcals per gram (when you run out, your done) -Fats (lipids: fatty acids) major source at lower-moderate intensity exercise and REST. 9 kcals per gram -Proteins minor contribution of ATP during exercise 4 kcals per gram made to serve as enzymes |
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atp and oxygen
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ATP can be produced in the presence (aerobic) or absence (anaerobic) of O2.
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ATP demand during exercise
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longer distance = More ATP supplied
greater intensity= Greater RATE of atp. (100 m sprint requires more atp per SECOND compared to a 2 mile run, but you may use less.) |
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3 metabolic systems that produce ATP
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1. ATP-PCr (phosphagen system)
-in the cytosol -anaerobic generation of ATP from PCr -PCr can get energy to make ATP (remember ATP being in the middle) -Use this initially. we already have it made. first 1-6 seconds 2.Glycolysis -in the cytosol -anaerobic generation of ATP from breakdown of glucose. -quick rate of ATP - too much, just running on glycolysis= lactic acid (pyruvate build up) 3. oxidative -in the mitochondria -AERobic generation of ATP via oxidation of energy nutrients derived from CHO, fats or proteins. |
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why are enzymes important?
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they determine which ones and how fast (rate) at which metabolic pathways (CHO, Fat, Protein) are active.
enzymes lower the activation energy biological catalysts: they speed up chemical reactions w/out being involved in the reaction or altering the free energy release. enzymes can change shape when bound to substrates and "induce" the correct orientation of the substrates as well as facilitate the flow of electrons and protons in the reaction mechanism enzymes may be very good at adding or taking away a phosphate (P) |
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why else are enzymes important?
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they are regulators of the metabolic pathways:
enzymes can be increased or decreased, thereby determining the extent to which each pathway is active or predominant under different cellular conditions. |
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7 factors that influence enzyme function
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1. Cofactors: molecules required for function (metals)
2. Coenzymes: organic cofactors (CoA, vitamins) 3. [S] and [P] high [S]= high activity; high [P]= low activity 4.Temperature- high temp= high activity 5. pH- specific enzymes function at optimal pH ex: low pH= inhibits PFK which is the rate limiting enzyme in glycolysis. 6. activators ('agonists') some enzymes raise activity when bound to certain molecules ex: ADP activates key enzymes in glycolysis 7. inhibitors: same as above just opposite ex: citric acid inhibits PFK |
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allosteric enzymes
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enzymes that can be activated and inhibited
they have increased or decreased activity at a given substrate concentration when bound to specific molecules. they have binding sites for agonists and antagonists. |
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what else do allosteric enzymes do?
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-inhibition of a given enzyme allows the associated substrate to be directed into another metabolic pathway
stops it going down stream and directs it somewhere else. -activation of an enzymes could affect the activity/operation of an entire metabolic pathway. makes it get pulled down stream. |
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examples of allosteric enzymes
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PFK is the main allosteric enzyme regulating glycolysis.
citrate can inhibit PFK citrate and PCr inhibit, AMP and ADP stimulate |
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covalent regulation of enzyme activity
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covalent regulation involves the formation of a covalent bond on the target/ regulated enzyme.
this is almost ALWAYS the adding or removal of a PHOSPHATE molecule (PO4) to one of the AA residues on the regulated enzyme. this is known as PHOSPHORYLATION. phosphorylation usually involves high energy phosphates (PCr) and is generally downstream of a hormone binding its receptor (insulin, epinephrine) |
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system #1 ATP-PCr (phosphagen system)
(picture on phone) |
PCr: -stored in muscle cells
-P is bound to Cr by a high energy phosphate bond -used to resynthesize ATP (1 ATP: 1 PCr) during a brief high intensity activity lasting a few seconds -also serves as ATP buffer (eating more creatine = more phosphate) -Cr can be synthesized by the body or obtained from your diet. |
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(#1) importance of PCr
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rapidly available
does not require a long series of chemical reactions |
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(#1) creatine phosphate into atp
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Creatine phosphate--CK-->creatine+ inorganic phosphate+ Energy+ ADP+ inorganic phosphate---> ATP
CK is used to break creatine phosphate apart |
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(#1) activities associated with ATP-PCr
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activity lasting between 1-6 secs
explosive intensity |
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#1 key points
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anaerobic
PC breakdown coupled with synthesis of ATP 1 ATP synthesized: 1PC degraded provides ATP for about 10 secs stores in muscle are small |
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production of ATP from Carbs
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in the glycolytic system (glycolysis)
contains saccharides (mono, di, poly)- glucose, fructose, sucrose. |
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how carbs are used as fuel
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eat CHO turns to glucose and stays taht way if you use it right away, if not then it is stored as glycogen then converted back to glucose when you need it.
glycogen- branched glucose chains stored form of CHO large stores in muscle and liver glycogen forms around the protein P-glycogenin |
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what is glycogenolysis?
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glycogen break down
putting the glucose into glycogen sequential removal of glucose molecules from the parent glycogen chain catalyzed by the enzyme glycogen phosphorylase |
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Lactate
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is GOOD.
lactate production from pyruvate, requires NADH lactate production regenerates NAD+ so glycolysis can continue at a high rate when oxygen is limited. if O2 is abundant (rest, low intensity) the H from some NADH produced in glycolysis can be transported to mitochondria to ETC= more atp is not bad= accumulation of H+ makes it acidic = fatigue lactate actually consumes H+ |
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why are blood lactate and blood pH so well correlated?
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raise in muscle lactate release= raise in blood lactate= lower blood pH
lactate is cotransported with H+ which is good for the cells but it looks like lactate is making that acid with the H+ the H+ is coming from ATP hydrolysis |
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ultimate fate of lactate
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-fuel source: enters for oxidation and production of ATP.
if BG is normal it can be oxidized into ATP transported into the mitochondria by MCTS for reconversion into pyruvate by LDH (same as before just now in mitochondria to move on to the krebs) -converted into glucose or glycogen if BG is below normal (coris cycle) -converted into protein (AA) -excreted in sweat and urine |
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the oxidative system (krebs and ETC) also known as aerobic glycolysis
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relies on O2 to break down fuel
produces ATP in mitochondria (much more than anaerobic), primary source during rest and endurance fat and protein can only be catabolized in this system |
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complete oxidation of glucose yields how many ATP?
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38
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oxidative phosphorylation (oxidative metabolism)
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components:
krebs cycle= substrate oxidation ETC= ADP phosphorylation |
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oxidative phosphorylation of ADP
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- electrons and H+ removed from nutrients in the dehydrogenase reactions provide potential energy for ATP synthesis
-occurs via the ATP synthase in the inner mitochondrial membrane -driven by H+ formed by the pumping of H+s across the inner mitochondrial membrane by ETS complexes. |
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regulation of glycolysis (essay)
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- feedback inhibition of hexokinase by G6P
- + of PFK by ADP - - of PFK by ATP, citrate, H+, PCr -+ of glycogen phosphorylase by AMP, cAMP at rest PFK is off because you aren't using ATP just using fatty acids. |
