Microbiology Exam 3

You are given an unknown, pure sample of a eukaryotic organism. Which of the following tests would allow you to determine if the sample contains algae?

Place the sample in a clear container filled with media containing no sugars, and leave it in a sunny window. After a few weeks, look for growth of the organism.

Proteinaceous infectious agents

Prions

State at least two reasons why eukaryotic reproduction is more complex than prokaryotic reproduction.

Prokaryotic reproduction typically involves replication of DNA and binary fission of the cytoplasm to produce two identical offspring. Eukaryotes have a variety of methods of asexual reproduction, including binary fission, budding, fragmentation, spore formation and schizogony. Eukaryotes reproduce sexually, a process that involves the formation of sexual cells called gametes, and the subsequent fusion of two gametes to form a cell called a zygote.

Describe the phases of mitosis distinguishing between chromosomes, chromatids, centromeres and spindles.

Prophase- the cell condenses its DNA molecules into visible threads called chromatids. Two identical chromatids, sister DNA molecules are joined together in a region called a centromere to form one chromosome. A set of microtubules is constructed in the cystol to form a spindle. Metaphase is when the chromosomes line up on the plane in the middle of the cell and attach near their centromeres to microtubules of the spindle. Anaphase is when the sister chromatids separate and crawl along the microtubules toward opposite poles. Chromatid is now a chromosome. Telophase is when the cell restores its chromosomes to there less compact, and nuclear envelopes form around the daughter nuclei.

What are some pathogens that cross the placenta barrier?

Protozoan- Toxoplasmosis gondii Bacteria- Treponema pallidum Bacteria- Listeria monocytogenes DNA Virus- Cytomegalovirus DNA Virus- Parvovirus B19 RNA Virus- Rubivirus

Decline

The time when the body gradually returns to normal as the patient's immune response and/or medical treatment vanquish the pathogen.

Explain some reasons for the many different taxonomic schemes for protozoa.

There is many different taxonomic schemes for protozoa because they classify them based on 18S rRNA nucleotide sequencing nd features made visible by microscope.

Mucous membrane barrier

These are the "major" portals for entry. They line the respiratory, gastrointestinal, urinary, reproductive tracts, and the conjunctiva. They also contain tightly packed cells, but are relatively thin, moist, and warm with living cells. This make a more hospitable environment for pathogens.

List three conditions that create opportunities for normal microbiota to cause disease.

These condition allow the microbiota to become "opportunistic pathogens". 1)Introduction of normal microbiota into an unusual site of the body. 2) Immune Suppression 3)Changes in normal Microbiota

How do leukocidins of some bacteria affect virulence?

They are chemicals capable of destroying phagocytic white blood cells outright.

List several beneficial roles or functions of lichens.

They are partnerships between fungi and photosynthetic microbes. They surround the ohotosynthetic cells and provide them nutrients, water, and protection from desiccation and harsh light. They create soil from weathered rocks, and provide nitrogen to nutrient-poor environments. Used for food for animals, nests for birds, and camouflage.

Noncommunicable disease

They arise outside of hosts or from normal microbiota. They are not spread from one host to another, and diseased hosts are not a source of contamination for others.

List five ways in which fungi are beneficial.

They decompose dead organisms and recycle their nutrients. They assist the plants to absorb water and dissolved minerals. Humans use fungi for food. They are important research tools in the study of metabolism, growth, and development, and in genetics and biotechnology. They produce antibiotics.

List four ways in which water molds differ from true fungi.

They differ from fungi in they have tubular cristae in their mitochondria. They have cell walls of cellulose instead of chitin. Their spores have two flagella, one whiplike and one hairy. They have true diploid bodies

How does Streptococcus pyogenes affect virulence?

They produce a protein on its cell wall and fimbriae , called M protein, that resists phagocytosis and thus increases virulence.

Describe asexual reproduction in fungi.

They reproduce asexually by producing lightweight spores, which enable the fungi to disperse vast distances on the wind.

Convalescence

This is when the patient recovers from the illness, tissues are repaired and returned to normal.

Symbiosis; Symbiotic relationship

This means to live together. We have these types of relationships with countless microorganisms.

What is droplet transmission?

