cellular respiration Flashcards
Cellular Respiration
Degredative pathways to release ATP energy for cell functions
(catabolic)
how did Anaerobic Fermentation evolve
evolved in primitive bacteria still used by some unicellular organisms
in cellular respiration all start with what and convert it into what
all start with glucose and convert it into inorganic carbon carbon dioxide
Anaerobic Fermentation steps
Glycolysis then regeneration of NAD+
describe anaerobic fermentation
2 ATP added to glucose unstable intermediate forms 2NAD+ picks up H (e-) from glucose Intermediate splits into 2 pyruvates 2CO2 released NADH drops hydrogen off on pyruvates forms 2 ethanol (alcohol)
net gain of anaerobic fermentation
Net gain of 2ATP is enough energy for a unicellular organism….
but not for a multicellular organism
Advent of non-cyclic photosynthesis
Caused free O2 to build up in the ocean
Obligate Anaerobes
die in presence of O2
Present day obligate anaerobes are limited to what
regulated to anaerobic environments
example of Present day obligate anaerobes
disease causing bacteria: Botulism and tetnus
oxidation
loss of electron from one substance
reduction
addition of electrons to a substance
reducing agent
electron donor
oxidizing agent
electron acceptor
what were the two ways obligate anaerobes survived
endospores inside cell like a wall to protrect or developed anti oxidants/ defense against the oxidative properties of O2 can
survive the presence of free oxygen
how did organisms use oxygen to generate more energy from glucose
aerobic cellular respiration
facultative aerobes
organisms that can use aerobic respiration when O2 is present then switch to anaerobic fermentation when in anaerobic conditions
example of facultative aerobes
yeast
aerobic respiration
using oxygen to get more ATP per glucose using oxygen
ATP gain for anaerobic fermentation
2
ATP gain for aerobic respiration
32
what are obligate aerobes
need oxygen
plants animals fungi
Aerobic respiration four parts
Step 1 ..Glycolysis
Step 2 .. Acetyl-CoA formation
Step 3…Krebs Cycle (citric acid cycle)
Step 4… Electron transport and oxidative phosphorylation
aerobic glycolysis process
Glucose split in cytoplasm (before entering mito.)
2ATP (activation energy) added to Glucose
Substrate level phosphorylation creates Unstable intermediate (fructose diphosphate)
then splits into 2 PGAL
NAD+ reduced into NADH
forms net 2 ATP
ends with 2 pyruvates
what is the products of aerobic glycolysis and where do they go
NADH carries e- and H+ to mitochondria
2 pyruvates move to mitochondria
2 ATP
Acetyl-CoA formation process
The pyruvate enters the mitochondrial matrix by transport protein
(in prokaryotes stays in cytoplasm)
One C is removed and converted to CO2
One NAD+ is reduced to NADH
Coenzyme A binds to the remaining 2 C forming Acetyl-CoA
why is doing acetyl coA formation in the mitochondria better
increases concentration of enzymes and makes an ideal microenvironment
Krebs cycle/ citric acid cycle process
Acetyl Co-A drops off 2 C onto oxaloacetate to form citrate (6 c)
3NAD+ and 1FAD reduced to form 3NADH and FADH2
To do this, a series of intermediates have all their Hydrogens removed (e-)
Remaining C and O released as 2CO2
1 GTP is produced
Oxaloacetate is reformed
first stable intermediate for Krebs cycle
citrate
ending molecule that is reformed in Krebs cycle
oxaloacetate
electron transport chain for cellular respiration
NADH and FADH2 drops off e- at ET chain
e- passed down chain of proteins in a series of oxidation/reduction reactions
Protein pumps use energy from e- to pump H+
H+ build up in intermembrane space creating electrochemical gradient (lots of Potential E)
e- at end of chain picked up by 1/2 O2 and H+ to form H2O
H+ pumped through ATPase creating ATP from ADP+Pi
Chemiosmosis
energy coupling mechanism
converts potential energy of electrochemical gradient into chemical energy (ATP)
Oxidative phosphorylation
Producing ATP using the energy of oxidation reactions (only) in the e- transport chain
Generates 26 – 28 ATP per glucose
why is there slightly less ATP formed from FADH2 than NADH
FADH2 drops off further down the chain so not as much energy generated
what is the final acceptor in aerobic respiration
oxygen
Lack of Oxygen in mitochondria
If no O2 oxidizes the last protein in e- transport chain, chain stops
Oxidative phosphorylation stops
NADH and FADH2 build up, NAD+ and FAD+ run out
Kreb cycle stops
NADH from glycolysis can’t drop of e- at mito
everything stops so it resorts back to anaerobic
Lactic Acid Fermentation-animals
glycolysis
NADH drops off electrons onto pyruvate from glycolysis
pyruvate is converted to Lactic acid
what is the only molecule that can run the entire aerobic respiration
glucose
the process for energy when carbs run out
Carbs converted to glucose before being used
When carbs run out Fats used
when fats used protein is broken into amino acids
how is fat used for energy
Triglycerides break into
fatty acids & glycerol
Glycerol converted to PGAL & enters glycolysis
Fatty acids are converted into acetyl-CoA and enters kreb
how are proteins used for fuel
broken into amino acids
amino acids broken into
NH3 (nitrogenous waste) converted to urea
carbon backbone converted to pyruvate or Acteyl Co-A
what are the products of alcohol fermentation/ anaerobic fermentation
2CO2 and ethanol (alcohol)
what is the activation energy for alcohol fermentation and how is it added
2ATP through substrate level phosphorylation
in cellular respiration where are the four parts located
glycolysis in cytosol
for Eukaryotas acetyl coA formation, Krebs cycle, and e- transport chain in mitochondria
how many times does the kreb cycle run per glucose
Cycle runs one time for each pyruvate
so twice per glucose
