nutrients are proteins, carbohydrates, fats; proteins break down into amino acids; carbohydrates break down into glucose; fats break down into glycerol + fatty acids;
Deamination
is removal of amino groups from amino acids to produce urea, primary excretory product of humans
Anabolism
is build-up of larger molecules from small ones; anabolism requires energy; energy supplied by ATP
Cellular Respiration
Respiration
is step-wise release of energy from molecules; aerobic respiration requires O2 and gives off CO2
Relationship between Breathing + Eating + Cellular Respiration
Oxygen is inhaled and Glucose ingested as food carried through blood into cells of digestive tract, then into mitochondria; ATP produced + CO2, which is exhaled from lungs
Overview of Cellular Respiration
Equation:
Glucose + 6 O2 in presence of ADP + P → 6 CO2 + 6 H20 + ATP (HIGH ENERGY)Almost all organisms on land or in water carry on cellular respiration
NAD+ and FAD are coenzymes involved in cellular respiration
coenzymes are organic non-protein molecules and help enzymes function properly
Phases of Cellular Respiration
Glycolysis + Preparatory Reaction + Citric Acid Cycle + Electron Transport Chain
Glycolysis
takes place within cytoplasm but outside of mitochondria; produces pyruvate and net gain of 2 ATPs
Preparatory Reaction occurs inside mitochondria
pyruvate transported into mitochondria and is oxidized into C2 acetyl group;
Citric Acid Cycle occurs in matrix of mitochondria;
cyclical series of reactions that give off CO2 and produce 1 ATP per cycle; cycle runs twice for each glucose metabolized; therefore, 2 ATPs produced
Electron Transport Chain
is series of carriers that accept electrons (but not H+) removed from glucose; occurs across membrane of cristae; results in 32 or 34 ATPs
Cellular Respiration
involves breakdown of Glucose into CO2 + Water + Energy in form of ATP
Each Glucose metabolized yields 36 or 38 ATPs [2 ATPs from Glycolysis + 2 ATPs from Citric Acid Cycle + 32 or 34 ATPs from Electron Transport Chain]
Glycolysis Outside of Mitochondria
Glycolysis
is breakdown of Glucose (6 carbons) into two Pyruvates (each is 3 carbons)
Energy-investment steps:
two ATPs used to activate Glucose into two C3 molecules
Energy- harvesting steps
four ATPs synthesized; four ATPs minus two ATPS = NET GAIN of two ATPs
Preparatory Reaction Inside Mitochondria
Occurs in matrix of mitochondria
Preparatory reaction
produces a molecules that can enter Citric Acid Cycle
Preparatory reaction is oxidation reaction
hydrogen atoms removed from Pyruvate
Reactions occurs twice per glucose molecule metabolized
Citric Acid Cycle
Occurs within matrix of mitochondria
Starts with C2 acetyl group carried by Coenzyme A; cycle ends with production of Citrate
Citrate is same as Citric Acid
two citrates produced from each Glucose metabolizedOutput of Citric Acid Cycle: 4 CO2 + 6 NADH + H+ 2 FADH2 + 2 ATP
Electron Transport Chain
Located in cristae of mitochondria
Electrons passed from one carrier to another
energy is used to produce ATP
Cytochromes
are electron carriers in Electron Transport Chain
Chemiosmosis
occurs within Inter-membrane Space of cristae; synthesis of ATPs
Electron Transport Chain
produces net gain of 32 or 34 ATP molecules
Energy Yield and Efficiency of Cellular Respiration
Glycolysis yields
2 ATPs
Citric Acid Cycle yields
2 ATPs
Electron Transport Chain
yields 32 or 34 ATPs
Total energy yield from metabolism of one glucose
is 36 or 38 ATPs
Efficiency of cellular respiration
is 39% of available energy from one glucose
Fermentation
Fermentation
occurs when no Oxygen available
Anaerobic
refers to lack of oxygen
Animals:
When oxygen is not available, two Pyruvates formed from one Glucose is converted into two Lactates + net gain of two ATPs
Yeast or bacteria
pyruvates converted into two alcohols + two CO2 + net gain of two ATPs
Lactate is toxic to cells
Lactate is Lactic Acid; lactic acid in blood lowers pH; makes muscles “burn”
Oxygen debt”
is amount of oxygen needed to convert lactate back into pyruvate