This type occurs during exhaling, coughing, and sneezing.

Latent disease

Those in which a pathogen remains inactive for a long period of time before becoming active. EX: Herpes

How can all 3 nosocomial infections be prevented?

Through disinfection, medical asepsis, good housekeeping, hand washing, bathing, sanitary handling of food, proper hygiene, and precautionary measures.

Which of the following arthropods would be considered a biological vector?

Ticks and mosquitoes-organisms that host and transmit pathogens

Which of the following pairs is mismatched?

Toxoplasma: cilia

Diseases of animals caused by fungi are called mycoses.

True

In fungi, aseptate hyphae are coenocytic by definition.

True

Most viruses cannot be seen by light microscopy.

True

Protozoa are susceptible to viral attack.

True

Unlike the term fungi, the terms algae and protozoa are not accepted taxa.

True

Name 4 Environmental factors that contribute to the activation of oncogenes

Ultraviolet light Radiation Carcinogens Viruses

What could have prevented Maria's infection?

Vector control

Extremely small, circular pieces of RNA that are infectious and pathogenic in plants

Viroids

Communicable disease

When an infectious disease comes from another infected host, either directly or indirectly. EX: Flu If it is easily transmitted between hosts, it is also considered a contagious disease.

What is Indirect contact transmission?

When pathogens are spread from one host to another by fomites EX: needles, toothbrushes, paper tissues, toys, money, bed sheets, etc.

When would endotoxins be released from a bacterial cell?

When the cell dies

What is the key difference between yeast and mold?

Yeast is unicellular, while mold is multicellular.

Which of the following viruses can be latent? a. HIV b. chickenpox virus c. herpesviruses d. all of the above

d. all of the above

Which of the following is not a criterion for specific family classification of viruses? a. the type of nucleic acid present b. envelope structure c. capsid type d. lipid composition

d. lipid composition

Give three different ways that viral nucleic acid can enter a host cell.

direct penetration membrane fusion endocytosis

made up of -ssRNA and +ssRNA

dsRNA

a membrane on the outside of a virus

envelope

An unknown organism is a saprobe, gathers nutrients by absorption, lacks chlorophyll, has cell walls and is coenocytic. In which group is it most likely to be classified?

fungi

Ascomycetes are members of the

fungi.

Which of the following is the most effective way to reduce the number of nosocomial infections?

handwashing

Among the virulence factors produced by Staphylococcus aureus are hemolysin, coagulase, hyaluronidase, and enterotoxin. Which of these factors contribute(s) to the ability of S. aureus to invade the body?

hyaluronidase

A nosocomial disease is a disease acquired

in a health care facility.

Fomites are

inanimate objects involved in the indirect contact transmission of pathogens

The ________ period is the time between infection and the occurrence of the first symptoms or signs of the disease. (FI)

incubation

A patient acquires an infection by touching a contaminated door handle. Which mode of transmission best describes this scenario?

indirect contact transmission

An epidemiologist collects drinking glasses, tissues, and bedsheets from the apartment of an individual infected with a particular disease. Which of the following modes of transmission is being investigated for this disease?

indirect contact transmission

Host specificity of a virus is due to

interactions between viral and cellular surface molecules.

The genome of Ebola virus is a negative-sense, single-stranded RNA molecule. When this virus replicates, _____________________.

its genomic RNA must be copied by viral RNA-dependent RNA transcriptase into a positive strand

During , viruses remain dormant in a cell.

latency

A protozoan and its resident bacteria invade the body of a worm. The bacteria release toxins and exoenzymes that immobilize and digest the worm, and the protozoan and bacteria absorb the nutrients produced. The relationship between the protozoan and the bacteria would best be described as

mutualism.

Which of the following is a beneficial association between the roots of a plant and a fungus?

mycorrhizae

Which of the following is an example of an exotoxin?

neurotoxins

Ebola virus, which has an RNA genome, infects endothelial cells that line blood vessels. Within these infected cells, synthesis of viral proteins takes place ___________________.

on host ribosomes in the cytoplasm

genes that can lead to cancer

oncogenes

Infection and disease are not the same thing because _____.

only one of the two results in presence of signs and symptoms

Water molds differ from the fungi in all of the following characteristics EXCEPT _____.

photosynthetic pigments

Viroids infect

plants.

inactive virus within bacterial cell

prophage

Lysogenic viral DNA integrating into the host genome is referred to as

prophage.

