Microbiology For Dummies

Jennifer Stearns, Michael Surette

• Publisher: For Dummies
• Year: 2019
• ISBN:
  9781119544760
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Microbiology
• Index: Biological Sciences

Microbiology For Dummies (9781119544425) was previously published as Microbiology For Dummies (9781118871188). While this version features a new Dummies cover and design, the content is the same as the prior release and should not be considered a new or updated product.

Microbiology is the study of life itself, down to the smallest particle

Microbiology is a fascinating field that explores life down to the tiniest level. Did you know that your body contains more bacteria cells than human cells? It's true. Microbes are essential to our everyday lives, from the food we eat to the very internal systems that keep us alive. These microbes include bacteria, algae, fungi, viruses, and nematodes. Without microbes, life on Earth would not survive. It's amazing to think that all life is so dependent on these microscopic creatures, but their impact on our future is even more astonishing. Microbes are the tools that allow us to engineer hardier crops, create better medicines, and fuel our technology in sustainable ways. Microbes may just help us save the world.

Microbiology For Dummies is your guide to understanding the fundamentals of this enormously-encompassing field. Whether your career plans include microbiology or another science or health specialty, you need to understand life at the cellular level before you can understand anything on the macro scale.

• Explore the difference between prokaryotic and eukaryotic cells
• Understand the basics of cell function and metabolism
• Discover the differences between pathogenic and symbiotic relationships
• Study the mechanisms that keep different organisms active and alive

You need to know how cells work, how they get nutrients, and how they die. You need to know the effects different microbes have on different systems, and how certain microbes are integral to ecosystem health. Microbes are literally the foundation of all life, and they are everywhere. Microbiology For Dummies will help you understand them, appreciate them, and use them.

Part 1

Getting Started with Microbiology

IN THIS PART …

Get a big-picture view of microbiology, including how microorganisms impact our lives in ways that we can and can’t see.

Get acquainted with the history of microbiology from before people knew that microbes existed to our current use of sophisticated techniques to study microorganisms.

Gain an understating of the vastness of microbial lifestyles and how microbes are everywhere living in communities.

Understand microbial diversity and all the different ways these tiny organisms have figured out to get energy from their environments.

Chapter 1

Microbiology and You

IN THIS CHAPTER

Seeing the importance of microbiology

Getting to know microorganisms

Listing the tools used to study microbes

When considering the imperceptibly small, it’s sometimes easy to lose sight of the big picture. In this chapter, we put the science of microbiology into perspective for you as it relates to human lives, as well as how it fits in with the other sciences. The goal is to give you an idea of the kinds of thinking you’ll use throughout the rest of the book. Don’t worry, we explain all that pesky biochemistry and molecular biology as it comes up in each chapter.

Why Microbiology?

The question of why to study microbiology is a good one — the impacts of microorganisms on your life may not be immediately obvious. But the truth is, microorganisms not only have a huge impact but are literally everywhere, covering all the surfaces of your body and in every natural and urban habitat. In nature, microorganisms contribute to biogeochemical cycling, as well as turnover of material in soil and aquatic habitats. Some are important plant symbionts (organisms that live in intimate contact with their host, with mutual benefit for both organisms) whereas others are important pathogens (organisms that cause disease) of both plants and animals.

Although not all microorganisms are bad, the treatment and prevention of the diseases caused by bacteria, viruses, protozoa, and fungi have only been possible because of microbiology. Antibiotics were discovered through microbiology, as were vaccines and other therapeutics.

Other applications of microorganisms include industries like mining, pharmaceuticals, food and beverages, and genetics. Microorganisms are important model organisms for studying principles of genetics and biochemistry.

Many professions require you to learn some microbiology. You may already know this because you’re in a micro class as part of the training for one of them. These professions include but are not limited to

• Nursing
• Medicine
• Clinical laboratory work
• Pharmaceuticals
• Brewing and winemaking
• Environmental engineering

Introducing the Microorganisms

So, what are microorganisms exactly? Microorganisms are actually a diverse group of organisms. The fact that they’re micro isn’t even true of all microorganisms — some of them form multicellular structures that are easily seen with the naked eye.

