MIC 102 Midterm 3

What are the different functions of hyphae?

Anchor, invade food source, or form reproductive structures

How is athlete's foot transmitted?

Between humans via fomites (anything that can carry the spores)

Lysozyme does which of the following? A) Disrupts cell membranes B) Hydrolyzes peptidoglycan C) Waterproofs the skin D) Propels gastrointestinal contents E) Propels the cilia of the respiratory tract

B) Hydrolyzes peptidoglycan

Holes produced in bacterial "lawns" by viruses are called A) Colonies B) Plaques C) Patches D) Lysis E) Clearance

B) Plaques

Viroids are _____ agents that infect _____. A) RNA; animals B) RNA; plants C) Protein; animals D) Protein; plants

B) RNA; plants

Which one of the following is NOT a function of complement? A) Stimulation of inflammation B) Stimulation of antibody formation C) Formation of membrane attack complexes D) Heightened level of phagocytosis

B) Stimulation of antibody formation

Bactrim, a sulfa drug used to treat urinary tract infections, does NOT harm host cells because eukaryotic cells A) Have efflux pumps for the drug B) Take in folic acid in the diet C) Do not transport the drug into the cell D) Are naturally immunized from the drug E) Make their own PABA precursors

B) Take in folic acid in the diet

What are the two most common bacteria used in probiotics?

Bifidobacterium and Lactobacillus

From where is histoplasmosis contracted?

Bird or bat droppings

What are germ-free animals referred to as?

Gnotobiotic animals

Which antifungal agent interferes with fungal growth and mitotic spindle?

Griseofulvin

Ringworm on the scalp is treated by which anti-fungal creams?

Griseofulvin Terbinafine Intraconazole Fluconazole

Different growth cycles of Histoplasma

Grow in the soil as molds Spores are inhaled into lungs and develop into yeast Yeast can travel to lymph nodes and spread via bloodstream

What is the scientific name for the False Morel? What is its active agent? What toxic compound is derived from it? How does it cause death?

Gyromitra esculenta Gyromitrin Monomethylhydrazine (MMH) Once the mushroom is ingested, vomiting and diarrhea several hours later, then dizziness, lethargy and headache. Severe infections leads to delirium, coma and death after 5-7 days

What are the symptoms of ergot poisoning?

Hallucinations, high fever, convulsions and death

What are the 4 general morphologies for viruses?

Helical, enveloped and non-enveloped Polyhedral, enveloped and non-enveloped

What two bacteria survive in the stomach?

Helicobacter pylori and Vibrio cholera

Three methods used for culturing animal viruses

Living animals Embryonated eggs Cell cultures

Immune cells produced by lymph nodes

Lymphocytes: T and B cells (adaptive immunity)

T cell can only bind to peptide antigen is presented by APC on a ____

MHC molecule

Which of the following are examples of an antigen-presenting cell (APC)? 1. Macrophage 2. Neutrophil 3. Dendritic cell 4. T cell 5. Plasma cell

Macrophage and Dendritic cell

**L11: Immune cells that are efficient in phagocytosis and intracellular killing

Macrophages

**L11: The Lectin Pathway is activated by ____

Mannose; Lectin binds to mannose

**L11: Immune cell that is found throughout the body but mostly in tissues that are exposed to external environment

Mast cells

**L11: Physical barrier protecting the respiratory tract?

Mucocuiliary escalator

Both septate and non-septate hyphae contain ____ ____.

Multiple nuclei

What is the difference between mycotoxicosis and mycetismus?

Mycotosicosis: fungi produce mycotoxins, which get transferred onto foods that we eat (don't eat the mushrooms) Mycetismus: poisoning from eating mushrooms

**L11: Immune cells that attack eukaryotic cells infected by microbes, destroy infected and cancerous host cells based on their lack of MHC class I antigens

Natural Killer cells

Classification of pathogenic fungi is determined by what 2 factors?

Nature of sexual spores Septation of hyphae

Human mouth is colonized by what bacteria?

