Introduction to Microbiology Flashcards
How can we exploit microorganisms for human use?
- As a study tool (used to define much of out understanding of cells and biochemistry)
- In genetic engineering/molecular biotechnology
- In genetic diversity
Outline Pseudomonas
- A genus of Gram-negative bacteria
- Involves 191 species
- It can be the cause of infection in humans
- It can degrade soil, and add phosphate and nitrogen sources
State some general uses of microbiological organisms
- Use bacteria to uptake and express new genes for use in medical research
- Used in food production/preservation
- Used in forensics to understand decomposition and identify disease
Who was Antoine van Leeuwenhoek?
- The founding farther of microbiology
- The first to look at bacterial cells (using a 1666 microscope with a 25-25x magnification)
Outline the germ theory of fermentation
- Louis Pasteur stated that every fermentation process is acted upon by certain microbes (he further extended the theory to animal and human diseases)
- Thus, the germ theory came afterwards; stating that microorganisms known as pathogens or “germs” can lead to disease
What did Robert Koch do?
- Developed lab methods for growing microbes
- Founded laboratory microbiology (agar media, petri plates, nutrient solutions, aseptic techniques, elucidation of bacterial species and staining techniques)
- Found a link between single microbes and specific diseases
- Found the microbes responsible for anthrax (in cattle) and tuberculosis (in humans)
What are Koch’s Postulates?
A set of criteria (published in 1890) that establishes whether a particular organism is the cause of a particular disease (confirms “cause and effect”)
- The microbe must be present in EVERY case of the disease
- The microbe must be isolated from an individual ‘case’ and grown in axenic culture
- The disease must be reproduced when this pure culture is inoculated into a healthy, susceptible host
- The same microbe should be able to be RE-ISOLATED from the infected host and grown in laboratory culture
Outline the seven key characteristics of living things
- Movement
- Reproduction
- Sensitivity
- Growth
- Respiration
- Excretion
- Nutrition
DOES NOT ALWAYS WORK (there are some non-motile bacteria, for example)
Outline the difference between the two ‘super-kingdoms’
- Prokaryotes = those WITHOUT (membrane-bound) nuclei
- Eukaryotes = those WITH (membrane-bound) nuclei
Give feature characteristics of prokaryotes
- Genetic material (DNA) is in the cytoplasm
- Includes organisms always regarded as bacteria (e.g., pathogens)
- Also includes photosynthetic bacteria (e.g., cyanobacteria - blue-green algae)
How do archaea compare to bacteria?
- Both are single-celled microorganisms, with no nuclei
- Both have a cell wall and use flagella to swim
- Archaeal cell walls lack peptidoglycan, and their cell membrane uses ether linked lipids instead of ester linked lipids (as observed in bacteria)
What key difference separates Eubacteria (bacteria) and archaebacteria (archaea)?
- Membrane structure
- Usually biological membranes are a phospholipid bilayer, containing fatty acids
- Archaea have complex isoprene-based lipids, which linked together form a monolayer (only in some archaea, especially in extreme thermophiles; Others have a lipid bilayer)
What is a micelle?
-A tiny particle made of substances that are soluble in water, and that come together to form a ball-like shape
What is an aggregate?
- The collection of units or particles (e.g., cells) forming a body or mass
What does the term ‘Micellar Aggregation’ (micelle aggregate) mean?
- The aggregation number is the number (and a description) of molecules present in a micelle when the critical micelle concentration (CMC) is reached
- A typical micelle in water forms an aggregate with the hydrophilic ‘head’ regions in contact with the surrounding solvent
- It is affected by different factors (such as the nature of the surfactant, temperature, type and concentration of added electrolyte, organic additives, etc)
