Micro Exam #3

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Exam #3 VoCabuLaRy WoRds...

Mycorrhizae

Symbiotic fungi which help [plants'] roots absorb minerals and water from the soil.

Mycology

The study of fungi.

Vegetative

Fungal colonies are vegetative because they are composed of the cells involved in catabolism and growth.

Thallus

The "body" of a mold or fleshy fungus.

Hyphae

The long filaments of cells that are joined together inside the thallus.

Septa

"Cross-walls" inside the hyphae of most molds, which divide the hyphae into distinct, uninucleate cell-like units.

Septate Hyphae

The hyphae which contain the "cross-walls," or septa, within most molds.

Coenocytic Hyphae

Hyphae (in a few classes of fungi) that contain no septa and appear as long, continuous cells with many nuclei.

Mycelium

A filamentous mass formed by hyphae, dependent upon environmental conditions.

Yeasts

Nonfilamentous, unicellular fungi that are typically spherical or oval; they are frequently found as a white powdery coating on fruits and leaves.

Budding Yeasts

[In "budding"] the parent cell forms a protuberance (bud) on its outer surface; As the bud elongates, the parent cell's nucleus divides, and one nucleus migrates into the bud. Cell wall material is then laid down between the bud and parent cell, and the bud eventually breaks away.

Pseudohypha

A short chain of cells that are formed by buds which have failed to detach.

Fission Yeasts

Divide evenly to produce two new cells. During fission, the parent cell elongates, its nucleus divides, and two daughter cells are produced. [Increases in the number of yeast cells on a solid medium produce a colony similar to a bacterial colony.

Dimorphism

Two forms of growth; Such fungi can grow either as a mold or as a yeast. Dimorphism in pathogenic fungi is temperature dependent: 37 deg. C = the fungus is yeastlike; 25 deg. C = it is mold-like.

Spores

Spores are formed from hyphae in a number of different ways, depending on the species. Both sexual and asexual reproduction in fungi occurs by the formation of spores. (Fungi are usually identified by spore type; Fungal spores can survive for extended periods in dry or hot environments. Fungal spores and bacterial endospores are different.)

Asexual Spores

Produced by an individual fungus through mitosis and subsequent cell division. Formed by the hyphae of one organism; When these spores germinate, they become organisms that are genetically identical to the parent.

Sexual Spores

Result from the fusion of nuclei from two opposite strains of the same species of fungus. A fungal sexual spore results form sexual reproduction, which consists of three phases: Plasmogamy, Karyogamy, and Meiosis. (Fungi produce sexual spores less frequently than asexual spores.)

Conidiospore/Conidium

Type of asexual spore; A unicellular or multicellular spore that is not enclosed in a sac. They are produced in a chain at the end of a Conidiophore.

Arthroconidia

Conidia formed by the fragmentation of a septate hypha into single, slightly thickened cells.

Chlamydoconidium

A thick-walled spore formed by rounding and enlargement within a hyphal segment. (i.e. - C. Albicans.)

Sporangiospore

Type of asexual spore formed within a sporangium, or sac, at the end of an aerial hypha called sporangiophore.

Sporangium

Sac which can contain hundreds of sporangiospores.

Plasmogamy

A haploid nucleus of a donor cell (+) penetrates the cytoplasm of a recipient cell (-).

Karyogamy

The (+) and (-) nuclei fuse to form a diploid zygote nucleus.

Meiosis

The diploid nucleus gives rise to haploid nuclei (sexual spores), some of which may be genetic recombinants.

Zygospore

A large spore enclosed in a thick wall. (This type of spore results from the fusion of the nuclei of two cells that are morphologically similar to each other.

Ascospore

Results from the fusion of the nuclei of two cells that can be either morphologically similar or dissimilar. These spores are produced in a sac-like structure called an ascus. These members of this phylum are called sac fungi because of the ascus.

Basidiospores

(Club fungi; Possess septate hyphae; Include mushrooms.) Formed externally on the base pedestal called a Basidium. There are usually four basidiospores per basidium. Some of the basidiomycota produce asexual conidiospores.

Teleomorphs

They produce both asexual and sexual spores. Some ascomycetes have lost the ability to reproduce sexually.

Anamorphs

Asexual fungi (ascomycetes) that have lost the ability to reproduce sexually, (i.e. - Penicillium.)

