Download Collision Theory

Figure 2.18
Collision Theory
 The collision theory states that chemical reactions
can occur when atoms, ions, and molecules collide
 Activation energy is the amount of energy needed
for them to collide ‘hard’ enough to disrupt electronic
configurations and produce a chemical reaction
 Reaction rate is the frequency of collisions with
enough energy to bring about a reaction.
 Reaction rate can be increased by enzymes or by
increasing temperature or pressure
Copyright © 2010 Pearson Education, Inc.
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 Reactions
 Oxidation: Removal of electrons. The general
process of electron donation to an electron acceptor
is also referred to as oxidation even though the
electron acceptor may not be oxygen.
 Reduction: Gain of electrons
 Redox reaction: An oxidation reaction paired with a
reduction reaction
Copyright © 2010 Pearson Education, Inc.
Oxidation-Reduction
Copyright © 2010 Pearson Education, Inc.
Figure 5.9
The Generation of ATP
 ATP is generated by the phosphorylation of ADP
Copyright © 2010 Pearson Education, Inc.
3 Ways ATP is Produced in Living Cells
1. Substrate-Level Phosphorylation.
Occurs during glycolysis (or alternate pathway
a. Fermentation (in Microbes and our
own skeletal muscle cells and brain
Cells)
b. Respiration: Glycolysis and Krebs Cyc
2. Oxidative Phosphorylation
Occurs during respiratory e- transport chains
(aerobic or anaerobic)
3. Photophosphorylation.
Occurs during photosynthesis
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.
 This is how the process of FERMENTATION
produces ATP.
Copyright © 2010 Pearson Education, Inc.
Oxidative Phosphorylation
 Energy released from transfer of electrons
(oxidation) of 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). 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 and NADH
Copyright © 2010 Pearson Education, Inc.
Figure 5.11
Representative Biological Oxidation
Copyright © 2010 Pearson Education, Inc.
Figure 5.10
Preparatory 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
Energy-Conserving Stage of Glycolysis
 2 glucose-3-phosphate oxidized to 2 pyruvic acid
 4 ATP produced
 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.
A Summary of 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 require oxygen
Does not use the Krebs cycle or ETC
Uses an organic molecule as the final electron acceptor
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) and 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.