The two most common bacterial arrangements are Staph- and Strep-. Staph- is a non-symmetrical arrangement like a cluster of grapes. Strep- indicates a chain of bacteria.

The three most common bacterial shapes are listed below.

Coccus—round or oval

Bacillus—rectangular or rod-shaped

Spirilla (spirochete)—spiral

By breaking down names into arrangement and shape, students can predict or identify the appearance of an organism by its name. In the example Staph indicates arrangement in a chain. Coccus indicates round or oval in shape. Therefore, Staphylococci are round or oval-shaped organisms arranged in a cluster.

Aldehydes are powerful, toxic chemicals which work by denaturing DNA and RNA (nucleic acids).

Modern antibiotics are less toxic and work by disrupting cells' production of ribosomes. Common household cleaners, containing chlorine, work by oxidizing cell membranes. Older antibiotics, such as penicillin, work by dissolving cell walls. These modes of destruction are also known as mechanisms of cell death.

Spores can survive most methods of control and are resistant to cold and heat. Pasteurization is a heating process that destroys some pathogenic microorganisms in foods and beverages, but does not kill spores. Boiling is not considered a reliable lethal control because the destruction of bacterial spores cannot be guaranteed. Cold temperature is a non-lethal means of microbial control that can slow multiplication or induce stasis, but cold is only effective while conditions are maintained.

Incineration is the use of extreme temperature to reduce matter to ash and is an effective means of sterilization.

Detergents, or soaps, are non-lethal microbial controls. They emulsify lipids and oils, making it easier to wash them away. The action of washing away substances is strictly a mechanical mode of action. Detergents provide only static control, and have no killing power.

Prokaryotes create their own proteins, which means that ribosomes are present in the cell. Viruses, however, rely on the ribosomes of the host cell in order to create proteins. This means that ribosomes are not present in viruses, but are present in prokaryotes.

DNA and RNA will both be found in prokaryotes. Some viruses will contain DNA, while others will contain RNA. Attachment proteins allow viruses to bind to cell membranes, but also can allow one cell to bind to another.

Recall that bacterial ribosomes contain a 30S and a 50S subunit. The ribosome itself is a 70S ribosome, as the combination of the two subunits results in a smaller mass than the two separate units. Eukaryotic ribosomes contain a 40S and 60S subunit and form an 80S ribosome.

Flagella are used for mobility by both prokaryotes (bacteria) and eukaryotes. In humans, you can find these structures in sperm cells, which are propelled by the motion of flagella. Similarly, bacterial cells move through the environment with the aid of flagella. The key difference between a bacterial and eukaryotic flagellum is its composition. Bacterial flagella are made up of a protein called flagellin, whereas eukaryotic flagella are made up of microtubules, formed from the protein tubulin.

Similar to eukaryotes, bacterial cells are in accordance with the central dogma of molecular biology. The flow of genetic information involves replication, transcription, and translation. Bacterial cells have to replicate their genetic material (replication), undergo transcription to convert DNA to mRNA, and go through translation to produce proteins from the mRNA.

Bacterial cells do not undergo mitosis or meiosis. Cell division can occur through other modes, such as binary fission. Since bacteria lack nuclei and other complex structures, their processes for cellular division are much more abbreviated and do not follow the same steps as eukaryotic mitosis.

First, remember that all bacterial cell walls contain peptidoglycan. The difference between gram-positive and gram-negative bacterial cell walls rises from the composition of peptidoglycan. Gram-negative bacteria appear pink when observed through a microscope, not purple. Also, gram-negative bacteria have thinner cell walls than their counterparts.

Gram-positive bacteria have half as many cell membranes as gram-negative bacteria. This is true because gram-negative bacteria contain an extra cell membrane outside their cell wall. Gram-negative bacteria have two cell membranes, whereas gram-positive bacteria only have one.

If you place a cell in a hypotonic solution it means that the solution contains less solute (and more water) than the cell’s cytosol. Recall that osmosis causes water to go from a region of high water content (few solutes) to a region of low water content (more solutes).

In this case, the water will go from the solution to the inside of the cell, causing the cell to swell.