Chapter 1 Scope and History

What is microbiology

The study of microbes-organisms/agents that are generally too small to be seen without magnification

Why are microbes important to humans and the environment

they have many roles:

helping maintain food chains, decomposition, digestion, fermentation, preventing/casuing disease, antibiotics, biotech, etc

what role do microbes play in decomposition

they break down dead organic material, returning nutrients to the environment

How can microorganisms benefit human health

-part of microbial communities and help aid processes like digestion

-others help develop vaccine, antibiotics, other medicines

A scientist wants thousands of organisms for an experiment and needs results relatively quickly. Why might microbes be a good choice?

They grow rapidly, produce large numbers

-allow researches to collect more data in less time

What are some harmful roles of microorganisms ?

Some microorganisms are pathogens that cause disease in humans or other organisms

What is bioremediation

The use of organisms to help Clean up or break down environmental pollutants

What are the two major groups of prokaryotic microbes

Bacteria and Archaea

What is a major characteristic of prokaryotic cells

They lack a nucleus and membrane bound organelles

You examine a microbe and determine that it has no nucleus or membrane bound organelles. Is it prokaryotic or eukaryotic?

Prokaryotic

What are bacteria

Prokaryotic, single celled organisms,

Some are pathogenic, most are harmful or beneficial

What are Archaea

Prokaryotic known for ability to live in unusualy extreme environments.. Not pathogenic to humans

A microorganism is found living in an extreme environment and is prokaryotic. Which major group is it

Archaea

What major groups of eukaryotic microbes are studied in microbiology

Algae, fungi, and protozoa

What distinguishes eukaryotic cells from prokaryotic cells

nucleus and membrane bound organelles

What are algae

eukaryotic, photosynthetic, single celled

What are fungi

eukaryotic may be single or multi celled, function as decomposers, some are pathogenic

What does saprobe mean

an organism that obtains nutrients by decomposing dead organic material

What are protozoa

single celled eukaryotic organisms, obtain food rather than performing photosynthesis; most have some form of motility, some are pathogenic

What are the two major groups of eukaryotic parasites

helminths and arthropods

what are helminths

parasitic worms

what are arthropods in relation to microbiology

insects and related organisms that can cause or transmit disease

What are the other major acellular infectious agents

viruses, viroids, and prions

What are basic structure of virus

a virus has nucleic acid surrounded by a protein coat called a capsid

why aren’t viruses classified the same way as cellular microorganisms

Viruses are acellular and do not have the cellular structure needed to reproduce independently

what does obligate intracellular parasite mean

a virus must enter a host cell and use the host cell’s machinery to reproduce

A virus is outside a host cell and cannot reproduce on its own Why?

its an obligate intracellular parasite and requires a host cell’s machinery for replication

How are viroids different from viruses?

viroids consists of nucleic acid without a protein covering/capsid

How are prions different from viruses

prions consist only of protein and do not contain nucleic acid

Where are microbes found

They are widely distributed throughout nature-essentially everywhere

Is microbe synonymous with single celled organisms

no, most microbes are singled celled, exceptions: multicellular organisms and acellular agents like viruses

what are three possible effects microbes can have?

they can be beneficial, harmless, or pathogenic

A bacterium is found in a healthy person’s body but isn’t causing disease. Does that mean it is a pathogen?

No, many microbes are harmless or beneficial

Compare prokaryotic and eukaryotic microbes

P: no nucleus or membrane bound organelles, bacteria and archaea

E: nucleus and membrane organelles, algae, fungi, protozoa

What is taxonomy

The classification of living organisms

What is binomial nomenclature

the two part scientific naming system consisting of the genus + specific epithet

How does viral naming differ from binomial nomenclature

viruses have their own naming system

Who was Robert Hooke

a scientist associated with the early development of microscopy who examined then slices of cork and described the structures he saw as “cells”

what did Hooke observe when examining cork?

thin slices of cork appeared to contain small compartments which he called cells

Who was Anton Van Leeuwenhoek

an early microscopist who made his own lenses/microscopes and observed microorganisms which he called animalcules

Why was Leeuwenhoek important to microbiology

his observations provided early evidence that microscopic life existed

Why was the development of microscopy so important

it allowed scientists to observe organisms and structures that could not be seen with the naked eye

What is spontaneous generation

The belief that living organisms could arise from nonliving material

What is biogenesis

the idea that living things arise from other living things

Who was Francesco Redi?

A scientist who performed experiments with meat and gauze covered jars that provided evidence against spontaneous generation

What did Redi’s meat experiment demonstrate

maggots did not arise from the meat; access to flies was associated with maggot formation

Who was Louis Pasteur

a scientists who used swan neck flasks to demonstrate that microorganisms did not appear is sterilized birth when contamination was prevented

Why were the swan necks important

allowed air to enter, prevented microorganisms from reaching the broth. Showed microbial growth came from contamination rather than spontaneous generation

What is germ theory of disease

the idea that microorganisms can invade other organisms and cause disease

why was germ theory important to medicine

established that microorganisms cause disease,

provided basis for infection prevention, treatment, disease control

Who was Robert koch

a major contributor to germ theory who identified disease causing bacteria, developed methods for obtaining pure cultures,

What is a pure culture?

A culture containing a single type/species of microorganism.

Why would a scientist want a pure culture when investigating a disease?

So they can study one specific microorganism without other organisms interfering with the results.