Neisseria (gram negative cocci), Streptococcus and Lactobaccillus (gram positive rods)

**L11: Most plentiful immune cell in the blood Engulf and destroy by phagocytosis Active in intitial stages of infection

Neutrophil

**L11: Cells of the immune system

Neutrophils, Basophils, Eosinophils, Mast cells, Monocytes, Macrophages, Dendritic cells, Natural Killer cells and Lympocytes

Innate immunity consists of...

Nonspecific defenses, immediately available, without memory

Most fungi are ____ aerobic or ____ anaerobic

Obligatory; Facultatively

**L12: What cells can launch adaptive immune responses?

Only "professional" antigen-presenting cells (APCs) Must express MHC I and MHC II Macrophages, B cells and Dendritic cells

Single-stranded DNA viruses are referred to as... (1 name)

Parvoviridae

What 2 mechanisms do NK cells use to kill infected cells?

Perforin, a peptide that forms pores in the plasma membrane of target cells Granzymes, induces apoptosis (programed cell death) in target cells

What are 3 sources of ringworm infection?

Person to person Animal to person Environment to person

What are the 3 kinds of endocytoses?

Phagocytosis= takes in whole bacteria Receptor-mediated= initiated by binding to surface receptors Pinocytosis= "drinking" small volumes containing macromolecules

Structure of the fungal cell wall (inside to outside)

Phospholipid bilayer, chitin, glucan, and mannan

Innate immunity offers both ____ and ____ barriers to infection. It has ____ responses to destroy invading cells. Innate immunity kicks in when?

Physical and chemical Nonspecific At birth

(+) strand RNA viruses are referred to as... (2 names)

Picornaviridae Togaviridae

Which antifungal agent contains at least 2 double bonds?

Polyenes

Structure of a complex virus

Polyhedral head and helical sheath

Human teeth are colonized by what bacteria?

Prevotella and Fusonacterium (between gums and teeth) and Streptococcus mutans (dental plaque)

Cells that are derived from tissue slices and tend to die out after only a few generations

Primary cell lines

**L11: Why is interferon produced? What role does interferon play?

Produced as a host response to viral infection Interferons warn healthy host cells of a nearby infection and makes them resistant to viral infection

What is happening during the eclipse period of viral multiplication?

Progeny phages are being assembled within the cell

How do cytotoxic T cells kill infected cells?

Release of granzymes and perforin initiates apoptosis (similar to NK cells)

Double-stranded RNA viruses are referred to as... (1 name)

Reoviridae

**L12: What is the advantage of adaptive immunity?

Response is faster and more potent than the primary response

Reverse transcriptase RNA viruses are referred to as... (1 name)

Retroviridae

Retroviruses contain what 3 enzymes?

Reverse transcriptase: infection Integrase: integration Protease: cleaves polypeptide into subunits

How do T helper cells assist other immune cells?

Secrete cytokine to direct actions of other cells

2 types of hyphae

Septate and non-septate

What is one benefit of using primary cell lines over continuous cell lines?

They maintain the same characteristics as those in the body

What are 3 candidiasis?

Thrush, yeast infection and invasive candidiasis (Candida in the bloodstream)

What are the primary lymphoid organs and what occurs there?

Thymus (T cells) and Bone marrow (B cells) Where lymphocytes mature

Fungus can cause disease in what 3 ways?

Toxicoses (poisoning via ingestion) Fungal infection (fungus growing in or on body, causing disease) Allergies (inhalation)

The genome of Influenza A Virus is divided into how many segments of [(+) strand/(-) strand] RNA? For what purpose?

8 (-) strands; All encode for different proteins

What are the virulence factors that make C. albicans harmful to its host?

Adhesin proteins promote binding and reduces removal from the host Morphogenesis creates invasive filaments Phenotypic switching alters yeast's adherence, antigen expression and tissue affinity

Aspergillus molds produce which mycotoxins?

Aflatoxin

4 body locations that ringworm can be found and their medical names?

Feet = tinea pedis Scalp = tinea capitis Groin = tinea cruris Beard = tinea barbae

What are the symptoms of a minor histoplasmosis infection? A major infection?

