1. Glycolosis Kreb’s Cycle Electron Transport Chain
Cellular Respiration
Glycolosis
Kreb’s Cycle
Electron Transport Chain

4. Terms to Know
ATP (cellular energy molecule) is an unstable molecule that is used to activate most cell processes by losing a phosphate group. The phosphate group binds to most molecules to change their shape or “activate” the molecule.
Reduced Carriers are molecules that store energy to be passed on later (2 types)
NADH (high energy carrier)
FADH2 (lower energy carrier)

5. ATP

9. Mitochondria Double membrane structure
Interior space = Matrix (like cytoplasm)
Site of Kreb’s Cycle
Inner membrane space (between membranes)
Site of electron transport chain
Kreb’s Cycle = TCA Cycle = Citric Acid Cycle
Oxidative phosphorization – movement of phosphate groups in the presence of Oxygen (Electron Transport Chain)

10. Overall Process Breakdown of glucose (or other sugar) into CO2 and H2O
Requires Oxygen to complete the full process
Net gain (per glucose + oxygen):
36 ATP, 6 CO2, 6 H2O
Net gain (per glucose without oxygen)
2 ATP, 2 molecules of lactic acid (3C)
Main process of creating energy is by concentration gradient across a membrane

11. Glycolosis
Glucose (food) must enter the cell, this requires active transport (-2 ATP).
The glucose moves across the membrane and into the cytoplasm
This is where glycolosis occurs.
Overall Process:
Start: Glucose (6 carbons)
Finish: Pyruvate x2 (3 carbons each)
2 NADH, 4 ATP (2 Net ATP)

15. Glycolosis
Glucose has two phosphate groups added (one to each end) to energize the molecule which also allows it to cross the membrane. (-2 ATP)
Glucose is then broken into two parts called glyceride 3-phosphate (3 carbons)
One phosphate group is removed to produce NADH (reduced carrier)
The 3 carbon molecules are then processed several times and the phosphate groups are removed to produce pyruvate and 2 ATP. (this occurs for each glyceride molecule)

18. Anaerobic Respiration
Without oxygen
Two Types
Lactic acid production (occurs in most animals). When not enough oxygen is present, cells cannot complete the process of cellular respiration. Instead of producing CO2, the body produces lactic acid which can be broken back down into pyruvate when oxygen is present.

20. Fermentation
The process of fermentation is a billion dollar industry ranging from alcoholic beverages to simple bread.
Occurs in yeast and some bacteria.
Instead of converting pyruvate to lactic acid, the pyruvate is broken down slightly, removing one carbon, to produce ethanol and CO2.
Why does this cause the liquid (such as grapes) to become acidic?

32. Kreb’s Cycle Also called the Citric Acid Cycle
Occurs in the matrix of the Mitochondria (interior region)
Objective: to produce reduced carriers
Start: Pyruvate (x2) and Oxaloacetate (4C)
Finish: 3 CO2 + 4 NADH + 1 FADH2 + Oxaloacetate + 1 ATP

33. The Cycle
Process is cyclic, meaning it always returns to the original materials so the process can occur many times.
Pyruvate is converted to Acetyl-CoA by an enzyme which removes one carbon (CO2 produced)
Acetyl-CoA (2C) is combined with Oxaloacetate (4C) to form Citric Acid (6C)
Through a process of chemical reactions (exothermic) and enzymes Citric Acid is oxidized back to Oxaloacetate, releasing 2C (as CO2)

34. In the process of oxidation, energy is released and is picked up by reduced carriers
4 NAHD are produced (per pyruvate)
1 FADH2 is produced (per pyruvate)
1 ATP is produced (per pyruvate)
The process is then ready to start all over, all the enzymes are recycled as well as staring products

35. NAD NADH
CO2
FAD+ FADH2
CO2
NAD NADH
ADP ATP
NAD NADH
CO2

37. Electron Transport Chain
Final step in cellular respiration
Focus is to synthesize ADP to become ATP
Requires oxygen as final electron acceptor
Occurs across the inner mitochondria membrane (inner membrane space + matrix)
Starting materials: 10 NADH, 2 FADH2
Final products: 32 ATP, 6 H2O

41. Review Recall membrane transport
Active transport across proteins
Ions (charged) cannot cross the membrane
There are 5 membrane bound proteins in the inner membrane, each with a higher electronegativity than the last (they attract electrons more)
Hydrogen contains 1 proton (+) and electron (-)

44. Process
NADH attaches to the first transport protein. The H is removed and split, electrons are passed down the protein chain, while protons are pumped into the inner membrane space
This electrons are passed from one protein to the next, causing more protons to be passed into the inner membrane space (3 from NADH, 1 from FADH2)
Oxygen acts as the final electron acceptor, it has a higher electronegativity than the proteins

45. Final Steps
All of the protons are trapped in the inner membrane space (high concentration)
A protein channel (ATP Synthase) allows the protons to pass into the matrix (low concentration) by diffusion
The energy created as the protons pass allows ADP to be phoshoralized into ATP (32 ATP)
NADH = 3 ATP, FADH2 = 1 ATP