BIOL 2420 Microbiology Unit 3 Study Guide

Vocabulary-style flashcards covering Unit 3: Viruses, Prions, Digestive Diseases, and Respiratory Infections based on the provided lecture transcript.

Virus

An acellular infectious agent that cannot reproduce on its own, lacks its own metabolism, has no cellular structure, and must infect a host cell to reproduce.

Capsid

The protein shell surrounding a virus's genetic material, made of subunits called capsomeres.

Capsomere

The individual protein subunits that make up the viral capsid.

Viral Envelope

A lipid membrane surrounding the capsid, usually derived from the host cell membrane and containing viral proteins like spikes or glycoproteins.

Spikes

Viral glycoproteins on the envelope that allow the virus to attach to, fuse with, and enter host cells.

Naked virus

A virus that lacks an envelope; it is generally more environmentally resistant to soap, detergents, and heat.

Antigenic drift

Small, gradual mutations in viral genes that slightly change antigens, allowing the virus to partially evade existing immunity.

Antigenic shift

A major genetic change occurring when different influenza viruses exchange genome segments, potentially leading to pandemics.

Tropism

The specific cells or tissues a virus is able to infect, often determined by the presence of correct host receptors.

Host range

The types of organisms or species a virus is capable of infecting.

Lytic cycle

A bacteriophage replication pathway where the virus immediately takes over the cell, resulting in cell lysis and death.

Lysogenic cycle

A bacteriophage pathway where viral DNA integrates into the bacterial chromosome as a prophage and is copied during cell division.

Prophage

Viral DNA that has been incorporated into the bacterial chromosome during the lysogenic cycle.

Uncoating

The third step of viral infection where the viral genome is released from the capsid inside the host cell.

Acute infection

An infection where the virus reproduces quickly and causes symptoms over a relatively short period, such as influenza.

Chronic persistent infection

An infection where the virus remains in the body and continues producing virus for a long period, such as chronic hepatitis B.

Latent persistent infection

An infection where the virus remains inactive inside cells for periods of time and can later reactivate, such as herpesvirus.

Oncogenic viruses

Viruses that can contribute to cancer by causing cells to divide uncontrollably or avoid cell death, such as HPV or Hepatitis B/C.

Plaque assay

A laboratory method used to measure viruses where clear areas called plaques represent evidence of viral infection and cell death.

RT-PCR

A laboratory technique used to detect RNA viruses by first converting RNA into DNA via reverse transcription before amplification.

Prion

An infectious, misfolded protein that contains no DNA or RNA and causes normal proteins to misfold; examples include Creutzfeldt-Jakob disease and Mad cow disease.

Gastritis

Inflammation of the stomach lining.

Enteritis

Inflammation of the small intestine.

Gastroenteritis

Inflammation involving both the stomach and the intestines.

Dysentery

Diarrhea that contains blood and/or mucus, usually associated with intestinal inflammation.

Hypovolemic shock

A severe loss of fluid leading to reduced blood volume and inadequate blood flow to organs.

Mumps

A viral infection characterized by swollen salivary glands, fever, and headache; prevented by the MMR vaccine.

Rotavirus

A leading cause of severe watery diarrhea and dehydration in infants, transmitted via the fecal-oral route.

Norovirus

An extremely contagious virus that causes outbreaks of vomiting and watery diarrhea, often through contaminated food or surfaces.

Hepatitis A

An acute liver infection typically transmitted through the fecal-oral route.

Hepatitis B

A liver infection transmitted through blood, body fluids, or childbirth that can become chronic.

Dental Caries

Tooth decay or cavities caused primarily by Streptococcus mutans metabolizing sugars into acids that damage enamel.

Periodontal Disease

Inflammation and damage to the tissues supporting the teeth caused by bacteria in dental plaque.

Helicobacter pylori

A bacterium that survives stomach acid to cause ulcers and is linked to an increased risk of stomach cancer.

Campylobacteriosis

An infection usually caused by Campylobacter jejuni from contaminated poultry; a potential complication is Guillain-Barr-Barr
syndrome.

Shigellosis

An illness caused by Shigella resulting in dysentery; it has a very low infectious dose and may involve Shiga toxin.

