Microbiology Final

Human serum contains over ______ complement proteins.

30

Mucous membranes, or mucosa, consist of

a layer of epithelial cells, specialized cells like goblet cells

Which of the following statements regarding the respiratory system is __**false?**__

Microbes that reach the alveoli are killed by antimicrobial peptides.

Select the **three** main functions of the human complement system.

Promote phagocytosis, Penetrate cell membranes, Recruit white blood cells

Bacteriocins are ______

antibacterial peptides released by bacteria

Coating microorganisms with complement proteins or antibodies to enhance their phagocytosis is called?

Opsonization

Complement proteins are typically found in human blood

plasma

Phagocytic cells have surface receptors that specifically recognize ______, proteins that bind to and coat pathogens.

opsonins

An important barrier layer that forms a protective covering that resists penetration and traps microbial invaders is called the

mucosa (mucous membranes)

Recruiting white blood cells, penetrating microbial cell membranes, and promoting phagocytosis are all functions of the ______ system of innate immunity.

complement

Proteins that coat a microbe to tag it for phagocytosis are called

opsonins

The degree of binding between a phagocyte and an opsonized pathogen will be greatest when ______ is/are bound to the microbe.

both complement protein C3b and an antibody

The alternative pathway is activated by

common molecules with repetitive structures (such as LPS)

Which __**two**__ of the following are effects of complement proteins C3a and C5a?

Dilating blood vessels, Stimulating nerves

A microbe is opsonized when it

is coated with antibodies or complement proteins

For the lectin complement pathway, the proteolytic cascade is initiated by

a protein that binds to a specific carbohydrate

Select the three pathways of complement activation.

Classical, Lectin, Alternative

Which molecule, found in Gram-negative bacterial cell walls, is an excellent stimulator of the alternative complement cascade?

Lipopolysaccharide

The binding of C3a and C5a to membrane receptors amplifies the inflammatory signals and recruits ______ to the site of infection.

Neutrophils

An important lectin target in bacterial and fungal cell walls is

mannose

Proteins that bind to specific carbohydrates are generally called

Lectins

If antibodies are somehow prevented from binding to the surface of the bacterium, that cell can resist the _____ pathway of complement activation.

classical

Any soluble, low molecular-weight protein or glycoprotein released by one population of cells that acts as an intercellular communication/signaling molecule on a different group of cells is called

Cytokine

Select __**three**__ correct descriptions of acute-phase proteins.

Some assist in the prevention of blood loss

Produced by the liver

Produced during periods of injury/infection

What is mannose?

A sugar component of bacterial cell walls, some fungal cell walls, and some viral envelopes

Select the best definition of hematopoiesis.

Blood cell development

When mast cells are stimulated, they release the contents of their granules _____, during a process called degranulation.

into the extracellular space

The classical pathway of complement activation is triggered by

binding of an antigen-antibody complex to C1qrs

Which __**three**__ of the following describe cytokines?

Act as mediators or signaling molecules

Typically proteins or glycoproteins

Relatively low molecular weight

The type of granulocyte that is most similar to mast cells is the ?

basophil

The main function of monocytes is to

migrate into tissues to mature into phagocytic macrophages or dendritic cells

In mammals, the majority of blood cell development occurs in the

bone marrow

Innate lymphoid cells are stimulated by

opsonized microbes, foreign antigens, and cytokines

The function of lymph nodes is to serve as a site for

dendritic cells to present antigen to lymphocytes

When mast cells are stimulated, they rapidly release the contents of their granules into the extracellular environment, a process called

degranulation

Primary, Lymphoid Organs

Sites of lymphocyte maturation and differentiation

Secondary, Lymphoid Organs

Sites where lymphocytes encounter and react to antigens

Negative selection deletes approximately what percentage of developing T cells in the thymus?

98%

The main function of basophils is to

release vasoactive substances, promoting inflammation

Which __**three**__ of the following describe monocytes?

Produced in the bone marrow

Kidney-shaped nucleus

Migrate into tissues to become macrophages or dendritic cells

The function of the spleen is to

filter blood and trap particles to be assessed for foreignness by phagocytes and B cells

During their development, T cells that cannot distinguish between ____ and ____ antigens are destroyed by a process known as negative selection.

Self, non-self

The spleen, the most highly organized secondary lymphoid organ, is located

in the abdominal cavity

In which two locations in the human body would you most likely find Langerhans cells?

Skin, Lymph Nodes

Once a Langerhans cell in skin-associated lymphoid tissue (SALT) has ingested a foreign particle or microorganism, what happens next?

It migrates from the epidermis to nearby lymph nodes.

Lymph nodes are typically located

throughout the body

Intracellular pathogens are separated from the cytoplasm and surrounded by membrane material inside the cell, then degraded/destroyed internally during a process called

autophagocytosis

A MAMP is a(n) _____ associated molecular pattern, a molecule that is commonly found on or in bacteria, viruses, or fungi.

microbe

A Langerhans cell is what type of cell?