Fever, cough, fatigue, chills, headache, chest pain and body aches Central nervous system infection

The hematopoietic stem cells in the bone marrow can become which of the following cell types? 1. Red blood cell 2. T cell 3. B cell 4. Monocyte 5. Macrophage

All of the above

What is the toxin produced by Amanita phalloides and what does it do?

Alpha-amanitin; inhibits RNA polymerase which inhibits mRNA synthesis

**L9: Three ways that fungi can be harmful?

Food spoilage, disease or poisonous

H. capsulatum has which iron acquiring enzyme? what does it do?

Gamma-glutamyltransferase Reduces ferric to ferrous iron

What anti-fungal medicine is used to treat histoplasmosis?

Itraconazole

Why is Histoplasma capsulatum unique from other intracellular fungal pathogens?

Its ability to prevent the acidification of phagolysosome following ingestion by alveolar macrophages, limiting antifungal effectiveness of the compartment

What is the hallmark of adaptive immunity?

Memory

**L12: How are antibodies produced?

B cells produce antibodies. Cytokine from helper T cells stimulate B cells to multiply and differentiate into antibody plasma cells and memory cells

TH1 cells activate _____. A) B cells B) Cytotoxic T cells C) Antibodies D) Humoral immunity

B) Cytotoxic T cells

Infections that are acquired during a stay in a hospital are called A) Clinical B) Nosocomial C) Gnotobiotic D) Resistant E) Pathogenic

B) Nosocomial

Infectious agents for which the nucleic acid genome is itself the entire infectious particle are called: A) Prions B) Viroids C) Viruses D) Bacteria E) Virions

B) Viroids

What two bacteria inhabit the intestines?

Bacteroides thetaiotaomicron and Escherichia coli

**L11: Immune cell that is a nonphagocytic cell that expresses Fc receptors for IgE Involve in allergic reactions

Basophils

__________ gained notoriety when they were implicated in brain infections, such as what is popularly known as mad cow disease. A) Viroids B) Viruses C) Prions D) Bacteria E) Virions

C) Prions

A bacterial strain exhibiting a mutation in the gene for DNA gyrase would most likely inhibit the activity of what class of antibiotics? A) Metronidazoles B) Tetracyclines C) Quinolones D) Rifampins E) Sulfa drugs

C) Quinolones

_____ cells are associated with _____ immunity while _____ cells are part of _____ immunity. A) B; cell-mediated; T; innate B) T; humoral; B; cellular C) T; cell-mediated; B; humoral D) T; humoral; B; nonspecific

C) T; cell-mediated; B; humoral

**L11: The Alternative Pathway is activated when ____

C3 combines with factors B, D, and P on the surface of a microbe. This causes C3 to split into fragments C3a and C3b

Dimorphic fungi...

Can grow as either mold or yeast, depending on environment

What fungus causes yeast infection?

Candida albicans

Fungi are ____heterotrophs

Chemo

Viruses have what kind of genomes?

Circular, linear or segmented

**L11: What are the 3 complement pathways?

Classical, Alternative and Lectin

Ergot is produced by what fungus?

Claviceps pupurea

Pseudomembranous enerocolitis is caused by what bacteria?

Clostridium difficile

Ringworm on the skin (athlete's foot and jock itch) are treated by which anti-fungal creams?

Clotimazole Miconazole Terbinafine Ketoconazole

Cell lines that are derived from transformed (cancerous) cells and grow indefinitely

Continuous cell lines

Which fungus causes excessive thirst, urination and severe pain the lumbar region upon ingestion? What is the toxin?

Cortinarius gentilis Orellanine

A pathogen that can avoid the complement component C3b would directly protect itself from? A) Opsonization B) Triggering inflammation C) Lysis D) Inducing interferon E) Antibodies

A) Opsonization

The genome of __________ ssRNA viruses can serve directly as mRNA. A) Positive-sense (+) B) Negative-sense (-) C) All D) Double-stranded E) Prion

A) Positive-sense (+)

How can you prevent contamination of a cell culture?

Addition of antibiotics

What are the 2 forms of fungi?

Yeast (unicellular) and Molds (multicellular, filamentous)

Polycistronic mRNA

mRNA that can give rise to several proteins

**L11: Immune cells that have no phagocytic capability until they enter body tissues and differentiate into macrophages

Monocytes

What is the appearance of normal or primary cells on solid medium? Transformed or continuous cells?

