Microbiology Final Exam Flashcards

Vocabulary flashcards covering core concepts, key structures, methods, pathogens, lines of defense, immunoglobulins, hypersensitivities, and blood typing for the Microbiology Final Exam.

Microbiology

The study of organisms and infectious agents too small to be seen clearly with the unaided eye.

Bacteria

Cellular prokaryotes without a nucleus, containing a peptidoglycan cell wall in most species, and reproducing by binary fission.

Archaea

Cellular prokaryotes that lack a nucleus and peptidoglycan, have distinctive cell membranes, and often inhabit extreme environments.

Fungi

Cellular eukaryotes with chitin cell walls and absorptive nutrition, including unicellular yeasts and multicellular molds.

Protozoa

Unicellular eukaryotic microorganisms that are often motile, many of which are parasitic.

Algae

Photosynthetic cellular eukaryotes that can be unicellular or multicellular and serve as major oxygen producers.

Helminths

Multicellular eukaryotic worms whose adult forms may be macroscopic, but whose eggs and larvae are microscopic and medically important.

Viruses

Acellular infectious agents containing DNA or RNA inside a protein coat that require host cells to reproduce.

Prions

Acellular infectious misfolded proteins that contain no nucleic acid.

Medical microbiology

The branch of microbiology focused on microbes that cause human and animal disease, including their prevention, diagnosis, and treatment.

Public health and epidemiology

The branch of microbiology that tracks, controls, and prevents disease across populations, with major bodies like the CDC and WHO.

Immunology

The study of host defenses, vaccination, blood testing, and allergy.

Industrial microbiology

The field that uses microbes to produce foods, drugs, enzymes, vitamins, amino acids, and other products.

Agricultural microbiology

The study of microbes associated with soil, crops, plant diseases, and farm animals.

Environmental microbiology

The study of microbial roles in aquatic, soil, geologic, atmospheric, and other ecosystems.

Bioremediation

The deliberate use of microbes to degrade or remove environmental pollutants, such as oil-degrading marine bacteria after a spill.

Last common ancestor

The ancestral cellular lineage from which bacteria, archaea, and eukarya diverged.

Pathogen

Any agent capable of causing disease, including viruses, bacteria, fungi, protozoa, and helminths.

Neutralization

A chemical process that combines an acid and a base to form water and salts.

Buffers

Chemical solutions that resist abrupt pH changes by accepting or releasing hydrogen ions ($H^+$).

Mycolic acid

Waxy lipids found in Mycobacterium species that resist ordinary stains and impart acid-fastness.

Pleomorphism

Variation in size and shape among cells within a single bacterial species.

Nucleoid

The non-membrane-bound region in a bacterial cell that contains the main circular chromosome.

Plasmid

Small extra-chromosomal bacterial DNA that may carry antibiotic resistance or virulence genes.

Glycocalyx

A capsule or slime layer surrounding bacteria that aids attachment, biofilm formation, and protection from desiccation and phagocytosis.

Fimbriae

Short attachment fibers that help bacteria adhere to host cells and environmental surfaces.

Pili

Bacterial appendages used for attachment and for transferring DNA during conjugation.

Endospore

A dormant, highly resistant survival structure produced by certain bacteria that is not reproductive.

Endosymbiotic theory

The theory proposing that mitochondria and chloroplasts originated as free-living prokaryotes engulfed by ancestral cells.

Streak plate

A method using successive mechanical streaking across agar to dilute cells and isolate individual pure culture colonies.

Defined medium

A synthetic culture medium whose exact chemical composition is known.

Complex medium

A culture medium containing extracts or digests such as peptone, whose exact chemical composition is not fully known.

Selective medium

A culture medium formulated to suppress the growth of certain organisms while favoring others.

Differential medium

A culture medium that displays visible biochemical differences among distinct organisms.

Sterilization

The process that destroys or removes all microbial life, including bacterial endospores.

Disinfection

The destruction of most vegetative pathogens on inanimate objects, which usually does not kill endospores.

Antisepsis

The direct chemical control and removal of pathogens on living tissue.

Sanitization

The mechanical removal or reduction of microbes on surfaces to safe public health levels.

Microbicidal

Refers to an agent or method that directly kills microorganisms.

Microbistatic

Refers to an agent or method that inhibits microbial growth without killing, allowing growth to resume when removed.

Germicide

A broad chemical agent intended to kill pathogenic microorganisms.

Autoclave

A sterilization apparatus that uses moist heat in the form of steam under pressure to denature proteins and kill endospores.

Nonionizing UV radiation

Light radiation that forms thymine dimers with poor penetration, used for surface and air disinfection.

Colonization

The growth and establishment of microbes on or inside a host without necessarily causing disease.

Infection

The process in which pathogenic microorganisms penetrate host defenses, enter tissues, and multiply.

Disease

Pathologic damage or functional disruption in the host caused by an infection or another process.

Resident microbiota

Microorganisms that establish long-term membership at a specific body site.

Transient microbiota

Microorganisms that occupy a body site temporarily without becoming permanently established.

Endogenous infection

An infection caused by normal biota entering a normally sterile site or proliferating due to weakened host defenses.

