Chapter 4

Endospores

"resting cells" formed by when essential nutrients are depleted, certain gram-positive. when released into environment they can survive heat, lack of water and exposure to toxic chemicals.

Flagellum 3 basic parts

Filament, flagellum and basal body

Peritrichous

Flagella distributed on entire cell

Polar

Flagella on both ends

Eukaryotic cell division

Involves mitosis, chromosomes replicate and identical set is distributed into each of 2 nuclei

Extra cellular polymeric susbstance (EPS)

Is a glycocalyx that helps cells in a biofilm attach to each other. Protects the cell and helps communicate and helps cell survive by attaching to various surfaces.

Flagella

Prokaryotic cells have them. Whip-like structures that help with cell movemen

Glycocalyx

(Sugar coat)The external surface of a plasma membrane that is important for cell-to-cell communication. Its a layer of material containing susbstantial amounts of sticky carbohydrates. Strengths the surface and helps attach cells together. Composed of polysaccharide, polypeptide or both. If unorganized and loosely attached to cell wall, it is decribed as a slime layer. Also know as capsules.

Osmotic Pressure

(the force in which the solvent moves) the pressure needed to stop the movement of water across the membrane. - is the pressure required to prevent the movement of pure water into a solution containing some solutes.

Gram stain

A staining method that distinguishes between two different kinds of bacterial cell walls.

Glidin motility

Another motility for glidin. Provides mobility for microbes to travel with lower water content, such as biofilms and soil.

Bacteria that lack flagella?

Atrichous

twitching motility

Atype of motility for pilin, retracts power stroke. Pilin subunit disassembled

Gram-negative cell wall

Contains thin layer of peptidoglycan and an outer membrane. No teichoic acid. It is in the periplasm gel like fluid between the outer membrane and the plasma membrane. Because they have only a small amount of peptidoglycan they may may easily have mechanical breakage.

Eukaryotic cell covered by glycocalyx are _____ bonded to __________ and ___________ in the ___________, forming ______ and _______ that anchor the _______

Covalently bonded to proteins and lipids in the plasma membrane. Forming glycoproteins and glycolipids that anchor the glycocalyx to the cell.

Binary fission

DNA is copied and the cell splits into two cells. Binary, fewer structures and processes than eukaryotic cell division

Protozoa

Do not have a typical cell wall; instead, they have a flexible outer protein covering called pellicle

Lipid A

Embedded in the top layer of the outer membrane. When gram-negative die they release lipid a witch functions as an endotoxins causing symptoms.

Eukaryotic cells do no contain ________.

Eukaryotic cells do not contain peptidoglycan, the framework of prokaryotic cell wall. Antibiotics act against peptidoglycan and therefore do not affect human eukaryotic cells.

O polysaccharide

Extends outward from the core polysaccharide and is composed of sugar molecules. Useful for distinguishing species of gram-negative bacteria.

gram positive cell wall

Gram-positive bacteria that consists of many layers of peptidoglycan (it's thick). Contains techoic acid - primarily of an alcohol(glycerol or ribitol)and phosphate. In acid-fast cells, contains mycolic acid. Sensitive to lysozyme.

Passive Process

In passive, substances cross the membrane form an area of high concentration to an area of low concentration. without any ATP by the cell. Passive Process includes simple diffusion.

Eukaryotic cells

Most eukaryotic cells have cell walls. Plants, fungi and algea. Algae has cell walls consisting of the polysaccharide cellulose.(as do plants) fungi cell wall contain (some) cellulose but its principal structure is polysaccharide chitin (nag)

Prokaryotic cells

No DNA, One circular chromosome, not in a membrane. No histones. No organelles. Peptidoglycan cell walls. Divide by Binary fission.

lipopolysaccharide (LPS)

Of the outer membrane contains lipids and carbohydrates and consist of 3 components. 1. Lipid A 2. A core polysaccharide 3. O polysaccharide

Philin

Similar to flagella but divided in two. One fimbriae and pili, both have very different functions.

Fimbrae

Similar to flagella but shorter, smaller and consists of a protein called pilin. Can occur at the poles of the bacterial cell. They adhere to each other and surface. Result form biofilms and allow attachment. Play role in I initiation of disease.

Passive and Active process

materials move across plasma membrane of both prokaryotic and eukaryotic cells by two kinds of processes: passive and Active.

eukaryotic cell

plants, algae and fungi. carbohydrates.

A becterial cell may be subjected to any kind of three osomotic solutions:

1. Isotonic solution 2. Hypotonic solution 3. hypertonic solution

Endoflagella

Also known as axial filaments. Spirochete a group of bacteria move by means of endoflagella, bundles of fibrils. Spirals around the cell. Structure similar to flagella. Move in spiral motion.

Mycoplasma

Among the prokaryotes, certain types of cell have no cell walls or little material. Mycoplasma are included among these. Mycoplasma are the smallest known bacteria that can grow and reproduce outside living host cells. No cell wall. their plasma membrane has lipids called sterols. Sterols are thught to help protect them from Lysis (rupture)

Gram stain mechanism

Based on differences in the structure of the cell wall of gram positive and gram negative bacteria and how each reacts to various reagents. cell walls are not sensitive to penicillin.

Gram negative bacteria outer membrane

Consists of lipopalysaccharides, lipoprotein and phospholipid. Special functions: strong negative charge evades phagocytes and the actions of colmpiment (lyes cells/ promotes phagocytosis) 2 components of the defenses of host. Also provides barrier to antibiotics but not to all because it still needs nutrients to maintain alive.

