AP Bio Ch 6 Goals Cellular Respiration• Diagram the flow of energy through the biosphere.• Describe the overall summary equation for cellular respiration.• Explain why cellular respiration is exergonic.• List the 3 metabolic stages of cellular respiration.• Distinguish between substrate level phosphorylation & oxidative

phosphorylation.• Define oxidation & reduction, oxidizing agent & reducing agent.• Explain why glucose doesn’t spontaneously combust in our cells.• Explain the importance of phosphorylation.• List the 2 coenzymes involved in cellular respiration & explain their roles.• Explain the role dehydrogenases in the oxidation of glucose.• Write a summary equation for glycolysis & describe where it occurs in

the cell.• Explain why glycolysis alone is not efficient.• Describe the structure of the mitochondrion.• Describe where pyruvate is oxidized to acetyl CoA, what molecules are

produced, and how it links glycolysis to the Krebs cycle.• Describe the locations, molecules in and molecules out for the Krebs

cycle.

• Explain at what point during cellular respiration glucose is completely oxidized.

• Explain the composition, location and function of the electron transport chain.

• Describe the process of chemiosmosis.• Trace the path of electrons during aerobic respiration (cellular

respiration).• State what energy source most directly drives ATP synthesis during

respiratory oxidative phosphorylation.• Summarize the net ATP yield from the oxidation of a glucose molecule by

constructing a chart that shows how many ATP are produced at each stage of cellular respiration (both by substrate level phosphorylation and oxidative phsphorylation).

• Describe the fate of pyruvate in the absence of oxygen.• Explain why fermentation is necessary.• Distinguish between aerobic and anaerobic metabolism.• Describe how food molecules other than glucose can be oxidized to make

ATP and state the type of food molecule that produces the most ATP per gram.

• Explain 3 reasons scientists believe that glycolysis is considered one of the first metabolic pathways to have evolved.

• Explain what role the allosteric enzyme phosphofructokinase plays in the control of ATP production in the cell.

AP Bio Ch 6 Goals Continued Cellular Respiration

Cell Respiration ch 6Break down of food molecules to release the energy

stored in them to make ATP for the cells use.

Type of rx?Delta G?Delta S?Oxidation – Reduction – Oxidizing agent – Reducing agent –

Energy flow through

ecosystem

Overview of Cell Respiration

• http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/interactivemedia/activities/load.html?9&B

Summary of Cell Res – 3 main parts

Just a reminder…

Summary of Glycolysis

Glycolysis

• breaks glucose into 2

molecules of pyruvate(which goes onto the next part of cell res)

• produces net gain of 2 ATP by sustrate level phosphorylation

• Produces 2 NADH • occurs in cytoplasm• no O needed

Glycolysis

Energy investment phase Energy pay off phase

Animation of glycolysis

• http://henge.bio.miami.edu/mallery/movies/glycolysis.mov

Dehydrogenase – enzyme that removes H+ from glucose & intermediates of

glucose & transfers it to NAD+ or FAD

Mitochondrial Structure

Oxidation of pyruvate – occurs after glycolysis & before Krebs as pyruvate enters

mitochondrion• CO2 released• e- transferred

to 2NAD+, producing NADH

• Coenzyme A added to produce Acetyl CoA which enters Krebs cycle

From this point out everything we go over occurs twice b/c in glycolysis glucose is broken into 2 molecules of pyruvate.

Krebs Cycle (aka Citric acid cycle)

• most enzymes for these rxns are located in mitochondrialmatrix

• 8 steps w/ 8 dif. enzymes

• oxaloacetate is recycled

• -2 Cs go in, 2 Cs come out in form of CO2

• -cycle turns twice for every glu molecule oxidized

Krebs Cycle (aka Citric Acid Cycle)

Coenzymes involved in cell respiration are electron carriers – they transport the high E

electrons from glucose & intermediates of glucose to the electron transport chain (ETC).

• NADH : has enough stored E to produce 3 ATPs through oxidative phosphorylation.

• FADH2 : has enough stored E to produce 2 ATPs through oxidative phosphorylation

Electron Transport Chain (ETC) – transfers the E stored in NADH & FADH2 to ATP

ETC• Composed of proteins

embedded in cristea – each one more electroneg. Than the previous.

• e- move from one to another.• As each protein has the e-, it

uses the E from it to pump H+ into the inner membrane space – creating an electrochemical gradient

• H+ rush through ATP synthase, the E released from rush is used to bond P to ADP making ATP - Chemiosmosis

• O is final e- acceptor & 2H+ are added to it to make H2O –breath out.

• NAD + & FAD can now go back to other steps of Cell Res to pick up more high E e-.

http://www.youtube.com/watch?v=Idy2XAlZIVA

Chemiosmosis – using a proton gradient to make ATPUsed in both

cell res & photosynthesis to create ATP

Summary of Cell Res

Adding up the ATPs in made in Cell Res

What if O2 isn’t present?

Anaerobic respiration takes place

Glycolysis + extra step to regenerate NAD+ so glycolysis can continue

2 types:Lactic Acid FermAlcoholic Ferm

Pyruvate is final electron acceptor – creating lactic acid (aka lactate)

Alcoholic Fermentation

Cell Respiration & Fermentation Compared:

Control of Cellular Respiration

• Phosphofructokinase – an allosteric enzyme in the 3rd step of glycolysis. – Acitvated by ADP– Inhibited by ATP &

citrate• Example of feedback

inhibition.

STUDY!