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phys exam, lecture 2
| Question | Answer |
|---|---|
| bioenergetics | flow of energy w/in living system metabolism= chem reaction to convert fat lipids +carbs ->usable energy. anabolic= synthesize molecules catabolic= break down Muscle cells need continuous source of energy to contract No energy=no contract=no work done |
| enzymes | -highly specific proteins- "lock and key" -they speed up reactions (catalysts) -reduce activation energy requirement - not consumed or altered, continually reused |
| coenzymes | -facilitators -vitamins and minerals FAD and NAD -transport H atoms and electrons in energy metabolism ex- NAD -> NADH |
| factors effecting enzymes | temp, pH, availability of substrate higher temp = higher enzyme activity if enzymes show down, it effects body's ability to make energy (also goes down) which leads to fatigue |
| oxidation oxidizing agent | -process of removing an electron from an atom or molecule -atom or molecule that receives the electron |
| reduction reducing agent | -process of adding an electron to an atom or molecule -atom or molecule that donates the electron |
| oxygen role in oxidation-reduction reactions | oxygen is not always part of the reaction, but oxygen tends to accept the electron and tends to act as the oxidizing agent important in ETC |
| example of agents | NADH= (reducing agent) -> NAD (oxidizing agent) 1 hydrogen atom = 1 electron |
| synthesis of ATP | ADP + P1 -> ATP (two phosphates (di) plus one makes three (tri)) |
| breakdown of ATP | ATP -> (ATPase enzyme) ADP + P1 + energy ATPase, an enzyme breaks down ATP into ADP, a phosphate and energy |
| why do we need to provide ATP | -muscle cells contain a limited amount of ATP -exercise requires constant ATP supply, so pathways must exist in order to provide ATP |
| three pathways for muscle to produce ATP | 1. phosphocreatine breakdown (PCr)- anaerobic 2. glycolysis- degradation of glycogen/glucose- anaerobic 3. aerobic metabolism- formation of ATP by using oxygen |
| how do we know which pathway is dominant? | pathway that makes most ATP is dependent on time (duration) and intensity of exercise |
| Immediate energy system PCr | short duration, high intensity work (8-10 s) ex 40 meter sprint has highest ATP turnover rate (produces ATP the fastest) |
| PCr breakdown | PCr + ADP -> (creatine kinase) ATP + creatine PCr donates a phosphate group to make ATP from ADP after enzyme creatine kinase breaks it down we are left with that ATP, and creatine that is left over after the PCr donated a phosphate |
| how do the byproducts of this reaction come together during recovery? | byproduct of PCr breakdown creatine and byproduct of breakdown of ATP P1 come together to make more PCr (takes about 3 mins to go back to 100%) |
| 2nd anaerobic energy system glycolysis | longer duration (30-90 s), high intensity work ex 400 meter sprint. moderate to high ATP turnover rate takes the bond energy in glucose/glycogen and uses that to form ATP (ADP + P1) system runs on blood glucose or glycogen in muscle |
| net gains in glycolysis | net gain changes based on what we use glucose net gain = +2 ATP, +2 pyruvate +2 LA glycogen net gain = +3 ATP, +2 pyruvate +2 LA |
| 2 phases of glycolysis | energy investment- chemical work costs ATP, so if we use glucose were -2 ATP, and if we use glycogen were only -1 ATP energy generation- production of ATP. we always produce 4 ATP but net gain is 2 and 3 bc we invested 2 and 1 |
| what is the rate limiting step of glycolysis | the enzyme phosphofrictokinase. either speeds up or slows down reaction |
| difference between anaerobic glycolysis and aerobic glycolysis | anaerobic - NAD(H) wants to get rid of hydrogen, will drop it off with pyruvate. LDH (lactaid dehydrinase enzyme speeds up reaction. LA is a byproduct aerobic- NADH takes H itself to ETC pyruvate enters mitochondria and becomes Acetyl-CoA (krebs cycle) |
| aerobic metabolism (oxidative phosphoralation) | any of three macronutrients can drive aerobic metabolism low intensity, dominant for activity over 2 minutes ex -4 mile run ATP turnover rate very slow, but produces abundant ATP |
| what are the two parts of aerobic metabolism | 1. krebs cycle 2. electron transport chain |
| krebs cycle | job= (not to produce energy, but to) complete the oxidation of macronutrients -if any of the three macros are put into the Kreb's cycle, it finishes breaking them down and spits out hydroegn/electrons every hydrogen/electron= energy |
| relationship btwn Krebs cycle and ETC | all macro are broken down into Acetyl-coA...the substance which spins the kreb's cycle krebs cycle produces H as it spins, which are caried to ETC by NADH and FADH the energy production occurs |
| significance of hydrogen transported from krebs to electron chain | each hydrogen that is transported from krebs to electron chain=ATP NADH= 3, FADH =1 |
| electron transport chain (1) | 5 cytocromes. electron is stripped, hydrogen moves thru. then electron moves down, allowing more hydrogen to go out. the more hydrogen NADH and FADH can bring, the more it can spit out. this creates a concentration gradient (first 4 cytocromes) |
| electron transport chain (2) | once gets to 5th cytochrome, H is allowed to move from high to low concentration (outwards) b/c of F complex thats like a gate (looks like a pinwheel). when H moves through F complex, it spins it. spinning releases potential energy, making ATP. |
| do electrons need to pass through all 5 gates to spin the F complex? | yes |
| what role does oxygen play in ETC | oxygen serves as an oxidizing agent. it's the last electron receptor. oxygen neutralizes extra hydrogen. 1/2 O2 + 2H -> H2O end result= biological water |
| what is the average/baseline of how much oxygen is needed at rest in terms of vo2 | 3.5mL/kg/min as we need more energy (doing exercise), we need more O2 b/c O2 needs to keep up to meet the demands of pairing w/ the H if we dont have enough O2, F complex closes, last cytocrome hangs on to electron, ATP production goes down= fatigue |
| what happens when there's not enough oxygen | everything will slow down then the body will rely on anerobic processes (glycolysis), so lactic acid is produced |
Created by:
emma.thornton