Dendritic Cell

Receptors that bind to microbe-associated molecular patterns (MAMPs) are called pattern _____ receptors (PRRs)

recognition

The basic function of Langerhans cells from skin-associated lymphoid tissue (SALT) is to

ingest foreign particles and present them to activate lymphocytes

Cells of the innate immune system recognize intracellular infectious agents like viruses with receptors located

in the cytoplasm

Phagocytosis Cellular Microbes

Cellular Microbes are recognized, ingested, and killed

Autophagocytosis intracellular pathogens

intracellular pathogens are recognized and destroyed

Which three of the following describe MAMP

recognized by phagocytes, inform the host of a potential microbial invader, specific regions within common microbial macromolecules.

Where are pattern recognition receptors (PRRs) located?

in cytosol or on cell surfaces

Cells of the innate immune system recognize extracellular infectious agents like bacteria with receptors located

on the cell surface

C-type lectin receptors (CLRs) are typically found on the surface of which type of cells?

Phagocytes

All of the following types of receptors can bind nucleic acids or dinucleotides except ____ receptors

c-type Lectin

Which __**two**__ cell types express high concentrations of C-type lectin receptors (CLRs)?

Macrophages, Dendritic Cells

Extensions of a cell's plasma membrane that can wrap around and engulf external particles are called

pseudopodia

The type of receptor found on the surface of phagocytic cells is the

C-type Lectin Receptor

The process in phagocytic cells by which the phagolysosome unites with the cell membrane, resulting in the extracellular release of microbial fragments is

exocytosis

Which two of the following are pattern recognition receptors found in the cytosol?

NOD-like receptors (NLRs)

RIG-1 receptors

Receptors that recognize and bind unique MAMPs of different classes of pathogens to initiate an appropriate gene expression response are called ____ - like receptors

Toll (TLRs)

The best term for the collection of essential innate defense reactions to tissue injury, such as those caused by a pathogen or a wound, is

inflammation

Phagocytosis of extracellular particles relies on pseudopodia, which are

extensions of the cell’s plasma membrane

Which cell type would be most likely to perform exocytosis?

Neutrophil

Select the __**five**__ cardinal signs of inflammation.

Swelling

Redness

Altered Function

Warmth

Pain

Which term describes substances released by bacteria, endothelial cells, and mast cells that attract neutrophils and other leukocytes?

Chemotaxins

Granulomas that form due to chronic inflammation may contain cells that result from the fusion of two or more cells. These are called multinucleated

giant cells

Selectins

Cell adhesion molecules that line blood vessels

Integrins

Receptors on the surface of neutrophils

Chronic inflammation due to a persistent infection or other stimulus may result in the formation of a well-organized mass of neutrophils, macrophages, fibroblasts, collagen, and other cells. This mass is called a(n) \n

granuloma

True or false: Humoral immunity is a part of innate immunity.

False

The main effector molecules of humoral adaptive immunity are

antibodies

The best definition of an antigen is

a self or nonself substance that elicits an immune response

Which one of the following is an example of naturally acquired active immunity?

getting a cold and recovering from it

The two main arms (or branches) of adaptive immunity are

cell-mediated immunity, humoral immunity

Killed or attenuated microorganisms, genetically engineered organisms, and inactivated bacterial toxins are all used to induce what type of adaptive immunity?

Artificially acquired active immunity

A small organic molecule that can't serve as an antigen by itself but may do so if it is combined with a larger carrier molecule is known as a(n)

hapten

When an individual acquires an infection that induces the immune system to produce a protective response, it is an example of which type of active immunity?

Naturally acquired active immunity

The human version of the MHC complex is called the HLA or human _____ antigen complex

leukocyte

Select the correct description of the structure of class I MHC molecules.

1 larger transmembrane alpha protein chain and 1 smaller beta 2-microglobulin chain.

During antigen processing, class I MHC molecules bind to peptides that originated from the

cytoplasm

MHC molecules are loaded with peptides, including those derived from non-self proteins, during antigen ____

processing

The human version of the MHC complex is called the

HLA complex

What are the cellular structures that digest intracellular antigenic proteins for subsequent presentation on the cell surface by class I MHC molecules?

proteasomes

Class I MHC (HLA) molecules are located on which human cells?

all nucleated cells

T cells have T-cell receptor complexes on their surface that bind to what type of molecules on the surface of other cells?

antigen fragments presented by MHC molecules

HLA types A, B, and C refer to which class of MHC molecule?

MHC class I only

The parts of a TCR complex that generate intracellular signals are the

cytoplasmic portions of some of the CD3 polypeptides

Foreign peptides derived from which **three** types of antigens would most likely be processed and presented on class I MHC molecules?

Peptides from viruses

Peptides from intracellular bacteria

Abnormal proteins in cancerous cells

Naive T cells require three signals for activation. Signal 1 is the binding of

an MHC molecule/antigen fragment to the TCR

The mammalian immune system is informed of the presence of pathogens (e.g., infections) by the presence of foreign peptides that are bound and presented by

Class I and class II MHC molecules

When the antigen bound to the MHC of an antigen presenting cell is recognized by the TCR of a T cell, the two cells become connected by a bridge known as the

immune synapse

The most important source of signal 2 for activation of naive T cells is

binding of B7 on antigen-presenting cells to CD28 on T cells

Another term for CD4+ T cells is T-

helper cells

The major function of the multiple polypeptides that make up the CD3 portion of the T-cell receptor is to

convert antigen binding into an intracellular signal

To become activated, how many signals do all naive T cells require?

3