EHEC

Enterohemorrhagic E. coli, such as O157:H7, which produces Shiga-like toxin and can cause Hemolytic Uremic Syndrome (HUS).

Hemolytic Uremic Syndrome (HUS)

A major complication of EHEC infection involving hemolytic anemia, low platelets, and kidney damage.

Typhoid Fever

A systemic infection caused by Salmonella Typhi, characterized by prolonged fever and abdominal pain.

Cholera

An infection caused by Vibrio cholerae characterized by massive 'rice-water stool' diarrhea and severe dehydration due to cholera toxin.

Clostridioides difficile

A bacterium that overgrows after antibiotic use disrupts normal microbiota, causing diarrhea and pseudomembranous colitis.

Giardiasis

A protozoan infection causing foul-smelling, greasy stool and malabsorption, usually from contaminated water.

Amebiasis

An infection caused by Entamoeba histolytica resulting in dysentery and potentially liver abscesses.

Pinworms

An infection caused by Enterobius vermicularis, diagnosed by a tape test, with intense anal itching at night as the main symptom.

Hookworms

Parasitic worms like Ancylostoma that penetrate the skin from soil and can cause iron-deficiency anemia by feeding on blood in the intestines.

Trichinellosis

An infection caused by Trichinella spiralis larvae forming cysts in muscles after eating undercooked infected pork or wild game.

Schistosomiasis

A disease caused by parasitic flatworms that penetrate human skin in contaminated freshwater.

Foodborne infection

An illness caused by ingesting living microorganisms that grow and infect the host, such as Salmonella.

Food poisoning

Also known as food intoxication; an illness caused by ingesting a toxin already produced in food, such as Staphylococcus aureus toxin.

Mucociliary escalator

A respiratory defense where mucus traps microbes and cilia move the mucus toward the throat to be swallowed or expelled.

Croup

A respiratory illness causing swelling around the upper airway, resulting in a barking cough and stridor.

Stridor

A harsh, high-pitched sound caused by a narrowed or obstructed upper airway.

Dyspnea

Difficulty breathing or shortness of breath.

Serovar

A group of microorganisms distinguished by specific surface antigens.

Respiratory syncytial virus (RSV)

A virus that can cause severe bronchiolitis and pneumonia, especially in infants and high-risk older adults.

SARS-CoV-2

The virus that causes COVID-19 by using its spike protein to interact with ACE2 receptors on host cells.

Otitis Media

A middle ear infection common in children due to their shorter, more horizontal Eustachian tubes.

Pertussis

Also known as whooping cough, caused by Bordetella pertussis; it involves toxins that damage respiratory cilia.

Tuberculosis

An airborne infection caused by Mycobacterium tuberculosis that leads to the formation of granulomas in the lungs.

Coccidioidomycosis

Also known as Valley fever, caused by inhaling fungal spores from the soil in the southwestern United States.

Typical pneumonia

Commonly bacterial (e.g., Streptococcus pneumoniae), characterized by sudden onset, high fever, productive cough, and alveolar consolidation.

Atypical pneumonia

Caused by organisms like Mycoplasma or Legionella, characterized by gradual onset, dry cough, and a diffuse/interstitial lung pattern.

Walking pneumonia

A milder form of pneumonia caused by Mycoplasma pneumoniae, which lacks a cell wall and is resistant to beta-lactam antibiotics.

Legionnaire's Disease

A form of pneumonia caused by Legionella pneumophila, typically transmitted via aerosols from contaminated water systems like hot tubs or AC units.

Q Fever

An infection caused by Coxiella burnetii, often transmitted through inhalation of particles from infected livestock.

Mucormycosis

An aggressive fungal infection in immunocompromised patients that can cause severe tissue destruction in the sinuses, brain, or lungs.

Histoplasmosis

A respiratory fungal infection associated with soil contaminated with bird or bat droppings.

Pneumocystis pneumonia

A fungal pneumonia caused by Pneumocystis jirovecii, seen primarily in people with weakened immune systems like those with HIV/AIDS.

Scarlet fever

A complication of Streptococcus pyogenes infection (strep throat) characterized by a toxin-induced rash.

Diphtheria

An infection caused by Corynebacterium diphtheriae characterized by a thick gray/white pseudomembrane in the throat that can obstruct breathing.