MODULE 1 Flashcards
How would you define a microorganism?
Organisms that have typical cellular features and are too small to be seen without the aid of a microscope, they can live and be cultured as single cells.
Explain the apparent contradictions in defining microbiology as the study of
microscopic organisms or single-celled organisms.
Many microbes can attach, aggregate or function together to be macroscopic in appearance, e.g algal blooms and mats, fungi, biofilms. Viruses are studied as part of microbiology but are not cellular organisms.
Name some ways microorganisms influence our everyday life.
Causing infectious diseases, producing antibiotics & other products, food spoilage & poisoning, water quality, waste treatment, biodegradation, etc.
Why is the study of microbiology important?
Microbes influence humans, animals & the ecosystem in many ways and are vital for the survival of all life. Understanding them will help us control infectious diseases and apply them for beneficial purposes. They provide a model for studying biological mechanisms and functions, and give insights into evolution and
extraterrestrial life.
Explain how bacteria can be both beneficial and detrimental to the food industry.
Beneficial: food production (alcoholic beverages, cheese, yogurt, fermented foods, etc.)
Detrimental: cause food poisoning and infection, food spoilage
What is the difference between prokaryotic and eukaryotic microorganisms?
Size, organelles, membrane bound nucleus, complexity
Why are microorganisms useful for biologists as experimental models?
Simple, grow quickly, can grow large quantities and inexpensive to work with.
Comparable metabolic pathways, biochemical and genetic similarities to higher organisms.
Suggest some reasons why there have been so many outbreaks of emerging and re-emerging diseases over the last 20 years.
Human demographics and behaviour, increased urbanization, increased international travel and transport, economic development and land use, microbial adaptation and change (increased strain virulence), antibiotic resistance
Explain why van Leeuwenhoek, Pasteur and Koch are seen as three of the most important microbiologists?
Leeuwenhoek: first to observe bacteria through a microscope.
Pasteur: disproved spontaneous generation, first to show fermentation and use sterilization.
Koch: germ theory of disease, infectious nature of disease, first developed solid agar growth medium and isolated pure cultures of bacteria.
Why is it necessary to stain bacteria before viewing under a microscope?
Bacterial cells are colourless and lack contrast with their background. In light microscopy, we stain to increase contrast through addition of colour, and to differentiate cells, determine cell morphology and specific structures of the cells. In electron microscopy, stains are used to increase contrast by scattering electrons not colouring. EM images are black & white, computers can add colour later solely to increase visual effect.
Why is the Gram stain important in microbiology?
Categorises most bacteria as either Gram positive or Gram negative based on the two main types of bacterial cell wall structures
Why are phase contrast and fluorescence superior to bright field microscopy when viewing bacteria?
Enables cells to be seen more clearly by using a special phase condenser to increase the contrast between the cell and background
When viewing microbes, what is the difference between scanning and transmission electron microscope?
TEM: electrons penetrate a thin section of the cell showing internal structures.
SEM: does not require sectioning and views surface of the cell
What are the advantages of electron microscopes over light microscopes?
Allows much higher resolution viewing because electrons have much shorter wavelength than light and this enables much greater magnification to be achieved (about 1000 times greater). Cell structures and components can be clearly seen.
What characteristics differentiate protozoa from other microbes?
Animal-like characteristics such as predation, ingesting particulate matter. All motile at some stage. Generally do not have cell walls, unlike most other microbes.
