Microbiology

Microbiology Study Guide

Chapter 2: Biology of Microorganisms

Objectives 1. Identify the anatomy of different types of cells. 2. Understand the basis of nutrients and growth of microorganisms. 3. Analyze the mechanism of metabolism and conversion of energy. 4. Discuss genetics in regard to variations in population, mutations, recombination, and gene manipulation. 5. Explain the structure and multiplication of viruses and their effects on cells. 2.1 Anatomy Prokaryotic Cells Prokaryotic cells are those cells that do not have a cell nucleus or any membrane-bound organelles, such as mitochondria. There are basically two types of prokaryotic cells: bacteria and archaea. Bacteria Gross morphology: size, shape, and arrangement • Prokaryotes are among the smallest of all organisms; they are usually from 0.5 to 2.0 mm in diameter and have a large surface to volume ratio; they typically display three basic shapes: o Spherical (coccus) o Rod-like (bacillus) o Spiral (vibrio, spirillum, or spirochete) • They can be found in distinctive arrangements: o Division in one plane produces cells in pairs (indicated by the prefix diplo-) o In chains (strepto-) o Division in two planes produces cells in tetrads o Division in three planes produces sarcinae o Random division planes produce grape-like clusters (staphylo-) Overview of structure: • Structurally, prokaryotic cells consist of the following: o Capsule: The outer slimy covering of the cell, often known as slime capsule, helps to protect the cell from outside microorganisms and helps maintain the moist habitat so that the bacteria can stay in their colonies. o Cell membrane o Internal cytoplasm

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