Lecture Exam 3

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What are the 4 kingdoms of eukaryotic organisms?

Protists, Fungi, Plantae, Animalia


What are the 2 groupings of the protists?

Algae, Protozoans


How are the 2 groupings of the protists different from one another?

Algae are photosynthetic and Protozoans are heterotrophic


What are the differences between eukaryotes and prokaryotes?

Prokaryotes are a single cell, no nucleus, 1 circular chromosome, 1 copy of gene (haploid), asexual, and have no organelles. Eukaryotes are single and multicellular, have a nucleus, have chromosomes in linear pairs, have 2 copies of each gene (diploid), reproduce asexual/sexual, have many organelles with different functions.


What are the characteristics of the fungi?

Contains chitin, excrete enzymes to degrade larger molecules, principal decomposers.


What are the reproductive structures of fungi?

Easily airborne, develop into yeast, not hyphae form when inhaled, cause disease.


What are the mycelium?

Visible mass of hyphae


Dimorphic fungi:

Can grow as single yeast cells or multicellular mycelia


Saprophytic fungi are:

rhizoids may anchor to substrate


Parasitic fungi are:

haustoria protrude into hosts


What are the hyphae of fungi?

Specialized hyphae: Parasitic fungi & Saprophytic fungi


What are the habitats of fungi?

Mostly terrestrial, found in nearly every habitat on Earth, including thermal pools, volcanic craters, high salt environments.


Mycorrhizas are:

beneficial association with plant roots; high surface area of hyphae supplies plant with water, minerals, nitrogen, phosphorous.


Lichens are:

association of fungus and photosynthesizer, where the fungus protects, absorbs water and nutrients & allows growth in ecosystems where neither alone could survive.


Name 2 symbiotic relationships that fungi form?

Lichens & Mycorrhizas


What are the characteristics of algae?

Most are aquatic, microscopic or macroscopic, unicellular or multicellular, all contain chloroplasts and chlorophyll a, rigid cell walls mostly cellulose


What are the characteristics of the photosynthetic protists?

No chloroplasts, cellulose or chitin cell walls; they are non-photosynthetic.


Do the photosynthetic protists directly cause disease to humans?

Some cause human diseases.


Do the photosynthetic algae directly cause disease to humans?

Algae does not directly cause human disease.


Do the photosynthetic protists indirectly cause disease to humans?

Yes, because they are extremely diverse.


Do photosynthetic algae indirectly cause disease to humans?

Yes, algae indirectly causes human disease by indirect pathogens.


What is the structure of the heterotrophic protists (protozoans)?

No chloroplasts, cellulose or chitin cell wall, non-photosynthetic.


How are the heterotrophic protists different than the algae?

Algae are simple autotrophs, protists are eukaryotes that are not fungi, plants, or animals.


What human diseases are the heterotrophic protists responsible for?

Trypanosma brucei, Entamoeba histolytica, Cryptosporidium, Giardia lamblia, Amebiasis.


What are helmiths?



List the 3 types of helmiths.

Nematodes (roundworms), cestodes (tapeworms), trematodes (flukes).


Why are helmiths considered with microorganisms?

Helmiths are not microorganisms by definition, because they are large enough to be easily seen with by the naked eye, but they live part of their life cycle in microscopic form. Since the parasitic helminths are of clinical importance, they are often discussed along with the other groups of microbes.


What are two ways that they enter the body?

Burrow through skin by bare feet that aid in transmission; Helminth eggs contaminate food, water, air, feces, pets and wild animals, and objects such as toilet seats and door handles. The eggs enter the body of a human through the mouth, the nose and the anus.


Why are arthropods important in the study of microorganisms?

Some attack our crops, attack stored products, attack our domestic animals, attack us and suck blood, are venomous, transmit diseases.


What is a vector?

An organism, such as a tick or mosquito, that transmits diseases or parasites to plants or animals.


What is a reservoir?

Any person, animal, plant, soil or substance in which an infectious agent normally lives and multiplies.


What is a virus?

Genetic information, either DNA or RNA, contained within a protective form.


What is a virion?

A viral particle that consists of nucleic acid surrounded by a protein coat.


What is a capsid?

Protects the nucleic acid from enzymes and toxic chemicals in the environment. Also carries any enzymes required by the virus for infection of host calls. Is a protein coat.


What is nucleic acid?

