Microbiology - CHAPTER 4

Describe other more unusual shapes of bacteria

1. Coccobacillus (short, plump) 2. Vibrio (gentle curved) 3. Spirillum (slightly curled or spiral shaped cylinder) 4. Spirochete (resembles a spring) 5. Branching Filaments (resembles tree branches)

Describe the three major shapes of bacteria

1. Coccus (spherical or ball shaped) 2. Bacillus (cylindrical, termed a rod) 3. Spirillum (spiral shaped)

Name four divisions ending in -cutes and describe their characteristics

1. Gracilicutes - Taxonomic category of bacteria that have gram-negative envelopes 2. Firmicutes - Taxonomic category of bacteria that have gram-positive cell envelopes 3. Tenericutes - Taxonomic category of bacteria that lack cell walls 4. Mendosicutes - Taxonomic category of bacteria that have unusual cell walls; archaea

Identify at least four structures that some, but not all, bacteria possess

Cell Wall Flagellum Pilus Fimbriae (S layer, fimbriae, outer membrane, cell wall, actin cytoskeleton, pilus, capsule, inclusion/granule, bacterial microcompartment, plasmid, flagellum)

Identify five structures that may be contained in bacterial cytoplasm

Complex mixture of sugars, amino acids, and salts Also contains chromatin, ribosomes, granules, and fibers that act as the cytoskeleton

List the structures ALL bacteria possess

Cytoplasmic (cell) Membrane Bacterial chromosome or nucleoid Ribosomes Cytoplasm

List some differences between archaea and bacteria

Distinguishable by type of cell walls and plasma membranes BACTERIA: unique compound called peptidoglycon in their cell walls. ARCHAEA: have a unique phosphlipids in their membranes. Hydrocarbon tails of the phospholipids contain isoprene.

- Pilus

External appendage used for drawing another bacterium close, in order to transfer DNA to it

- Frimbriae

Fine hairlike bristles extending from cell surface; help in adhesion to other cells/surfaces

Differentiate between the two main types of bacterial envelope structure

GRAM POSITIVE: thick cell wall - two layers GRAM NEGATIVE: three layers - outer membrane, thin cell wall, cytoplasmic membrane

Discuss why gram-positive cell walls are stronger than gram-negative cell walls.

Gram-positive cell walls are made of much thicker peptidoglycan than Gram-negative cell walls

Name a substance in the envelope structure of some bacteria that can cause severe symptoms in humans.

In Gram-negative bacteria, the outer membrane contains lipopolysaccharide which contain endotoxins that can cause fever and shock in humans

Differentiate between Bergey's Manual of Systematic Bacteriology and Bergey's Manual of Determinative Bacteriology

Systematic information will continue to be found in Bergey's Manual Of Systematic Bacteriology, with the Determinative manual serving as a reference to aid in the identification of unknown bacteria

- Cytoplasmic (cell) Membrane

a thin sheet of lipid and protein that surrounds the cytoplasm and controls the flow of materials into and out of the cell pool

- Bacterial chromosome or nucleoid

composed of condensed DNA molecules. DNA directs all genetics and heredity of the cell and codes for all proteins

- Ribosomes

makes proteins (particles composed of protein & RNA)

Provide at least four terms to describe bacterial arrangements

1. Tetrads (groups of four) 2. Staphylococci (irregular clusters) 3. Streptococci (chains of a few to hundreds) 4. Sarcina (cubical packet of 8, 16, or more cells)

- Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

- Flagellum

Long external appendage attached that holds a long rotating filament. Movement pushes the cell forward providing mobility

Explain how a flagellum works in the presence of an attractant

Moves in response to chemical signals by chemotaxis, runs and tumbles

- Cell Wall

Rigid casing that provides structural support and shape for the cell

Detail the causes and mechanisms of sporulation and germination

Sporulation is the process of a bacterium becoming a spore while germination is the process of germinating; The beginning of vegetation or growth from a seed or spore; the first development of germs, either animal or vegetable