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101 Cards in this Set

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How is an endospore formatted?

DNA is replicatedDNA align along cells long axisCytoplasmic membrane invaginates toform forespore

Cytoplasmic membrane…

A cortex of calcium and dipicolinicacid is deposited between membranes

Spore coat forms around endospore

Maturation of endospore completionof spore coat increase in resistance to heat and chemicals by an unknown chemical

Endospore released from originalspore

What are the three domains?


Why do Eukarya and Archaea have more in common?

Share themost recent ancestors

Livingthings change over time because of mutations and evolution-->organism different from ancestor

Evolutionexplains diversity and change of organisms

What are the Achaea characteristics?


Cellmembrane lipids have branched hydrocarbon chains

Lack tRNAspecific for thymine[amino acid in this case]

AUG codoncodes for methionine (prokaryotes – N-formylmethionine)

Reproduceby binary fission, budding, or fragmentation

Most arecocci, bacilli, or spiral forms; unusual shapes exist

Not knownto cause disease in humans or animals

Could begram positive or gram negative

Few lackscell wall

Rangingfrom aerobes to facultative anaerobes to strictly anaerobes

Not known to cause diseasein humans or animals

What are thecharacteristics of methanogens?


Some livein swamps and marshes

Otherslive in the gut of caws and termites Producemethane (CH4) as a waste product→methane gas→ used for energy purposes

Byoxidizing H2

What are thecharacteristics of deeply branching bacteria?

Scientistsbelieve these organisms are similar to earliest bacteria


Live inhabitats similar to those scientists think existed on early Earth

Aquifex-considered representing earliest branch of bacteria

What isimportant about Nitrogen Metabolism?

Prokaryotescan metabolize nitrogen in a variety of ways

Longchains of bacteria with some cells different from other with slightly differentproperties in same colonies as the divide they differentiate→role: all living things need nitrogen-->these cells called heterocyst arespecialized and convert atmospheric nitrogen and hydrogen and produce ammonia

Photosyntheticcells to survive need to have some sort of nitrogen

What are thecharacteristics of Bdellovibrio?

Pathogenic→not to us but to other bacteria specifically to gram-negative bacteria

Not apathogen to eukaryotes

InfectsGram negative bacteria→ they find a host, enter the host, stayoutside of cytoplasm, replicate, divide, pop out and go find another…infect another bacteria to reproduce

Drillsthrough the cell wall with hydrolytic enzymes

Thenlives in the periplasmic space

Uses thenutrients from the cell


What are all of the Archaea?





Explain why meiosis is necessary in sexuallyreproducing organisms

Diploid nuclei use meiosis toproduce haploid daughter nuclei for sexual reproduction

How does the cell wall of fungi differ from that ofplants?

the main difference is that plant cell walls aremade of cellulose and fungi cell walls are composed of chitin

Most fungi are saprobic. Explain

As they feed on dead organicmatter, saprophytic fungi decompose it into simple molecules that go back intothe soil and can be reused by plants and all other organisms.

Their ability todemolish organic matter has been used by man, in particular to destroy foodsand clothes (cotton and leather items).

What two groups of organisms make up Lichens? How do they benefit each other?

Fungus + algae

The fungal hyphae provide most ofthe lichen’s mass and give it its overall shape and structure.The algal component usuallyoccupies an inner layer below the lichen surface

Important in creation of soil fromrock

How do plants benefit from their associationwith mycorrhizae. Why?

Are mutualistic associations ofplant roots and fungi.

Fungal mycelium provides increasedsurface area.

The fungus provides minerals fromthe soil for the plant, and the plant provides organic nutrients.

Name a predatory fungi and the name of theirprey

Nematode trapping fungi, or“nematophageous fungi,” is carnivorous fungi that have developed methods andstructures that enable them to successfully trap and consume nematodes.Nematode trapping fungi are responsible for keeping the nematode population incheck and are an important part of the subsoil ecosystem.

What are the three layers the body of lichen is composed of?

A thin, tough upper layer and aloosely packed lower layer that shield the photosynthetic cells in the middlelayer.

What are the three types of lichen?

Compact crustose lichens

Foliose lichens

Fruticose lichens

What are the characteristics of Lichens?

