microbiology exam chapter 4

Epulopiscium and Thiomargarita

these organisms are large to be seen with the naked eye

pleomorphie

they alter their morphology in response to environmental conditions.

bacteriocins

are proteinaceous toxins encoded in plasmids that inhibit growth of other bacterial strains.

ribosomes

are sites protein synthesis in cells. composed of two unequal subunits consisting of polypeptides and ribosomal RNA.

membranes of archaea

Archaeal membranes are lipid monolayers whereby the hydrophilic group is a polysaccharide rather than a phosphate group. the cytoplasmic membranes of archaea lack the fatty acids found in bacteria and eukaryotes instead have side chains of repeating units of isoprene. in contrast to the lipids in bacteria and eukaryotes, in which ester linkages bond the fatty acid to the glycerol molecule, lipids from archaea have ether linkages.

peritrichous

flagella that project in all directions

spirochete

flexible spiral-shaped bacterium

resistance plasmids

confer resistance to antibiotics or poisons

nucleoid

contain bacterial chromosome

gram negative bacteria

contain only about 10% of peptidoglycan and outer membrane

cytoplasmic

a barrier separating the inside of the cell and the cytoplasm from the environment. the cytoplasmic membrane also known as the plasma membrane or the cell membrane is selectively permeable allowing certain molecules and ions to enter or leave the cell, it functions in energy production, and to harvest light energy in photosynthetic prokaryotes

sarcina

a cube like packet of eight cocci meaning a bundle

glycogen

a polymer of glucose and poly-Bi hydroxybutyric acid a lipid- like compound are storage depots of carbon and energy

polyphosphate granules

can be degraded and used as sources of phosphate for nucleic acid and phospholipid synthesis.

mycoplasma

the smallest prokaryotes are members of the genus. lack cell wall has no specific shape

caulobacter

Appendaged bacteria possess extensions of their cells as long tubes and stalks, and filamentous bacteria of the genus Norcardia form long, thin cells

fertility plasmids

carry instructions for conjugation a process of transferring genes from one bacterial cell to another.

monotrichous

cell with a single flagellum

lophottrichous

cells have a tuft of flagella at only one end of the cell

amphitrichous

cells have flagella at both ends

core

center of the endospore- contains the cell wall , cytoplasmic membrane, cytoplasm, and nucleoid.

thiobacillus

deposit sulfur granules in the cell, where they serve as an energy reserve

thiomargarita namibiensis

even larger bacterium lives in the ocean sediments off the cost of namibia. that name means sulfur pearl due to the microscopic granules of sulfur that cause the bacterial to glisten like a thin string of pearls.

virulence plasmids code

for enzymes for enzymes or toxins that enhance the pathogenicity of the bacterium

magnetosomes

found in aquatic bacteria that grow at very low oxygen concentration. the function of magnetosomes is to guide aquatic cells toward the sediments where oxygen levels are lower.

periplasmic space

gel like matrix between the cytoplasmic membrane and the outer membrane. it contains high concentrations of digestive enzymes and proteins involved in transport

flagella

long thin protein projections that extend from the cell surface to provide motility. the filament of bacterial flagella is composed of subunits of a protein called flagellin. flagellum may be either clockwise or counter clock wise. If

vibrios

look like curved rods.

cortex

made up of loosely cross-linked peptidoglycan surrounds the core

Cocci

may remain in pairs called diplococci after cell division. If cocci remain chains they are termed streptococci.

Morphology

refers to the shape of an organism. An spherically shaped bacterium is known as a coccus, a term derived from the Greek word kokkos, meaning," berry". cocci may remain in pairs called diplococci after cell division.

inclusion granules

reserve deposits often found within the cytoplasm of prokaryotes.

