Microbiology - Chapter 3: Bacteria and Archaea (simplify)

Prokaryotes with rod-shaped or cylindrical shape

Bacilli

Spherical or ball-shaped bacteria cell

Can be perfect spheres, ovals, bean- shaped, or pointed variants

Coccus

Spiral-shaped bacteria that can appear as vibrios, spirilla, and spirochete

Spiral

A comma-shaped spiral bacteria

Vibrios

A helical shaped spiral bacteria

Spirilla

Flexible spring shaped spiral bacteria

Spirochete

What are the three bacterial arrangements?

Pairs

Clusters

Chains

Bacterial arrangement known as "diplo"

e.g. diplobacilli or diplococcus

Pairs

Bacterial arrangement known as "staphylo"

e.g. Staphylococci

Clusters

Bacterial arrangement known as "Strepto"

e.g. streptococci or streptobacilli

Chains

Appendage on the outside bacteria cell wall that is use for movement of the cell

Attached to a protein hook and anchored to the membrane by a basal body

Flagella

Surface appendage of a bacterial cell that allows for attachment

Small, bristle-like fibers that protrude off of the surface of the cell

Fimbriae

A long, rigid tubular bacterial surface appendage that provides adhesion and facilitates the transfer of DNA from one bacterial cell to another

"mating bridge"

Pili

What are the four arrangements of bacterial flagella?

Monotrichous

Lophotrichous

Amphitrichous

Peritrichous

Single flagellum

Monotrichous

Small bunches or tufts of flagella

Lophotrichous

Flagella at both ends of the cell

Amphitrichous

Flagella are dispersed randomly over the surface of the cell

Peritrichous

Endoflagella in spirochetes that are anchored to one end of a cell

Rotation causes the cell to move

Axial Filaments

A surface coating of repeating polysaccharide or glycoprotein units that is sticky and protects the cell

Can be a slime layer or a capsule

Glycocalyx

A loose glycocalyx shield that protects from loss of water and nutrients

Slime Layer

A tightly bound glycocalyx layer that is denser and thicker and prevents phagocytosis

Capsule

Single protein linked layer produced by bacteria in hostile environments

Do not grow in nonthreatening conditions

"armor" of the bacteria cell

S-Layer

A mesh-like layer outside the plasma membrane of bacteria that form the cell wall

Provides strength to resist rupturing due to osmotic pressure (lysis)

Peptidoglycan

Structure that lies outside of the cell and is composed of a cell wall, cell membrane, and an outer membrane in some bacteria

Cell Envelope

Fluid mosaic model with a lipid bilayer with embedded proteins

Regulates the passage of nutrients into or out of the cell

Plasma Membrane

The site of cellular respiration and ATP synthesis in bacteria cells

Plasma Membrane

Structure that is the site of nearly all chemical reactions

70-80% water

Contains DNA in the nucleoid

Cytoplasm

Bacteria that exists in the form of a single, circular chromosome

Aggregated in the nucleoid

Contain plasmids

Bacterial DNA

A molecule made of lipids and polysaccharides

Polysaccharides function as signaling molecules and receptors

Lipids are an endotoxin that stimulate fever and shock reactions in gram negative infections

Lipopolysaccharide

Microbial structure that protects bacteria cel against hostile conditions

Exists internally inside the cell, but are on their own when the cell disintegrates

Protect against radiation and chemicals

Endospore

Name for the process of endospore formation

Sporulation

The passive transport of molecules from areas of high concentration to areas of low concentration

Diffusion

Diffusion of water molecules across a membrane

Osmosis

Cell walls with thick sheets of peptidoglycan (20-80 nm thick)

Contain teichoic and lipoteichoic acids which function in cell maintenance and enlargement

Gram Positive Cell Walls

Cell wall with thin sheets of peptidoglycan (1-3 nm thick)

Has an outer membrane and a periplasmic space

Stimulates antibody response (antigen production)

Gram Negative Cell Wall

The space between the cytoplasmic membrane and the outer membrane

Periplasmic Space

Circular pieces of DNA

Plasmids

What are the steps in producing a Gram Stain?

1.) Crystal violet added to smear; all cells purple

2.) Add mordant (Iodine) > stabilizer

3.) Apply alcohol to dissolve lipids and remove dye

4.) Add safranin to the colorless gram negative cells to turn them pink

What does the Gram stain tell you about bacteria?

If the bacteria is positive or negative

Tell us about the cell wall structure of a sample

What does a simple stain tell you about an organism?

The organism's size, shape, and arrangement