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51 Cards in this Set

  • Front
  • Back
What is bioenergetics?
The flow of energy within a living system
What does the term aerobic mean?
aerobic = oxygen requiring energetic reactions
What is the law of thermodynamics?
Energy is neither created nor destroyed, just transformed form one state to another without being used up
What are the 3 forms of work in humans?
Mechanical Work
Chemical Work (synthesizing cellular molecules)
Transport Work (cellular level)
1. What is a reducing agent?
2. What is an oxidizing agent?
1. a substance that donates or loses electrons as it oxidizes
2. a substance that gains electrons/is reduced
What is lactic acid?
compound formed when pyruvate accepts additional hydrogens caused by exercise
What 2 forms does energy exist in?
Potential and kinetic
what is a redox reaction?
a reaction that powers the body's energy transfer process
What 2 factors do energy transformations in the body rely on?
Oxidation-reduction reactions
chemical reactions that conserve and liberate the energy in ATP
What are the cells' 2 major energy-transforming activities?
1. extracting energy from food and conserving it within the bonds of ATP
2. Extracting and transfering the chemical energy in ATP to power biologic work.
What part of ATP splits to liberate energy?
The outermost phosphate bond
What forms of biologic work does ATP power?
ATP powers ALL forms of biologic work
When is the energy available from a splitting ATP molecule?
How much oxygen is used?
Energy from ATP breakdown is available immediately and without oxygen.
What does the rate of energy transfer depend on?
the intensity of the exercise
What two substances represent the major energy sources that maintain continual ATP resynthesis?
Glycogen and Fatty Acids
What is phosphocreatine and what does it do?
Phosphocreatine (PCr) is another high energy phophate compound that releases energy when creatine and phosphorus split.
How long does PCr hydrolize for energy during an intense bout of exercise?
About 10 seconds
What is phosphorylation?
energy transfer through phosphate bonds
1. Where does most of the energy required for phosphorylation of ATP come from?
oxidation of macronutrients
What is a substance doing when it is oxidizing?
it is donating electrons
What is a substance doing if it is reducing?
It is gaining electrons
The oxidation-reduction process most often involves the transfer of ______ atoms.
1. What process passes electrons extracted from hydrogen to oxygen?
2. What is the end result?
1. The Respiratory chain
2. Water
1. What is the final electron acceptor in the respiratory chain?
2. What does it combine with to form water?
1. Oxygen is the final acceptor
2. O2 combines with H to form water
How much of the potential energy in food nutrients transfers to ATP? (%)
Where does cellular oxidation occur?
on the inner lining of the mitochondrial membranes
The energy released in macronutrient breakdown serves one purpose. What is it?
To phosphorylate ADP to reform the energy rich compound ATO.
What are the 4 sources of macronutrient fuel that supply substrate for for oxidation and formation of ATP?
1. glucose derived from liver glycogen
2. triaglycerol and glycogen molecules stored in muscle cells
3. free fatty acids from triacylglycerol in the bloodstream
4. intramuscular and liver-derived carbon skeletons of amino acids
What is the primary function of CHO?
To supply energy for cellular work
Describe the 2 stages of glucose degredation
1. Stage 1 - glucose breaks down to 2 molecules of pyruvate. Energy transfers without oxygen (anaerobic)
2. Stage 2 - Pyruvate breaks down to CO2 and water. Energy transfers from these reactions require electron transport and accompanying phosphorylation (aerobic)
1. What is the only macronutrient whose stored energy generates ATP anaerobically?
2. Why is this important in maximal exercise?
1. CHO
2. When aerobic metabolic reactions can't supply enough energy to meet demand, ATP resynthesis must come from stored intramuscular glycogen.
How much of the body's energy is supplied by carbohydrates during light and moderate aerobic exercise?
about 1/3
What does the brain metabolize for fuel under normal conditions?
What does the brain metabolize once this substance has run out?
1, CHO under normal conditions (blood glucose)
2. fat as an alternative fuel after 8 days
1. What is glycogenesis?
2. What compound regulates glycogenesis?
1. The breakdown of glycogen into glucose
2. glycogen phosphorylase
What is a good function of lactate?
It provides H+ atoms for ATP production during intense exercise.
What does the Cori cycle do? (3 steps)
1. lactic acid is removed from the muscle and converted to lactate.
2. Lactate the eneters the liver for conversion to pyruvate and glucose synthesis.
3. glucose goes back to the muscle.
How does lactic acid form? (2)
1. Excess hyrdogens from the coenzyme NADH combine temporarily w/pyruvate to form lactic acid.
What is the second stage of CHO breakdown called?
The citric acid cycle (Krebs cycle)
1. CHO depletes to 50% capacity after _____ (time) of initial exercise activity?
2. After this what starts to provide energy?
1. 2 hours
2. fat energy after 2 hours
What is the most important function of the Citric Acid Cycle?
It generates H+ electrons for passage in the chain to NAD+ and FAD
What is the body's most plentiful source of stored energy?
How many Kcal of energy is stored in fat reserves in the typical young male?
60,000 to 100,000 Kcal
What does lipase do?
Lipase catalyzes triacylglyerol breakdown
What (4) substances augment lipolysis from adipose tissue?
Hormones: Epinephrin, norepinephrine, glucagon, and growth hormone.
What macronurient powers exercise at 25% aerobic capacity?
Fat oxidation
What is lipogenesis and where does it occur?
Lipogenesis is the formation of fat mostly in the cytoplasm of liver cells.
What is transamination?
The passage of nitrogen from an amine group to other compounds.
carbon skeletons of amino acids participate directly in energy metabolism.
When glucose breaks down, how much energy is conserved in ATP bonds and what happens to the rest?
34% of kcal is conserved in ATP bonds
Remainder dissipated as heat
How many ATP molecules does the complete breakdown of a glucose molecule yeild?
What situation is happening if a biochemical steady state exists?
Hydrogen atoms are being oxidized at their rate of formation
The complete breakdown of a triacyglycerol molecule yeilds _____ ATP atoms?