cellular respiration
the aerobic harvesting of energy from sugar by muscle cells (or other cells); produces CO2, H2O, and lots of ATP
the three main stages of this:
1. glycolysis
2. citric acid cycle
3. oxidative phosphorylation
kilocalories (kcal)
the quantity of heat required to raise the temperature of 1 kilogram (kg) of water by 1 degree C; same thing as the "calories" on food packages
redox reaction
the movement of electrons from one molecule to another; an oxidation-reduction reaction
oxidation
the loss of electrons from one substance; occurs in a redox reaction
reduction
the addition of electrons to a (another) substance; occurs in a redox reaction
dehydrogenase
key player in the process of oxidizing glucose: an enzyme
NAD+
key player in the process of oxidizing glucose: nicotinamide adenine dinucleotide; a coenzyme; an organic molecule that cells make from the vitamin niacin and use to shuttle electrons in redox reactions
electron transport chain
molecules that carry electrons; middle part of a (metaphorical) downward energy "staircase" in redox reactions
glycolysis
glucose is broken into two 3-carbon compound (pyruvate) molecules in the cytoplasmic fluid of the cell; a metabolic pathway (chain of reactions) in which one molecule becomes (through reactions) 2 pyruvate molecules; it harvests chemical energy by oxidizi
citric acid cycle
breakdown of glucose is completed in the mitochondria and a very small amount of ATP is produced; second main stage of cellullar respiration
oxidative phosphorylation
phosphorylation of ADP, and then (therefore) creation of lots of ATP; occurs through chemiosmosis involving the electron transport chain embedded in the inner mitochondrion membrane
chemiosmosis
a process in which the potential energy of the concentration gradient of H+ is used to make ATP
ATP synthases
the concentration of H+ drives the diffusion of H+ through these; they are protein complexes built into the inner membrane that synthesize ATP
substrate-level phosphorylation
a process in which an enzyme transfers a phosphate from a substrate molecule directly to ADP, forming ATP; produces a small amount of ATP in both glycolysis and the citric acid cycle
intermediates
the compounds that form between the inital reactant (glucose, in glycolysis) and the final product (pyruvate, in glycolysis)
steps of glycolysis
______________________________:
1. a fuel molecule is energized, which uses ATP
2. a six-carbon intermediate splits into 2 three-carbon intermediates
(1-2 use energy; energy investment phase)
3. a redox reaction generates NADH
4. ATP and pyruvate are prod
pyruvate
groomed
before the citric acid cycle, this is how __________ is "_________":
1. a carboxyl group (COO-) is removed from pyruvate and given off as a molcule of CO2 (this is the first time CO2 is released in respiration)
2. the 2-carbon compound remaining is oxidiz
Acetyl CoA (abbrevaition of "Acetyl coenzyme A")
a high-energy fuel molecule for the citric acid cycle; for each molecule of glucose that entered glycolysis, two molecules of this are produced and enter the citric acid cycle
citric acid cycle
steps of the _____________: (diagram on page 97, section 6.9 in textbook)
1. Acetyl CoA stokes the furnace (adds fuel)
2. NADH, ATP and CO2 are generated during redox reactions
3. redox reactions generate FADH2 and NADH
Reactants: 2 carbons, acetyl CoA (n
poisons
these interrupt critical events in cellular respiration, and they can kill you for this reason
fermentation
a process that allows cells to produce ATP without oxygen by providing an anaerobic pathway for recycling NADH back to NAD+
lactic acid fermentation
a process by which your muscle cells, a few other cells types, and certain bacteria can regenerate NAD+, pyruvate is reduced to lactate
alcohol fermentation
used for thousands of years in brewing, winemaking, and baking; many yeasts recycle NADH back to NAD+; produces ethanol and CO2 from pyruvate
obligate anaerobes
prokaryotes that live instagnant ponds and deep in the soil; require anaerobic conditions and are poisoned by oxygen (unlike muscle cells and yeast)
facultative anaerobes
these things (organisms?) can make ATP either by fermentation or by oxidative phosphorylation, depending on whether O2 is available (includes yeast, muscle cells, and other bacteria)
biosynthesis
the production of organic molecules using energy-requiring metabolic pathways; food molecules provide raw materials for this process