Ch 3 Bacterial Structure Flashcards
Cocci (coccus)
Roughly spherical cells.
Diplococci
Pairs of cells observed
Streptococcus
Chain of cocci
Tetrads
Arrangement of two pairs on top of each other to form a quartet
Sarcinae
Two tetrads stacked
Staphylococcus
Arrangement of cocci in “grape clusters”
Bacilli (bacillus)
Rod shaped bacteria
Coccobacilli
Short rods that resemble cocci
Diplobacilli
Pairs of rods
Streptobaccilus
Chains of bacilli
Palisades
Chains or stacks of bacilli attached by the length instead of the end as in Streptobacillus
Vibrios
Comma shaped
Spirilla
Rigid spiral shaped bacteria
Spirochetes
Flexible spiral shaped bacteria
Pleomorphic
Lacking single defining characteristic form; variable in shape
Filamentous
Filament like
Surface area
4pi r^2
Volume
4/3 pi r^3
Cell envelope
Plasma membrane and all the layers external to it
Plasma membrane
Membrane that encases the cytoplasm and defines the cell
Amphipathic
Structurally asymmetric; ie polar and nonpolar ends
Peripheral membrane proteins
Loosely connected to membrane. Easily removed.
Integral membrane proteins
Embedded in the plasma membrane, have hydrophobic regions that span the membrane. Not easily extracted.
Hopanoids
Phospholipid similar to cholesterol found in plasma membrane of bacteria
Functional membrane microdomains
Portion of membrane that has distinct lipid composition that localizes protein complexes (ie secretion systems)
Flotillins
Integral membrane proteins org secretion systems for transport out of cell and complexes that transmit signals from environment to cell
Macronutrients
Nutrients required in large amounts (C & N)
Micronutrients
Nutrients required in small amounts (
Growth factors
Orgo compounds required in the diet. Essential components or precursor of components and can’t be synthesized
Passive diffusion
Small uncharged particles cross membranes from high to low concentration with no assistance
Facilitated diffusion
Substances move across the membrane with assistance of transport protein (channels or carriers). Still according to concentration gradient.
Saturation effect
Facilitated diffusion reaches max transport rate when all carrier proteins are loaded
Active transport
Transport of solute molecules to higher concentrations; require ATP
Primary active transport
Transport proteins that use ATP to transport a single molecule across the membrane. (Uniporters)
ATP-Binding Cassette transporters
Important primary transporters, move vitamins, sugars and other molecules into cells
Solute binding proteins
Proteins employed by ABC transporters to deliver solute molecule to the transporter
Siderophores
Proteins excreted by some bacteria to bind Iron and escort to ABC transporter
Secondary active transport
When two molecules move across the transporter. One molecule has a gradient that drives transport and the other is moved with the assistance of this. Can be simpler or antiport
Symport
Secondary transport where both go in the same direction
Antiport
Transport where one molecule goes in and the goes out
Cell wall
Layer right outside the membrane
Peptidoglycan
Polymer of Nam and Nag subunits linked first in chains and then cross linked like a chain link fence. Polypeptides connect rows, teichoic acids connect sheets
Gram positive bacteria
Contain a single membrane surrounded by a thick (20-80nm) peptidoglycan layer. Stains purple
Gram negative bacteria
Has a thin peptidoglycan layer (2-7nm) and then an outer membrane (12-14 nm). Stains red or pink
Periplasmic space
Space between the inner and outer membranes in gram negative bacteria
Periplasm
Substance in the periplasmic space