Which of the following stages of meiosis is most important for the generation of genetic variation?

prophase I

The outermost layer of a virion fulfills which of the following functions of the virus?

protection and recognition

Single-celled organisms called Ciliates are

protozoa.

transcribes DNA from RNA

provirus

Enveloped viruses have a layer of lipids surrounding their capsid. This envelope is made mostly of host cell membrane. In which step does the virus acquire this envelope?

release, During budding release, the virus "steals" some of the host membrane to use for itself.

If a haploid cell has 16 chromosomes in its nucleus, how many would be present in the diploid state?

32

What type of infection does Nancy's Clostridium difficile infection represent?

A nosocomial infection

Which of the following is an example of the parenteral route?

A person steps on a rusty nail.

Acute disease

A rapidly developing disease that last a short amount of time. EX: Common cold

Prodromal period

A short time of generalized, mild symptoms such a malaise and muscle aches that precedes the illness.

Adhesion factor for Protozoa.

Adhesion disks

What are Ligands called specifically on bacteria?

Adhesions

Understand the general physical features of insects and the features specific to various groups of insect vectors

All insects have three pairs of legs and three body regions, head, thorax, and abdomen. Many insects have larval stages.

Put the following stages of a lytic replication cycle in order, from earliest to latest stages: I. Synthesis II. Assembly III. Attachment IV. Release V. Entry

III, V, I, II, IV

What is an example of changes on the normal microbiota?

If you have a female patient on prolonged antimicrobial therapy for a bacterial blood infection, there normal microbiota could be decreased. This allows an opportunistic microbiota like Candida albicans to thrive and cause a yeast infection.

Commensalism

One member of the relationship benefits without significantly affecting the other. ***EX: Staphylococcus epidermis growing on the skin typically cause no measurable harm to a person. The Staphylococcus may inhibit pathogenic microbes from colonizing on the skin.***

Describe the relationship among the terms parasite and pathogen.

Parasites need a host in order to survive. It is only considered a Pathogen if it causes a disease.

What is foodborne transmission?

Pathogens in and on food that is poorly processed, undercooked, or poorly refrigerated.

What is contract transmission?

Person-to-person spread, typically involves body contact between hosts. EX: Touching, kissing, and sexual intercourse can lead to warts, herpes, and gonorrhea.

Name 3 ways that a virus can cause cancer

1. Some carry oncogenes 2. Some promote oncogenes 3. Some interfere with tumor repression

Viruses cause ___% of human cancers

20-25 %

acts as mRNA allowing direct translation of vial proteins

+ssRNA genome

not capable of directing translation, used to transcribe +ssRNA

-ssRNA

Describe three nosocomial infection?

1) Exogenous Nosocomial infection- Caused by pathogens acquired from the health care environment. 2) Endogenous nosocomial infection- Arise from normal microbiota within the patient that become pathogenic because of factors within the health care setting. 3) Iatrogenic infection- a subset of nosocomial infections that are the direct result of modern medical procedures such as catheters, invasive diagnostic procedures, and surgery.

List some ways health care agencies work to limit the spread of disease.

1) Immunization 2) Enforce standards of cleanliness in water and food. 3) Work to reduce the number of disease vectors and reservoirs. 4) Locate and prophylactically treat individuals exposed to contagious pathogens. 5) Establish isolation and quarantine measures to control the spread of pathogens.

What are the 5 typical stages of infectious diseases?

1) Incubation period 2) Prodromal period 3) Illness 4) Decline 5) Convalescence

Distinguish between the different types of symbiosis and list them in order from most beneficial to most harmful for the host.

1) Mutualism 2) Commensalism 3) Paratism

What are the factors that influence nosocomial infections?

1) Presence of microorganisms in hospital environment 2) Immunocompromised patients 3) Transmission of pathogens between staff and patients and among patients.

What are some limitations of Koch's postulates?

1) Some pathogens cannot be cultures in the lab. 2) Some diseases are caused by a combination of pathogens or by a combination of pathogens and physical, environmental, or genetic factors. 3) Some ethical considerations prevent applying Koch's postulates.

