Chapter 9: Cellular Respiration
Objectives
The student is responsible for:
1.
The definitions of all bold faced words in the chapter
2.
Knowing the entire chapter.
The student is not responsible for:
1.
Memorizing or drawing the structures of glycolysis or Kreb’s cycle
Principles of Energy Harvest
Fermentation: decomposition of glucose without the use of oxygen
Cellular Respiration: oxygen is a reactant when glucose is broken down
Figure 9.1 Energy flow and chemical recycling in ecosystems
There is an integral relationship
between photosynthesis and
respiration.
The production of ATP is an
exergonic process
Figure 9.x1 ATP
Adenosine Triphosphate
ATP -> ADP + Pi
ADP  AMP + Pi
Figure 9.2 A review of how ATP drives cellular work
Why do we care so much about ATP?
Figure 9.3 Methane combustion as an energy-yielding redox reaction
Oxidizing Agent: that substance that is being reduced.
O is “going” from O (no charge) to O2-.
Reducing Agent: that substance that is being oxidized.
C is gaining oxygen.
Figure 9.19 The catabolism of various food molecules
Various foods can be oxidized to
produce ATP.
Figure 9.4 NAD+ as an electron shuttle
The molecule that is used to move hydrogen ions throughout the oxidation of food
is NAD+. Therefore NAD+ is an oxidizing agent.
NAD+ + H+  NADH
Figure 9.5 An introduction to electron transport chains
Figure 9.6 An overview of cellular respiration (Layer 1)
But if we could get this pyruvate into the mitochondria
we could make a whole lot more ATP!!
Figure 9.6 An overview of cellular respiration (Layer 2)
Figure 9.6 An overview of cellular respiration (Layer 3)
Figure 9.7 Substrate-level phosphorylation
What is this substratelevel phosphorylation?
This is when a phosphate
group is moved from an
organic compound to
ADP.
What is oxidative
phosphorylation?
When electrons and H+
are used to make ATP.
Figure 9.8 The energy input and output of glycolysis
Couldn’t these
NADH’s that are
made be used to make
ATP?
Figure 9.9 A closer look at glycolysis: energy investment phase (Layer 1)
Figure 9.9 A closer look at glycolysis: energy investment phase (Layer 2)
Figure 9.9 A closer look at glycolysis: energy payoff phase (Layer 3)
Figure 9.9 A closer look at glycolysis: energy payoff phase (Layer 4)
Figure 9.10 Conversion of pyruvate to acetyl CoA, the junction between glycolysis
and the Krebs cycle
Could the NADH produced here be used to make ATP?
Figure 9.11 A closer look at the Krebs cycle (Layer 1)
Keep track of the number of carbons!!
Figure 9.11 A closer look at the Krebs cycle (Layer 2)
More NADHs!!!
Figure 9.11 A closer look at the Krebs cycle (Layer 3)
Figure 9.11 A closer look at the Krebs cycle (Layer 4)
Figure 9.12 A summary of the Krebs cycle
Figure 9.13 Free-energy change during electron transport
NADH and FADH2 deliver electrons to
different locations in the ETC.
The role of oxygen is to serve as a
hydrogen ion acceptor to form water.
Figure 9.14 ATP synthase, a molecular mill
ATP Synthase
Chemiosmosis: the coupling of
the movement of H+ through a
protein complex (ATP
Synthase) making ATP.
Figure 9.15 Chemiosmosis couples the electron transport chain to ATP synthesis
A Proton-Motive Force is produced
Figure 9.16 Review: how each molecule of glucose yields many ATP molecules
during cellular respiration
Figure 9.17a Fermentation
Figure 9.17b Fermentation
Figure 9.18 Pyruvate as a key juncture in catabolism
Figure 9.19 The catabolism of various food molecules
Power Bars?
Luna Bars?
Promax?
Goo?
Versatility of Catabolism
Use of Proteins
1.
Proteins  amino acids and then the amino acids must have their
amino groups removed before being used as an energy source. So all
the energy bars that have amino acids in them are at least one step
closer to being used for energy than a protein.
2.
Fats must go through beta oxidation which takes a fat and breaks off 2
carbon fragments from the fatty acids and these 2 carbon fragments
enter at acetyl-CoA.
Figure 9.20 The control of cellular respiration
The Control of Cellular Respiration
1.
PFK: allosteric enzyme
a)
Receptor sites for ATP, AMP
and citrate
b) ATP: inhibitor
c)
AMP: stimulator
d) Citrate: inhibitor
The Evolutionary Significance of Glycolysis
Earliest organisms were in an anaerobic environment (3.5 billion yrs
ago)
Glycolysis was probably used as an energy making process
Oxygen accumulated about 2.7 billion years ago
Glycolysis is the most widespread pathway amongst organisms
suggesting it evolved early on.
Glycolysis requires only the cytoplasm and membrane-bound
organelles were not present until eukaryotic cells appeared (2 billion
years after prokaryotes)