Opportunistic pathogen

A microbe that causes disease mainly when host defenses are weakened or when introduced to an unusual anatomical site.

Virulence

The degree of pathogenicity of an organism, influenced by adhesion, invasion, enzymes, toxins, and immune evasion.

Signs

Objective, measurable evidence of disease observed by an examiner.

Symptoms

Subjective evidence of disease felt and reported directly by the patient.

Syndrome

A complex or collection of signs and symptoms that consistently occur together to characterize a particular condition.

Tuberculosis

An airborne disease caused by Mycobacterium tuberculosis, characterized by acid-fast bacilli, granulomas/tubercles, and delayed hypersensitivity.

Leprosy

A chronic skin and peripheral-nerve disease caused by the acid-fast bacterium Mycobacterium leprae, transmitted via prolonged close contact.

Staphylococcus

Gram-positive, catalase-positive cocci arranged in clusters; S. aureus causes abscesses, food intoxication, toxic shock, and MRSA.

Streptococcus

Gram-positive, catalase-negative cocci arranged in chains or pairs; S. pyogenes causes strep throat and skin disease, while other species cause pneumonia.

Emphysema

Noninfectious chronic obstructive pulmonary disease involving destruction of alveolar walls and loss of elastic recoil.

Malaria

A parasitic infection caused by Plasmodium protozoa transmitted by female Anopheles mosquitoes, affecting liver and RBC stages.

First line of defense

Innate, nonspecific external barriers including physical structures (skin, mucous membranes, cilia), secretions (lysozyme, acid), and normal microbiota.

Second line of defense

Innate, nonspecific internal responses including phagocytes, inflammation, fever, complement, interferons, and natural killer cells.

Third line of defense

Adaptive, specific host defenses mediated by B and T lymphocytes, antibodies, clonal expansion, and immunological memory.

Natural killer cells

Innate lymphocytes that destroy virus-infected and tumor cells without requiring antigen-specific sensitization or memory.

Helper T CD4 cells

Thymus-matured T cells that release cytokines to activate B cells, macrophages, and cytotoxic T cells.

Cytotoxic T CD8 cells

Thymus-matured T cells that directly kill infected, malignant, or foreign target cells.

Regulatory T cells

Thymus-matured T cells that suppress immune responses to maintain self-tolerance and prevent autoimmunity.

IgG

The most abundant serum antibody class responsible for secondary immune responses, opsonization, neutralization, complement activation, and placental transfer.

IgA

The primary antibody class found in mucosal areas, secretions, tears, saliva, and colostrum/breast milk, existing as a dimer in mucosal sites.

IgM

A massive pentameric antibody that serves as the first immunoglobulin class produced in a primary immune response.

IgE

An antibody class that binds mast cells and basophils, triggering immediate allergic responses and defense against helminth endoparasites.

IgD

An antibody class functioning primarily as an antigen receptor on the surface of B cells, present at low levels in serum.

Natural active immunity

Immunity acquired through direct infection or natural allergen exposure, triggering the host's immune response and forming memory.

Natural passive immunity

Temporary immunity passed from mother to child via placental IgG transfer or colostrum/breast milk IgA.

Artificial active immunity

Immunity stimulated by vaccination, inducing a primary immune response and memory cell formation.

Artificial passive immunity

Immediate, short-term protection provided by administering prepared antibodies or immune globulin from an outside source.

Type I Hypersensitivity

An immediate allergic reaction mediated by IgE on mast cells and basophils causing histamine release (e.g., anaphylaxis, hay fever, asthma).

Type II Hypersensitivity

A cytotoxic reaction in which IgG or IgM antibodies target cell-surface antigens, triggering complement and cell lysis (e.g., ABO transfusion reactions).

Type III Hypersensitivity

An immune complex reaction where circulating antigen-antibody complexes deposit in tissue and induce inflammation (e.g., SLE, serum sickness).

Type IV Hypersensitivity

A delayed cell-mediated response driven by sensitized T cells and macrophages occurring 24–72 hours post-exposure (e.g., TB skin test, contact dermatitis).

Anaphylaxis

A severe, life-threatening systemic Type I hypersensitivity emergency causing airway compromise and hypotension, requiring immediate intramuscular epinephrine.

Immunopathology

The study of disease conditions resulting from immune system overactivity (hypersensitivity, autoimmunity) or underactivity (immunodeficiencies).

Autograft

A tissue transplant moved from one location to another within the same individual, having the lowest rejection risk.

Isograft

A tissue graft exchanged between genetically identical individuals, carrying a very low rejection risk.

Allograft

A tissue graft exchanged between genetically non-identical members of the same species, carrying a significant rejection risk.

Xenograft

A tissue transfer conducted between different species, bearing the highest risk of immune rejection.

Type O blood

Blood type whose red blood cells carry neither A nor B antigens and whose plasma contains both anti-A and anti-B antibodies, making it the universal RBC donor.

Type AB blood

Blood type whose red blood cells present both A and B antigens and whose plasma contains neither anti-A nor anti-B antibodies, making it the universal RBC recipient.

Rh factor

An RBC surface antigen (D antigen); maternal sensitization in Rh-negative mothers can lead to anti-D IgG crossing the placenta and lysing fetal RBCs.