Chapter 3 - Cell Structure and Function

outermost layer of Gram + bacteria

thick peptidoglycan

outermost layer of Gram - bacteria

outer membrane

periplasmic space

The space between the inner and outer cell membranes in Gram-negative bacteria.

teichoic acids

polymers used to reinforce the G+ cell walls

bacterial cell envelope

plasma membrane, cell wall, layers outside the cell wall

most abundant molecule in prokaryotes besides water

iorganic ions

least abundant molecule in prokaryotes

DNA/chromosomes

Archaea membrane lipids

are extremely sturdy and hydrophobic, to sustain life in extreme places

ester linkage

in bacterial cell membrane, makes bacteria more susceptible to hydrolysis/coming apart

ether linkage

in archaic cell membranes, a sturdy, hydrophobic kind of bond

what makes organelle membranes differ?

the proteins embedded within the membranes

passive diffusion

movement of a substance without the use of energy

what passively diffuses through the cell membrane?

water, small ions

facilitated diffusion

movement of a substance without energy, facilitated by a membrane protein

what molecules require facilitated diffusion?

sugars, amino acids

active transport

the movement of a substance using energy, usually against its concentration gradient.

if water is able to passively diffuse through the cell membrane, what is the use of aquaporins?

rapid diffusion of water in or out of the cell

group translocatiation

when a substrate is modified during transport, so that the source substrate is constantly moving down its concentration gradient (into the cell)

how do weak acids and bases affect the pH of a cell?

the pH of a cell can be lowered/increased by WEAK acids and bases

why isn't the pH of a cell affected by strong acids and bases?

in water, strong acids and bases completely dissociate. weak acids and bases can cross the cell membrane before dissociating completely, subsequently altering the pH of a cell.

firmicules

gram +

proteobacteria

gram -

s layer

layer of protein used for protection and/or attachment/virulence

clinically what diseases can the gram stain be used to identify?

meningitis, gonorrhea

non-clinically, what is the gram stain used for?

identification of bacteria

what are bacterial cell walls made of?

NAM and NAG (N-acetylmuramic acid, N-acetyl glucosamine)/peptidoglycan

why do cells keep themselves slightly hypertonic?

osmotic pressure helps them keep their shape

crosslinking

between NAM molecules

how does vancomycin work?

binds to terminal amine

how does penicillin work?

interferes with cross linking

how have bacteria become resistant to vancomycin?

instead of a terminal amine, bacteria may have different terminal amino acid

how have bacteria become resistant to penicillin

beta lactamase

what does beta lactamase do to penicillin?

destroys the beta-lactam ring (key chemical structure of penicillin)

why are gram negative bacteria more resistant to antibiotics?

penicillin and vancomycin both inhibit cell wall building. gram negative bacteria have an additional membrane that surrounds the cell wall, inhibiting the effect of antibiotics

which membrane is most selective in gram negative bacteria?

the inner cell membrane

which kinds of cells have an LPS layer?

gram negative

endotoxin

a toxin that is present inside a bacterial cell and is released when the cell lyses

significance of LPS layer

Lipid A acts as an endotoxin

mycoplasma

no cell wall, very small

archaea

cell wall made of pseudomurein

pseudomurein

a substance similar to peptidoglycan that is found in the cell wall of archaea

mycobacteria

acid fast bacteria, hydrophobic+complex cell envelope, waxy

capsule

lays outside the cell envelope, hides virulence from antibodies. GENETICALLY CODED

slime layer

loose, water-soluble "slime" produced by some bacteria in nutrient rich conditions. NOT genetically coded

biofilm

A surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation. GENETICALLY CODED

FtsZ protein function

determines center of the cell, makes "Z-ring" during cell division

in which cells is FtsZ present?

ALL prokaryotic cells

MreB protein

creates "scaffolds" for where cell wall synthesis is occuring

in which cells is MreB present?

rod shaped cells

CreS protein

curves ONE inner side of crescent shaped bacteria

in which cells is CreS present?

SOME rod shaped cells

septation

the creation of a new cell wall in the middle of a cell

septum

where new cell envelope development is occurring

divisome

a complex of proteins that directs cell division processes in prokaryotes

nucleoid

area wherever prokaryotic chromosomes are

DNA domains

independent loops of DNA in prokaryotes

ori site

origin of replication; attached to cell equator

how many chromosomes do prokaryotes have?

one circular chromosome

DNA gyrase

relieves DNA supercoiling

polysome

a series of ribosomes translating a single transcription

where are proteins synthesized in prokaryotic cells?

cytosol

replisomes

complex of several enzymes and proteins that coordinate replication

when the first replisomes reach the terminator sequence…

new replisomes start synthesizing DNA from two new ori sequences

the end of DNA replication triggers…

"Z-ring" formation and septation

what factors make prokaryotes grow so quickly?

1. small chromosome

2. polysome formation

3. fast cell division

fimbriae

attachment structures on the surface of some prokaryotes, many in number

pili

specialized structures on the surface of some prokaryotes, few in number

twitch motility

pili extend, attach, and pull the cell forward

polar aging

cell poles differ in their origin and age

old cell walls are susceptible to cell lysis, WHY?

over time, cell wall material degrades

Caulobacter stalks

bacteria become immobile until conditions become unfavorable; then, the stalk turns into a flagellum

autotrophy

produce their own food

lithotrophy

obtain electrons from chemical oxidation

phototrophy

obtain electrons from light

thylakoids

cell membrane foldings that are packed with photosynthetic pigment

gas vacuoles

protein-covered cylinders that maintain buoyancy

what kind of bacteria would NOT have gas vacuoles?

lithotrophs (gas vacuoles change the bacteria's buoyancy depending on their access to light)

carboxysomes

organelles for autotrophs that concentrate enzymes for INORGANIC carbon fixation (RuBisCO)

magnetosomes

magnetic storage inclusions, acts as a compass for the prokaryote, pulling the bacteria north/south, and DOWN

metachromatic granules

phosphate storage

polysaccharide granules

glycogen and starch storage

PHB

polyhydroxybutyrate, a lipid storage material

sulfur granules

insoluble sulfur as a byproduct of sulfur metabolism

nanotubules

intercellular connections that pass material from one cell to the next