What is the general purpose of Koch's postulates?

To establish a connection between a particular microorganism and a particular disease.

What is the first Koch's postulate?

The specific causative agent should be found in every case of the disease.

What is the second Koch's postulate?

The organism must be isolated in pure culture.

What is the third Koch's postulate?

The isolated organism should cause the same disease when introduced into a healthy, susceptible host.

What is the fourth Koch's postulate?

The disease-causing organism must be recovered again from the experimentally infected host.

What is epidemiology?

The study of the source, cause, and mode of transmission of disease.

Who was Ignaz Semmelweis?

A physician who recognized a connection between contaminated hands and puerperal (childbirth) fever and instituted handwashing.

Why was Semmelweis's handwashing practice significant?

It showed that improving hygiene could reduce the transmission of infection.

Who was Joseph Lister?

A physician who used carbolic acid to reduce infection and developed an early aseptic technique.

Who was John Snow?

A physician who investigated a cholera outbreak in London in 1854 and traced the outbreak to a public water source.

Why is John Snow important to epidemiology?

His investigation demonstrated how studying disease patterns and transmission sources can identify the cause of an outbreak.

What general principle connects Semmelweis, Lister, and Snow?

Understanding how infections are transmitted can be used to prevent and control disease.

What is immunology?

The study of the immune system and immune responses.

Who was Edward Jenner?

A scientist who contributed to vaccination through his work with smallpox.

Why was Jenner's work important?

It demonstrated that exposure to a related, less dangerous infection could provide protection against smallpox.

What is variolation?

An earlier smallpox prevention technique involving deliberate exposure to material from smallpox lesions.

How did Jenner's vaccination differ from variolation?

A: Jenner used material from cowpox to provide protection against smallpox rather than deliberately exposing people to smallpox material as in variolation.

Why was vaccination safer than earlier variolation?

Vaccination used a less dangerous related infection rather than intentionally exposing someone to smallpox.

What vaccines did Pasteur contribute to developing?

vaccines for rabies and cholera.

Who was Martinus Beijerinck?

A scientist who was the first to characterize viruses.

Who was Wendell Stanley?

A scientist who studied the tobacco mosaic virus and showed that viruses could be crystallized.

Why was tobacco mosaic virus important in the development of virology?

Its study helped scientists understand that viruses had distinct chemical/physical properties and could be studied experimentally.

Who were Hershey and Chase?

Scientists who demonstrated that DNA is the genetic material of some viruses.

Who was Paul Ehrlich?

A scientist who developed the concept of a "magic bullet" and coined the term chemotherapy.

What did Ehrlich mean by a "magic bullet"?

A chemical treatment designed to specifically target a microorganism while causing minimal harm to the patient.

Why is the "magic bullet" concept important?

It represents the idea of selectively targeting a pathogen rather than damaging the patient's cells indiscriminately.

Who was Alexander Fleming?

A scientist who observed that mold inhibited the growth of the bacterium Staphylococcus and recognized its potential for treating infections.

What antimicrobial discovery is Fleming associated with?

Penicillin

How did Ehrlich and Fleming contribute differently to chemotherapy?

Ehrlich developed the concept of targeted antimicrobial treatment/"magic bullets" and chemotherapy; Fleming discovered the antibacterial potential of penicillin.

Who was Frederick Griffith?

A scientist whose work demonstrated transformation, showing that previously harmless bacteria could acquire genetic characteristics that made them harmful.

What is transformation?

A process in which bacteria acquire genetic material that changes their characteristics.

Who were Edward Tatum and George Beadle?

Scientists who helped establish the relationship between genes and metabolism, including the idea that genes control enzymes.

A mutation changes a gene, and the resulting organism can no longer make a particular enzyme needed for metabolism. Which concept does this illustrate?

The relationship between genes and metabolism, associated with Beadle and Tatum.

Who was Barbara McClintock?

A scientist associated with the discovery of transposons.

what are transposons?

Genetic elements that can move from one location in DNA to another.

What are recombinant microorganisms?

Microorganisms whose genetic material has been altered/combined to give them useful characteristics.

Why might recombinant microorganisms be useful?

They can potentially be engineered to produce useful products such as drugs, hormones, and vaccines.

What is gene therapy?

A developing medical approach that uses genetic material to treat disease.

What is bacteriophage therapy?

Using bacteriophages—viruses that infect bacteria—to target bacterial infections.

Why could bacteriophage therapy be useful?

Because bacteriophages can specifically target bacteria.

What is genomics?

The study of genomes/genetic information.

What is the Human Genome Project?

A major effort to determine/understand the sequence and organization of the human genome.

What are emerging diseases?

Diseases that are newly appearing, increasing, or appearing in new populations/locations.

Why is microbiology important when diseases emerge in new places?

Microbiology helps scientists identify infectious agents, understand transmission, develop treatments/vaccines, and control outbreaks.

What future areas of microbiology are listed

• Recombinant microorganisms

• Drugs, hormones, and vaccines

• Gene therapy

• Bacteriophage therapy

• Genomics

• Emerging diseases

• Bioterrorism

A patient has a disease caused by a microorganism. Researchers isolate the microorganism, grow it separately, introduce it into a susceptible host, and then recover the same organism. What historical concept are they applying?

Koch's postulates.

A scientist discovers an infectious agent containing only protein and no nucleic acid. What is it?

Prion