Chapter 4

vibrios

(1) a curved or comma-shaped bacterium. (2) when written as a genus, a gram-negative, motile, facultatively anaerobic curved rod.

spirilla

(1) a helical or corkscrew-shaped bacterium. (2) when written as a genus, refers to aerobic, helical bacteria with clumps of polar flagella.

streptococcus

(1) cocci that remain attached in chains after cell division. (2) when written as a genus, refers to gram-positive, catalase-negative bacteria.

lysis

(1) destruction of a cell by the rupture of the plasma membrane, resulting in a loss of cytoplasm. (2) in disease, a gradual period of decline

1. There are three basic shapes of bacteria: coccus, bacillus, and spiral. 2. Based on planes of division, the coccus shape can appear in several distinct arrangements: diplococcus, streptococcus, tetrad, sarcina, and staphylococcus. 3. The bacillus shape can appear as a single bacillus, a streptobacillus, or a coccobacillus. 4. The spiral shape can appear in several forms: vibrio, spirillum, and spirochete.

What are the basic shapes of bacteria and their cellular arrangements (singles, chains, clusters)?

spirochete

a corkscrew-shaped bacterium with axial filaments.

slime layer

a glycocalyx that is unorganized and loosely attached to the cell wall

organelle

a membrane-enclosed structure within eukaryotic cells

plasmid

a small circular DNA molecule that replicates independently of the chromosome

isotonic

a solution in which, after immersion of a cell, osmotic pressure is equal across the cell's membrane

hypertonic

a solution that has a higher concentration of solutes than an isotonic solution

hypotonic

a solution that has a lower concentration of solutes than an isotonic solution

coccus

a spherical or ovoid bacterium

porins

a type of protein in the outer membrane of gram-negative cell walls that permits the passage of small molecules

fimbriae

an appendage on a bacterial cell used for attachment

pili

an appendage on a bacterial cell used for conjugation and gliding motility

capsule

an outer, viscous covering on some bacteria composed of a polysaccharide or polypeptide

staphylococcus

cocci in a grapelike cluster or broad sheet

amphitrichous

having flagella at both ends of a cell

peritrichous

having flagella distributed over the entire cell

pleomorphic

having many shapes, characteristic of certain bacteria

diplobacillus

rods that divide and remain attached in pairs

streptobacillus

rods that remain attached in chains after cell division

osmosis

the net movement of solvent molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration

sporulation

the process of spore and endospore formation; also called sporogenesis

germination

the process of starting to grow from a spore or endospore

peptidoglycan

the structural molecule of bacterial cell walls consisting of the molecules N-acetylglucosamine, N-acetylmuramic acid, tertrapeptode side chain, and peptide side chain

1) add color; add primary stain (which is crystal violet) 2) add mordant (which is iodine) 3) add the decolorizer (which is ethanol) 4) adding a counter stain (which is Safranin-pink) *Gram-positive will always be purple *Gram-negative will always be pink

Briefly describe what happens at each stage of the Gram stain and how each type of organism (+ and -) would look during each stage.

1) prokaryotic and eukaryotic cells are similar in their chemical composition and chemical reactions 2) prokaryotic cells typically lack membrane-enclosed organelles (including a nucleus) 3) peptidoglycan is found in prokaryotic cell walls but not in eukaryotic cell walls 4) eukaryotic cells have a membrane-bound nucleus and other organelles

In what ways are prokaryotic cells different from eukaryotic cells? In what ways are they similar?

spiral

Spirillum: (1) a helical or corkscrew-shaped bacterium. (2) when written as a genus, refers to aerobic, helical bacteria with clumps of polar flagella. Spirochete: a corkscrew-shaped bacterium with axial filaments.

bacillus

any rod-shaped bacterium

diplococcus

cocci that divide and remain attached in pairs

matrix

fluid in mitochondria

cristae

folding of the inner membrane of a mitochondrion

monotrichous

having a single flagellum

monomorphic

having a single shape; most bacteria always present with a genetically determined shape

taxis

movement in response to an environmental stimulus

active transport

net movement of a substance across a membrane against a concentration gradient; requires the cell to expand energy

motility

the ability of an organism to move by itself

diffusion

the net movement of molecules or ions from an area of higher concentration to an area of lower concentration