Microbiology Chapter 1

mutualism, colonization

Normal Microbiota versus Pathogens Normal microbiota live in or on a host and both benefit from their host and provide benefits to that host. How would biologists describe this relationship?

immunopathology

Often the signs and symptoms of an infectious disease are caused by the host's immune system killing microbes and nearby host tissues in an array of consequences called __

safe sterile cabinets airborne negative escaping positive buildings

Organisms that are generally regarded as safe are at biological safety level I and can be worked with on a benchtop using sterile techniques. Organisms that have a moderate potential hazard can cause disease in humans, and they require the use of biohazard safety cabinets only. These precautions are part of the biological safety level II precautions. In addition to the biosafety level II precautions, dangerous organisms that can be contracted via airborne routes are handled in specially designed biological safety level III laboratories with negative pressure to prevent pathogens from escaping. Biosafety level IV laboratories incorporate all of the level III precautions as well as positive-pressure lab suits and are often housed in separate buildings.

Lyme disease

People living near a forest often encounter deer, which puts them at greater risk for contracting which disease?

host ranges

Salmonella enterica serovar Typhimurium has a very low LD50 in mice but is generally not lethal in humans. Salmonella enterica serovar Typhi causes typhoid fever in humans and has a very low LD50 in humans, but it doesn't kill mice. This phenomenon can be explained by the fact that the two serovars have different ___________.

host range

Several viruses, such as smallpox, measles, and chicken pox, only infect humans. We would describe these viruses as having a narrow __________

The microbe is isolated from the diseased host and grown in pure culture.

Some pathogens, such as Chlamydia species, can only replicate within host cells. This pathogen life cycle makes which of Koch's postulates impossible to satisfy?

bubonic plague

This image depicts a medieval church procession to ward off an infectious disease that wiped out a third of Europe's population in the fourteenth century. What is the infectious disease?

Tropical deforestation, urban sprawl, global warming

What are factors that lead to increasing rates of mosquito-borne tropical diseases?

Immunopathogenesis

When a host's white blood cells attack infecting pathogens, they will often damage nearby tissues and cause symptoms. What do physicians and researchers call the process that causes this damage?

autoclave

Which is used to sterilize the materials necessary for the controlled study of microbes and for medical procedures?

Correct Answer(s) patients not completing the course of antibiotics the presence of multi-drug resistant strains of tuberculosis

Which of the following are barriers to effectively treating tuberculosis today?

Nightingale tracking causes of mortality during the Crimean War Semmelweis comparing the death rates of women who gave birth in a usual hospital ward vs. women who gave birth in a midwife-run birthing center

Which of the following are examples of medical statistics?

Specific diseases are caused by specific kinds of microbes.

Which of the following best describes the germ theory of disease?

Microbes are shown to cause infectious diseases. Antiseptic measures are put in place prior to surgery.

Which of the following first occurred during the "Golden Age of Microbiology" that spanned from 1855-1899?

parenteral

Which portal of entry is employed by organisms that are transmitted by flea or tick bite?

insect vector, West Nile virus, reservoir, formites, cat, food eg salmonella

all of the sources of indirect disease transmission shown in the infection cycle diagram.

Archaea

are cells lacking a nucleus (prokaryotes) and are distantly related to other microbes. Methanogens live in the human intestine (among other places), where their metabolism releases methane. Archaea never cause disease.

Bacteria

are cells lacking a nucleus (prokaryotes). Bacteria grow in all habitats. Most human-associated species are harmless, but some cause disease.

Viruses

are noncellular microbes that must infect a host cell.

Antonie van Leeuwenhoek

developed microscopes

Lazzaro Spallanzani

helped disprove spontaneous generation

Eukaryotic microbes

include protists (protozoa and algae) and fungi. Prasitic protozoa and fungi may infect humans.

What does this chart show?

medical statistics

Microbes

microscopic, they are organisms too small to be seen without a microscope. Different species of microbes grow as single cells, in filaments, in biofilms, or in simple differentiated structures.