Are efficient at acquiringnutrients; they survive with low moisture, temperature, or poor soil.Live in extreme environments and onbare rocks; they help form soil.

Take up pollutants and cannotsurvive where the air is polluted

Reproduce asexually by releasingfragments that contain hyphae and an algal cell

What is the nutrition of fungi?

Acquire nutrients by absorption

Most are saprobes→ eatdecaying tissues…beef… animalbodies and absorb the goodiesSome trap and kill microscopicsoil-dwelling nematodes

Haustoria allow some to derivenutrients from living plants and animals

Most are aerobic; some are anaerobic;many yeasts are facultative anaerobes

How are people infected by giardia?

Peoplemost often become infected with Giardia by drinking water contaminatedwith human feces containing the parasite in the dormant cyst stage.

Boiling or filtering water that may becontaminated can prevent infection

What is the distribution of Protozoa?

Require moist environments

Most live worldwide in ponds,streams, lakes, and oceans; critical members of plankton

Some live in moist soil, beachsand, and decaying organic matter

Very few are pathogens

What is the classification of Protozoa?



Lack a cell wall

With exception of apicomplexans,they are also motile by means of cilia, flagella, and/or pseudopodia

What are the main differences between diploid and haploid?

Body cells have 46 chromosome[diploid] total while sex cells have only 23 chromosomes [haploid]

What aresome of the characteristics that distinguish organisms in Domain Archaea fromthose in Domain Bacteria?

DomainArchaea: no peptidoglycan in their cell wall, ether linkage membrane lipids,methionineDomainBacteria: contains peptidoglycan in their cell wall, ester linkage for membranelipids, Formylmethionine

What are viruses’ characteristics?

Miniscule, acellular, infectiousagent having one or several pieces of either DNA or RNA

No cytoplasmic membrane, cytosol,organellesHave extracellular andintracellular state

What are viruses’ functions?

Cause many infections of humans,animals, plants, and bacteria

Cannot carry out any metabolicpathwayNeither grow nor respond to theenvironmentCannot reproduce independently
Obligate intracellular parasites

What are the characteristics of viruses- extracellular state

Called virion

Protein coat (capsid) surroundingnucleic acidNucleic acid and capsid alsocalled nucleocapsidSome have phospholipid envelope

Outermost layer providesprotection and recognition sites for host cells

What are the characteristics of viruses- intracellular state

Capsid removed

Virus exists as nucleic acid

What are the structure, origin, and function of viralcapsid?

Structure: Capsid composed ofproteinaceous subunits called capsomeres-->some capsids composed of single type of capsomere; other composed of multipletypes-->capsomere is a bunch of proteins

Function: protein coats thatprovide protection for viral nucleic acid and means of attachment to host’scells

Origin: capsules come from arecells, host cells but put there on proteins on it to modify it

What are the structure, origin, and function ofviral envelope?

Origin: Virus gains the envelopefrom their host.Structure: Membranes surroundingits capsid, envelopes are made up of proteins, phospholipid bilayer, and someglycoproteins protruding out (looking like spikes) at the surface of the virus.

Function: Protection, hostrecognition, and providing shape to the virus

How viruses are specific for their host?

Most only infect particular kindsof host’s cellsDue to affinity of viral surfaceproteins or glycoproteins for complementary proteins or glycoproteins on hostcell surface

May only infect particular kind ofcell in hostGeneralists – infect many kinds ofcells in many different hosts

Compare two mechanisms of entry used by animalviruses to enter the host

1st mechanism: thevirion attaches to the host cell receptors by specific proteins on its surfacecalled spikes. The envelop of the virus fuses w/ the plasma membrane of thehost and the nucleocapsid is released directly into the cytoplasm. The nucleicacid then separates from the protein coat.

2nd mechanism: the enveloped virus absorbs to the host cell byspecific proteins on its surface and the virion is taken in by endocytosis. Inthis process the host cell plasma membrane surrounds the whole virion and formsa vesicle. The envelope of the virion then fuses w/ the plasma membrane of thevesicle and the nucleocapsid is release into the host’s cytoplasm. The capsidprotein is then removed, releasing the nucleic acid in of the virus.

Viruses are classified based on what criteria?

