cell theory
- The basic unit of life is the cell
- All living things are made of cell(s)
- All cells come from pre-existing cells
Eukaryotic cells
A cell in which the DNA is enclosed in a membrane0enclosed organelle known as the nucleus
Animals, Plants, fungi, protozoa, and algae
Prokaryotic cells
A cell in which the DNA is not enclosed within a membrane-enclosed nucleus
bacteria and archaea
Prokaryotes and Eukaryotes
Similarites
- composed of carbohydrates, lipids, proteins, and necleic acids
- genetic information encoded in DNA
- similar production of proteins
- ribosomes present
Eukaryotes
- variety of membrane bound organelles
- Nucleus
- larger
Prokaryotes
- No membrane bound organelles
- No nucleus
- smaller
- plasmid
Bacterial cell shape
- bacilli - rod
- cocci - spherical
- spirilla - loose spiral
- spirochete - tight spiral
- vibro - comma-shaped
Bacterial cell arrangements
- diplo - pairs
- strepto - chains
- staphylo - clusters
virulence factor
characteristic that increases the disease-causing capacity of the microorganism
glycocalyx
The gel-like layer composed of polysaccharides, secreted by many bacteria to form a layer exterior to the cell wall
glycocalyx subcategories
capsule, slime coat, EPS
EPS (extracellular polysaccharides)
thin sugary layer
stick and hydrate
Capsule
big, organgized
lots of attachment sites
virulence factor
Slime coat
polysaccharides and proteins
big, loosely attached
stick, food, protection
What are the domains and what organisms fall in each?
- Archea
- extremophiles
- Bacteria
- mycoplasmas, cyanobacteria, Gram-positive bacteria, and Gram-negative bacteria
- Eukarya
- plants, animals, fungi, protists
What criteria must be met for something to be considered “living”?
- respond to environment
- make and use energy
- reproduce
- maintain homeostasis
- genetic material (DNA)
- made up of cell(s)
What is the basic structure of the flagella?
hook, filament, basal body
- monotrichous
- single flagellum at one pole
- amphitrichous
- single flagellum at both poles
- peritrichous
- surrounded by flagella
- lophotrichous
- multiple flagella at end (like a horse tail)
How are scientific names determined and how are they properly presented?
Genus species
Taxis
If the organism moves towards the stimulus the taxis is positive
while if it moves away the taxis is negative
Please explain what the following are: axial filaments, fimbriae, pili, and what purpose(s) they may serve for the bacteria.
- axial filaments
- a filament that wraps around the cell and makes the cell move in a cork screw movement
- fimbiae
- help cells adhere to surfaces
- pili
- are involved in twitching motility and DNA transfer.
What is the plasmid? How does this “extra” DNA benefit bacteria? How do we exploit this “extra” DNA?
A genetic structure in a cell that can replicate independently of the chromosomes, typically a small circular DNA strand in the cytoplasm of a bacterium or protozoan.
antibiotic resistance
Plasmids are much used in the laboratory manipulation of genes
Inclusions and their benefit
- metachromatic granules
- PO4
- synthesis of ATP
- PO4
- polysaccharide granules
- glycogen/starch
- lipid inclusions
- PHB
- reserve carbon and energy source
- PHB
- sulfur granules
- reserve of electrons (reducing source) in phototrophs; reserve energy source in lithotrophs
- carboxysomes
- “fix” CO2
- Magnetosomes
- Fe3O4
- orienting and migrating along geo- magnetic field lines
- Fe3O4
- gas vacuoles
- buoyancy (floatation) in the vertical water column
Endospores
A structure formed by some bacteria that allows the cell to persist in a metabolically inactive state when the environment is not conductive of growth
Not all bacteria can form endospores
Peptidoglycan
disaccharide (sugar) - NAG NAM NAG NAM
selective toxicity
penicillin blocks the formation of pentaglycine bridge
4 amino acids, interbridge, ß-1,4 glycosidic bond (linkage)
eukaryotes do not have peptidoglycan
