bioenergetics

the study of how energy from the sun is transformed into energy in living things

energy

the capacity to perform work

work

force x distance, to transfer motion to other matter (e.g. leg muscles to a bike, wings to the air)

kinetic energy

MOTION energy, does work by moving matter (e.g. heat, light)

potential energy

STORED energy, capacity to perform work that matter has because of position or shape or compression or mass (e.g. dam, negatively charged electrons, atom arrangement, chemical energy)

chemical energy

potential energy of molecules

First Law of Thermodynamics

energy conservation: energy is neither created or destroyed simply TRANSFERRED, fixed amount of energy in the universe

Second Law of Thermodynamics

Energy Conversions Reduce the Order of the Universe: energy transfer leads to less organization (universe tends toward disorder / entropy / heat)

heat

random molecular motion

When energy is ADDED to a system, entropy...

decreases, like when you use your energy to clean your room or arrange amino acids

When energy is TRANSFERRED, entropy...

increases (heat is released)

endergonic reactions

require energy input to yield high potential energy products from low potential energy reactants

exergonic reactions

require output of energy to yield low potential energy products from high potential energy reactants

cellular metabolism

the sum of ALL chemical reactions (endergonic and exergonic) in an organism

energy coupling

released energy from exergonic reactions are used in endergonic reactions

transition state

when the reactants turn into a high energy molecule, occur at every step of a reaction between the reactants and products, must reach before starting a reaction

reaction intermediates

formed between each step of a multi step reaction, one is made in one reaction and goes into the next reaction whose product goes into the next and so on

activation energy

certain amount of energy required to reach the transition state

energy barrier

the amount of energy reactants need to start a chemical reaction, why molecules in cells do not break down spontaneously

inorganic cofactors

ions, usually metals (e.g. zinc, iron, copper, Fe2+, Mg2+)

coenzymes

cofactors that are organic nonprotein helpers (e.g. vitamins)

enzyme reactions can be affected by...

temperature, pH, relative concentration of substrates and products, salt concentrations

saturation point

the concentration of substrate where all of the enzyme in a reaction is bound by substrate, Additional substrate past this point no longer increases the speed of the reaction

optimal temperature

the highest contact rate with the enzyme and substrate

optimal pH

around or at 7, except for pepsin (a digestive enzyme) which has a pH of 2 and lysosome enzymes which also have an acidic pH

adenosine triphosphate (ATP)

made of adenine, ribose, and 3 phosphate groups

energy coupling of ATP

exergonic reactions of the 3rd phosphate group being removed and endergonic reactions of the phosphorylation, which releases in exergonic and attaches again to ADP in endergonic

fast twitch muscle fibers

anaerobic (no oxygen), quick but powerful bursts of energy, cause fermentation when lactic acid is generated and causes leg cramps, less mitochondria, only 2% of glucose power

slow twitch muscle fibers

aerobic (yes oxygen), long and repeated contractions, for long distance/ endurance running, many mitochondria, uses 40% of glucose power