chapter nine part one Flashcards
location of glycolysis
- euk - cytosol
- prok - cytosol
location of pyruvate oxidation
- euk - mitochondrial matrix
- prok - cytosol
location of Krebs cycle
- euk - mitochondrial matrix
- prok - cytosol
location of oxidative phosphorylation
- euk - inner mitochondrial membrane
- prok - plasma membrane
catabolism
breakdown of complex molecules in living organisms
anabolism
synthesis/building of complex molecules
fermentation
catabolic process where there is a partial degradation of sugars or other organic fuel w/o the use of oxygen
- glycolysis + additional step to recycle NAD+
- produces ATP less efficiently
aerobic cellular respiration
most efficient catabolic pathway where oxygen is being consumed as reactant along w/ organic fuel
- takes place in mitochondria
balanced equation for respiration
C6H12O6 + 6O2 —> 6CO2 +6H2O + ATP
free bond energy change
breakdown of fuel
- exergonic
- -7.3 kcal/mol
photosynthesis and chemical coupling
- light energy generates organic molecules and O2 used in cellular respiration
- respiration breaks down fuel using O2
- generates ATP and produces CO2 and H2O as waste
- CO2 and H2O raw materials for photosynthesis
oxidation
loss of e- from one substance
reduction (redox) reaction
transfer of 1+ e- from 1 reactant to another
- addition of e- to another substance
reducing agent
electron donor
oxidizing agent
electron acceptor
stepwise energy harvest
cellular respiration doesn’t oxidize organic fuel in single explosive step, instead fuel broken down in series of steps each catalyzed by enzyme
NAD+
nicotinamide adenine dinucleotide - coenzyme suited as electron cycle, can cycle easily between oxidized (NAD)+ and reduced (NADH) form
how does NAD+ –> NADH + H+ work
- enzymes remove pair of H toms from substrate to oxidize it
- enzyme delivers 2 electrons w/ 1 proton to coenzyme NAD+ to form NADH
- other proton released into solution
electron transport chain
consists of # of molecules (mostly proteins) built into inner membrane of mitochondria to provide several energy-releasing steps to break fall of electrons
where does NADH shuttle electrons to?
higher end of chain
- lower energy end has O2 and captures H+ to form water
steps of cellular respiration
- glycolysis
- pyruvate molecules converted to CoA - Krebs cycle
- oxidative phosphorylation (ETC)
glycolysis
process in cytosol that breaks glucose into 2 molecules of pyruvate
- sugar splitting
conversion of pyruvate to CoA
pyruvate enters mitochondria and is oxidized to acetyl CoA, which leads to citric acid cycle
substrate level phosphorylation
smaller amount of ATP formed directly in some glycolysis and citric acid cycle
- occurs when enzyme transfers phosphate group from substrate to ADP other than adding inorganic P group to ADP
Krebs cycle
where acetyl CoA is oxidized to form CO2 and coenzymes are reduced, which generates ETC
oxidative phosphorylation
ETS + chemiosmosis (harness H+ gradient to power ATP synthase)
- harnesses reduction of O to generate high-energy phosphate bonds in form of ATP
- powered by redox reactions of ETC
energy input needed for glycolysis
2 ATP
produced during glycolysis
- 2 net ATP (4 ATP - 2ATP)
- 2 pyruvate molecules
- 2 NADH
- water molecules
2 phases of glycolsyis
- investment phase - ATP used, series of transformations
- payoff phase - ATP produced by substrate-level phosphorylation and NAD+ is reduced to NADH by electrons related from oxidation of glucose
what happens when pyruvate enters the mitochondria via a transport protein?
- CO2 produced
- oxidation occurs to form one NADH (H+)
- acetate molecule to which coenzyme A is attached forms 2-C acetyl CoA
