Download Reading Guide for Week 4

Reading Guide for Week 4 – Bio260
Colleen Sheridan
Stage 02 – Colonization and Infection
Unfortunately, some bacteria managed to make it into our host’s body before we were able to take steps to
reduce disease transmission. In this unit you will be trying to figure out how bacteria adhere to the host’s cells
and grow to colonize the host. In last week’s reading guide you learned how our normal microbiota help to
keep pathogenic microbes from adhering and growing. But, sometimes, pathogenic microbes make it past this
line of defense and adhere to our cells. So we also learned how certain prokaryotic cellular structures were used
to adhere to host cells to begin colonization. Then you learned of the incredible variety of different
environmental conditions that different bacteria could grow (colonize) in and how they transport nutrients into
their cells. Now that our bacteria have attached, their environmental conditions are right, and they’ve got
nutrients inside their cells, let’s find out how bacteria harvest energy to fuel their growth and get a sense of the
immense diversity of prokaryotic metabolism.
In this week’s reading you will learn about:
1. How chemoorganoheterotrophic bacteria utilize organic compounds that are transported into the cell
to harvest energy and produce precursor metabolites (through catabolism) that are then used by
the cell to synthesize subunits which are used to build macromolecules which are used to build
cell structures (through anabolism) all driven by the activity of enzymes.
2. A brief look at the diversity of chemoorganotrophic prokaryotes.
Chapter 6: Metabolism: Fueling Cell Growth (whole chapter)
1. Define metabolism and describe the difference between anabolism and catabolism.
Be able to draw and explain Figure 6.1.
2. Review the components of metabolic pathways, like enzymes, ATP, and electron carriers.
3. Understand a key concept to harvesting energy: the roles of the chemical energy source and the terminal
electron acceptor and the oxidation-reduction reactions and electron carriers that transfer the electrons
between them. What is reducing power?
4. What are precursor metabolites and where do they come from? No need to memorize the names of the
precursor metabolites, but you should understand that the central metabolic pathways produce them
and that they are used to make subunits:
Subunits (made from precursor metabolites)
amino acids
nucleotides
monosaccharides
glycerol
fatty acids
Macromolecules (made from subunits)
proteins
nucleic acids
carbohydrates
lipids
5. Understand the following terms and processes at the level of detail found in the “Overview of Catabolism”
section found on p.132-134: glycolysis, pentose phosphate pathway, Tricarboxylic acid cycle, respiration
(anaerobic and aerobic respiration), and fermentation, and how the following processes play a role in those
catabolic processes: oxidation/reduction reactions, electron transport chain, oxidative phosphorylation, and
substrate level phosphorylation.
6. Define enzymes and their characteristics. What biological macromolecule is an enzyme made out of?
7. What are cofactors? What are coenzymes? What are electron carriers?
8. Understand the environmental factors that influence enzyme activity: temperature and pH. (You’ll learn
more about allosteric regulation and enzyme inhibition when we talk about how antibiotics work.)
9. From section 6.3, know that these pathways generate: ATP by substrate-level phosphorylation, reducing
power, and precursor metabolites. Compare the relative amounts of each made by each pathway.
10. From section 6.4, know the difference between substrate-level phosphorylation and oxidative
phosphorylation. What are the two sequential processes of oxidative phosphorylation? Make sure to review
how the proton motive force is generated. Be able to explain Figure 6.18.
11. From section 6.4, know that cytochromes are oxidases and are components of the electron transport chain.
(Why is iron important?) Why do the oxidase test?
11. Know that eukaryotic mitochondrial electron transport chain and prokaryotic electron transport chains are
very similar, but no need to memorize the names of the complexes and proteins involved.
12. What is the difference between aerobic respiration, anaerobic respiration, and fermentation? How do they
differ in the amount of energy (ATP) produced? What is the final electron acceptor in each pathway?
12. What are the uses of the proton motive force in prokaryotes (Figure 6.20)?
13. What is the final end product from fermentation of glucose by E. coli? By Clostridium? By lactic acid
bacteria? By Saccharomyces? How do the fermentation end products help us to explain our results on the
EMB agar plate in Lab Ex. 7?
14. What type of energy harvesting pathway(s) might be used by chemoorganoheterotrophic
- obligate aerobes?
- obligate anaerobes?
- facultative anaerobes?
14. Know that lipids, amino acids, and nucleotides are synthesized from precursor metabolites. Why do
fastidious bacteria require growth factors?
Chapter 11: The Diversity of Prokaryotic Organisms (11.1, 11.5-11.6, 11.8) Skim this
No need to memorize the following, but become familiar enough with these so that, should an in-class exercise
on prokaryotic diversity occur, you will be able to finish the project in a timely manner!
Metabolic Diversity
1. Where can you find anaerobic environments in/on the human body?
2. Understand that some anaerobic chemoorganotrophs harvest energy through fermentation. Be able to briefly
describe the genera: Clostridium and Propionibacterium, and the lactic acid bacteria (particularly
Streptococcus) and give an example of each if one is provided in the book.
3. If you want to, skim through the rest of the sections not required and get an idea of the incredible metabolic
diversity that prokaryotes have.
4. What is an aerobic chemoorganotroph? What is an obligate aerobe? Be able to briefly describe the genera:
Micrococcus, Mycobacterium, and Pseudomonas and give an example of each if one is provided in the
book.
5. What is a facultative anaerobe? Be able to briefly describe the genus Corynebacterium and the Family
Enterbacteriaceae and give an example of each if one is provided in the book. What is an “enteric”?
What are “coliforms”?
Ecological Diversity
6. What soil living bacterial genera form endospores? Do you know if any of these cause human disease?
7. Describe the skin environment. Be able to briefly describe the genus Staphylococcus and give an example.
8. Describe where you would find mucous membranes in the human body. Be able to briefly describe the
genera: Bacteroides, Bifidobacterium, Campylobacter, Helicobacter, Haemophilus, Neisseria,
Mycoplasma, Treponema, Borrelia and Chlamydia and give an example of each if one is provided in the
book.