Majed Sharayha
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Join date : 2011-08-23
Age : 31
 |  Subject: Sheet 1, Dr.Nafeth, by sukaina hawamdeh 522012 "corrected by Lana Al Ajlouni"  Wed Feb 08, 2012 2:20 am | |
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Introduction
*Energy production starts through the breakage of the bonds between the molecules.
* ATP has several functions:
1. Maintainance of the electrochemical gradient across the plasma membrane.
2. Movement
3. Synthesis of DNA, proteins.
The food, substrates by oxidation transform to ATP (inside the mitochondria) hydrolyzation ADP+ Pi , if the body needs it (in the energetic processes, ex: movement), but if the body doesn’t need it, it is stored in the form of heat.
*All the energy production processes occurs inside, around or at the mitochondria. Most of the proteins and the enzymes required for the process of energy production are located on the inner membrane & inside the matrix of the mitochondria.
Q: How the process of ATP production happenes?
It’s all about the transport of the electrons (accepting) at the molecular level.
*The oxidation of the nutrients causes the breakage of the high energy bonds (just the bond that gives > 7 Kcal we consider it as high energy bond), this energy which is in the form of electrons, join certain molecules (NAD+,FAD) that carry it to the O2,this process coupled directly to ATP production.
*If there’s no equilibrium between the production & consumption of the energy it causes problems.
*In the case of decrement:
1. cyanide poisoning , how? The cyanide join the iron which prevents the binding of O2 no transport of O2(which is the terminal acceptor of the transport chain) no accepting of electrons energy production failed death.
2. Ischemia or MI : partial or complete blockage of the arteries that supply the heart less blood supply less O2 less energy production, also the disorder in the genetic code of some enzymes(found in the nucleus or mitochondria ) that participate in ATP production .
*In the case of increment :
1.Diabetes : less insulin so less ATP production, either type1 or2 .
*ATP homeostasis : ATP must be produced at a constant level(constant concentration not amount) , for ex: the heart consumes with each single beat 2% from the total ATP so with 50 beat we will use all the ATP stored because of that the body doesn’t depend on the storage of ATP.
* Obesity: too much intake with less burning (no balance).
* hyperthyroidism : high activity of the thyroid gland high hormones secretion( T3 &T4 as catalyst) high ATP production high heat generation, so people with this condition suffers from sweating more than others & feel that they have too much energy.
*Energy terms :
Δ G = G products – G reactants
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Δ G⁰: the same as Δ G but at 1 mol concentration.
Δ G⁰ : Δ G under standard conditions, (at room temp. 25 C, pressure 1 barometer, and pH 7) , so it doesn’t change ((constant))
*Most of the reactions inside the body are spontaneous with - Δ G (which means it gives you energy), exergonic but if there is no pathway to consume the energy it’s then called exothermic (gives heat).
*The reactions that consume energy are called ”endergonic” or “endothermic” if there is no pathway of consumption.
* ΔG is related to ΔE how??
More energy means more difference in voltage between reactants & products; fats have more energy because it has more negative charges than carbohydrates.
Q: How does ATP gives energy at the molecular level?
We have (-ve) charges opposite to each other so they repel each other, if we take the first (P) more resonance more stable, so it gives energy(7.3Kcal/mol, the same as the second but the third gives 3.4 because the bond between P & C on ribose( phosphor ester bond)).
*Some mitochondrial enzymes capture the phosphate from the ATP so the energy is transported to them to form intermediate with high energy which can be used inside the pathways.
*some effects of ATP on the cells:
1. Movement (muscles): ATP joins myosin heads conformational changes relaxation, ATP ADP +Pi which cause stiffening & then movement and this movement helps in re-attaching to another place .
2. Maintenance of the electrochemical composition inside the cell (plasma membrane): Na+/K+ pump; ATP causes conformational changes that turn the state from close to open (inside) & from open to close (outside).
*Not all the reactions inside the body are spontaneous, how does the body behave with the un-spontaneous ones?
- It links all the steps in the pathway so they need less energy.
1. The body use some intermediate molecules easy to decompose & with high energy, decrease the concentration of the products for ex: UDP glucose, pyrophosphate (from ATP production), CTP, GTP, Acetyl co-A.
2. Change the difference between the concentration of substrate & products: for ex the conversion of Glucose 6 phosphate to Glucose 1phosphate this reaction is un-spontaneous but if the concentration becomes 6:3 the reaction proceed spontaneously with 1.4 Kcal.
* Thermogenesis: maintenance of the body temp at 37⁰ all the time.
Q: why when we move from warm to cold environment we shivers? The body wants heat so it breaks too much ATP rapidly & this makes a sudden movement of the muscles & generates heat as byproduct.
Note: if the change of the temperature of the environment gradually we call it non-shivering thermogenesis (Adapted thermogenesis).
Dr’s name: Nafeth Abo Tarboush
Date: 5-2-12 // Sunday
Sheet #1
Sheet Writer: Sukaina Alhawamdeh
Correction: Lana Ajlouni
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