Bioenergetics

[Sportsmedjosh]

Here is some infomation from a PowerPoint I have, I will eventually upload all these PowerPoints but for now I will post the test.

Metabolic process whereby cells convert foodstuffs into a biologically usable form of energy

Metabolism = the total of all cellular reactions that occur in the body; both anabolic and catabolic
1st Law of Thermodynamics
Energy is neither created or destroyed, it is converted from one form to another

Example: all energy on earth comes from the sun….plants use light energy from the sun to drive chemical reactions to form CHO, fats and proteins. Animals eat plants to obtain the energy required to maintain cellular activities.
Biological Energy Transformation
Forms of energy:
electrical
mechanical
chemical

All are interchangeable:
Muscle contraction: chemical-->mechanical


Cellular chemical reactions
Energy transfer within the body occurs by releasing energy trapped within chemical bonds of various molecules.

Chemical bonds containing large amts of potential energy are called “high energy bonds”
Cont’d
Energy transfer in the cells occurs as a result of a series of chemical reactions. Reactions that require energy to be added to the reaction before it will proceed = endergonic reactions. Reactions that give off energy as a result of the chemical process = exergonic reactions.

Kinetic vs. Potential Energy
Potential and kinetic energy constitute the total energy of a system.
Potential energy = stored energy
battery, macronutrient

Kinetic energy = energy of motion
Muscle contraction

Enzymes
Catalysts which regulate the speed of cellular chemical reactions
Proteins which play a major role in the regulation of metabolic pathways
Do not cause a reaction to occur
Does not change the nature of the reaction or its final result

Cont’d
Energy of activation=the energy required to initiate a chemical reaction.
Enzymes work as catalysts by lowering the energy of activation.
End result=an increase in the rate at which these reactions take place.
Cont’d
Mode of enzyme action

Lock and Key Model


Cont’d
Naming system
Most reflect the job category of the enzyme and the reaction it catalyzes
Most end with suffix “ase”
Kinases – groups of enzymes that add phosphate groups to the substrates
Dehydrogenases – groups of enzymes that remove hydrogens from their substrates
Lactate dehydrogenase:
lactic acid+NAD --> Pyruvic acid+NAD+H+

Role of Coenzymes
Non-protein organic substances which facilitate enzyme action by binding the substrate to its specific enzyme

Some enzymes remain dormant without activation by coenzymes

Eg. NAD+
Cell Compartmentalization
The basic functional unit of the body=cell
A highly organized factory capable of synthesizing a large number of compounds necessary for normal cellular function.

Cont’d
1. Cell membrane
Semipermeable membrane that separates the cell from the EC environment
Encloses the components of the cell
Regulates the passage of various types of substances in and out of the cell
Cont’d
2. Nucleus
Contains cellular genetic components (DNA)

3. Cytoplasm
Fluid portion of cell between the nucleus and the cell membrane
Contains various organelles that are concerned with specific cellular functions

Cytoplasm Cont’d
Mitochondria = powerhouse of the cell
Is involved in the oxidative conversion of foodstuffs into usable cellular energy

Enzymes – that regulate the breakdown of glucose (glycolysis)



Transport Work
Cellular materials normally flow from an area of high concentration to an area of lower concentration = passive diffusion and requires no energy.

Cellular materials requiring transport uphill, against a concentration gradient require active transport which is an energy-requiring process.

Equilibrium = state of equal concentration
Hydrolysis and Condensation
Hydrolysis Reactions:
Catabolizes complex organic molecules (CHO, lipids and proteins) into simpler forms the body easily absorbs and assimilates.
A decomposition process which splits chemical bonds by adding H+ and OH-
CHO?monosaccharides (various enzymes)
TG?fatty acids and glycerol (lipases)
Proteins? amino acids (proteases)

AB + HOH?A-H + B-OH

Cont’d
Condensation Reactions
An anabolic process, opposite of hyrolysis
The structural components of nutrients bind together to form more complex molecules and compounds
AB + HOH ? A-H + B-OH

Oxidation and Reduction Reactions
Oxidation = any process in which atoms in an element are lost (i.e. oxidation reactions transfer oxygen atoms, hydrogen atoms or electrons)

Oxidizing agent = electron acceptor
Cont’d
Reduction = any process in which the atoms in an element gain electrons

Reducing agent = substances that donate or lose electrons
Cont’d
OILRIG

Oxidation is loss

Reduction is gain
Cont’d
Electron transfer requires both an oxidizing agent and a reducing agent.

Whenever oxidation occurs, the reverse reaction also takes place; when one substance loses electrons, the other substance gains them = redox reaction