Week 2 - Bioenergetics and Exercise Metabolism Flashcards
Bioenergetics
Flow and exchange of energy within a living system.
The conversion of food (fats, proteins, carbohydrates) into usable energy for cell work (chemical –> mechanical).
Metabolism
sum of all the chemical reactions that occur in the body (anabolic and catabolic).
Explain the two types of reactions in the body.
1) Anabolic reactions: synthesis of molecules (glucose being stores as glycogen)
2) Catabolic reactions: release of chemical energy through the breakdown of molecules to simpler molecules (glycogen broken down into glucose)
What is the difference between endergonic and exergonic chemical reactions?
Endergonic
> requires energy to be added to the reactants
> Ex: Glycogen formation or ATP synthesis
> Overall increase in energy
> Energy in products greater than reactants
Exergonic
> releases energy
> Ex: ATP hydrolysis
> Overall decrease in energy
> Energy in reactants greater than products
Coupled reactions
Liberation of energy in an exergonic reaction drives an endergonic reaction.
Oxidation and oxidised electron carriers
Oxidation is the loss of electron (OIL)
Oxidised electron carriers include NAD+ and FAD
Reduction and reduced electron carriers
Reduction is the gain of electrons (RIG)
Reduced electron carriers include NADH and FADH2
Enzymes
They act as catalyst in chemical reactions in the body by lowering the activation energy required for a reaction to occur (They increase the rate of product formation.)
Match the classification of enzyme with the description.
Kinase, dehydrogenases, oxidases, isomerases
a) Remove hydrogen atoms
b) Catalyze oxidation-reduction reactions involving oxygen
c) Rearrangement of the structure of molecules
d) Add a phosphate group
A = Dehydrogenases
B = Oxidases
C = Isomerases
D = Kinase
How does cellular environment factors influence enzyme activity during exercise?
Temperature - exercise increases temp slightly which improves enzyme activity, but after 40degrees enzymes become denatured.
pH - exercise produces H+ ions which reduces pH and inhibits enzyme activity with roles in ATP production.
Describe the two pathways that produce ATP and how they differ.
Anaerobic pathway (substrate-level phosphorylation) - doesn’t involve oxygen, ATP-PC system and glycolysis (leading to lactate).
Aerobic pathway - requires oxygen, oxidative phosphorylation, fat and carb oxidation, dependent on cardiorespiratory system to deliver adequate oxygen.
What is the net gain of glycolysis if
a) glucose is the substrate
b) glycogen is the subtsrate
a) 2ATP, 2NADH, 2 pyruvate/lactate, 2H+
b) 3ATP, 2NADH, 2 pyruvate/lactate, 2H+
Glycogen in the muscle doesnt require phosphorylation by ATP but is phosphorylated by inorganic phosphate instead.
How is NAD+ reformed?
In the absence of oxygen, pyruvate is converted into lactate (PDH) and tis allows the recycling of NAD+ that allows glycolysis to continue.
Describe the Citric acid cycle (Krebs cycle/TCA cycle) and list the products.
completes the oxidation (removes electrons) of acetyl-coa (formed from fuels: fats, CHO, protein) to provide electrons for the ETC.
Products of x1 Acetyl-CoA = ATP, 1FADH2, 3NADH, 4H+, 2CO2, CoA
Aerobic ATP production
32 ATP (38ATP)