Monolayer Clumped in a non-monolayer

Where do Aspergillus molds grow?

Mostly on grain and nut crops

Fungal toxins are called what?

Mycotoxins

How does Amanita phalloides cause death?

Once the mushroom is ingested, damages liver and kidneys, causing hepatic and renal failure

When double-stranded DNA or a retrovirus is integrated permanently into a chromosome of the host cell it is called?

Provirus

RNA viruses must carry what in order to replicate?

RNA polymerase

(-) strand RNA viruses are referred to as... (1 name)

Rhabdoviridae

**L11: What are the chemical barriers to infection?

Sebum (oil from sebaceous glands), perspiration, gastric juices, urine, vaginal pH and transferrin (iron-binding protein in blood)

Inflammation: Capillary cells express ____ Damaged tissue secretes ____

Selectins Bradykinin

Ergot's mechanism of action is complex; it is structurally similar to ____, ____, and ____, and can therefore bind to several receptors acting as an ____.

Serotonin, dopamine, and epinephrine; agonist (a substance that initiates a physiological response)

How are viruses classified?

Type of nucleic acid, strategy for replication, and morphology

Biosynthesis mechanism of double-stranded DNA viruses

Uses either host or viral RNA polymerase. One strand of viral DNA is transcribed into mRNA. DS-DNA >> mRNA >> capsomere protein + DNA

What is the name for a complete infectious viral particle?

Virion

Lytic cycle definition

Host cell fills with virions and bursts, ends with lysis and cell death

Activated T cells undergo clonal expansion and differentiate into either ____ cells or ____ cells

Effector (action cells; cytotoxic T cells) Memory

**L11: Immune cell that defends against parasites, such as helminths

Eosinophil

What are two therapeutic forms of Ergot and each of their uses?

Ergometrine: Stimulate labor contractions and constrict blood vessels after birth Ergotamine: Treat migraines and lower high blood pressure

Exposure to mutagens can lead to ____ of the prophage and initiation of the ____ cycle.

Excision; Lytic

Poisonous mushrooms are also referred to as....

Toadstools

What does an MOI of 1 mean?

# bacteriophage = # bacteria This means that every host cell is infected

Biosynthesis of (+) single-stranded RNA viruses

(+) strand is already mRNA, which can be directly translated into viral proteins (+) >> (-) or (+) >> capsomere protein

Biosynthesis of (-) single-stranded RNA viruses

(-) strand CANNOT be used as mRNA Must be copied into a (+) template strand (-) >> (+) or mRNA >> capsomere protein or (-)

Biosynthesis mechanism of double-stranded RNA viruses

(-) strand is copied into mRNA

What are 6 ways that antibodies protect us?

-Block binding of pathogens/toxins on host cells -Fixes complement to bacterial structures, leading to lysis -Opsonization (increases phagocytosis) (killing of bacterial cells) -Agglutination (clumping of antigen, increasing phagocytosis) (killing of viruses) -ADCC killing of infected cells by NK cells (killing of antibody-coated cells) -Activates eosinophils, basophils, and mast cells by providing an exposed FC region for the cells to bind to (Killing of helminths)

Virus family names end in -____ Genus names end in -____

-viridae -virus

**L10: 6 Steps of Multiplication of Animal Viruses

1) Attachment 2) Penetration: Via endocytosis or fusion 3) Uncoating: Separating of viral nucleic acid from its protein coat by viral or host enzymes 4) Biosynthesis 5) Maturation 6) Release: Via budding with enveloped viruses (may or may not kill host) or rupture with non-enveloped viruses (kills)

**L10: 5 Steps of the Lytic Cycle

1) Attachment: Phage attaches by tail fibers to cell wall and binds to components of host cell 2) Penetration: *Phage lysozyme* breaks down part of cell wall, DNA enters cell 3) Biosynthesis: Eclipse period; use of cell machinery 4) Maturation: Assembly of virions 5) Release: *Phage lysozyme* breaks down cell wall and lyses cell

