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Cellular Respiration. C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6H 2 O + 38 ATP. Cellular Respiration: An Overview. Process by which cells convert the energy in food (usually glucose) into usable ATP. Terms to Know… Oxidation = the loss of electrons Compound becomes more positive - PowerPoint PPT Presentation
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Cellular Respiration
C6H12O6 + 6 O2 6 CO2 + 6H2O + 38 ATP
Cellular Respiration: An OverviewProcess by which cells convert the energy in
food (usually glucose) into usable ATP. Terms to Know…
Oxidation = the loss of electrons Compound becomes more positive
Reduction = the gain of electrons Compound becomes more negative
Electrons and protons (H+) travel TOGETHERNAD+ = coenzyme derived from niacin; acts
as a H+ and e- acceptor. AN ENERGY CARRIER!
Cellular Respiration: An Overview
Substrate-Level Phosphorylation
An enzyme transfers a phosphate group directly from an organic molecule to ADP to form ATP
The ATP produced in Glycolysis & the Krebs Cycle is produced by this method.
Oxidative Phosphorylation(ETC + Chemiosmosis) The production of ATP by using energy
derived from the redox reactions of the Electron Transport Chain.
The enzyme ATP synthase is needed to phosphorylate the ADP to produce ATP.
Almost 90% of the ATP produced from cellular respiration is produced this way.
Cellular RespirationGlucose
Anaerobic Respiration(Fermentation)
Aerobic Respiration(Krebs Cycle &
ETC)
Glycolysis
Oxygen Absent Oxygen Present
ATP
ATP
Glycolysis “glucose-splitting” Big Picture:
Glucose (6-C) is broken down into 2 molecules of pyruvate (3-C)
Occurs in the cytosol Occurs with or without oxygen Made up of 2 phases:
Energy investment phaseEnergy yielding phase
Glycolysis: Energy Investment Phase Glucose is converted
into 2 G3P (Glyceraldehyde-3-phosphate)
Requires 2 ATP
Glycolysis: Energy-Yielding Phase
2 G3P are converted into 2 Pyruvate (3C) molecules.
Dehydrogenase enzymes remove H from intermediate compounds and attach them to 2 NAD to produce 2NADH
Net Gain in Glycolysis
2 ATP- 2 ATP (Energy investment phase)+ 4 ATP (Energy yielding phase) + 2 ATP
2 NADHElectron carriersWill be used to make ATP later
Choices, Choices! If oxygen is absent, anaerobic respiration
occursFermentation
Yeast & some bacteria alcoholic fermentation Animal muscle lactic acid fermentation
If oxygen is present, aerobic respiration occursKrebs Cycle and Electron Transport Chain
Cellular RespirationGlucose
Anaerobic Respiration(Fermentation)
Aerobic Respiration
Glycolysis
Oxygen Absent Oxygen Present
ATP
ATP
Fermentation 2 major types:
Alcoholic and lactic acid fermentation NAD+ acts as a hydrogen acceptor during
glycolysis If the supply of NAD+ runs out, then glycolysis
would have to stop.Fermentation occurs as simply a means of
recycling the NAD+, so that glycolysis can occur again.
Alcoholic Fermentation Occurs in some BACTERIA and
YEAST 2 step process:
Carbon dioxide is released from pyruvate (3-C), forming acetaldehyde (2-C)
Acetaldehyde is reduced by NADH (gains an electron), forming ethyl alcohol (ethanol)
NAD+ is regenerated, thereby allowing glycolysis to continue
Used to produce beer and wine
Lactic Acid Fermentation Occurs in ANIMALS 1 step process:
Pyruvate is reduced by NADH (gains an electron), forming lactic acid
NAD+ is regenerated, thereby allowing glycolysis to continue
Occurs in muscle cells, causing muscle pain and fatigue
Cellular RespirationGlucose
Anaerobic Respiration(Fermentation)
Aerobic Respiration
Glycolysis
Oxygen Absent Oxygen Present
ATP
ATP
Aerobic Respiration After glycolysis, most of the
energy from glucose remains “locked” in 2 molecules of pyruvate
If oxygen is present, the pyruvate enters the mitochondrial matrix to complete the Krebs Cycle
Pyruvate (3-C) is converted to Acetyl CoA (2-C) CO2 is released as a
waste product NADH is produced
The Krebs Cycle Yield per pyruvate molecule:
4 NADH 1 FADH2 1 ATP 2 CO2
Yield per glucose molecule (two turns of Krebs Cycle): 8 NADH 2 FADH2 2 ATP 6 CO2
CO2 released as a waste product
Electron Transport Chain The ETC converts the NADH and FADH2
from glycolysis and the Krebs Cycle into ATP Occurs in inner membrane of mitochondrion The energy in each NADH molecule moves
enough protons (H+) into the mitochondrial matrix to create 3 ATP
1 FADH2 2 ATP
The Electron Transport Chain The electrons from NADH and FADH2 are
passed from one electron acceptor molecule to another.
Each electron acceptor is more electronegative than the last.
Oxygen is the final electron acceptore-
ETC
oxygen
Chemiosmosis Similarly to photosynthesis,
the energy the electrons lose along the way moves H+ out of the matrix and into the intermembrane space of the mitochondrion
As H+ ions diffuse through the membrane, ATP synthase uses the energy to join ADP and a phosphate group ATP
Oxidative Phosphorylation: ETC & Chemiosmosis
Aerobic Respiration: Total Energy Yield Glycolysis:
2 ATP (Net)2 NADH 6 ATP
Krebs Cycle:2 ATP8 NADH 24 ATP (ETC)2 FADH2 4 ATP (ETC)
TOTAL:8 ATP + 30 ATP 38 ATP