Download Chapter 5

Copyright © 2010 Pearson Education, Inc.
The Mechanism of Enzymatic Action
Copyright © 2010 Pearson Education, Inc.
Figure 5.4a
Enzyme Inhibitors: Competitive
Inhibition
Copyright © 2010 Pearson Education, Inc.
Figure 5.7a–b
Enzyme Inhibitors: Competitive Inhibition
Example-Sulfa drugs (sulfonamides)
Discovered in the 1930s
Copyright © 2010 Pearson Education, Inc.
Oxidation-Reduction
Copyright © 2010 Pearson Education, Inc.
Figure 5.9
Representative Biological Oxidation
Copyright © 2010 Pearson Education, Inc.
Figure 5.10
The Generation of ATP
 ATP is generated by the phosphorylation of ADP
1. Substrate-level Phosphorylation
2. Oxidative Phosphorylation
3. Photophosphorylation
Copyright © 2010 Pearson Education, Inc.
Substrate-Level Phosphorylation
 A chemical reaction where a phosphate group is
transferred from one molecule to ADP. This requires
a specific enzyme that can transfer the phosphate
from this specific molecule to ADP.
 ATP is produced this way during
 FERMENTATION
 Glycolysis (or alternative pathways)
 Krebs cycle
Copyright © 2010 Pearson Education, Inc.
Oxidative Phosphorylation
 Energy released from transfer of electrons
(oxidation) from one compound to another
(reduction) is used to generate ATP in the electron
transport chain
 An electron transport chain(ETC) couples a
chemical reaction between an electron donor (such
as NADH) and an electron acceptor (such as O2) to
the transfer of H+ ions across a membrane, through
a set of mediating biochemical reactions.
http://en.wikipedia.org/wiki/Electron_transport_chain
Copyright © 2010 Pearson Education, Inc.
Photophosphorylation
 Light causes chlorophyll to give up electrons. The
electrons go through a process similar to what
happens during respiration (an electron transport
chain and chemiosmosis occur). This process
releases energy used to bond a phosphate to ADP
producing ATP.
 The ATP produced is used to produce food
molecules (sugars-glucose).
Copyright © 2010 Pearson Education, Inc.
Glycolysis
 The oxidation of glucose to pyruvic acid produces
ATP (Substrate level phosphorylation)and NADH
2 Stages: See next 2 slides
Copyright © 2010 Pearson Education, Inc.
Figure 5.11
Energy Using Stage of Glycolysis
 2 ATP are used
 Glucose is split to form 2 glucose-3-phosphate
Copyright © 2010 Pearson Education, Inc.
Figure 5.12, steps 1–5
ATP Creating Stage of Glycolysis
 2 glucose-3-phosphate oxidized
to 2 pyruvic acid
 4 ATP produced
 Substrate-level phosphorylation
 2 NADH produced
Copyright © 2010 Pearson Education, Inc.
Figure 5.12, steps 6–10
Preparatory Step Intermediate between
Glycolysis and Krebs Cycle
 Pyruvic acid (from glycolysis) is oxidized and
decarboyxlated
Copyright © 2010 Pearson Education, Inc.
Figure 5.13
The Krebs Cycle
Copyright © 2010 Pearson Education, Inc.
Figure 5.13
Chemiosmotic Generation of ATP
Copyright © 2010 Pearson Education, Inc.
Figure 5.16
Comparing Eukaryotic and Prokaryotic
Cellular Location of Catabolic
Processes
Pathway
Eukaryote
Prokaryote
Glycolysis
Cytoplasm
Cytoplasm
Intermediate step
Cytoplasm
Cytoplasm
Krebs cycle
Mitochondrial matrix
Cytoplasm
ETC
Mitochondrial inner membrane Plasma membrane
Copyright © 2010 Pearson Education, Inc.
Aerobic and Anaerobic Respiration
 Aerobic respiration: The final electron acceptor in
the electron transport chain is molecular oxygen
(O2).
 Anaerobic respiration: The final electron acceptor
in the electron transport chain is not O2. Yields less
energy than aerobic respiration because only part of
the Krebs cycles operates under anaerobic
conditions.
Copyright © 2010 Pearson Education, Inc.
Anaerobic Respiration
Electron Acceptor
Products
NO3–
NO2–, N2 + H2O
SO4–
H2S + H2O
CO32 –
CH4 + H2O
Copyright © 2010 Pearson Education, Inc.
Fermentation
 FERMENTATION Scientific definition:




Releases energy from oxidation of organic molecules
Does not use oxygen
Does not use the Krebs cycle or ETC
Uses an organic molecule (pyruvic acid) as the final
electron acceptor to form ‘end-products’ (acids and
alcohols)
 2 ATPs netted
Copyright © 2010 Pearson Education, Inc.
An Overview of Fermentation
Copyright © 2010 Pearson Education, Inc.
Figure 5.18a
Types of Fermentation
Copyright © 2010 Pearson Education, Inc.
Figure 5.19
Types of Fermentation
Copyright © 2010 Pearson Education, Inc.
Table 5.4
Types of Fermentation
Copyright © 2010 Pearson Education, Inc.
Table 5.4
Catabolism of Organic Food Molecules
Copyright © 2010 Pearson Education, Inc.
Figure 5.21
Photosynthesis
 Conversion of light energy into chemical energy
(ATP) which is used to synthsize nutrients (glucose)
 Overall Summary Reaction?
 Compare and Contrast: Oxidative Phosphorylation
and Photophosphorylation.
Copyright © 2010 Pearson Education, Inc.
Photosynthesis
 Oxygenic:
6 CO2 + 12 H2O + Light energy 
C6H12O6 + 6 H2O + 6 O2
 Anoxygenic:
6 CO2 + 12 H2S + Light energy 
C6H12O6 + 6 H2O + 12 S
Copyright © 2010 Pearson Education, Inc.
Metabolic Diversity among Organisms
Nutritional Type
Energy Source
Carbon Source
Example
Photoautotroph
Light
CO2
Oxygenic: Cyanobacteria
plants
Anoxygenic: Green,
purple bacteria
Photoheterotroph
Light
Organic
compounds
Green, purple nonsulfur
bacteria
Chemoautotroph
Chemical
CO2
Iron-oxidizing bacteria
Chemoheterotroph
Chemical
Organic
compounds
Fermentative bacteria
Animals, protozoa,
fungi, bacteria.
Copyright © 2010 Pearson Education, Inc.
Amphibolic Pathways
Copyright © 2010 Pearson Education, Inc.
Figure 5.33
Amphibolic Pathways
Copyright © 2010 Pearson Education, Inc.
Figure 5.33
Copyright © 2010 Pearson Education, Inc.