List Koch's postulates.

1)The suspected agent must be present in every case of the disease. 2) The agent must be isolated and grown in pure culture. 3) The cultured agent must cause the disease when it is inoculated into a healthy, susceptible experimental host. 4) The same agent must be reisolated from the diseased experimental host.

What are the 5 stages of Lysogeny?

1. ATTACHMENT and ENTRY are the same as lytic cycle 2. PROPHAGE in chromosome host chromosome and viral DNA RNA combine 3. REPLICATION host chromosome and virus are replicated 4. INDUCTION host chromosome disintegrates and lytic cycle begins 5. SYNTHESIS, ASSEMBLY and RELEASE are the same as the lytic cycle

Give 3 characteristics of the Viral Envelope

1. Acquired from host cell during viral replication or release 2. Composed of phospholipid bilayer and proteins like glycoproteins 3. Envelope's proteins and glycoproteins often play role in host recognition

What are five phases of a generalized lytic replication cycle?

1. Attachment 2. Entry 3. Synthesis 4. Assembly 5. Release

Name 2 things that mediate attachment of animal viruses.

1. Chemical attraction 2. Glycoproteins

Compare and contrast three types of alveolate

Alveolates are protozoa with small membrane bound cavities called alveoli beneath their cell surfaces. Ciliates alveolates have cilia by which they either move themselves or move water past their cell surface. Apicomplexans are all chromohetertrophic athogens of animals. Dinoflagellates are unicellular microbes that have photosynthetic pigments such as carotene and chlorophylls.

Compare and contrast three types of amoeba.

Amoebae are protozoa that move and feed by means of pseudopodia. Cercozo is threadlike pseudopodia. A major taxon is composed of armored marine amoebae . Radiolaria make up another taxon with threadlike pseudopodia, but they have ornate shells composed of silica and live in marine water as part of the plankton. Amoebozoa are distinguished from the other two taxa of amoebae by having lobe-shaped pseudopodia and no shells.

What are the three types of reservoirs of infection in humans?

Animal Reservoirs Human Carriers Non-Living Reservoirs

What is a vector transmission?

Animals that transmit disease from one host to another. They can biological or mechanical. EX: Mosquitos

What are Ligands called specifically on viruses?

Attachment proteins

Describe the deuteromycetes and explain why this group no longer constitutes a formal taxon.

Because scientists have not observed sexual reproduction in all fungi, taxonomists in the middle of the 20th century created the division Deuteromycota to contain the fungi whose sexual stages are unknown either because they do not produce sexual spores or because their sexual spores have not been observed. However sequences has revealed most deuteromycetes in fact belong in the division Ascomycota as a formal taxon.

Why is it difficult to treat viral infections?

Because viral replication uses cellular structures and path- ways involved in the growth and maintenance of healthy cells, any strategy for the treatment of viral diseases that involves disrupting viral replication may disrupt normal cellular processes as well. In other words the virus is so good at disguising itself to look like a host cell that most treatments to disrupt a virus also disrupt non viral cells.

Explain how a biofilm may facilitate contamination and infection.

Biofilm is a way of bacteria attaching to host cells indirectly. They interact with each other to forma sticky web of bacteria and polysaccharides and adheres to the surface within a host. **EX: Dental plaque is a biofilm that contains bacteria that causes dental carries.**

Mutualism

Both members benefit from their interaction. ***EX: Bacteria in colon receives a warm moist, nutrient rich environment in which to thrive while we absorb vitamin precursors and other nutrients released from the bacteria.***

is a mechanism of release for enveloped viruses.

Budding

Describe the unique distinguishing characteristic of algae.

Can be unicellular or colonial, or they can have simple multicellular bodies called thalli. The thalli of large marine algae, commonly called seaweed, can be complex. Most algae are aquatic.

Human Carriers

Carriers incubate the pathogen in their body and eventually develop the disease while others remain a continued source of infection without ever becoming sick. Those that do not develop the disease are considered asymptomatic.

Explain how microbial toxins affect virulence?