Mycosis

Any fungal infection [is called mycosis]. Mycoses are generally chronic (long-lasting) infections because fungi grow slowly. Mycoses are classified into five groups according to the degree of tissue involvement and mode of entry into the host: Systemic, Subcutaneous, Cutaneous, Superficial, or Opportunistic.

Systemic Mycoses

Fungal infections deep within the body. They are not restricted to any particular region of the body but can affect a number of tissues and organs. Systemic Mycoses are usually caused by fungi that live in the soil; Inhalation of spores is the route of transmission; these infections typically begin in the lungs and then spread to other body tissues. They are not contagious from animal to human or human to animal. Two systemic mycoses: Histoplasmosis & Coccidioidomycosis.

Subcutaneous Mycoses

Fungal infections beneath the skin caused by saprophytic fungi that live in soil and on vegetation. Occurs by direct implantation of spores or mycelial fragments into a puncture found in the skin.

Dermatophytes

Fungi that infect only the epidermis, hair, & nails. Their infections are called dermatomycoses, or Subcutaneous Mycoses. Dermatophytes excrete keratinase, an enzyme that degrades keratin (a protein found in hair, skin, & nails. Infection is transmitted from human to human or from animal to human by direct contact. (i.e.- Barber shops have blue anti-bacterial where they soak their tools in order to prevent this kind of fungal infection.)

Superficial Mycoses

The fungi that cause this particular mycosis are localized along hair shafts and in superficial (surface) epidermal cells. These infections are prevalent in tropical climates.

Opportunistic Pathogen

Generally harmless in its normal habitat but can become pathogenic in a host who is seriously debilitated or traumatized, who is under treatment with broad-spectrum antibiotics, whose immune system is suppressed, or who has a lung disease. Pneumocystis is an opportunistic pathogen and is the most common life-threatening infection in AIDS patients.

Yeast Infection

a.k.a. Candidiasis; Frequently occurs in newborns, people with AIDS, and in people being treated with broad-spectrum antibiotics.

Lichen

A combination of a green alga (or a cyanobacterium) and a fungus. Lichens are placed in the Kingdom Fungi and are classified according to the fungal partner, most often an ascomycete (the two exist in a mutualistic relationship-if the partners are separated, the lichen no longer exists). Lichens cans be grouped into three morphologic categories: Crustose Lichens (grow flush or encrusting onto the substratum), Foliose Lichens (more leaflike), and Fruticose Lichens (fingerlike projections).

Medulla

The lichen's thallus, or body, forms when fungal hyphae grow around the algal cells to become the medulla.

Rhizines

Fungal hyphae project below the lichen body to form rhizines, or holdfasts.

Cortex

Fungal hyphae also form a cortex, or protective covering, over the algal layer and sometimes under it as well.

Holdfasts

Anchor alga to a rock.

Stipes

Stemlike and hollow.

Blades

Leaflike.

Algin

A thickener used in many foods (i.e.- ice cream & cake decorations), is extracted from their cell walls. Algin is also used in the production of a wide variety of nonfood goods (i.e.- rubber tires and hand lotion).

Domoic Acid Intoxication

Domoic acid is a toxin, with symptoms ranging from diarrhea to memory loss. Diatoms are responsible for releasing this toxin. (Diatoms store energy captured through photosynthesis in the form of oil.)

Plankton

Dinoflagellates are unicellular algae collectively called Plankton, or free-floating organisms. Their rigid structure is due to cellulose embedded on the plasma membrane.

Saxitoxins

Neurotoxins produced by dinoflagellates in the genus Alexandrium.

Paralytic Shellfish Poisoning (PSP)

The toxin (saxitoxin) is concentrated when large numbers of dinoflagellates are eaten by mollusks, such as mussels or clams. Humans who eat these mollusks develop PSP.

Red Tide

Large concentrations of Alexandrium gives the ocean a deep red color.

Ciguatera

A disease which occurs when the dinoflagellate Gambierdiscus Toxicus passes up the food chain and is concentrated in large fish. Ciguatera is endemic (constantly present) in the south Pacific Ocean and the Caribbean Sea.

Zoospores

Oomycote spores that have two flagella. They were previously classified with fungi (b/c they are superficially similar to fungi) however they are in fact "water molds." Oomycotes are decomposers that form cottony masses on dead algae and animals, usually in fresh water.

Algal Blooms

Periodic increases in numbers of planktonic algae.