Biopolymers, or large biomolecules, essential for all known forms of life; includes RNA/DNA.


What is nucleocapsid?

capsid plus nucleic acids.


What is naked?

They are non-enveloped viruses that lack envelope and are more resistant to disinfectants.


What is enveloped?

Have lipid bilayer envelope that is picked up from the host; includes a plasma membrane, nuclear envelope. More sensitive to disinfectants.


What are 3 basic shapes of capsid?

Icosahedral, Helical, Complex.


What kinds of genomes can a virus have?

Linear or circular; either double-stranded or single-stranded.


Why isn't a virus considered alive?

They are incapable of metabolism, replication, or motility.


What does it mean when we say that viruses are informally grouped together?

Share routes of infection


What is a lytic virus?

Exit the host at the end of the infection cycle by lysing the cell.


What is the infection cycle of a lytic virus?

Attachment, Genome Entry, Synthesis, Assembly, Release.


What example did we use?

T4 phage (dsDNA)


What is a temperate virus?

Have the option of either directing a lytic infection or incorporating their DNA into the host cell genome.


What is the infection cycle of a temperate virus if it chooses the lysogenic route?

Attachment, Genome Entry, Integration, Cell division, Excision, Synthesis, Assembly, Release.


What is the infection cycle of a temperate virus if it chooses the lytic route?

Attachment, Genome Entry, Synthesis, Assembly, Release.


How is this different from a lytic virus?

Some of the phage will enter the lytic cycle, and others will lysogenize their host.


What are the stages of the viral infection cycle? Use the T4 virus as your example.

Expression of viral genes to produce structural and catalytic proteins, such as capsid proteins and any enzymes required for replication, and synthesis of multiple copies of the viral genome. Synthesis of multiple copies of the viral genome.


What are the stages of the viral replication cycle?

Attachment (Adsorption), Penetration, Uncoating, Targeting, Gene expression, Genome replication, Virion assembly/maturation, Release of new infectious virus


What are the stages of animal virus infection?

Attachment, Penetration and uncoating, Synthesis, Assembly, Release.


What are the differences between the animal viruses and the bacteriophages?

The bacteriophages don't have the uncoating stage and the synthesis is in the cytoplasm, whereas in animal viruses they go through the uncoating stage and synthesis is in the nucleus or cytoplasm.


What is meant by the innate immune system?

Non-specific, basic defenses meant to protect us against any type of pathogen.


Does the innate system learn or remember pathogens?

Same response with every encounter of a pathogen; no memory and no changes.


What are the first line defenses against microbial invasion?

Prevent microbial entry; skin and mucous membranes, antimicrobial substances.


What are the defenses that we have if an invasion does occur?

Interferon response, Phagocytosis, complement activation, inflammatory response, fever.


How do the normal microbiota help protect us?

Competitive exclusion of pathogens: have all the turf covered, no space for new ones, use up all available resources, production of toxic compounds: compounds produced to kill off or inhibit growth of competitors, essential to the development of the immune system: teach our adaptive immune system to tolerate normal microbial on surfaces


What roles do the macrophages and dendritic cells have in innate immunity?

Macrophages: engulf and destroy. Dendritic cells: messengers; process antigen material and present it on the cell surface to the T cells of the immune system.


What is complement system?

Enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacked the pathogen's plasma membrane.


How does the complement system work?

The plasma proteins can be activated directly by pathogens or indirectly by pathogen-bound antibody, leading to a cascade of reactions that occurs on the surface of pathogens and generates active components with various effector functions.


What are the 3 outcomes of the complement response?

Stimulation of inflammatory reactions via release of proinflammatory mediators, which induce chemotaxis of leukocytes & inflammatory, opsonizations of pathogens by depositing fragments of complement proteins on the pathogens, making them more susceptible to phagocytosis, complement-mediated cytolysis via formation of a membrane attack complex which can insert itself into bacterial membrane and cause osmotic lysis.


What are macrophages?

large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.


How do phagocytes do phagocytosis?

By chemotaxis, recognition and attachment, engulfment, phagosome maturation and phagolysosome formation, destruction and digestion, exocytosis.


What is the inflammatory response?

To contain a site of damage, localize the response, eliminate the invader, and restore tissue function.


What is the cascade of events that occurs when the inflammatory response is initiated?

Dilation of small blood vessels, migration of leukocytes from bloodstream to tissues, clotting factors wall off site of infection, dead neutrophils, tissue debris accumulate as pus.