Type of genetic material theycontain

Kinds of cells they attack

Size of virus

Nature of capsid coat

Shape of virus

Presence or absence of envelope

Classified viruses similar to theLinnaean classification system: order, family, genus, species.

What are Viroids characteristics?

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

Similar to RNA viruses, but lackcapsid

May appear linear due to H bonding

What are Prions and how do Prions replicate?

Prions are unique pathogens in thatthey appear to have no nucleic acid and thereby differ from viruses, bacteria,fungi and other pathogens. Prions are resistant to procedures that break downnucleic acid and destroy biological forms of pathogens.

Lacking nucleic acid, prions cannot reproduce, but they replicate bystimulating normal cellular prion protein to refold into a form called PrPscrapie (PrPSc) – named after scrapie,the first TSE discovered.

The conversion of normal prion protein (PrPC)into abnormal prion protein (PrPSc) and replication of prions in thebrain causes degeneration of neural tissue and, ultimately, death.

What are two diseases that are caused by prions?

Mad cow disease

Trasmissible spongiformencephalopathies (TSE) are neurodegenerative diseases that destroy nerve tissuein the brain. TSEs are untreatable and fatal.

What method can be used to disinfect thepresence of prions?

Only destroyed by incineration; notcooking or sterilization

What are Prions characteristics?

Composed of single protein PrP

Prion PrP converts cellular PrPinto prion PrP by inducing conformational change

All mammals contain gene that codesfor primary sequence of amino acids in PrPNormally, nearby proteins andpolysaccharides force PrP into cellular shape

Excess PrP production or mutationsin PrP gene result in initial formation of prion PrP

When prions present, they causenewly synthesized cellular PrP to refold into prion PrP

What are proto-oncogenes?

A normal gene which, when alteredby mutation, becomes an oncogene that can contribute to cancer.

Proto-oncogenesmay have many different functions in the cell.

Some proto-oncogenes providesignals that lead to cell division.

Other proto-oncogenes regulate programmedcell death

How do protooncogenes become oncogenes? Explain the role of viruses in this process.

Genetic damage found in cancercells is of two types, one of the types is called dominant and the genes havebeen termed proto-oncogenes. The distinction between the terms proto-oncogeneand oncogene relates to the activity of the protein product of the gene.

Aproto-oncogene is a gene whose protein product has the capacity to inducecellular transformation given it sustains some genetic insult.

An oncogene is agene that has sustained some genetic damage and, therefore, produces a proteincapable of cellular transformation.

The process of activation ofproto-oncogenes to oncogenes can include retroviral transduction or retroviralintegration (see below), point mutations, insertion mutations, geneamplification, chromosomal translocation and/or protein-protein interactions.

At least how many mutations are necessary for development ofa cancer cell?

Cancer usually requires at least 6mutations to occur before the normal growth control checks are removed and thehealthy cell changes into a malignant one. It usually takes many years forthese mutations to build up and transform a normal cell into a malignant(cancerous) cell.

Chicken eggs are used for culturing viruses for a variety ofuses, such as vaccine development and other research areas. Why is the chicken egg a good site forculturing viruses.

Eggs support a fairly wide range ofanimal and human viruses – hence their importance in the diagnostic service.

Embryonatedhen’s eggs will support the growth of some viruses.

Not all viruses will growin the tissues of embryonated eggs initially but many can be adapted to growthin eggs without much difficulty.

Eggs provide a suitable means for the primaryisolation and identification of viruses, the maintenance of stock cultures andthe production of vaccines.

Besides chicken eggs, what else is used toculture viruses?

Animals and cell cultures

How does Viruses Cause Cancer?

Some carry copies of oncogenes aspart of their genomes

Some stimulate oncogenes alreadypresent in host

Some interfere with tumorrepression when they insert into host’s repressor gene

Several DNA and RNA viruses areknown to cause ~15% of human cancers

What is the Factors Involved in Activation of Oncogenes?

Ultraviolet light




What is the latency of animal viruses?

When animal viruses remain dormantin host cells

May be prolonged for years with noviral activity, signs, or symptoms

Some latent viruses do not becomeincorporated into host chromosome

When provirus is incorporated intohost DNA, condition is permanent; becomes permanent physical part of host’schromosome

What are the difference between Lytic andLysogenic cycle?