Trophozoite

The feeding and growing stage of Protozoa. During this stage, Protozoa feed upon bacteria and small particulate nutrients.

Schizogony

Multiple fission; The nucleus undergoes multiple divisions before the cell divides. After many nuclei are formed, a small portion of cytoplasm concentrates around each nucleus, and then the single cell separates into daughter cells. (Protozoa reproduce asexually by fission, budding, or schizogony.)

Conjugation

During protozoan conjugation, two cells fuse, and a haploid nucleus from each cell migrates to the other cell.

Gametes/Gametocytes

Haploid sex cells produced by some protozoa. During reproduction, two gametes fuse to form a diploid zygote.

Cyst

Permits the organism to survive when food, moisture, or oxygen are lacking, when temperatures are not suitable, or when toxic chemicals are present.

Oocyst

A reproductive structure in which new cells are produced asexually.

Cytostome

A mouthlike opening on protozoa.

Vacuoles

Enclosed in a membrane, these are where protozoan digestion takes place.

Anal Pore

Where protozoans' excrete their waste. (The waste can also be eliminated through the plasma membrane.)

Archaezoa

Eukaryotes that lack mitochondria.

Mitosome

A unique organelle within archaezoa (in place of/rather than the mitochondria).

Undulating Membrane

Highly modified flagellum on some protozoa; Consists of a membrane bordered by a flagellum.

Microspora

Unusual eukaryotes (because they lack mitochondria); Cause chronic diarrhea, etc.

Amoebazoans

Amoebas (a group of protozoans that move by means of pseudopods).

Pseudopods

Temporary extension of a cell's cytoplasm and plasma membrane; used by certain protozoans in movement and feeding.

Apicomplexa

Obligate intracellular parasites that are characterized by the presence of a complex of special organelles at the apexes (tips) of their cells; The organelles in these complexes contain enzymes that penetrate the host's tissue. They have a complex life cycle which involves transmission between several hosts (i.e.- Plasmodium).

Sporozoite

The infective stage of Plasmodium; One of the minute active bodies into which sporozoans divide in one stage of their life cycle.

Merozoites

New cells that emerge from the liver and infect red blood cells.

Ring Stage

young plasmodium trophozoite that looks like a ring (the cytoplasm and nucleus are visible) in red blood cells.

Definitive Host

The host in which the sexual reproduction of a parasite takes place.

Intermediate Host

An organism in which a parasite undergoes asexual reproduction.

Tachyzoites

Trophozoites of toxoplasma gondii which reproduce sexually and asexually in an infected cat.

Ciliophora

Ciliates that have cilia similar to but shorter than flagella; The cilia are arranged in precise rows on the cell. They are moved in unison to propel the cell through its environment and to bring food particles to its mouth.

Euglenozoa

Photoautotrophs with a semirigid plasma membrane called a pellicle; Move by means of a flagellum at the anterior end; Also have a red eye spot at the anterior end which senses light and directs the cell.

Hemoflagellates

Blood parasites transmitted by blood-feeding insects;Found in the circulatory system of the bitten host.

Slime Molds

Fungal organisms which also contain amoebal characteristics; They live on soil, leaves, or decaying wood, and help to recycle organic matter.

Cellular Slime Molds

Typical eukaryotic cells that resemble amoebas; Remain disticint forms their entire life; When their food supply is exhausted they send out chemical signals to others, which soon aggregate into a large sluglike colony that functions as a single organism. It produces a fruiting body which produces spores; It scatters the spores, which can grow into another organism.

Plasmodial Slime Molds

Exist as a mass of protoplasm with many nuclei; The entire plasmodium moves as a giant amoeba; It engulfs organic debris and bacteria.

Cytoplasmic Streaming

During cytoplasmic streaming, the protoplasm within the plasmodium moves and changes both its speed and direction so that the oxygen and nutrients are evenly distributed; It continues to grow as long as there is enough food and moisture for it to thrive.

Helminths

Flatworms and Roundworms (Nematodes); Multicellular, eukaryotic animals that generally possess digestive, circulatory, nervous, excretory, and reproductive systems. Parasitic helminths must be specialized to live inside their hosts.

Larval

Developmental stage of parasitic helminths.

Dioecious

Helminths which have male reproductive organs in one individual and female reproductive organs in another individual.

Monoecious/Hermaphroditic

One [animal/helminth] has both male and female reproductive organs.

