The objective is to the introduce the concept of oxidation-reduction reactions, enzymes and their properties,and two major catabolic pathways and the types of reactions to derive intermediates, energy, reducing power, and release of carbon dioxide. Emphasis is also placed on understanding aerobic and anaerobic metabolism.
Metabolism -- the array of chemical reactions occurring in the cell
2.1.1. Anabolism -- biosynthetic reactions
2.1.2. Catabolism -- decomposition reactions
2.2.1. Reactions to remove and store energy from food
2.2.2. Biosynthetic reactions to build new cells (polymer synthesis and connecting polymers)
2.2.3. Decomposition of old cell material yielding waste products
2.2.4. Active transport of compounds across membrane
2.2.5. Motility
2.2.6. Replication
2.3.1. Raw materials
2.3.2. Energy
2.3.3. Enzymes and cofactors
2.3.4. Control center
2.4.1. Enzymes - catalysts of metabolic reactions
2.4.2. Always composed of proteins
2.4.3. Effective in very small concentrations
2.4.4. Not used up in the reaction
2.4.5. Not a substrate or product of the reaction it catalyzes
2.4.6. Usually quite specific for a specific reaction, however, some exhibit broad specificity
2.4.7. Usually heat labile
Effect of temperature on enzyme activity (3-1)
2.4.8. Function by lowering the energy of activation
 | Exergonic versus endergonic reactions (3-2) |
| Reduction of necessary activation energy by catalysts (3-3) |
2.5.1. Metabolic reactions found in one organism often exist in many other organisms
2.5.2. Much of the known metabolism of man was discovered by the study of microorganisms
Reduced compounds have a lot of energy and are referred to as compounds with a LOW redox potential
Oxidized compounds have little energy and are referred to as compounds with a HIGH redox potential
| What is Oxidation? |
| Types of oxidation (3-4) |
For every oxidation there must be a reduction, hence the term redox reaction
| Typical redox reaction (3-5) |
Burning of hydrogen or methane results in a sudden release of energy in the form of light and heat
| Energy yielding oxidation (3-6) |
The living cell burns the hydrogen in organic compounds very slowly and stores the energy as ATP
| Biological oxidation (3-7) |
4.1.1. Polysaccarides are broken into monosaccarides
4.1.2. Proteins dissimilated to amino acids
4.1.3. Triglycerides are broken into fatty acids and glycerol
4.1.4. Nucleic acids are broken into bases, riboses, and phosphate
4.1.5. Hydrolytic reactions all require energy (ATP)
4.1.6. Hydrolytic reactions yield products small enough to get into the cell
4.2.1. Compounds are burned slowly and the energy is stored as ATP
4.2.2. Glycolysis
4.2.3. Citric Acid Cycle
4.2.4. Numerous other pathways
4.3.1. use of enzymes
4.3.2. use of ATP
4.3.3. isomerization
4.3.4. oxidation
4.3.5. generation of NADH or reducing power
4.3.6. synthesis of ATP by substrate phosphorylation
4.3.7. use of cofactors
4.3.8. use of coenzymes
4.3.9. decarboxylation
| Overview of glycolysis (3-9) |
| Glycolysis reactions 1-5 (3-10) |
| Glycolysis reactions 6-10 (3-11) |
| Glycolysis reactions 11-12 (3-12) |
| Summary glycolysis reactions (3-13) |
| Overview of TCA Cycle (3-14) |
| TCA overview (3-15) |
| TCA simplified overview (3-16) |
| Summary of TCA reactions (3-17) |
4.6.1. Some are reoxidized by biosynthetic reactions
4.6.2. This reducing power can be used by the cytochrome system to produce a lot more ATP via a process called oxidative phosphorylation.
Cytochrome system (3-18)
4.7.1. Oxidative phosphorylation - ATP formation via cytochrome system
Oxidative phosphorylation (3-19)
4.7.2. Substrate phosphorylation - high energy phosphate transferred from substrate in pathway to ADP yielding ATP
| 1st substrate phosphorylation in glycolysis (3-20) |
| 2nd substrate phosphorylation in glycolysis (3-21) |
| Substrate phosphorylation in TCA cycle (3-22) |
4.7.3. Photophosphorylation - plants and photosynthetic bacteria
4.7.4. Phosphorylation in chemolithotrophs
Classification based on the H or e acceptor
4.8.1. Aerobic Respiration - molecular oxygen is the terminal (e) acceptor
Aerobic respiration (3-23)
4.8.2. Anaerobic Respiration - some inorganic compound other than O is the (e) acceptor
Anaerobic respiration (3-24)
4.8.3. Fermentation - some organic compound is the terminal (e) acceptor
Fermentation (3-25)
5.1. What are five type of activities dependant on metabolism?
5.2. How do enzymes function in metabolic reactions?
5.3. What are three types of oxidation reactions? Use examples.
5.4. Show that every oxidation reaction requires a reduction reaction. What is the electron donor and electron acceptor in your example?
5.5. What are hydrolysis reactions? Give two examples. How is water involved in these reactions?
5.6. Using the pathways for glycolysis and Kreb's cycles, indicate which reactions (rxn. nos.) use ATP, make ATP, are oxidation reactions, generate reducing power, illustate substrate phosphorylation, use coenzymes, use cofactors, are decarboxylation reaction.
5.7. Which specific reactions in Kreb's cycle release each of the numbered carbons of glucose (1 - 6)?
5.8. How much energy in the form of ATP and calories is formed by glycolysis and glycolysis coupled with Kreb's cycle by the oxidation of one mole of glucose?.
5.9. Illustrate with specific examples the differences between aerobic respiration, anaerobic respiration, and fermentation.
5.10. Why do fermentative organism have lower growth rates and cell yields?
5.11. Illustrate the differences between oxidative, substrate, and photophosphorylation.
| aerobic respiration | alcoholic fermentation | ATP |
| electron transport | FADH2 | glycolysis |
| Krebs cycle | NADH | lactate fermentation |
| Mitochondrion | substrate-level phosphorylation | electron acceptor |
| oxidative phosphorylation | photophosphorylation | fermentation |
| oxidation-reduction reaction | decarboxylation | coenzyme |
Biochemistry - The Biology Project, Biology, University of Arizona Activities, Problems sets, and Tutorials: Chemistry review; Energy, Enzymes, and Catalysis; Large Molecules; Metabolism; Photosynthesis
Metabolic Pathways of Biochemistry - K.J. Miller, student at George Washington University "...online reference of metabolism for students, scientists, and the world. This site is designed to graphically represent all major metabolic pathways, primarily those important to human biochemistry."