In the Lytic Cycle:

Viral DNA destroys Cell DNA, takes over cell functions anddestroys the cell.

The Virus replicates and produces progeny phages.

There are symptoms of viral infection.

Virtulant viral infection takes place.

In the Lysogenic Cycle:

Viral DNA merges with Cell DNA and does not destroy the cell.

The Virus does not produce progeny.

There are no symptoms of viral infection.Temperate viral replication takes place.

In mucous membranes, what is the most commonly used site ofentry/ examples?

Respiratory Tract-- entry is through the nose,mouth or eyes

Pathogens can use gastrointestinal tract as a route ofentry?

Those pathogens are able to survivethe acidic pH of the stomach

Interactions of ligand with host receptor can what for hostcells?

Determine specificity for hostcells

Infection versus Disease

Infection is the invasion of thehost by a pathogen

Disease results only if theinvading pathogen alters the normal functions of the body

Disease is also referred to asmorbidity

What are the manifestationsof disease?




Asymptomatic,or subclinical

What is etiology?

Studyof the cause of disease

What did Robert Koch develop?

RobertKoch developed a set of postulates one must satisfy to prove a particularpathogen causes a particular disease

What are the Exceptions toKoch’s Postulates?

UsingKoch’s postulates is not feasible in all cases

Somepathogens can’t be cultured in the laboratory

Somediseases are caused by a combination of pathogens and other cofactors

Ethicalconsiderations prevent applying Koch’s postulates to pathogens that require ahuman host

What are the difficulties insatisfying Koch’s postulates?

Diseasesthat can be caused by more than one pathogen

Pathogensthat are ignored as potential causes of disease

What are the Virulencefactors of infectious diseases?



What are the virulencefactors that contribute to an organism’s virulence?

Adhesionfactors→ how do they attach canfind a way to block it

Extracellularenzymes→ block enzymesToxins→ fight the toxins they releaseAntiphagocyticfactors→ factors preventphagocytosis by the host’s phagocytic cells

What are the two types oftoxins?



What factors preventphagocytosis by the host’s phagocytic cells?


Antiphagocyticchemicals: some prevent fusion of lysosome and phagocytic vesicles

What are the stages ofInfectious diseases?






What is the movement ofPathogens out of the host?

Pathogensleave host through portals of exits

What are the three types ofreservoirs?

Animalreservoir: zoonoses



What are the various routesto acquire zoonoses?

Directcontact w/ animal or its waste



What are the three groups ofmodes of infectious disease transmission?




What are the twotypes of Vehicle Transmission?



What are themany different methods of classification of infectious diseases?

Thebody system they affect

Thetaxonomic groups of the causative agentTheirlongevity and severity

Howthey are spread to their host

What are the 3approaches that Epidemiologists use to Study Disease Dynamics




What are the 3types of nosocomial infections?




How do theycontrol nosocomial infections?

Involvesprecautions designed to reduce the factors that result in diseaseUniversalPrecautions instituted by the CDC to limit exposure to pathogens

Handwashing is the most effective way to reduce nosocomial infections

How do publichealth agencies work to limit disease transmission?

Monitorwater and food safety

Publichealth agencies campaign to educate the public on healthful choices to limitdisease

What areopportunistic pathogens? Under whatconditions do they become harmful?

OpportunistPathogens: Normal microbiota that can cause disease under certain circumstancesConditionsthat provide opportunities for pathogens


-Changesin the normal microbiota- changes in relative abundance of normal microbiotamay allow opportunity for a member to thrive and cause disease

-Introductionof normal microbiota into unusual site in the body

Examples of Contact transmission:

Touching, handshaking, animal bite,sexual intercourse (rabies, anthrax, syphilis, genital herpes)

Examples of Direct Contact transmission:

Sexual intercourse and kissing

Examples of Indirect Contact transmission


Bedding,dishes, money, thermometer, contaminated needles

Examples of Vehicle transmission:

(Whooping cough, influenza,pneumonia) Cooking or eating utensils, beddingor clothing, toys, surgical or medical instruments (like catheters) ordressings

Water, food, drinks (like milk) andbiological products like: blood, serum, plasma, tissues or organs can also bevehicles.