Chemicals that harm tissues or trigger host immune responses that cause damage. They enter the bloodstream and are carried to other parts of the body. There are 2 types. **EXOTOXINS- Secrete central to their pathogenicity in that they destroy host cells or interfere with host metabolism.** **ENDOTOXINS- Are also called Lipid A and are the lipid portion of the bacteria membranes lipopolysaccharide. They can be released when Gram-negative bacteria divide.

List four groups of algae and describe the distinguishing unique characteristic of each.

Chlorophyta are green algae that share numerous characteristics with plants, they have chlorophyll, and use sugar and starch as food reserves. Unicellular or filamentous and live in freshwater ponds, lakes and pools. Multicellular grow in the marine interidal zone. Rhodophyta are red accessory pigments phycoerythrin; the storage molecule glycogen. Allows red algae to absorb short wave length blue light and photosynthesize at depths greater than 100m. Range from green to blck to red in deeper water. Phaeophyta based on their gametes being motile by means of two flagella. They have chlorophylls and brown pigments. May appear dark brown, tan, yellow-brown, greenish brown, or green. Chrysophyta are diverse group with respect to cell wall composition and pigments. They are unified in using the polysaccharide as a storage product. Some additionally store oils. Most are unicellular or colonial.

Skin barrier

Composed of thick layers of tightly packed, dead, dry cells. It forms a barrier against pathogens as long as it stays intact. Pathogens can still pass the barrier through hair follicles, sweat glands, abrasions, cuts, scrapes, stab wounds, and surgeries.

Describe the relationship between contamination and infection.

Contamination refers to the mere presence of microbes in or on the body. Infection is the successful invasion of the pathogen in the body.

Distinguish among nuclear division, cytokinesis and schizogony.

Cytokinesis is division of a cell's cytoplasm. Schizogony is a special type of asexual reproduction in which the protozoan Plasmodium undergoes multiple mitoses to form a multinucleate schizont. Nuclear division is the process by which a nucleus divides, resulting in the segregation of the genome to opposite poles of a dividing cell.

List diseases transmitted by fleas, lice, true flies, mosquitoes and kissing bugs.

Fleas transmit plague carried by rat fleas. Lice are vectors involved in epidemic outbreaks of typhus. Flies transmit leishmaniasis, and African sleeping sickness. Mosquitoes carry pathogens that cause malaria, yellow fever, dengue fever, filariasis, viral encephalitis, and Rift Valley fever.

Maria was infected by a eukaryotic vector-the mosquito Aedes aegypti. If you were to microscopically examine the cells of this eukaryote and compare it to the cells of the prokaryotic organisms in Chapter 11 in the textbook, what characteristic would all the cells share?

Deoxyribonucleic acid

Explain three approaches epidemiologists use to study disease in populations.

Descriptive epidemiology- careful tabulation of data concerning a disease. Analytical epidemiology- investigates a disease in detail, including analysis of data acquired in descriptive epidemiological studies to determine the probable cause, mode of transmission, and possible prevention of the disease. Experimental epidemiology- Involves testing a hypothesis concerning the cause of disease.

Chronic disease

Develops slowly and are continual or recurrent. EX: Hepatitis C or TB

Paratism

Drives benefit from its host while harming its host., though some hosts only sustain slight damage. ***EX: Parasites that allow their host to live are more likely to spread. If the host tolerates the parasite, it is more likely to reproduce. Over time, there will be a coevolution toward commensalism or mutualism.

What is an example of an introduction of normal microbiota into an unusual site of the body?

E-coli is normal microbiota in the intestine, but if introduced to the vaginal area, it will become a pathogen.

________ are toxins that affect the lining of the gastrointestinal tract. (FI)

Enterotoxins

Identify several features of a typical euglenid.

Euglenids are photoautotrophic, unicellular microbes wih chloroplasts containing light-absorbing pigments. They store food as a unique polysaccharide called paramylon instead of as starch. They lack cell walls, have flagella, are chemoheterophic.

Which of the following events might trigger induction of a temperate bacteriophage?

Exposure to UV light

In which state of the virus does it have a capsid?

Extracellular State

What are the 2 states of a virus?

Extracellular State Intracellular State

True of False A virus can be both DNA or RNA at the same time.

FALSE A virus can be either DNA or RNA at one time.