What are the 4 cardinal signs of the inflammatory response?

Swelling, redness, heat and pain.


How is the inflammatory response damaging to host tissues?

Normal blood flow in the tissue as the injury occurs > inflammatory mediators are released in response to microbial components and tissue damage > neutrophils are the first phagocytes recruited to the site > phagocytic cells destroy and remove invaders > as the infection is brought under control, macrophages ingest dead cells and debris.


What is the role of a fever?

Slows down viral replication and slow down bacterial reproduction.


What are the functions of the lymphatic system?

Brings population of B and T cells into contact with antigens, home to adaptive immune system, returns excess body fluids to the circulatory system.


What are the primary lymphoid organs?

Bone marrow and thymus.


What 3 cell types are formed in the bone marrow?

Lymphocytes, T Cells, and B cells.


What are the secondary lymphoid organs?

Lymph nodes, spleen, tonsils, adenoids, and appendix.


What is an antigen?

compounds that induce antibody production; antibody generator


What are epitopes?

antigenic determinants


What types of antigen are there?

T-dependent & T-independent.


What types of epitopes are there?

Proteins, lipids, carbs.


What kinds of compounds make good antigens?

Proteins and Lipopolysaccharide


What are the 2 strategies used by the adaptive immune response?

Humoral and cell-mediate response.


Humoral is:

also known as antibody-mediated immunity; effective against extracellular pathogens such as bacteria and soluble pathogen products


Cell-mediated immunity is:

an immune response that does not involve antibodies, but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.


What are the cells, activities and responsibilities of the humoral system?

B-cell receptors, plasma, and memory B cells. B-cell receptors bind directly to antigens, B cells give rise to plasma cells, plasma cells product antibodies, Memory B cells retain sensitivity to a particular pathogen and will react faster and stronger to a second exposure to the same pathogen


How and who activates B cells?

B-cells are activated by the binding of antigen to receptors on its cell surface which causes the cell to divide and proliferate. Some stimulated B-cells become plasma cells, which secrete antibodies.


What are the types of B cells?

Plasma, Memory B cells,


Plasma is:

the clear, straw-colored liquid portion of blood that remains after red blood cells, white blood cells, platelets and other cellular components are removed. It is the single largest component of human blood, comprising about 55 percent, and contains water, salts, enzymes, antibodies and other proteins.


Memory B cells are:

a B cell sub-type that are formed within germinal centers following primary infection and are important in generating an accelerated and more robust antibody-mediated immune response in the case of re-infection (also known as a secondary immune response).


What are the types of antibodies?

IgM, IgG, IgA, IgD, IgE


What is the structure of an antibody?

Y-shaped proteins that have 2 general parts, the arms and the stem. The arms are called the Fab regions which bind antigen. The stem is the FC region. The heavy chain (high-molecular polypeptide chain) is at the FC region, and the light chain (low-molecular polypeptide chain) is at the Fab region. The variable region is the portion at the ends of the Fab regions, which is the antigen-binding site. The constant region includes the entire Fc region, and part of the two fab regions.


What are the 5 effects that antibodies have in the immune response?

Neutralization, Opsonization, Complement system activation, Immobilization and prevention of adherence, Cross-linking.


How do the B and T cells interact?

When the Helper T cell is activated, it activates the B cells, which causes the B cells to divide.


How and who activates the T cell response?

T cells can only recognize antigens when they are attached to a special protein complex (MHC) that presents the antigen to the T cell.


What are the classes of T cells?

Helper, Cytotoxic, Memory


T helper cells:

regulate/coordinate adaptive immunity between the T & B cells


T cytotoxic is:

Cells that kill virus-infected cells and cancer cells.


Memory cells are:

sensitized to a particular pathogen and will cause a faster stronger immune response to a second exposure to a pathogen


What is the difference between the 1st and 2nd exposure to a pathogen with regards to the immune response?

Activation of Cytotoxic, Memory, Helper, and B cells.


What makes the 1st and 2nd exposure to a pathogen different with regards to strength, quickness and efficiency of response?

In Primary some B cells differentiate to form plasma cells, plasma cells generate antibodies, undergo apoptosis after a few days, activated B cells continue proliferating and differentiating in presence of antigen, so titer steadily increased; Secondary is significantly faster, more effective than primary due to memory T cells, Memory B cells responsible for greater numbers present.