Flatworms

Members of the Phylum Platyhelminthes; Dorsoventrally flattened; Classes of parasitic flatworms include trematodes and cestodes. They cause disease or developmental disturbances in a wide variety of animals.

Flukes

a.k.a. trematodes; Have flat, leaf-shaped bodies with a ventral sucker and an oral sucker, which [together] help to hold the organism in place. They obtain food by absorbing it through their nonliving outer covering, called the cuticle.

Cuticle

Nonliving, outer covering of flukes/trematodes.

Tapeworms

a.k.a. cestodes. Intestinal parasites. Have suckers for attaching to the intestinal mucosa of the definitive host; Some species also have small hooks for attachment. They completely lack a digestive system, so in order to obtain nutrients from the small intestine, they absorb food through their cuticle.

Scolex

The head of a tapeworm/cestode.

Proglottids

Segments produced by the neck region of the scolex, as long as the scolex is attached and alive. Each mature proglottid contains both male and female reproductive organs. The proglottids farthest away from the scolex are the mature ones containing eggs. (Mature proglottids are essentially bags of eggs, each of which is infective to the intermediate host.

Cysticerci

Encysted larvae within muscle meat of the host; When cysticerci are ingested by humans, all but the scolex is digested. (The scolex anchors itself to the small intestine and begins producing proglottids.)

Hydatid Cyst

A cyst formed in the tissues resulting from the development of certain tapeworm; May grow very, very large over a period of years.

Roundworms

a.k.a. Nematodes; Members of the Phylum Nematoda; They are cylindrical and are tapered at each end, have complete digestive systems (consisting of a mouth, intestine, and anus), and are dioecious. Males are smaller than females and have one or two hardened spicules on their posterior ends. [Some nematodes are free-living in soil and water, and others are parasites living on plants and animals. Some pass their entire life-cycle, from egg to mature adult, in a single host. 2 types of nematode infections: those which the egg is infective, and those which the larva is infective.]

Spicules

Used to guide sperm to a female's genital pore.

Sexual Dimorphism

The male and female worms look distinctly different., A special case of polymorphism based on the distinction between the secondary sex characteristics of males and females.

Heartworm

Parasitic worm; The adult stage is often in the animal host's heart, where it can kill its host through congestive heart failure.

Vectors

Arthropods that carry pathogenic microorganisms; i.e. Scabies & Pediculosis.

Obligatory Intracellular Parasites

Viruses that require living host cells in order to multiply.

Viruses

Entities that: Contain a single type of nucleic acid (DNA or RNA), Contain a protein coat (sometimes itself enclosed by an envelope of lipids, proteins, and carbohydrates) that surround the nucleic acid, Multiply inside the living cells by using the synthesizing machinery of the cell, Cause the synthesis of specialized structures that can transfer the viral nucleic acid to other cells. Viruses have few or no enzymes of their own for metabolism. To multiply, they must take over the metabolic machinery of the host cell.

Host Range

The spectrum of host cells a virus can infect.

Bacteriophages/Phages

Viruses that infect bacteria.

Virion

A complete, fully developed, infectious viral particle composed of nucleic acid and surrounded by a protein coat that protects it from the environment and is a vehicle of transmission from one host cell to another. Viruses are classified by differences in the structures of these coats.

Capsid

Protein coat that protects the nucleic acid of a virus.

Capsomeres

Protein subunits which comprise each capsid.

Envelope

Sometimes cover the capsid of a virus; Usually consists of some combination of lipids, proteins, and carbohydrates.

Spikes

Dependent upon the virus, spikes may or may not cover the envelope. Spikes are carbohydrate-protein complexes that project from the surface of the envelope.

Non-Enveloped Viruses

Viruses whose capsids are not covered by an envelope.

Complex Viruses

Some viruses, particularly bacterial viruses, that have complicated [or complex] structures.

Viral Species

A group of viruses sharing the same genetic information and ecological niche (host range).

Plaques

Clearings which are visible against a lawn of bacterial growth on the surface of an agar plate.

Plaque-Forming Units (PFU)

The concentrations of viral suspensions measured by the number of plaques.

Cytopathic Effect (CPE)

Cell deterioration caused by viruses.

Primary Cell Lines

Viruses grown in primary or continuous cell lines.

Diploid Cell Lines

Certain cell lines; Developed from human embryos, can be maintained for about 100 generations and are widely used for culturing viruses that require a human host.