True or False Naked viruses cause persistent infections

FALSE Enveloped viruses cause persistent infections

True or False Most RNA viruses assemble in nucleus

FALSE Most DNA viruses assemble in nucleus

True or False Enveloped viruses are released by exocytosis or lysis

FALSE Naked (non enveloped) viruses are released by exocytosis or lysis

All diseases go through the stages known as incubation period, prodromal period, and illness.

False

Fungi reproduce only asexually

False

Koch's postulates can be applied to every infectious disease to identify its causative pathogen.

False

Protozoa are eukaryotic organisms that lack a cell wall and can be unicellular or multicellular.

False

Which of the following would be the first sign of an infection that resulted in the release of endotoxin?

Fever

Subacute disease

Have durations and severities that lie somewhere between acute and chronic. EX: Subacute endocarditis

Describe BRIEFLY the major groups of eukaryotes as they were first classified in the late 18th century and as they were classified in the late 20th century.

In late 18th century, Linnaeus classified all organisms as either plants or animals. Late 20th century Whittaker placed fungi in their own group and recognized a new kingdom Protista. Today they are classified into numerous kingdoms based largely on their genetic relatedness.

Infection vs. disease

Infection is the invasion of a pathogen and most of them succumb to the body's defenses. Whereas disease is the result of a pathogen multiplying sufficiently enough to adversely affect the body.

Nosocomial infections

Infections acquired by patients or health care workers while they are in health care facilities.

Asymptomatic or subclinical infections.

Infections that go unnoticed because they have no symptoms.

If the virus exist as nucleic acid then it must be in which state?

Intracellular State

Why is a release of endotoxin into the bloodstream potentially deadly?

It can lower blood pressure and cause the patient to go into shock.

What is an example of an immune suppressed situation?

It is caused by disease, malnutrition, emotional or physical stress, the very young and the very old *EX: Immunosuppressed due to chemo, radiation, or AIDS.***

What is the fate of the prophage during the lysogenic stage?

It is copied every time the host DNA replicates.

Refers to animal viruses remaining dormant in host cells

Latency

Endotoxins are also known as

Lipid A.

This type of viral replication allows the infected host cells to grow and reproduce normally for generations before they lyse

Lysogeny

This replication cycle usually results in death and lysis of host cell

Lytic replication

Explain the alternation of generations in algae.

Many multicellular algae reproduce sexually with an alternation of generations of haploid and diploid individuals. In such life cycles, diploid individuals undergo meiosis to produce male and female haploid spores that develop into haploid male and female thalli.

Explain how microbial extracellular enzymes affect virulence?

Many pathogens secrete enzymes that enable them to dissolve structural chemicals in the body and thereby maintain an infection, invade further, and avoid body defenses.

Name 3 mediums that could be used to culture a virus

Mature Organisms Embryonated Chicken Eggs Cell (Tissue) Culture

Morbidity

Means the same as disease. It is a change in state of health.

Contrast mitosis with meiosis, distinguishing homologous chromosomes, tetrads, and crossing over.

Mitosis cells have two main stages in their life cycle: a stage called interphase, during which cells grow and eventually replicate their DNA and a stage during which the cell's nucleus divides. It begins after the cell has duplicated its DNA such that there are two exact DNA copies. Meiosis is nuclear division that involves the partitioning of chromatids into four nuclei such that each nucleus receives only half the original amount of DNA. are chromosome pairs of approximately the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding loci. One homologous chromosome is inherited from the organism's mother; the other from the organism's father. Tetrads are two chromosomes, which are each made up of two DNA molecules, physically associated together during prophase 1 and metaphase 1 of meiosis. Crossing over is the process in which portions of homologous chromosomes are recombined during the formation of gametes.

Describe the normal microbiota, including resident and transient members.

Normal Microbiota- Microbes that colonize on the surface of the body without normally causing disease. ***These Microbes can change from week to week*** Resident Microbiota- They remain a part of the normal microbiota of a person throughout life. ***These are found on skin, mucous membranes of digestive tract, upper respiratory tract, distal portion of the urethra and vagina.***

Where are adhesions found on bacteria?

On fimbriae, flagella, and glycocalyces of many pathogenic bacteria.