**L11: Describe phagocytosis

1) Bacterium binds to the surface of phagocytic cell. 2) Phagocyte pseudopods extend and engulf the organism 3) Invagination of phagocyte membrane traps the organism within a phagosome 4) A lysosome fuses and deposits into the phagosome. Enzymes cleave macromolecules and generate reactive oxygen species, destroying the organism

**L11: Describe the 5 steps that all 3 complement pathways share

1) Inactivated C3 splits into activated C3a and C3b 2) C3b binds to microbe, resulting in opsonization 3) C3b splits C5 into C5a and C5b 4) C5b, C6, C7, and C8 bind together sequentially and insert into the microbial plasma membrane. C5b through C8 act as a receptor to attract a C9 fragment, and additional C9 fragments are added to form a channel. Together, C5b through C8 and the multiple C9 fragments form the membrane attack complex, *resulting in cytosis*. 5) C3a and C5a cause mast cells to release histamine, resulting in inflammation; C5a attracts phagocytes

**L11: Describe steps of inflammation

1) Infection introduces pathogens 2) Macrophages engulf pathogens and release chemical alarm signals (*cytokines*) and vasoactive factors 3) Vasoactive factors and cytokines help deliver additional phagocytes 4) Cytokines initiate healing as pathogens are destroyed

A patient who accidentally takes too many does of chloramphenicol during a Salmonella sp. infection could possibly come down with A) Aplastic anemia B) Liver cancer C) Gastroenteritis D) Ulcers E) Growth plate defects

A) Aplastic anemia

Which of the following is the clade that is home to the deadly poison-producing mushrooms called Amanita or "destroying angel"? A) Basidiomycota B) Ascomycota C) Oomyctes D) Zygomycota E) Yeasts

A) Basidiomycota

Yarrowia lipolytica is a dimorphic yeast; this means that it can" A) Be single-cellular or form a mycelia B) Form linear or branching hyphae C) Undergo mitosis or meiosis D) Have one or two flagella E) Form aerial or surface mycelium

A) Be single-cellular or form a mycelia

Which drug-resistance mechanism allows bacteria to become resistant to more than one drug at the same time? A) Drug efflux B) Modification of the target C) Inactivation of the drug D) Modification of the drug

A) Drug efflux

What is a Prion?

An abnormal form of a normally occurring cell protein that assumes an abnormal conformation. Which contain no nucleic acid

Which markers are found on all nucleated cells? A) MHC class I molecules B) MHC class II molecules C) CD4 D) CD8

A) MHC class I molecules

How does antigenic variation affect adaptive response?

Adaptive response depends on *structure based memory*. If the virion has changed, the AR will not recognize it.

Which mushroom produces the deadliest poison?

Amanita phalloides aka "death cap"

Which antifungal agents increases membrane permeability such that essential substances leak from the cell?

Amphotericin B and Nystatin

Which antifungal drugs are used for treating systemic fungal infections?

Amphotericin B and Nystatin

**L11: The Classical Pathway is activated by ____

Antibody-antigen complexes

**L12: 4 ways adaptive immune responses are initiated for T cells?

Antigen presentation Cell signaling Productions of stimulatory molecules

How does antigenic shift effect virus-host interactions?

Antigenic shift can cause a mix of 2 different viruses (avian and human influenza) such that a single virion will be able to produce both kinds of HA, therefore the virus can evade host defense because the host will not recognize the foreign HA

Adaptive immunity reacts to ____. Adaptive immunity can act faster after a second exposure because it retains a ____.

Antigens Memory

Viroids... have circular, single stranded RNA that does not code for ____ >> They have no ____ They replicate by ____ RNA polymerase They have some catalytic ability: ____

Any protein Capsid Host Ribozyme

Plaques on a solid media represent what?

