Microbiology and Parasitology: An Introduction Midterm Quiz

Definition of Microbiology

• Microbiology is the science of microorganisms and how they work.
• It includes diversity and evolution of microbial cells, their associations, and cooperation with each other.

Types of Cells

• There are two types of cells: Eukaryotic and Prokaryotic cells.
• Eukaryotic cells are further classified into Animals and Plants.
• Plant cells have cell walls and chloroplasts that are not present in animal cells.
• Bacterial cell walls are composed of Peptidoglycan.

Genes, Genomes, Nucleus, and Nucleoid

• A cell's life processes are controlled by its genes and genome.
• The nucleus is present in eukaryotes, while prokaryotes have a nucleoid.
• The genome is the sum total of all genes in an organism.

Age of Earth and Microbial Ecosystems

• The Earth is approximately 4.6 billion years old.
• Microorganisms are present everywhere on Earth that supports life.
• Microbial cells outnumber human body cells by a factor of ten.

Ribosomal RNA and Phylogeny

• Ribosomal RNA (rRNA) is a conserved region used to study genetic evolution.
• rRNA genes can be used to construct a phylogenetic tree.

History of Microbiology

• Microbial cells first appeared between 3.8 and 3.9 billion years ago.
• Alexander Flemming discovered Penicillin, the first antibiotic.
• Joseph Lister is considered the father of antiseptic surgery.

Impact of Microorganisms

• Microorganisms play a role in:
  • Food and agriculture (pasteurization)
  • Producing valuable human products (insulin)
  • Generating energy (bioreactors)
  • Cleaning up the environment (bioremediation)

Microorganisms and Agriculture

• Microorganisms aid in digestion of cellulose by ruminants.
• Nitrogen-fixing bacteria help convert nitrogen into ammonia.
• Microbes play important roles in the food industry, including food spoilage, safety, and production.

History of Microbiology

• Van Leeuwenhoek discovered "wee animalcules" (microorganisms).
• Cohn discovered that some bacteria form endospores.
• Pasteur countered the theory of Spontaneous Generation using his swan-necked flask experiment.
• Koch's postulates are used to link cause and effect in infectious diseases.

Koch's Achievements

• Discovery of the causative agent of tuberculosis
• Development of microscopy, staining, and pure culture isolation
• Devised a staining procedure for M.tuberculosis cells
• Causative agent of cholera (Vibrio cholerae)
• The tuberculin skin test