There are three main kinds of microorganisms, based on evolutionary lines (see Figure 1-1):

• Bacteria are a large group of unicellular organisms that scientists loosely group as Gram-negative and Gram-positive, but in reality there are many different kinds.
• Archaea are another group of unicellular organisms that evolved along with bacteria several billion years ago. Many are extremophiles, meaning that they thrive in very hot or very acidic conditions. Archaea are more closely related to eukaryotes than to bacteria.
• Eukaryotic microorganisms are a structurally diverse group that includes protists, algae, and fungi. They all have a nucleus and membrane-bound organelles, as well as other key differences from bacteria and archaea. All the rest of the multicellular organisms on earth, including humans, have eukaryotic cells as well.
  

  Along with the many eukaryotic microorganisms, the Eukaryotes include all multicellular life on earth, like plants, animals, and humans.
• Viruses are smaller than bacteria and are not technically alive on their own — they must infect a host cell to survive. Viruses are made up of some genetic material surrounded by a viral coat, but they lack all the machinery necessary to make proteins and catalyze reactions. This group also includes subviral particles and prions, which are the simplest of life forms, made of naked ribonucleic acid (RNA) or simply protein.

FIGURE 1-1: Types of microorganisms.

The bacteria and archaea are often talked about together under the heading of “prokaryotes” because they lack a nucleus. They do share a few characteristics and aren’t easily distinguished from one another at first, but they are distinct groups.

Deconstructing Microbiology

Microbiology involves studying microorganisms from many different angles. Each perspective uses a different set of tools, from an ever-improving and changing toolbox. These include

• Morphology: The study of the shape of cells. It is analyzed using stains and microscopy.
• Metabolism: How an organism gets energy from its environment and the waste it produces as a result. Metabolism is studied using principles from biochemistry.
• Growth: How an organism, well, grows. The growth of a microbe is used to see how quickly the population can divide and help to distinguish between one microbe and another. Growth is measured using principles of physics, as well as good old-fashioned counting. Qualitative measures of how growth looks are also important.
• Genotype: The genetic makeup of a microbial strain. Genes are studied using genetics, which has recently begun to involve a lot of molecular biology.
• Phenotype: The name of the observable traits of a microbe. A phenotype is due to the interaction between the constellation of genes and environmental factors. It’s used to describe a microorganism and to study the function of genes. To measure a phenotype, you have to use some microbiology know-how to see changes in growth and metabolism, as well as other biochemical processes for communication and defense.
• Phylogeny: The history of the evolution of microorganisms. Phylogeny is important not only because it helps us identify newly discovered microbes but also because it allows us to see how closely related different microbes are to one another. The study of a group’s phylogeny involves genetics and molecular biology, as well as evolutionary biology.

When you put all the pieces back together again, you have the science of microbiology. Microbiologists are some of the most creative scientists out there — they have many tools at their disposal that they can use in a variety of ways. The trick is to think up sneaky ways to study microbes, which is why the field is always evolving.

The term microbiology is often used to mean the study of mainly bacteria and archaea because the study of other microbes are specialties of their own. For example, the study of viruses is virology, the study of fungi is mycology, and the study of algae is phycology.

Chapter 2

Microbiology: The Young Science

IN THIS CHAPTER

Remembering a time before microbiology

Discovering microorganisms step-by-step

Looking forward

Compared with other more ancient fields of science, microbiology is a relative baby. Physics began in ancient times, mathematics even earlier, but the knowledge of tiny living things, their biology, and their impact on human lives has only been around since the late 19th century. Until about the 1880s, people still believed that life could form out of thin air and that sickness was caused by sins or bad odors.

As with other fields in science, there are two aspects to microbiology research: basic and applied. Basic microbiology is about discovering the fundamental rules governing the microbial world and studying all the variety of microbial life and microbial systems. Applied microbiology is more about solving a problem and involves using microbes and their genes or proteins for practical purposes such as in industry and medicine.

In this chapter, we introduce the key concepts and experiments that gave rise to the discovery of microbes and their importance in disease. This chapter also highlights the many different areas of study within microbiology and some advances and challenges in the prevention and treatment of infectious diseases.

Before Microbiology: Misconceptions and Superstitions

Medical practices in ancient times were all heavily tinged with supernatural beliefs. Ancient Egypt was ahead of its time in terms of medicine, with physicians performing surgery and treating a wide variety of conditions. Medicine in India was also quite advanced. Ancient Greek physicians were concerned with balancing the body’s humors (the four distinct body fluids that they believed were responsible for health when in balance, or disease when out of balance), and medicine in medieval Europe was based on this tradition. None, however, had knowledge of the microbial causes of disease.

Opinions about why diseases afflicted people differed be...