Areas where bacteriophage have replicated and spread

Humoral immunity is related to __ cells

B

The fungus Neocallomastix sp. is found in animal rumens and directly helps with: A) Methanogenesis B) Digestion of tough plant material C) Nutrient absorption through the intestinal wall D) Fermentation processes E) Preventing ulcer formation

B) Digestion of tough plant material

What do all viruses contain? A) A genome and an envelope B) A capsid and an envelope C) A capsid and a genome D) A capsid, an envelope, and a genome

C) A capsid and a genome

Tinea pedis, the fungi that causes athlete's foot, has male and female mycelium tips that can fuse and ultimately form ascospores. Which phyla do they belong in? A) Chytridiomycota B) Zygomycota C) Ascomycota D) Basidiomycota E) Sporomycota

C) Ascomycota

Perforins and granzymes are found in _____. A) Helper T cells B) Antigen-presenting cells C) Cytotoxic T cells D) B cells

C) Cytotoxic T cells

Some viral species may derive their __________ from intracellular membranes, such as the nuclear membrane or endoplasmic reticulum. A) Capsid B) Genome C) Envelope D) Neck E) Tail fibers

C) Envelope

The branching structures seen in fungi are called: A) Spores B) Conidia C) Hyphae D) Blastoconidia E) None of the above

C) Hyphae

This dimeric antibody class often occurs in secretions of the respiratory and gastrointestinal tracts. A) IgE B) IgM C) IgA D) IgG

C) IgA

The capsid is composed of protein subunits called what?

Capsomeres

What is happening during the Rise period or viral multiplication?

Cells lyse and virions are released

What function does reverse transcriptase perform?

Copies the single-stranded viral RNA into a complementary strand of DNA. It also degrades original viral RNA

A patient suffering from a systemic mycosis with aspergillosis would best be served by which antifungal? A) Imidazole B) Lamisil C) Nystatin D) Amphotericin B E) Griseofulvin

D) Amphotericin B

Which of the following statement about inflammation is false? A) Vasodilation results in leakage of blood components B) The process can cause damage to host tissues C) Neutrophils predominate at the site during the early stages of acute inflammation D) Apoptosis induces inflammation E) The cardinal signs of inflammation are redness, swelling, heat, and pain

D) Apoptosis induces inflammation

Quorum sensing is a new approach to antibiotic therapy that works by A) Preventing horizontal transfer of genes B) Stopping bacterial motility C) Binding virulence transcription factors D) Halting bacterial cell-cell communications E) Regulating nutrient uptake to alter metabolism

D) Halting bacterial cell-cell communications

A key factor in the evolution of killer strains of influenza is that they: A) Only have eight genes B) Have an RNA genome C) Contain reverse transcriptase D) Have a segmented genome E) Have a circular chromosome

D) Have a segmented genome

Which class of antibody can cross the placenta? A) IgA B) IgD C) IgE D) IgG E) IgM

D) IgG

Which one of the following statements about interferon is FALSE? A) Interferon is produced in response to a viral infection B) Interferon is a naturally produced protein C) Interferon puts uninfected cells in an antiviral state D) Interferon binds to RNA virus genomes

D) Interferon binds to RNA virus genomes

Enterocytozoon bieneusi is an organism classified as a microsporidia; this organism is of clinical importance because it: A) Causes severe allergic reactions in some people B) Causes trypanosomiasis C) Causes ringworm infections D) Is an opportunistic pathogen in immunocompromised individuals E) Infects catheters by producing biofilms

D) Is an opportunistic pathogen in immunocompromised individuals

Viruses require _____ for growth. A) Plants B) Animals C) Bacteria D) Living cells E) Fungi

D) Living cells

All of the following are characteristics or components of innate immunity except _____. A) Nonspecific B) Mechanical barriers C) Mucociliary escalator D) Memory E) Toll-like receptors

D) Memory

Which of the following cell types cannot replicate in response to a specific antigen? A) B cells B) Cytotoxic T cells C) Helper T cells D) Plasma cells E) All of the above can replicate in response to a specific antigen

D) Plasma cells

All of the following drug-target combinations are matched correctly EXCEPT A) Quinolones: inhibit DNA synthesis B) Rifampins: inhibit RNA synthesis C) Gramicidins: disrupt membranes D) Polymyxins: inhibit protein synthesis

D) Polymyxins; inhibit protein synthesis

Which is not true of virions? A) Contain DNA B) Contain RNA C) Are extracellular D) Reproduce independently E) Induce host metabolism

D) Reproduce independently

The secondary lymphoid tissues include the _____ and _____. A) Thymus; bone marrow B) Bone marrow; tonsils C) Spleen; thymus D) Spleen; lymph nodes

D) Spleen; lymph nodes

Viruses contain [DNA/RNA/Both]

DNA or RNA

**L10: What are the general characteristics of a virus?

DNA or RNA Single or Double stranded Circular, linear or segmented genome Protein coat around nucleic acid

**L11: Immune cells that regulate both innate and adaptive immune responses, have strategic locations, activated after capturing and processing signals from infectious organisms then move to lymph

Dendritic cells

Athlete's foot is what type of fungus?

