Books and Articles by Jennifer Stearns

The way that DNA encodes the instructions for proteins is through a set of four molecules called bases, each of which represents a letter of the genetic code (A = adenine, C = cytosine, G = guanine, and T = thymine). The bases are made of carbon and nitrogen rings and are bound to a sugar and a phosphate to form a nucleotideThe nucleotides are connected together to form a long chain with the bases pointing out.

When you're studying microbiology, you need to know the key differences between the three domains of life, how scientists name and classify organisms, and how scientists identify microorganisms.Differences among bacteria, archaea, and eukaryotic microorganismsThere are three domains of life: bacteria (also known as eubacteria), archaea, and eukarya.

Prokaryotic cells come in many different shapes and sizes that you can see under a microscope. A description of the shape of a cell is called the cell morphology. The most common cell morphologies are cocci (spherical) and bacilli (rods).Coccibacillus are a mix of both, while vibrio are shaped like a comma, spirilla are shaped like a helix (a spiral, sort of like a stretched-out Slinky), and spirochetes are twisted like a screw.

Cells can use sugars for all sorts of other things. For example, the backbone of peptidoglycan, a major component of the bacterial cell wall, is made of sugars. Hexoses are six-carbon sugars like glucose, and pentoses are five-carbon sugars like ribose. When hexoses need to be made, they’re synthesized with gluconeogenesis using intermediates from glycolysis and the citric acid cycle.

Cell division is a process that is necessary for microbial growth. It starts with a single cell that stretches in size until it separates into two separate cells, in a process called binary fission. Each new cell is equipped with the right amount of proteins, nutrients, and importantly, the chromosome, to function as an independent cell.

Scientists have been peering at microorganisms through microscopes for centuries. For some, the shape of their cells can offer clues to their identity, but it’s often necessary to use stains that tell you a bit more about their cellular structure. Simple stains contain a single dye that can bind to microbial cells and show off their basic structure.

Unlike the physical requirements where a specific range or concentration is necessary for optimum growth, the chemical requirements just need to be present in the environment and a microbe will use what it needs. Microbes use compounds containing the following elements and vitamins to make everything in the cell including membranes, proteins, and nucleic acids: Carbon: Carbon is necessary for all life.

The breakdown of compounds by respiration releases much more energy than does the breakdown of the same compounds by fermentation. This is because the complete reduction of the products of fermentation isn’t possible without oxygen or oxygen substitutes to act as terminal electron acceptors. The star of this phenomenon is the electron transport chain, which involves several electron acceptors positioned within a membrane in order of reducing power so that the weakest electron acceptors are at one end of the chain and the strongest electron acceptors are at the other end.