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