Introduction to Microbiology Flashcards
What are microorganisms ?
creatures that are too small to be seen with the naked eye
- includes both prokaryotes and eukaryotes
- range in size
What is an example of the smallest microorganism ?
viruses
What is an example of the largest microorganisms ?
parasites and fungi
What are prokaryotes ?
means pre-nucleus
- no membrane bound organelles
- have no true nucleus
- Ex.) bacteria
What are Eukaryotes ?
means “true-nucleus”
- possess membrane bound organelles
- Ex.) parasites, amoeba, paramecium, man
Are viruses microorganisms as well ?
yes
- consist of protein and nucleic acid
- viroids and prions as well
What is the function of the Flagellum ?
provides some motility
- Protus Miriabilis is an example of a bacteria that has high motility because of the flagellum
What is the function of the Fimbria ?
helps bacteria stick to each other and surfaces
- small bristle like fibers on surface
What is the function of the Pillus ?
for sexual reproduction through conjugation
- elongated, rigid tubular structure
What is conjugation ?
where DNA is transferred from one cell to another
- bacteria become resistant to drugs through this
What is the function of the cell envelope ?
protects the cell
- composed of the glycocalyx, cell wall, and cell membrane
What is the function of the cell membrane ?
controls in/out transport of substances
- via proteins in membrane
- right on the surface of the cell
What is the function of the cell wall ?
provides rigidity, strength, and protection
- site of action of some of the most effective antibiotics
- in many species causes symptoms of disease
What is the function of the glycocalyx (external layer) ?
helps protect cell, and helps cell adhere to its environment
- consists of the slime layer and capsule
What is the function of the slime layer ?
aids bacteria in colonizing surfaces (attaches to surface)
- not bound to cell
- lets bacteria slide along surface
What is the function of the capsule ?
makes bacteria more virulent and protects bacteria from phagocytosis by the cells of the host
- protects the bacteria from WBC which can easily destroy the bacteria without the capsule
- bound to cell
- thick gummy consistency
- prevents bacteria from drying out
- aids in attachment to surfaces for colonization
What is the purpose of phagocytosis ?
cells engulfs and destroy microorganisms
- way for the immune system to destroy bacteria
What is the function of Protoplasm ?
site of biochemical and synthetic activity
- contains: 70-80% H2O, sugars, amino acids, salts, enzymes, chromatin body, ribosomes, mesosomes, granules
What is the function of the Chromatin Body ?
DNA aggregates in dense area called the nucleoid
- bacterial chromosome in prokaryotes
- don’t have a true nucleus
- where most genetic material is found
What is the purpose of the Plasmid ?
circular piece of genetic material in prokaryotes that is outside of the chromosome
- provides resistance to drugs
- Advantage of man: use this in genetic engineering techniques
- not every bacterium has one
What is the function of the ribosomes ?
used in protein synthesis
What is the function of Inclusion Granules ?
concentrate nutrients inside the cells, storage. & are not permanent
- where bacteria will store excess material when not needed (temporary)
Do viruses have DNA or RNA ?
their genetic material can be either
- but never both
Do viruses contain a true cell ?
no
- they do have a protein coat
What are viroids ?
infectious genetic material
What are prions ?
infectious proteins that infect others and makes them infectious as well
- always fatal
- no cure
- Ex.) Mad Cow Disease
Where is the genetic material of a prokaryote ?
in the nucleoid
- only about 1 chromosome
Does every bacteria has a pilus ?
no
How does a donor bacteria exchange it’s genetic material ?
through the donor’s pilus
What genetic material can be exchanged by the pilus ?
the plasmid (the circular genetic material in prokaryotes)
- not the chromosomes
Why can conjugation cause bacteria to become resistant to drugs ?
the plasmid tend to have factors that make bacteria more resistant
What is the outermost later of the bacteria ?
glycocalyx
What is the innermost layer of the bacteria ?
cell membrane
What gives the bacteria cell its shape ?
cell wall
What is the difference between the cell wall in a Gram + and - bacteria ?
the cell wall is way thicker in Gram +
What makes up the glycocalyx ?
coating of macromolecules
What makes up the slime layer ?
loose soluble polysaccharides
What in the bacteria can cause it to be more virulent ?
the capsule
What is chemotaxis ?
chemical attraction of phagocyte to the bacteria
- the way the phagocyte looks for the bacteria they are trying to destroy
What is adherence ?
attachment of phagocyte plasma membranes to microorganisms
Where in the cell is most antibiotics most effective ?
cell wall
What is the chemical structure of the cell wall ?
peptidoglycan
- what gives the cell wall that structure
- only found in bacteria
- similar to chitin (which gives lobster insects that crunch)