Spiral

shaped patterns are called spirilla. A rigid spiral shaped bacterium is called a spirillum.

cell walls of Archaea

some archaea cell wall is composed of glycoproteins or polysaccharides. the cell walls in archaea function to provide shape and prevent osmotic lysis. some species of archaea lack peptidoglycan in their cell walls and hence are susceptible to the action of lysozyme and penicillin.

spore coat

spore-specific proteins which covers the cortex

glycocalyx

structures consist of polysaccharides and a few consist of polypetides. considered a slime layer when the glycoproteins are unorganized and loosely attached to the cell wall. plays a pivotal role in contributing to bacterial virulence

phototaxis

the ability of organisms to move directionally in response to a light source.

fluid mosaic model

the mosaic of phospholipids and proteins are not cemented in place but rather they can move laterally in the membrane surface.

chemical composition of the cytoplasmic membrane

the plasma membrane consists primarily of phospholipids. The phospholipids in the plasma membrane are arranged in two layers called a phospholipid bilayer. each phospholipid molecule consists of a phosphate head, which hydrophilic(water loving) and hydrophobic fatty acid chains. the hydrophilic portions are exposed to the aqueous external environment cytoplasmic membrane has proteins that aid transport. integral proteins span the entire bilayer while peripheral proteins are anchored to one side of the membrane. proteins of cell membranes may act as carries, channels, enzymes recognition proteins or receptors.

capsule

when the glycocalyx is composed of polysaccharides that are tightly associated with the cell wall.

prokaryote ribosome

is called the 70s ribosome

taxis

is th term for movement in response to a stimulus

cytoplasm

is the fluid contained within the cell where all metabolic processes occur. It consists of substance such as proteins, carbohydrates, lipids, and ions dissolved in water. in prokaryotes, the major structures in the cytoplasm contain the nucleoid ribosomes and inclusion granules

chemotaxis

is the movement of an organism in response to a chemical stimulus.

bacilli

is the plural form of the Latin word bacillus , meaning little rod. Bacilli divide only across their short axis to conserve energy and nutrients. most rods occur singly, but some are arranged into long chains called streptobacilli. some bacilli have a shape that is intermediate between a coccus and a bacillus, such as Haemophilus influenzae.

protoplast

lacking cell wall, assume a spherical shape and are still capable of carrying out cellular metabolism

peptidoglycan

also known as murein is composed of two alternating sugars called N-acetylglucosamine and N-acetylmuramic acid

tetrad

another arrangement of cocci is the tetrad, consisting of four cocci forming a square.

Prokaryotes

are generally smaller and simpler than eukaryotes are able to be structurally simpler because of their small size the smaller the cell the greater its surface volume ratio

plasmids

are small circular molecules of DNA that replicate independently of the chromosome. they do not encode essential genes required for the normal function of the cell but confer certain advantages to the cell.

vibrio cholera

is atypical prokaryote in that it has two chromosomes

gram negative cell wall

gram negative bacterial cell walls consist of 10% peptidoglycan and an outer membrane. unlike gram-positive bacteria the cross links in peptidoglycan are composed of an unusual amino acid called meso-diaminopimelate. gram negative cell wall does not contain teichoic acids. the outer membrance of gram negative cells consist of lipopolysaccharides, lipoproteins and phospholipids. gram negative cell wall can also be an impediment to the the treatment of disease.

gram positive bacteria cell wall

gram positive bacteria is sensitive to the action of lysozyme and penicillin. the enzyme lysozyme found in animal secretions such as tears, saliva, and other body fluids functions as major line of defense against infection by bacteria.

Degradative plasmids

harbor genes that code for enzymes responsible for the catabolism of substances such as toluene and salicylic acid.

borrelia burgdorferi and streptomyces

have linear chromosomes.

Gram positive bacteria

have several layers of peptidoglycan, contains aniontic polysacchride derivative called teichoic acid are partially responsible for the negative charge of the cell surface and they assist in the transportation of ions through the cell wall. Most positive bacteria have cocci lysine have other amino acids that form the crosslinks in the peptidoglycan.

carboxysomes

inclusion bodies found in photosynthetic bacteria such as Thiobacillus, nitrifying bacteria and cyanobacteria. they contain the enzyme ribulose 1, 5- diphosphate carboxylase which is required for carbon dioxide fixation.

Penicillin

inhibits cell wall synthesis by preventing the formation of cross links in the peptidoglycan causing the cell to lyse. This antibiotic is used to treat strep throat infections caused by gram positive bacteria.

staphylococcus

irregular grape like cluster of cells. it is important to note that the words streptococcus and staphylococcus can be used ti describe cell shape and arrangement, of the genus of the bacterium.

Epulopiscium fischelsoni

is a symbiont of the surgeonfish that ranges from 200- 700um in length.

exosporium

outermost layer of the endospore that is made up of protein