AP Bio
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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.
AP Bio Ch 6 Goals Continued
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Cellular Respiration
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.
Cell Respiration ch 6
Break 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_camp
bell_biology_7/media/interactivemedia/acti
vities/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=Id
y2XAlZIVA
Chemiosmosis – using a proton gradient to make
ATP
Used in both
cell res &
photosynth
esis 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 Ferm
Alcoholic 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!