Chapter 1 — Identification & Characterization

Phenotypic identification

Identifying microbes from observable traits, such as shape, staining, growth patterns, and metabolism.

Genotypic identification

Identifying microbes by examining their DNA or other genetic information.

Coccus (plural: cocci)

Spherical or oval bacterial cell shape.

Diplococcus

Cocci arranged in pairs.

Streptococcus arrangement

Cocci arranged in chains.

Tetrads

Cocci arranged in groups of four.

Sarcinae

Cocci arranged in cube-like packets.

Staphylococcus arrangement

Cocci arranged in grape-like clusters.

Bacillus

Rod-shaped bacterial cell.

Diplobacillus

Bacilli arranged in pairs.

Streptobacillus

Bacilli arranged in chains.

Spirillum

A curved or spiral-shaped bacterium with a relatively rigid spiral form.

Spirochete

A tightly coiled, flexible spiral-shaped bacterium.

Vibrio

A comma-shaped bacterium.

Peptidoglycan

A polysaccharide-and-peptide material in bacterial cell walls that provides structural strength.

Gram-positive cell wall

Thick peptidoglycan layer; cells typically retain crystal violet and appear violet in a Gram stain.

Gram-negative cell wall

Thin peptidoglycan plus an outer membrane; cells typically appear pink or red after counterstaining.

Motile organism

An organism capable of self-powered movement using its own metabolic energy.

Non-motile organism

An organism that does not move independently under its own power.

What does turbidity in liquid medium usually indicate?

Cloudiness caused by microbial growth.

DNA sequencing

Determining the order of nucleotides in a DNA molecule.

Nucleotide

A basic molecular building block of nucleic acids such as DNA and RNA.

DNA

is usually double-stranded and stores genetic information long-term

RNA

is usually single-stranded and commonly serves as a working copy in gene expression.

PCR (polymerase chain reaction)

A method that amplifies a selected DNA segment, producing many copies.

DNA fingerprinting

Using distinctive DNA patterns to help identify or distinguish individuals or samples.

Taxonomy

The science and practice of naming, classifying, and organizing organisms into groups based on shared characteristics.

Bacteria: broad traits

Usually unicellular prokaryotes; bacterial cell walls commonly contain peptidoglycan.

Archaea: broad traits

Unicellular prokaryotes that lack bacterial peptidoglycan; some live in extreme environments. Their cell walls, when present, are made of other materials.

Protozoa: broad traits

Unicellular, animal-like eukaryotes; many reproduce by binary fission.

Binary fission

Asexual cell division in which one cell divides into two daughter cells.

Algae: broad traits

Photosynthetic organisms that are not classified as plants; examples in the notes include Spirulina and Chlorella.

Fungi: broad traits

Eukaryotes that may be unicellular or multicellular and obtain energy and carbon from organic compounds.

Yeast

are generally unicellular and may reproduce by budding;

Mold

grows as filaments and commonly produce spores.

Virus: basic composition

Genetic material surrounded by a protein coat; viruses require host cells to replicate.

Prion

An infectious protein without DNA or RNA that can cause normal proteins to misfold.

What does prokaryotic mean?

A cell type without a true nucleus.

Eukaryotic cells

Cells that have a true nucleus enclosed by a nuclear membrane and contain membrane-bound organelles.

Prokaryotic cells?

Cells that do not have a true nucleus or membrane-bound organelles. Their DNA is located in the nucleoid region.

Examples of eukaryotic organisms?

Animals, plants, fungi, and protists.

Examples of prokaryotic organisms?

Bacteria and Archaea.

Tue nucleus

A nucleus enclosed by a nuclear membrane that contains the cell's DNA.