Dermatophyte

What are the functions of inflammation?

Destroy the injurious agent Limit the effects on the body by confinement Repair damaged tissue

Toll-like receptors are triggered by all of the following compounds except? A) Double-stranded RNA B) Lipopolysaccharide C) Flagellin D) Lipoteichoic acid E) All of the above trigger toll-like receptors

E) All of the above

Which of the following antifungal-target combinations are correctly matched? A) Azoles: inhibit sterol synthesis B) Polyenes: form pores in membranes C) Griseofulvin: disrupts the mitotic spindle D) Two of the above E) All of the above

E) All of the above

Which of the following traits are shared by most fungi? A) Absorptive nutrition B) Cell walls composed of chitin C) Cell membranes containing ergosterol D) Two of the above E) All of the above

E) All of the above

Which of the following is NOT a common trait shared by most mycelium-forming fungi? A) Absorpitve nutrition B) Hyphae production C) Multinucleated cells D) Chitinous cell walls E) Budding reproduction

E) Budding reproduction

Which of the following is a mismatched pair? A) CD8 T cells: class I MHC molecules B) Cell-mediated immunity: T cells C) Th2 cells: extracellular pathogens D) Humoral immunity: B cells E) CD4 T cells: class I MHC molecules

E) CD4 T cells: class I MHC molecules

Antiviral therapy for the human immunodeficiency virus (HIV) usually consists of a protease inhibitor that interferes with which step of the infection cycle? A) Release of newly formed virions by budding B) Fusion of the viral envelope with the host cell membrane C) Binding to the CD4 receptor on human cells D) Insertion of viral DNA into the host cell DNA E) Cleavage of polypeptide chains to make functional HIV proteins

E) Cleavage of polypeptide chains to make functional HIV proteins

Which of the following statements about antibodies is false? A) If you removed the Fc portion, antibodies would no longer be capable of opsonization. B) If you removed the Fc portion, antibodies would no longer be capable of activating the complement system. C) If you removed the Fab portion, an antibody would no longer be capable of agglutination. D) If IgG were a pentamer, it would be more effective at agglutinating antigens. E) If IgE had a longer half-life, it would protect newborn infants.

E) If IgE has a longer half-life, it would protect newborn infants

Which of the following statements about phagocytosis is false? A) Phagocytes move toward an area of infection by a process called chemotaxis B) The vacuole in which bacteria are exposed to degradative enzymes is called a phagolysosome C) Phagocytes have receptors that recognize complement proteins bound to bacteria D) Phagocytes have receptors that recognize antibodies bound to bacteria E) Macrophages die after phagocytizing bacteria but neutrophils regenerate their lysosomes and survive

E) Macrophages die after phagocytizing bacteria but neutrophils regenerate their lysosomes and survive

Which of the following would provide the best target for a new antibacterial antibiotic? A) Phospholipids in the cell membrane B) Proteins of the glycolysis pathway C) Pyrimidine bases D) Nuclear envelope E) Ribosomes

E) Ribosomes

**L12: What are the different adaptive responses for extracellular and intracellular pathogens?

Extracellular antigens are taken in by endocytosis, where they are digested and presented on MHC II molecules. Humoral immunity is good against extracellular Intracellular pathogens are fragmented by proteasomes, which are loaded onto MHC I molecules. Cel-mediated immunity is good against intracellular

How do fungi obtain food?

Extracellular digestion, where food is broken down by enzymes and small molecules diffuse into the hyphae

What is a viral envelope composed of and from where is it obtained?

