CH 3

Characteristics that prokaryotes lack

Characteristics that prokaryotes lack

lack membrane-bound nucleus, cytoskeleton, membrane-bound organelles, and internal membranous structures

cocci

spherical cells, can be single or in arrangements that is useful for identification

rods

oblong cells

arrangement

determined by plane of division, determine by sepratation or not

Diplococci

divide and remain in pairs, circle balls

Staphylcocci

divide in random planes making grape-like clusters

tetrads

divide in 2 plans forming a sqaure of 4 cocci

sarcina

divide in 3 planes making cubic packet of 8 cocci

Bacilli

rods, length to width ration differ

coccobacilli

short and wide rods

Vibrios

comma shaped

spirilla

rigid spiral shaped

mycelium

network of long filamets

pleomorphic

organisms that are variable in shape, irregular

streptobacilli

rod shaped organism that make chain

mycoplasma

smallest bacteria, no capsule, make people very sick, DO NOT PRESCRIBE PENICILLIN, lack cell wall, irregular shape

Cells want high surface area-to-volume

increases efficiency of nutrient uptake and diffusion of molecules within a cell

more effcient

smaller cell has more surface area

cell envelope

layers that surround cell (plasma membrane and cell wall)

peptidoglycan

cell wall, rigid structure lying outside the plasma membrane

nucleiod

chromosomal DNA, no nuclei membrane, usually 1 closed circular DNA molecule

Cell envelope

plasma membrane and all the surrounding layers external to it

capsule is helpful with

virulence factor, more organized than slime

plasma membrane functions

detects and responds to surrounding chemicals, transport systems used for nutrient uptake, metabolic processes

hopanoids

hydrophobic molecule similiar to cholesterol, impacts fluidity and shape, distors bilayer, FORM FUNCTIONAL MEMBRANE MICRODOMAINS

Most fluid membrane

bacteria cell membrane

growth factors

essential cell componets that the cell cannot synthesize and must be supplied by the environment

amino acids, purines, pyrimidines, vitamins

growth factors

auxotroph

organism that requires growth factor

wild type

no growth factor

Passive diffusion

molecules move from a region of higher concentration to one of lower concentration

Facilitated diffusion

movement across plasma with help of transport proteins

PTS

best translocation system, phosphoenolpyruvate, phosphoylates them

translocation

chemically modification

Siderphores

secrete by bacteria and complex with ferric ion for transport into cell, for iron uptake

iron uptake

helps virulene factor

bacterial cell wall

maintains shape, helps protect from osmotic lysis and toxis matierials, may contribute to pathogeniticty

Gram-positive

stain purple; thick peptidoglycan, hold dye tightly

gram-negative

stain pink, thin peptidoglycan and outer membrane

D amino acids

found ONLY in alternating with peptidoglican

lysozyme

breaks bond between NAG and NAM

penicillin

inhibits peptidoglycan synthesis

peptidoglucan structure

alternating NAG and NAM, peptide interbridge may form

gram-positive cell walls

teichoic acids, maintain cell envelope, protect from enviornmental substances, may bind to host cells and intiate infection

periplasmic space of gram-positive bacteria

between plasma membrane and cell wall

gram-negative cell wall structure

thin layer of peptidoglycan, outer membrane, lipopolysaccharides

periplasm

hydrolytic enzymes, transport proteins, and other proteins

Lipid A

buried in outer membrane, acts as an endotoxin (what gives infection)

Core polysaccharide

10 sugar structure joined to lipid a

O side chain

polysaccharide that extends outward from the core

Gram-negative membrane transport

facilitated by porins, first solute crosses outer membrane, crosses plasma membrane

protoplast

gram-positive cells that lose cell wall in isotonic environments

spheroplast

gram-negative cells that lose cell wall in isotonic environments (outer membrane remians)

capsules

well-organized layers made of polysaccharides that covalently bonded and DIFFCULT TO WASH OFF

slime layers

polysaccharides layers that are unorganized and easily washed away, facilitate movement

glycocalyx

capsules, slime layers, polysaccharides extension that aids in attachment to solid surfaces

S-layers

geometric pattern made of protein that aid in protecting from ion and pH fluctations, more important in arhcea

Capsule protective advantages

resistant to phagocytosis, protect from desiccation, exclude ciruses and detergents

cytoskeleton

protein filaments that polymerize to form functional filaments that extend to full inner dimensions of the cell

storage granules

carbone granules to store carbon

carboxysome

contain CO2 fixing enzymes in CO2 fixing bacteria

gas vacoules

provide buoyancy to aquatic bacteria

magnetosomes

used by cells for orientaton in Earth's magnetic field

Ribosomes

complex protein/RNA strucutres, site of protein sysntheis

rRNA

16s in small subunit, 23S and 5S, bacterial

plasmids

extrachromosomal DNA that is usually small, closed circular DNA molecules

episomes

are able to integrate into chromosome, carry selective advantage

motility

ALL (pili, fimbrae, flagella)

frimbae

short, hairlike, protein appendages

sex pili

conjugation, gene transfer and uptake

Flagella

motility, attachment to surfaces, virulence factors

monotrichous

one flagellum on one pole

polar flagellum

flagellum at the end of the cell

amphitrichous

one flagellum at each end of the cell

Lophotrichous

cluster of flagella at one or both ends

Peritrichous

flagella all over

twitching motility

the type of movement of bacteria involving a pilus (pili) that makes contact with the surface of another cell, then retracts in a powerstroke

Chemotaxis

Cell movement that occurs in response to chemical stimulus

run

striaght line, will spend more time if running away or to something

tumble

turns, will spend more time if there is nothing there