Continuous Cell Lines

Transformed (cancerous) cells that can be maintained through an indefinite number of generations. They are sometimes called immortal cell lines.

Lytic Cycle

A viral reproductive cycle in which copies of a virus are made within a host cell, which then bursts open, releasing new viruses. Ends with the lysis and death of the host cell. (1. Attachment, 2. Penetration, 3. Biosynthesis, 4. Maturation, 5. Release.)

Lysogenic Cycle

A method of viral replication in which a viral genome is replicated as a provirus without destroying the host cell.

Phage Lysozyme

Enzyme that breaks down a portion of the bacterial cell wall.

Eclipse Period

The period during viral multiplication when complete, infective virions are not yet present.

Lysis

The final stage of viral multiplication is the release of virions from the host cell. The term lysis is used for the Release Stage in the multiplication of T-even phages because in this case the plasma membrane actually breaks open (lysis).

Lysogeny

The phage remains latent (inactive). The participating bacterial host cells are known as lysogenic cells.

Prophage

Phage DNA that is intergrated into a specific site of the host cell's chromosomes.

Phage Conversion

The host cell may exhibit new properties.

Specialized Transduction

The third result of lysogeny.

Pinocytosis

An active cellular process by which nutrients and other molecules are brought into a cell. A cell's plasma membrane continuously folds inward to form vesicles.

Fusion

Alternative method by which enveloped viruses can enter; The viral envelope fuses with the plasma membrane and releases the capsid into the cell's cytoplasm. One example of a virus which penetrates cells using this method is the HIV virus.

Phage Conversion

A result of lysogeny; The host cell may exhibit new properties.

Specialized Transduction

Another result of lysogeny, bacterial genes can be picked up in a phage coat and transferred to another bacterium.

Uncoating

The separation of the viral nucleic acid from its protein coat once the virion is enclosed in the vesicle. The capsid is digested when the cell attempts to digest the vesicle's contents, or the non-enveloped capsid may be released into the cytoplasm of the host cell. (This process varies with the type of virus.)

Provirus

Never comes out of the chromosome; Remains in its latent state and replicates when the DNA of the host virus replicates. In other words, the provirus is expressed and produces new viruses which infect adjacent cells.

Budding

Asexual reproduction in which a part of the parent organism pinches off and forms a new organism; Envelope develops around around the capsid by this process.

Sarcoma

Cancer of connective tissue.

Adenocarcinoma

Cancer of glandular epithelial tissue.

Oncogenes

Genes that cause cancer by blocking the normal controls on cell reproduction.

Oncogenic Viruses

a.k.a. Oncoviruses; Viruses capable of inducing tumors in animals.

Transformation

Tumor cells acquire properties that are distinct from the properties of uninfected cells or from infected cells that form tumors.

Tumor-Specific Transplantation Antigen (TSA)

Virus-specific antigen on cell surface of many tumor cells. (Tend to be less round than normal cells, and usually exhibit certain chromosomal abnormalities. i.e.- unusual numbers of chromosomes and fragmented chromosomes.)

T Antigen

Antigen in the nucleus of tumor cells. (Tend to be less round than normal cells, and usually exhibit certain chromosomal abnormalities. i.e.- unusual numbers of chromosomes and fragmented chromosomes.)

Latent Infection

Phase in a cycle of an infection after initial onset and the multiplication of pathogens comes to a halt. Pathogen is still there. Common in viruses (Herpes Simplex, HIV, Epstein-Barr), Hepatitis B). NOT the same as remission.

Persistant/Chronic Viral Infection

Viral infection which occurs gradually over a long period. Typically, persistent viral infections are fatal.

Prion

Proteinaceous infectious particle.

Viroids

Short pieces of naked RNA, only 300 to 400 nucleotides long, with no protein coat.

Antibiotic

A substance produced by microorganisms that in small amounts inhibits another microorganism.

Narrow Spectrum of Microbial Activity

Range of different microbial types that antibiotics affect.

Broad-Spectrum Antibiotics

Antibiotics that affect a broad range of gram-positive or gram-negative bacteria.

Superinfection

Infection that occurs while you are being treated for another infection. Growth of a target pathogen that has developed resistance to an antibiotic. (A secondary infection from the removal of normal microbiota, allowing colonizatiion by pathogenic, and often antibiotic resistant microbes.)

Bactericidal

Kill microbes directly.

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