biob34 mod 2

energy

capacity to do work; measured in joules (J)

work

transfer of energy by force acting on an object as it is displaced; measured in joules (J)

power

rate at which work is done; measured in watts (W)

metabolism

set of processes by which cells and organisms acquire, rearrange, and void commodities in ways to sustain life; sum of metabolic pathways for synthesis and breakdown of molecules

metabolic rate

animal’s rate of energy consumption; rate at which animal convert chemical bond energy to heat & work; measurement of power

metabolic pathways

series of enzyme-catalyzed rxn converting substrates to prod

carbs

contains many -oh groups; used for energy metabolism; biosynthesis of this macromolecule is precursor to many rxn

monosaccharides

used for energy and biosynthesis; small carbs have 3-7c; commonly 6c

complex carbs

polysaccharides for energy storage / struc support

glycolysis

glucose breakdown releasing energy; glucose + 2adp + 2nad+ → 2atp + 2 pyruvate + 2nadh + 2h+; anaerobic process in cytoplasm converting glucose / lactate and amino acid into pyruvate; pyruvate is carried into mitochondria

pyruvate dehygrogenase (pdh)

oxidizes pyruvate to form acetyl coa & nadh

lipids

hydrophobic molecules with c backbone; used for energy metabolism, cell structure, signaling

aliphatic lipid

linear c backbone

aromatic lipid

ring c backbone

fatty acids

c chain ending w carboxyl group -cooh; usually has even number of c; more dense energy storage than carb; requires more oxidation to unlock energy → no significant anaerobic atp production possible

saturated fat

no c=c in structure

unsaturated fat

at least 1 c=c

beta oxidation

breakdown of fatty acid in mitochondria to form acetyl coa, which is then oxidized

ketogenesis

fatty acid → acetyl coa → ketone; ketone body can move through circulation

ketolysis

ketone → acetyl coa; acetyl coa can undergo oxidative phosphorylationm

mitochondrial metabolism

energy yielding rxn requiring oxygen; nutrient → metabolites using enzymes; metabolites enter mitochondria; metabolites → acetyl coa; acetyl coa enter tricarboxylic (krebs) cycle; acetyl coa → reducing equivalent → energy through oxidation; o2 is final e- acceptor

oxidative aerobic metabolism

acetyl coa → co2 + reducing equivalent (nadh & fadh2) + gtp at tca cycle → reducing equivalent oxidized to release energy at ets → atp synthesis (phosphorylation)

tricarboxylic acid cycle (tca / krebs cycle)

acetyl coa + 3nad+ + fad+ + gdp + pi → 2co2 + 3 nadh + fadh2 + gtp; generates reducing equivalent in mitochondria; amphibolic pathway

amphibolic pathway

some anabolic rxn & some catabolic rxn

anabolic pathway

building complex molecules from simple molecules

catabolic pathway

breaking complex molecules into simple molecules

e- transport system (ets)

composed of 4 complex proteins and 2 e- carriers; located in inner mitochondrial membrane; generates proton gradient, heat, water, reactive oxygen species; 4h+ + o2 + 4e- → 2h2o

atp synthesis

phosphorylation of adp to form atp; proton motive force is pH gradient and membrane potential; oxidation and phosphorylation coupled through proton motive force

phosphocreatine

alternative high energy phosphate comp; creatine + atp → phosphocreatine + adp; reversible reaction so relative atp/phosphocreatine production depend on concentration; can enhance flux of high energy phosphate molecules to move from sites of synthesis to usage

reciprocal regulation

avoid simultaneous synthesis and degradation

hess’s law

“total amount of energy (released as heat) from breaking down given amount of fuel is always the same regardless of intermediate steps”

direct calorimetry

measures heat of chem/phys processes in calories; accounts for aerobic and anaerobic energy production

indirect calorimetry

infers metabolic heat production; dependent on aerobic metabolism only

respirometry

indirect calorimetry through respiratory gas exchange

respiratory quotient (RQ)

monitors type of fuel used at mitochondrial level; RQ = rate of co2 production/rate of o2 consumption; gives ratio of carb/fat when negligible protein catabolism

respiratory exchange ratio (RER)

measured at respiratory auraface of entire organism; can be uncoupled from mitochondrial rq

chamber respirometry

animals enclosed in chamber; accounts for all expired gases; easier to control environment

mask respirometry

chamber only covers mouth/nose/head; greater temporal resolution; difficult to control gas composition; assumes environment gas concentration

cori cycle

liver gluconeogenesis; glucose return to tissue to rebuild glycogen

lactate shuttle

substrate for oxidative phosphorylation in aerobic tissue; lactate → pyruvate → acetyl coa

basal metabolic rate (BMR)

metabolic rate of homeothermic animals at rest, post absorptive, at temp within thermal neutral zone

standard metabolic rate (SMR)

metabolic rate of poikilothermic animals at rest, post absorptive, at defined environmental temperature

resting metabolic rate (RMR)

animal metabolic rate at rest under defined conditions

maximum aerobic metabolic rate (VO2max)

maximum sustainable volume of o2 consumption

supramaximal metabolic rate

metabolic rate in bursts only, measure maximum metabolic rate of organism

field metabolic rate

actual metabolic of animal behaving in wilderness

daily energy expenditure

total amount of energy needed for day of life; not rate