Incubation period

The time between the infection and occurrence of the first symptoms or signs of disease.

Non-Living Reservoirs

Soil, water, and food can contain pathogens. ***EX: Water containing fecal matter can harbor Clostridium bacteria. This contamination can lead to botulism, tetanus, and other diseases.***

Adhesion factors

Specialized structures or attachment protein used by microorganisms for attachment or adhesion of themselves to a cell.

List three basic types of asexual spores found in molds.

Sporangiospores form inside a sac called a sporangium. Chlamydospores form with a thickened cell wall inside hyphae. Conidispores are produced at the tips or sides of hyphae, but not within a sac.

Adhesion factors for Helminths.

Suckers and hooks

Adhesion factors for Viruses and many Bacteria.

Surface lipoprotein and glycoprotein molecules called ligands enable them to bind to the receptors on the hosts cell.

What is the difference between symptoms, signs, and syndromes?

Symptoms- subjective characteristics of a disease that can only be felt by the patient. Signs- They are objective manifestations of disease that can be observed by others. Syndromes- A group of signs and symptoms that characterize a disease.

True or False Incorporation of provirus into host DNA is permanent

TRUE

True or False Most RNA viruses develop solely in cytoplasm

TRUE

List some of the problems involved in the classification of protists in particular.

The Protista included both large, photosynthetic, multicellular algae and nonphotosynthetic, unicellular protozoa. So they then abandoned classifying schemes that are so strongly grounded in large-scale structural similarities in favor of schemes based on similarities in nucleotide sequences and cellular ultrastructure.

Pathogenicity

The ability of a microorganism to cause disease.

Explain how microbial antiphagocytic factors affect virulence?

The body's phagocytic cells are called Macrophages and they engulf and remove invading pathogens. *Some bacteria produce chemicals that prevent the fusion of lysosomes with phagocytic vesicles and allows the bacteria to survive on phagocytes.

What occurs during viral uncoating?

The capsid breaks apart, releasing the viral genome.

Virulence

The degree to which a microorganism causes disease.

How is the lytic cycle different from the lysogenic cycle with respect to the infected host cell?

The host cell dies during the lytic stage.

Animal Reservoirs

The more similar an animal's physiology is to a humans physiology, the more likely it's pathogens will affect human health. Diseases that naturally spread from their usual animal host to a human host are called zoonoses.

Illness

The most severe stage of an infectious disease. S/S are most evident during this time.

Identify and describe the portals through which pathogens invade the body.

The pathogens can gain access through the skin, mucous membranes, and placenta. The parenteral route isn't exactly a portal, but is a way of circumventing the usual portals.

Placenta barrier

The placenta has two blood supplies. One for nutrients and one for waste. Since the two are separate, the fetus has an effective barrier. Although rare, some pathogens cross the placenta and can cause spontaneous abortion, birth defects, or premature birth.

What is airborne transmission?

The spread of a pathogen farther than 1 meter into the respiratory mucous membranes of a new host via an aerosol.

What is waterborne transmission?

The spread of disease via a water reservoir.

What is vehicle transmission?

The spread of pathogens via air, drinking water, food, and bodily fluids being handles outside of the body.

Etiology

The study of the cause of disease.

Compare and contrast three three divisions of fungi with respect to the formation of sexual spores.

Zygomycota are coenocytic molds called zygomycetes. Reproduce via sporangiospores to but the distinctive feature of most zygomycetes is the formation of sexual structures called zygosporangia. Ascomycota are characterized by the formation of haploid ascospores within sacs called asci. Asci occur in fruiting bodies called ascocarps. Basidiomycota characterized by production of basidiospores and basidiocarps.

Which of the following new chemicals would NOT be effective against Giardia?

a chemical that inhibits the formation of cell walls

Which of the following is an example of a mechanical vector?

a fly crawling on a sandwich

A reservoir is

a source of microbial contamination

A naked virus a. has no membranous envelope. b. has injected its DNA or RNA into a host cell. c. is devoid of capsomeres. d. is one that is unattached to a host cell.

a. has no membranous envelope.

