microbiology midterm

Exhibit different shapes within the culture.

Spherical organisms

Spherical grape-like clusters.

Cocci divided along 3 perpendicular axes.

Rod shape

Short helix, bend rod shape.

Longer helical cell, flexible and changes its shape during movement.

Long helical cell that's rigid and unbending.

• Gram positive bacteria have more peptidoglycan layers. Has teichoid acidand teichuronic acid.
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Multicellular rod-shape organisms that produce long filaments containing many cells.

Multicellular shape encountered in cyanobacteria. Superficially resembles a chain, adjoining cells have a much spatial and physiological relationship than the other cells in a chain.

DNA is released into the environment by lysis of one organism and is taken up by another.

Cell-to-cell contact between two closely related bacteria.

Prokaryotic viruses are involved in transferring DNA from one to another.

Resting stage unique stage unique to bacteria that's formed within the cell.

• -Gram positive bacteria.
• -Allow bacterium to survive extended periods of desiccation and high temp, UV radiation and disinfection.

Composed of extracellular polymeric substances (EPS). Physical barrier that protects the cell from the external environment.  Prevents virus attachments and infection. Helps with attachment to surfaces.

Move by a type of motility called gliding. Requires that the organism remain in contact with a solid substrate. Gliding bacteria produces an EPS termed "slime," part of which is lost in the trail.

Sheathed bacteria produce a much denser and highly organised  external later, or sheath.  Sheath bacteria form filamentous chains that protect against the turbulence in water.

Also called protein jackets and are often highly textured surfaces. May function in place of a cell wall or may help bacterial viruses adhere.

When a bacteria has a single flagella on one end.

• Behavior towards a specific compounds.
• Positive - it is attracted to the molecule.
• Negative - it is repelled by the molecule.