Drinking glass

Examples of Vector transmission:

Arthropods, mosquitoes, ticks, lice

Examples of Droplet transmission:

Sneezing, coughing, laughing,talking

Examples of Airborne transmission:

Measles virus, spores born by fungithat cause histoplasmosis

Examples of Mechanical Vector transmission:

House flies walk across feces ofinfected person to food of non-infected person

Examples of Biological Vector transmission:

mosquitoes and ticks

How do resident Microbiota help?

They compete w/ other organism→ reducethe possibility of bad microorganisms that are pathogenic

Why cannot transient microbiota persist in the body?

Competition from othermicroorganismsElimination by the body’s defensescells→ ifparasitic

Chemical or physical changes in thebody

What are the four major portals of entry for pathogens?


Mucous membranes


Parenteral route

What are the functions of the capsid?

1. PROTECTS genome against inactivation by nucleases

2. carries VAP

3. antigenic characteristic

4. structural symmetry

5. packaging essential enzymes

host must provide virus with?

1. energy producing system

2. protein synthesizing machinery

3. low molecular weight precursors for synthesis of viral proteins and nucleic acids

How can all these different things allow to survive in a competitive environment?

it can be allowed in the competitive enviroment because of attachment. If the things find attachment they will be able to survive, if not the acid in our digest system will kill them. for example: glycocalyx can attach to our teeth.(morseals)

Identify and discuss the main factors affecting disease transmission

overall health of the host, age 5<70, gender, lifestyle, occupation, emotional state, climate

Define a compromised host

Host competence, risk factors for infection are immunocompromised, lifestyle, occupation, trauma, travel, age.A person or something having something wrong with them

List and discuss the five fundamental requirements for a pathogen to successfully infect a host.

1. Enter the host (portal of entry)

2. Establishment (sticking)

3. Avoid, evade, or compromise, the host's defenses

4. Damage the host (virulence factors)

5. Exit the host (portal of exit)

List the types of adhesion factors and the roles they play in infection.

Glycocalyx, flagella, fimbrae these all have a sticky outer coat that allow for sticking onto the host. Attachment proteins. Viruses & Bacteria

Explain how capsules and cell wall components contribute to pathogenicity.

Capsules and cell walls camouflage the disease so she WBC is checking for disease or foreign objects, it goes unnoticed and is able o break out later. Are able to grow and multiply and become stronger.

Describe the role of enzymes (leukocidins, hemolysis, coagulase, kinases, hysaluronidase, and collagenase) in a pathogen's virulence.

Leukocidins - chemicals that kill WBC

Hemolysins - Enzymes that break down RBC

Hyaluronidase - Breaks down connective tissue and collagen in host, which allows for infection to spread.

Collagenase is the same as hyaluronidase.

What is the overall picture?

CONTAMINATION --> Port of Entry --> adhere (stick/stay ex. glycocalyx) --> avoid host defenses (avoiding phagocytosis) --> virulence factors (what makes a pathogen) --> INFECTION --> DISEASE

Describe the relationships among the terms parasite, host, and pathogen

Parasite is what benefits. The pathogen is the parasite that damages the host.

Explain how a human is colonized with their normal (resident) microbiota

Coming down the birth canal during childbirth and being handled by relatives.

List Koch's postulates. Explain some exceptions to Koch's postulates.

1. the same pathogen must be present in every case of the disease

2. the pathogen must be isolated from the diseased host and grown in pure culture.

3. the pathogen from the pure culture must cause the disease when it is inoculated into a healthy susceptible laboratory animal.

4. the pathogen must be isolated from the inoculated animal and must be shown to be the original organism.

Differentiate a communicable from a noncommunicable disease.

communicable disease= a disease that spreads from one host to another, either directly or indirectly. EX: chick pox, herpes, TB (CONTAGIOUS)

noncommunicable disease= is not spread from one host to another. EX: tetanus; produces disease only when introduced into the body via abrasions or wounds. they are diseases cause by opportunistic pathogenic MO's

What are all the examples of Protozoa?







Gardia Lamblia

Trichomonas vaginalis





Phaeophytes [brown algae]

Rhodophyta [red algae]

Chlorophyta [green algae]

Volvox [green algae]

What are all the examples of fungi?

Basidiomycota [club fungi]



Parasitic fungi


What are the functions of bacterial endospores?

Provide resistance, ensure survival