for Microbiology, 2e

Instructors Manual for Microbiology, 2e Dave Wessner, Christine Dupont, Trevor Charles, Josh Neufeld (All Chapters) 1 / 4

Chapter 1 The Microbial World

Lecture Outline:

• What is microbiology?
• Microbiology is the study of microorganisms (aka microbes).

i) Examples of microorganisms include bacteria, archaea, eukaryotes, and viruses

ii) Living organisms share common features such as metabolism, growth, reproduction, genetic variation, responding to stimuli and internal homeostasis.iii) The simplest structure capable of carrying out all the process of life is the cell.iv) Cells contain a variety of macromolecules (polypeptides, nucleic acids, lipids and polysaccharides).(1) Polypeptides can function as enzymes (chemical reactions).

• All living organisms are either prokaryotes or eukaryotes. Today, we classify organisms

by placing them in one of three domains: Bacteria, Archaea and Eukarya.

i) The domain classification scheme reflects the phylogeny of all living organisms.

ii) PCR (polymerase chain reaction) has assisted scientists in classifying microbes.iii) Viruses are also classified as microbes.(1) They are regarded as sub-cellular.

• Microbes are very important research models because of their simplicity in design.

II) Evolution of life and genetics of microbes

• Living organisms possess similar molecules and processes for changing genetic

information into functional molecules.

i) Life evolved on Earth approximately 3.8 billion years ago.

ii) Simple organic molecules became enclosed within a lipid membrane.iii) The discovery of ribozymes supports the idea that the precursors of life may have used RNA as a major informational molecule.iv) Eukarya arose through endosymbiosis.

v) In all living organisms, the major informational molecule is DNA.

(1) DNA is double-stranded and easily converted into functional molecules using processes such as protein synthesis (transcription and translation).vi) DNA mutation allows for genetic variation and is also a prerequisite for evolution.

• Understanding basic genetic processes has led to the development of recombinant DNA

technologies. DNA molecules can be modified and inserted into microbial hosts to produce human proteins.

i) DNA sequencing technologies and increased computing power have both led to the

new fields of genomics and bioinformatics.III) Obtaining energy and interaction with the world

• All living organisms must acquire organic molecules. 2 / 4

i) Heterotrophs ingest organic molecules.

ii) Autotrophs produce their own organic molecules.iii) Most autotrophs generate organic molecules through the process of photosynthesis.iv) Organic molecules can be converted into energy (ATP) through glycolysis, fermentation and respiration.

v) Microbial metabolism has influenced the biosphere.

(1) As a result, microbes are involved the biochemical cycling of elements such as nitrogen, phosphorus, and sulfur.vi) Microbes are capable of interacting with each other and other organisms in a variety of ways.IV) Microbes and Disease

• Microbiologists are responsible for the development and acceptance of the germ theory

of disease. Louis Pasteur was a major contributor to this theory.

i) Robert Koch developed a set of postulates which provided a means of

demonstrating how a particular microbe causes a particular disease.ii) Infectious diseases have a history of impacting humans that continues on till today.iii) Antibiotics, antivirals and vaccines are common day methods used to prevent or treat infectious diseases.(1) The development of these agents is based upon our understanding of microbial structure and how they replicate.(2) Microbes have also been destroyed using techniques such as pasteurization.iv) Infectious diseases affect large numbers of people throughout the world even today. 3 / 4

In Class Activities Instructor Notes for In-Class Activity One

Title: Studying Microbiology

Time: 5 min prep; 20-25 min in class

Materials: Packet of notecards

Handouts: None

Procedures: Have students make a set of flashcards with the following vocabulary: Microorganisms, Microbiology, Bacteria, Archaea, Viruses, Microbes, Metabolism, Growth, Reproduction, Genetic variation, Evolution, Stimuli, Homeostasis, Cell, Macromolecules, Lipids, Polypeptides, Polysaccharides, Nucleic acids, Enzymes.

Student Instructions: Bring set of blank notecards to class.

Specific Suggestions: Have students play a game in pairs with the flashcards testing one another.

Objectives: The objective of this exercise is to familiarize students with the vocabulary associated with studying microbiology at the undergraduate level.

• / 4