Unit Two - Metabolism Flashcards
metabolism
The sum of all the chemical reactions in the body. Many of these reactions are related where the product is the substrate of another.
catabolism
Metabolic processes that involve the breakdown of energy yielding nutrients (and other molecules). The release of free energy and electrons.
Anabolism
Metabolic process that builds molecules the body needs. This requires energy.
bioenergetics
study of the science of energy conversions in living organisms. Also known as thermodynamics.
first and second laws of thermo
- Energy cannot be created nor destroyed, but it can be changed from one form to another.
- Energy transfer will always proceed in the direction of increased entropy.
calorie, kcal
- A calorie is the amont of heat necessary to raise the temp. of 1 g (ml) of water 1 degree C.
- A kCal is 1000 calories. Caloric cotent on our food is usually referred to in kCals also shown with a capital C, Calorie.
coupled reaction
Free energy from one rxn that can drive another reaction.
enzyme
A catalytic protein that helps speed up the rate of chemcial reactions by decreasing the activation energy.
exergonic
Reactions that release energy. Breakdown of ATP releases energy. High energy stored in the phosophate bonds. Occur spontaneously
endergonic
Reactions that require energy. Including the synthesis of ATP. Non spontaneous reactions.
co-enzyme
A nonprotein compond that is necessary for the functioning of an enzyme. Such as pyruvate being converted into acetyle coenzyme A (Acetyle CoA) when intercellular reactions favor aerobic catabolism of pyruvate.
ATP, ADP, Pi
Adenosine triphosphate, ATP, is the energy required for the body to function. ATP is the fuel for muscle contraction and exercise. The high energy is stored in its phosphate bonds. When broken down, ATP yields an inorgainc phosphate (Pi) and adenosine diphosphate, ADP.
creatine phosphate
Creatine phosphate is a pathway to generate ATP. CP is a high-energy phosphate compoud that regenerates ATP at a very high rate. CP transfers its phosphate group to ADP in order to produce ATP (and Cr). This is a pathway used at the very beginning of exercise and is anaerobic.
creatine kinase
PCr (creatine phosphate) breakdown is regulated by creatine kinase, enzyme, activity. This is a rate-limiting enzyme. Creatine kinase, CK, is activated when SR ADP concentration increases and is inhibited by high ATP concentration. at beginning of exercise, ATP ADP + Pi + Energy muscular contraction
the immediate increase in [ADP] stimulates CK to trigger the breakdown of PCr to make ATP.
anaerobic metabolism
Does not require oxygen for the chemical reaction to proceed. For example, glycolysis is anaerobic metabolism to breakdown glucose.
glycolysis
ATP can be produced through the breakdown of glucose in glycolysis. This occurs in the cytosol of the cell (sarcoplasm of the muscle cell). This involves ten steps and two stages: the investment of energy and then the regeneration of energy. Glucose is broken down into lactate or pyruvate with the net production of 2 ATP and 2 NADH.
lactic acid/lactate
At the end of glycolysis there are two pyruvates. If oxygen is present and depending on rate of glycolysis reaction, the pyruvate can enter into the oxidative pathway of the Kreb’s cycle. However, if the exercise is anaerobic, it cannot go into oxidative pathways therefore pyruvate is reduced to lactacte. This is sometimes necessary (even when O2) is present because too much NADH will accumulate (not enough NAD+ for glycolysis to continue), but if pyruvate is reduced to lactate then NADH is oxidized to NAD+. Lactate causes muscle cramps and soreness DURING and right after exerise. As Lactate accumulates, pH decreases, thus glycolysis slows down.
NAD-NADH
electron carrier. 2 are NAD+ molecules are reduced to NADH during glycolysis.
FAD-FADH2
Electron carrier