Infectious Agents Overview

These flashcards cover key topics related to infectious agents, including fungi, protozoa, helminths, viruses, prions, and viroids, as well as their characteristics, pathogenesis, and medical importance.

Which of the following is a recognized type of infectious agent?

A) Bacteria

B) Plants

C) Fungi

D) Mammals

C) Fungi

What is the primary medical significance of fungi?

A) They are mainly used in antibiotic production.

B) They have an increasing incidence of serious illnesses, especially in immuno-compromised patients.

D) They are primarily beneficial for gut health.

C) They are a major cause of minor skin irritations.

B) They have an increasing incidence of serious illnesses, especially in immuno-compromised patients.

Approximately how many known fungal species are considered pathogenic?

A) 100,000

B) 200

C) 1,000

D) 5,000

B) 200

Which of the following is a beneficial role played by fungi?

A) Acting as obligate intracellular parasites

B) Creating harmful toxins

C) Decomposing dead plants

D) Causing widespread crop diseases

C) Decomposing dead plants

What is the approximate optimal pH level for the growth of most fungi?

A) 7

B) 5

C) 9

D) 2

B) 5

Based on their reproduction method, what are the two main forms of yeast?

A) Aerobic and anaerobic yeasts

B) Spore-forming and non-spore-forming yeasts

C) Budding yeasts and fission yeasts

D) Pathogenic and non-pathogenic yeasts

C) Budding yeasts and fission yeasts

What is mycelium?

A) A single filamentous cell of a fungus

B) A type of fungal spore

C) The reproductive structure of a mushroom

D) A visible mass of hyphae

D) A visible mass of hyphae

What is the basic structural characteristic of mold?

A) It exclusively infects plant roots.

B) It consists of long filaments of cells joined together called hyphae.

D) It is primarily unicellular.

C) It reproduces solely by binary fission.

B) It consists of long filaments of cells joined together called hyphae.

How do budding yeasts differ from fission yeasts in their reproduction?

A) Budding yeasts divide by binary fission, while fission yeasts reproduce by budding.

B) Budding yeasts are multicellular, while fission yeasts are unicellular.

C) Budding yeasts reproduce by budding off from the parent cell, while fission yeasts divide by binary fission.

D) Budding yeasts form spores, while fission yeasts do not.

C) Budding yeasts reproduce by budding off from the parent cell, while fission yeasts divide by binary fission.

What is the medical term for a fungal infection?

A) Sepsis

B) Mycosis

C) Bacteremia

D) Viremia

B) Mycosis

What defines cutaneous mycoses?

A) Systemic fungal infections affecting internal organs.

B) Deep tissue fungal infections.

C) Fungal infections exclusive to the respiratory system.

D) Infections that affect the outer layers of the skin, hair, and nails.

D) Infections that affect the outer layers of the skin, hair, and nails.

Which of the following is a common route of infection for fungal pathogens?

A) Insect bites exclusively

B) Blood transfusions

C) Respiratory pathways

D) Ingestion of contaminated water only

C) Respiratory pathways

Which of the following is an example of a systemic mycosis?

A) Histoplasma capsulatum infection

B) Athlete's foot

C) Oral thrush (Candida albicans localized)

D) Ringworm

A) Histoplasma capsulatum infection

Which fungal species is frequently associated with opportunistic infections, particularly in immuno-compromised patients?

A) Agaricus bisporus

B) Candida albicans

C) Penicillium

D) Saccharomyces cerevisiae

B) Candida albicans

Which of the following is an example of a pathogenic protozoan?

A) Escherichia coli

B) Giardia lamblia

C) Staphylococcus aureus

D) Saccharomyces cerevisiae

B) Giardia lamblia

What is a defining characteristic of protozoa?

A) They are eukaryotic and unicellular organisms.

B) They are prokaryotic and multicellular.

C) They are obligate intracellular parasites.

D) They lack genetic material.

A) They are eukaryotic and unicellular organisms.

Where do protozoa typically inhabit?

A) Inside plant cells exclusively.

B) Primarily the deep ocean floor.

C) Water and soil.

D) Only in extreme environments like hot springs.

C) