Lab 7: Microbiology Flashcards
Prokaryotes vs eukaryotes
Prokarytoic cells: no nucleus or membrane-bound organelles (bacteria and cyanobacteria).
Eukaryotes: contain membrane-bound organelles. (animal, plants, fungi, protists).
Bacteria, bacterial colony
- single-celled organisms.
- When exposed to nutrients like agar, forms bacterial colony: macroscopic growth of cells that all resulted from the division of a single cell. Genetically identical.
Why is asceptic technqnique used?
To keep all equiment and media sterile, so that you grow only the microorganisms of interest.
How to identify fungi and spores in agar plate
fuzzy solonies or strands of growth.
Why are the bacterial colonies on “after” side of plate look to be of the same type of bacteria than on “before” side?
Some bacteria were washed away, but some live on the surface of the skin (seen on “before” and “after” plate).
Control of bacterial growth is important in:
- Prevention of food spoilage
- Prevention of bacterial infections
- Recovery from bacterial infections
Ways to prevent food from going bad
- Cooking: high temp. kills bacteria.
- Refrigeration: slows down growth of bacteria.
- Freezing: stops bacterial growth but doesn’t neccessarily kill the cells.
- High salt or high sugar content: creates a hypertonic environment, resulting in the bacteria losing water by osmosis which kills them.
- Pickling: pickling food in vinegar kills baceria by exposing them to acidic pH.
Optimal temperature and pH for E. coli.
21 degrees (looks cloudy). pH 7.
Prevention of bacerial infections
Soaps and detergents: mechanically remove bacteria from surfaces. Don’t usually kill bacteria.
Disinfectants: kill bacteria in the environment. Only immune compromised people need bacteria-free environment.
Recovery from bacterial infections
antibiotics are used to help immune system control bacterial growth. Some bacteria become resistant to some or all currently available antibiotics.
Zone of inhibition
A clear area with no bacterial growth, measures diameter, compared to Antibiotics Effectiveness Chart:
For bacteria to be susceptible to an antibiotic: the diameter must be bigger than diameter on chart.
For bacteria to be resistant: the dimater must be smaller than diameter on chart.
Bacterial shapes
Bacterial shapes
Cocci: round.
Bacili: rod-shaped.
Spirila/spirochete: grows in chains or clusters, but each cell is an independant organism.
Cyanobacteria
larger than other prokaryotes.
photosynthetic.
See GD
Between euglena and paramecium, which organism is photosynthetic?
Eugena, it has green pigments found in chlorophyll and chloroplasts, the organelle that conducts photosynthesis..
Protists
See euglena and paramecium
Informal eukaryotes that don’t fit with animal, plants, or fungi.
Vary:
* Single-celled or multicellular
* Some are photosynthetic, using light energy and CO2 to synthesize sugar.
* Some rely on consumption of other organisms for energy.
* Some are motile.
2 ways tht euglena and paramecium are the same and different.
same: unicellular, have nuclei.
Different: euglena has chloroplasts and is photosynthetic. Euglena have flagella, and paramecium have cilia.
Viruses
Not cells. Don’t have plasma membrane or any organelles.
Fungi
Decompose deade organis material and absorb resulting chemical products as their food. Flesh is composed of hyphae. Mostly reproduce asexually by releasing spores. Includes yeast, mushrooms, lichen.
Unicellular fungi
Group of organisms that includes yeast.
Mushrooms
See GD
Made of hyphae.
Spores for reproduction.
Lichen
Fungi and algae living in symbiotic relationship (partnership between 2 dissimlar organisms in which both partners benefit):
* Fungus absorbs water and minerls for alga and alga performs photosynthesis to provide carbohydrates for fungus.
Cellular respiration
Most organisms, like yeast, convert energy stored in carbs to ATP. By products: CO2 WATER.
Alcoholic fermentation
Yeast. Waste products: CO2 and ehtanol. Without using electron transport chain and produces less ATP than cellular respiration.
What 2 variables were manipulated in the experiment?
Concentration of yeast and temperature.
What temperature produced the most CO2 and why?
37 degrees. The tubes at 37 degrees had more concentration of yeast and were placed the optimal temperature for yeast productivity.
