exam #1 micro short answer questions

Biofilms and their medical significance

biofilms- complex relationships among numerous microorganisms, form on surfaces, medical devices, mucous membranes of digestive system

medical- dental plaque is a biofilm that can lead to cavities

Osmotic pressure and different environments (hypertonic, hypotonic and isotonic)

osmotic pressure- pressure exerted on a semipermeable membrane by a solution containing solutes that cannot freely cross membrane

hypertonic- greater solute concentrations

hypotonic- lower solute concentrations

isotonic- equal solute concentration

Scientific method and how it was used by Pasteur

-observation, question, hypothesis, experiment, results prove or disprove

-Pasteur conducted a series of experiments that addressed the cause of fermentation

-this led to the development of pasteurization, and began the field of industrial microbiology

Spontaneous generation and how it was challenged

-spontaneous generation proposes that living organisms can arise from nonliving organisms

-experiments by Francesco Redi and Pasteur challenged it.

Composition of the bacterial cell wall

-bacterial cell walls contain peptidoglycan

-most have a cell wall, but not all do

-provide structure and shape and protect cell from osmotic forces

-can target cell wall of bacteria with antibiotics

Gram-positive vs. Gram-negative cell envelope comparison

gram += cell membrane, thick peptidoglycan, no lipopolysaccharides, techoic and lipotechoic acid, purple stain, mycobacterium

gram -: cell membrane, thin peptidoglycan, lipopolysaccharides (Lipid A), pink stain, may be impediment to treatment of disease

Bacterial vs. eukaryotic flagella comparison

bacterial- rotation can be counter or clockwise, bacteria move in response to taxis, major protein is flagellen, basal body anchors filament and hook to cell wall with the help of 2-4 integral proteins

eukaryotic- move counterclockwise, shaft composed of tubulin arranged to form microtubules (9+2 pair arrangement), anchored to cell by basal body

Koch’s postulates and exceptions

1. suspected causative agent must be found in every case of the disease and be absent from healthy hosts

2. agent must be isolated and grown outside host

3. when agent is introduced to healthy and susceptible host, it must get the disease

4. same agent must be found in diseased experimental host

-exceptions- 1. some pathogens not cultured in the lab 2. some diseases are caused by a combination of pathogens or a combination of physical, environmental, or genetic factors

importance of microbial populations (Ecosystem, pharmaceutical, food and beverages, immune system and bioremediation)

ecosystem- responsible for chemical transformations that maintain ecological balance

bioremediation- uses microbes to clean up pollutants

pharmaceutical- antibiotics produced by bacteria and fungi

immune system- normal flora to have an antagonistic effect on bad populations

food and beverage- ex: beer and wine production through fermentation

endosymbiotic theory

The endosymbiotic theory proposes that eukaryotic cells originated through a symbiotic relationship between early prokaryotic cells, the cells formed a permanent partnership where the smaller bacteria became the cell's specialized parts, like mitochondria and chloroplasts.

Inclusions and their applications in the field

inclusions may include reserve deposits of chemicals, such as polyhydroxybutyrate granules that serve as energy or nutrient reserves for bacteria.

Toxic forms of oxygen and how some bacteria produce enzymes remove them

1. singlet oxygen 2. superoxide radicals 3. peroxide anion, 4. hydroxyl radical

2. need to have a mechanism such as catalase enzyme converting H202 to water and oxygen

-a few superoxide radicals are formed from incomplete oxidation of oxygen during ETC (ex; aerobic respiration must product enzyme “superoxide dismutase”- h202 formed