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- is the set of life-sustaining chemical transformations within the cells
- of living organisms. These enzyme-catalyzed reactions allow organisms
- to grow and reproduce, maintain their structures, and respond to their
is the set of metabolic pathways that breaks down molecules into smaller units to release energy.
is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy.
-The science that studies how energy is converted in living things.
1st & 2nd Laws of Thermodynamics
- Bioenergetics is based on two very important laws:
- 1. Energy cannot be created or destroyed, but can be changed from one form to another.
- 2. Energy transfer will always proceed in the direction of increased entropy
the approximate amount of energy needed to raise the temperature of one gram of water by one degree Celsius at sea level.
The large calorie is thus equal to 1000 small calories or one kilocalorie
free energy from one reaction can drive another reaction.
- Enzymes are protein molecules that function to increase the rates of chemical reactions. On the surface of an enzyme are specific binding sites for substrates, and depending upon the enzyme, other binding
- sites exist for molecules that either decrease or increase enzyme activity. Enzymes do not alter the free energy change of chemical reactions.
The factors that can alter enzyme activity are cofactors, temperature, pH, enzyme concentration, substrate concentration, the type of isozyme, inhibitors, and activators.
Enzymes that can be activated and inhibited
- "releasing energy in the form of work".
- An exergonic process is one in which there is a positive flow of energy from the system to the surroundings
- -breakdown of glucose
- "absorbing energy in the form of work."
- wherein the system absorbs energy from the surroundings.
derived from vitamins and from required organic nutrients in small amounts. A coenzyme that is tightly or even covalently bound is termed a prosthetic group.
- -Adenosine triphosphate
- -Transports Chermical Energy within cells for metabolism
- -a large molecule that contains three phosphate (PO3-) groups, adenine, and ribose
ATP formation/ breakdown
- formation: ADP + Pi -> ATP
- Breakdown: ATP --ATPasde-->ADP + Pi + energy
- adenosine diphosphate
- an important organic compound in metabolism
- -Most rapid means to regenerate ATP
- -As ATP is used, CP reforms more ATP from the ADP-a phosphorylated creatine molecule that serves as a rapidly mobilizable reserve of high-energy phosphates in skeletal muscle and the brain.
- -catalyzed by creatine kinase
catalyses the conversion of creatine and consumes adenosine triphosphate (ATP) to create creatine phosphate
creation of energy through the combustion of carbohydrates in the absence of oxygen.
-> pyruvate, ATP, NADH
it can lose a proton from the carboxyl group, producing the lactate ion
- glucose is broken down and oxidized to pyruvate, and lactate is produced from the pyruvate faster than the tissues can remove it, so lactate concentration begins to rise.
- Pyruvate can be reduced to lactate by the enzyme lactate dehydrogetiase (LDH)
Lactate and muscle fatigue?
Lactate does not directly contribute to muscle fatigue. accompanying acidosis
- NAD participates in many redox reactions in cells, including those in glycolysis and most of the reactions in the citric acid cycle of cellular respiration.
- Lactate Dehydrogenase use NAD to accelerate the reactions they catalyze.
- Substrate loses H+ to NAD. NAD is reduced to NADH, yields "product"
FAD is a redox cofactor.