Lecture 3 Flashcards
Characteristics of a prokaryote
Before nucleus
DNA no membrane
Single and circular chromosome
Chromosome in nucleoid
No membrane organelles
Single celled organisms only
Characteristics of eukaryotes
True nucleus
DNA in nucleus
Multiple chromosomes
Organelles present and membrane bound
Single or multicellular (most are multi)
What are types of eukaryotes?
Protists, fungi, plants, animals
What is bacterial morphology?
Shape of a bacteria: spherical, rods, spiral
What are the characteristics of a glycocalyx external structure?
Sugar coat
Gelatinous, stick polymer
Can be polysaccharide, protein or both
Secreted from prokaryote into outside of cell wall
What are the types of glycocalyx external structures?
Capsules
Slime layers
Flagella
What are the characteristics of capsules?
This is their ability to cause disease due to its protective qualities from phagocytosis (makes slippery)
Allows organism to adhere and colonize to host cells
Protects against dehydration and holds nutrients or as an energy source and break down its sugars for energy
What are prokaryotes flagella’s?
Only found on some prokaryotes
Used for mobility (corkscrew movement)
Composed of 3 primary parts
What are the 3 components of flagella?
Filament - circle protein around hollow core (no sheath)
Hook - different protein
Basal body - anchors flagellum to plasma membrane
What are the 4 flagella arrangements?
Pertitrichous - all over
Monotricious - single polar flagella
Lopotrichous - two or more flagella at one or both ends
Amphitrochous - a tuft of flagella at each end
Why can flagella arrangement important?
Because it can indicate which strain type an organism is
What are the different bacterial motility?
Can change speed and direction on its own
Speed depends on energy available
Run/ swim - one direction
Tumbles - abrupt change in direction (change of flag rotation)
Taxis - run away from scary environments
- chemotaxis - toward chemical stimulus
- phototaxis - toward light stimulus
What bacteria gram commonly has pili and fimbriae?
Gram neg
What are pili and fimbriae made of?
Pilin protein
What are the characteristics of fimbriae?
Hair like appendages - shorter, thinner, straighter than flag
All over or only at poles
Can be few or hundreds
Allows organism to adhere and colonize
What is a pili?
Longer than fimbriae
Conjugation that transfers DNA between two bacterial cells
What are the characteristics of bacterial cell wall?
Semi rigid and semi permeable
Cell shape
Protects from environment (water absorption)
Classifies bacteria
Composed of polysaccharide peptidoglycan
What is a polysaccharide composed of?
Repeating disaccharides (NAG and NAM)
Linked together by short peptides (amino acids)
What makes a cell gram positive and gram negative?
Gram +
- thick layer of peptidoglycan outside membrane
- teichoic acid attached to peptidoglycan
- lipoteichoic acid attached to plasma membrane to peptidoglycan
Gram -
- thin peptidoglycan layer between two membranes
- lipid A with lipopolysaccharide attached on the outer membrane
- O sugars to distinguish the gram - organism
What are the steps for a gram stain?
Crystal violet dyes all cells -> mordant iodine used to intensify the stain -> alcohol washes outer membrane of gram neg away with violet dye -> safranin counterstain stains gram neg pink
Why is peptidoglycan important?
Unique to bacteria
Is a target for host defences and chemo therapies
Antibiotics are active against it like penicillin to synthesis peptidoglycan
What enzyme degrades peptidoglycan?
Lysosome found saliva, tears, and mucous
Cuts nam and nag bonds
What are the characteristics of plasma membrane?
Semi permeable membrane
Selective barrier
Phospholipid bilayer
Semi fluid state
Break down in alcohol
What are the characteristics of cytoplasm?
Within plasma membrane
80% water
Contains amino acids, carbs, nucleotides, enzymes, ions, ribosomes, bacteria endospores
Aqueous thick bus semi-transparent