Pili

Involved in motility. Extensions on the outside of cell that enable it to stick to other cells

Core polysaccharide

Is attached to lipid A and contains unusual sugars. It has a structural role. Provides stability.

Capsules protect

Protect pathogenic bacteria from phagocytosis.

Motility

The ability of organisms to move by itself. Bacteria can control the flagella causing different movements.

Peptidoglycan

The bacterial cell wall is composed of a macromolécular network called peptidoglycan. Consists of disaccharides attached by polypeptides that form lattice to protect the entire cell. The disaccharide portion is made up of monosaccharides called n-acetylglucosamine. (NAG)And n-acetylmuric acid (NAM) which are related to glucose.

Crystal violet stain

The primary stain, stains both gram(+/-). when iodine is added it form large crystals that are to big to escape through the cell wall.

Eukaryotes are

Their DNA is in the nucleus, seperated from the cytoplasm by the nuclear membrane. DNA is in multiple chromosomes. Membrane enclosed organelles: mitochondria, endoplasmic reticulum, golgi complex, lysosomes sometimes chloroplast.

teichoic acid

There are two classes: lipoteich acid which span the peptidoglycan layer and links to plasma membrane and wall teichoic acid which is linked to peptidoglycan layer. Techoic acid regulates the movement. Make it possible to ID gram positive bacteria.

Inclusions

Within the cytoplasm of prokaryotic cell are several kinds of reserve deposits.

group translocation

a special form of active transport that occurs exclusively in prokaryotic, the substance is chemically altered during transport across the membrane. it requires energy supplied by high-energy phosphate compounds, such as PEP.

stain - Gram Negative

alcohol dissolves the outer membrane of gram negative cells and even leaves small holes in peptidoglycan layer through wich crystals violet-iodine diffuses(washes out). negative bacteria lacks color after the alcohol wash, the addition of safarin turns the cells pink or red.

Selective Permeability

allows passage of some molecules. the permeability depends on several factors: large molecules cannot pass because to big. small can pass. ions pass very slowly. substanance that dissolves in lipids can pass through

stain - Gram positive

application of alcohol dehydrates the peptidoglycan of gram-positive cells to make it more impermeable to the crystal violet-iodine.

Why are enzymes in the membrane?

because bacteria don't have organelles.

Lophotrichous

cluster of flagella at one or both ends

Amphitrichous

flagella at both poles of the cell

L forms

if proteus loose their cell wall and swell into irregulary shaped cells call L forms. develop in response to penisilun or lysosyme.

hypertonic solution

is a a medium having a higher concentration of solutes than inside the cell has. most bacterial shrink and collapse or plasmolyse because water leaves the cells

Isotonic solution

is a medium in which overall concentration of solutes equals that found inside a cell.

Osmotic lysis

is a rupture of protoplasts and spheroplasts that burst in pure water because the water molecules from the surrounding fluid rapidly move into and enlarge the cell which has a much lower internal concentration of water.

Plasma Membrane

is a thin structure lying inside the cell wall and enclosing the cytoplasm of the cell. phospholipids and protein molecules move freely in the membrane. selective

Simple Diffusion

is the movement of a solute from an area of high concentration to an area of low concentration. the movement continues until the molecules or ions are evenly distributed. Called equilibrium. Oxygen and carbon dioxide.

active transport

is used when a bacterial cell is in an environment in which nutrients are in low concentration, to accumulate the needed substance. the cell uses energy in the form of ATP to move substance across the plasma membrane.

spheroplast

is when lysosyme is applied to gram-negative cells, the cell wall is not completely destroyed. the remaining outer wall layer is speroplast.

Archaea

lack cell walls or have walls composed of polysaccharides and protein but not peptidocglycan. the walls do contain substance similar to petiddoglycan call pseydomurein. Pseydomurein contains N-acetyltalosaminuronic acid instead of NAM and lack the D-amino acid found in the bacterial walls. archea cannot be gram stain but appear gram-negative because they dont contain peptidoglycan.

plasmolysis

lysist of the plasma - breaking down of the cell.

hypotonic solution

outside the cell is a medium whose concentration of solutes is lower that that inside the less.

magnetosomes

protect cell from hydrogen peroxide accumulation. bacteria uses magnetosomes to move downward until it reaches a suitable environment. composed or iron oxide.

facilitated diffusion

solute combines with a transporter protein in the membrane. integral proteins(transporters or permeases) function as channels/carriers that facilitate the movement of ions or large molecules accross the membrane. the cell does not expand. small transporters allow the passage of small ions unlike simple diffusion. these trans. are common in prokaryotes.

Active process

the cell must use energy (ATP) to move substance from areas of low concentration to areas of high concentration.

fluid mosaic model

the dynamic arrangement of movement between phospholipids(move and rotate laterally) and proteins in the membrane do not cause rupture and are able to move to due their functions.. maintains membrane shape. membrane must be a viscous as olive oil, which allows the membrane proteins to move freely and perform their functions without destroying the structure.

Osmosis

the movement of water across selectively permeable membrane from one are of high water concentration to area of lower concentration. water molecules may pass through plasma membranes by moving through the lipid bylayer by simple diffusion.

Acid-Fast stain

used to identify all bacteria of the genus Mycrobacterium and pathogenic species of nocardia. these bacteria contain high concentration of a hydrophobic waxy lipid( mycolic acid) in their cell walls that prevent s the uptake of dyes including those use in gam stains. acid fast bacteria retains the color red of carbolfuchism because it is more soluble in the cell eall mycolic acid than in alcohol.

Protoplast

wall-less cell - the cellular contents that remain surrounded by the plasma membrane may remain intact if lysis does not occur. - termed protoplast.