Microbiology

Microbiology Study Guide

2.2 Growth and Nutrition of Microorganisms Patterns of Nutrition Nutrients that are acquired from the environment are used for growth and metabolism. All living things have an absolute requirement for these bio-elements that include carbon, oxygen, hydrogen, phosphorus, potassium, nitrogen, sulfur, calcium, iron, sodium, chlorine, magnesium, and a few other elements. Microbes do have significant variances when it comes to the source, chemical form, and the amount they will need. Stages in Normal Growth Curve A population of bacteria does not maintain its potential growth rate and does not double endlessly because, in most systems, numerous factors prevent the cells from continuously dividing at their maximum rate. Quantitative laboratory studies indicate that a population typically displays a predictable pattern or growth curve over time. Amethod traditionally used to observe the population growth pattern is a viable count technique, in which the total number of live cells is counted over a given time period. Essential Nutrients Essential nutrients are any molecular or elemental form of nutrient that is required by organisms. There are two categories of essential nutrients, macro-nutrients and micro-nutrients. • Macro-nutrients are needed in larger amounts. They are used to help with cell structure and the cell’s metabolism. Examples are proteins and carbohydrates. • Micro-nutrients, or trace elements, are needed in a lot smaller amount. They help enzyme function and help to maintain protein structure. They include elements such as zinc, manganese, and nickel. The sources of common essential nutrients are referred to as “CHNOPS,” standing for: • Carbon • Hydrogen • Nitrogen • Oxygen • Phosphorous • Sulfur Organisms and Energy Pathways Organisms can be divided into heterotrophs, autotrophs, and chemoautotrophs on the basis of energy pathways. The majority of carbon involved in the structure and metabolism of cells is organic.

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