Lipids, proteins and carbs Obtained from the host

What is one important protein coded for within the Influenza A genome and what does it do?

Hemagglutinin (HA) Key protein involved in attachment to host cells (Some human antibodies can protect against HA carrying viruses and therefore against certain diseases

Double-stranded DNA viruses are referred to as... (3 names)

Herpesviridae Papovaviridae Poxviridae

What happens to the host cell during phage conversion?

Host cell may exhibit new properties due to viral genes carried on the prophage

**L11: What are TLRs? How do they work?

Host receptors that are used to differentiate between self and non-self antigens. Once bound to ligands, they trigger intracellular regulatory cascade, which includes antiviral response (Type I interferons), antibacterial response (cytokines) and bind to various immune cells to direct them to invaders

**L9: Basic structural unit of fungi

Hyphae, which cluster to form mycelium

What is the most common polyhedral shape?

Icosahedral, 20 triangular faces and 12 corners

Which immunoglobulin is always the first antibody in a primary response?

IgM

Which antifungal drugs are used for treating topical skin infections?

Imidazole, Triazoles, and Griseofulvin

Which antifungal agents affect fungal plasma membranes by disrupting the synthesis of membrane sterols?

Imidazoles and Triazoles

How do prions spread from one host to another?

Ingestion, transplant or surgical instruments

Antigenic shift

Involves *major* changes in the virion structure, resulting from *acquisition of new genes* either from *co-infection* or through *recombination*

Antigenic drift

Involves *small* changes in the virion structure, resulting from *mutations*, and occurs *after* the infection has begun,

Which metal acts are a cofactor of many enzymes? Its limitation plays an important role in what? Its acquisition is critical for what?

Iron Antimicrobial defense Microbial pathogenesis

How does Aspergillus toxin cause death?

Liver damage and liver cancer

Retroviruses are [single/double] stranded, enveloped RNA viruses, which consists of ____ duplicated copies of RNA

Single; Two

**L11: What are the physical barriers to infection?

Skin, mucous membranes, lacrimal apparaturs in eyes, saliva and epiglottis

**L11: Physical barrier protecting the GI tract?

Specialized M cells and Peyer's patch

What determines a virus' host range?

Specific host attachment sites and viral cellular factors (Host and virus must match up

Adaptive immunity can be described as...

Specific, takes several days to develop, has memory

What are the secondary lymphoid organs and what occurs there?

Spleen and lymph nodes Where lymphocytes encounter antigens

Human nasal cavities are colonized by what bacteria?

Staphylococcus aureus and epidermidis

Human skin is colonized by what gram-positive bacteria?

Staphylococcus epidermidis and Propionibacterium acnes

Cytopathic effect

Structural changes in host cells that are caused by viral invasion. The infection causes lysis of the host cell or when the cell dies without lysis due to an inability to reproduce. Can be cytocidal or non-cytocidal. *Can be used to identify viruses because CPE can be characteristic of individual viruses*

Define antigenic variation

Structural changes in virions

Cellular immunity is related to __ cells

T

**L12: What are the central cells of adaptive immunity?

T and B cells

Which bacteriophages can undergo the lytic cycle in their host (E. coli)?

T-even bacteriophages (T2, T4, T6)

Which bacteriophages can proceed through either lytic or lysogenic cycles?

Temperate phages

How do prions work?

Their abnormal structure alters the conformation of other normal proteins.

What is one drawback of using continuous cell lines?

They don't appear as they would in the body

What are the 3 families that cause ringworm?

Trichophyton, Microsporum, and Epidermophyton

What are the two types of interferons?

Type I Interferons: have high antiviral potency Type II Interferons: has immunomodulatory function

Biosynthesis mechanism of single-stranded DNA viruses

Uses host cell's DNA polymerase. SS-DNA >> complementary copy >> mRNA >> capsomere protein + (+)DNA

What are two serious fungal infections that depend on where a person lives or visits?

Valley fever and histoplasmosis

Lysogenic cycle definition

Viral genome becomes incorporated into the host cell's DNA and the host cell remains alive

Classification of medical fungi is determined by what 3 factors?

rRNA type Tissue types they parasitize Diseases they produce