A virus that is specific for a bacterial host is called a a. phage. b. prion. c. virion. d. viroid.

a. phage

Another name for a complete virus is a. virion. b. viroid. c. prion. d. capsid

a. virion.

The Clinical Case Follow-Up reveals that the African village has been afflicted with Ebola hemorrhagic fever caused by Ebola virus. This virus is an enveloped virus that acquires its outer covering when ___________________________.

an envelope is acquired during budding through a host cell's membrane

Which of the following describes the typical relationship between the resident microbiota and the transient microbiota?

antagonism

The phenomenon of transduction is associated with which of the stages of a bacteriophage infection cycle?

assembly

We sometimes are able to generate antibodies (immune system proteins) that bind to and cover up some of the proteins on the outermost portion of a virus while it is in the bloodstream. This renders the virus unable to reproduce. Which step of viral replication are antibodies directly preventing?

attachment

A clear zone of phage infection in a bacterial lawn is a. a prophage. b. a plaque. c. naked. d. a zone of inhibition.

b. a plaque.

Which of the following statements is false? a. Viruses may have circular DNA. b. dsRNA is found in bacteria more often than in viruses. c. Viral DNA may be linear. d. Typically, viruses have DNA or RNA, but not both.

b. dsRNA is found in bacteria more often than in viruses.

a virus that infects a bacterium

bacteriophage

Nancy's urinary tract infection from Escherichia coli is an example of an opportunistic pathogen ________________.

being introduced into an unusual site of the body

harmless neoplastic cells

benign tumor

Which of the following is considered part of the indigenous microbiota of the female reproductive system?

both Candida and Lactobacillus

Parasitology is the study of

both helminths and protozoa.

The fungus Pneumocystis jiroveci is found in the lungs of most people in low numbers, but in immunocompromised people it overgrows, resulting in severe respiratory problems. The fungus is best described as

both resident microbiota and opportunistic pathogen.

Which of the following statements is true? a. Viruses move toward their host cells. b. Viruses are capable of metabolism. c. Viruses lack a cytoplasmic membrane. d. Viruses grow in response to their environmental conditions.

c. Viruses lack a cytoplasmic membrane.

When a eukaryotic cell is infected with an enveloped virus and sheds viruses slowly over time, this infection is a. called a lytic infection. b. a prophage cycle. c. called a persistent infection. d. caused by a quiescent virus.

c. called a persistent infection.

Which of the following is not an acellular agent? a. viroid b. virus c. rickettsia d. prion

c. rickettsia

invasive neoplastic cells

cancer

protein coat of virus

capsid

Conjugation is a reproductive process associated with which of the following types of protozoa?

ciliates

Staphylococcus bacteria are commonly present in the human nasal cavity but rarely cause disease of the upper respiratory system. This situation is an example of __________.

commensalism

Which of the following is a protozoan stage that allows for transmission of intestinal parasites from one host to another?

cyst

transcribes DNA from RNA

retrovirus

Reverse transcriptase is associated with which of the following?

retroviruses

Consider the bacterial agents responsible for Nancy's urinary tract infection and intestinal infection. These organisms can be described as _____________.

symbionts that are typical normal microbiota

Axenic systems of the body include

the kidneys.

Most of the fungal species are classified into three divisions based on _____.

the type of sexual spore produced

When shellfish ingest dinoflagellates, _____.

they can become poisonous

Which of the following situations might cause normal microbiota to become opportunistic pathogens?

treatment of a cancer patient with radiation

Number of viruses produced depends what?

type of virus and size and initial health of host cell

removal of capsomeres from a virion

uncoating

Plague is transmitted through the bite of an infected flea. Which of the following best describes this mode of transmission?

vector transmission

A dog develops a diarrheal disease after drinking water from a creek during a hike with his owner. Which of the following best describes this method of disease transmission?

vehicle transmission

A group of campers becomes ill from drinking stream water that has been contaminated by wastes from a farm upstream. Which choice contains the terms that could describe transmission of this disease?

vehicle, waterborne, fecal-oral

Why do most viruses infect only particular host's cells?

viral surface proteins are complementary to proteins on host cell surface

complete viral particle (not infecting cell)

virion

Which of the following infectious particles do not have protein in their structure?

viroids

The fusion of two gametes produces a

zygote.