Catherine of Siena

nursed victims of plague and leprosy

AGent 1 LD50

o compare the relative virulence of different infectious agents, researchers often infect animals with varying doses of each agent. As the dose given to each animal increases, the rate of mortality increases as well. Please click on the areas of the graph that researchers would use to determine the LD50 of each organism.

petri dish agar colonies

A round plastic holder known as a(n) petri dish is filled with a gel-like substance such as agar. A dilute bacterial sample is spread onto the substance and incubated until isolated colonies appear, each a distinct population grown from a single cell.

4

According to Koch, how many criteria must be satisfied to show that a microbe is the causative agent of a specific disease?

Some engineered viruses are used in gene therapy to deliver good copies of genes. Weakened forms of microbes are used as vaccines. Microbes are screened as sources of new antibiotics.

Although some microbes are pathogens, humans also harness microbes to enhance human health. Which of the following are ways microbes are used in health care?

cell wall

Antibiotics work by poisoning pathogenic bacteria more than host cells. Some antibiotics, such as penicillin, achieve specificity by poisoning bacterial components not present in animal cells. Which of the following is a component present in most bacterial cells but not animal cells?

attachment, immune avoidance, obtaining nutrients

Any microbe that is capable of causing disease in a human host has the same initial encounters with the host's system. Place these events in order, starting with the first contact between host and microbe.

True

For any organism, the infectious dose 50% (ID50) is ALWAYS lower than the lethal dose 50% (LD50).

Endemic

How do scientists describe a disease that is always present in a community?

latent

If a person has had chicken pox in the past, his or her immune system will remove most of the virus. However, a few viral particles will invade nervous tissue, where they will remain hidden for years. If the person is stressed, host-pathogen interaction can become imbalanced, and shingles will develop in skin that is in contact with the infected nerves. This is a classic example of a(n) _________ infection.

a virus

In attempting to find the causative agent for a particular disease, you find that the agent remains infectious even after treatment with DNAse, an enzyme that degrades DNA. What could the disease's causative agent be?

Correct Answer(s) prior exposure to cowpox

In the eighteenth century, it was observed that milkmaids were less likely to contract smallpox than others. What caused this trend amongst milkmaids?

ectoparasites

Insects like fleas and lice that both harm a host and benefit from living on a host are described as ___________ .

naturally growing microbes

Like many other antibiotics, penicillin was first found in what?

nursed victims of plague and leprosy Catherine of Siena developed microscope Antonie van Leeuwenhoek Robert Hooke helped disprove spontaneous generation Lazzaro Spallanzani Louis Pasteur John Tyndall

Match individuals with their achievements.

human immunodeficiency virus Correct label: AIDS Helicobacter pylori Correct label: stomach ulcers Mycobacterium tuberculosis Correct label: tuberculosis

Match the disease with its causative agent. hum

the entry and growth of an organism in and on a host Correct label: infection an organism's ability to cause disease Correct label: pathogenicity condition where the human host has been damaged Correct label: disease measure of the severity of a disease caused by a pathogen Correct label: virulence

Match the word with its meaning.

The microbe is found in all cases of the disease but is absent from healthy individuals. The microbe is isolated from the diseased host and grown in pure culture. When the microbe is introduced into a healthy, susceptible host, the same disease occurs. The same strain of microbe is obtained from the newly diseased host.

Place Koch's postulates into the order used to determine what microbe is responsible for causing a specific disease.

Symptom fatigue pain soreness sign fever increased heart rate rash

Please identify each disease event as either a sign or a symptom.

indirect,vehicle direct,accidental

Please label each different type of transmission, indicating the different ways disease-causing organisms complete the infection cycle, moving from one host to the next.

commensalism benefited benefit mutualism Pathogens disease

The eukaryotes, bacteria, and archaea that live in and on the human body are called normal microbiota. When they were originally discovered, scientists thought that the relationship between these organisms was commensalism because they thought that the organisms benefited from living on the host but did not help the host. In recent years, researchers have determined that most of our resident microbes derive and give benefit to the host. This makes the relationship between host and microbe one of mutualism. Pathogens, on the other hand, are microbes that cause disease.

the discovery that fermentation is caused by microbes the development of a rabies vaccine the invention of the swan-necked flask

The famous French scientist Louis Pasteur contributed which of the following to the field of microbiology?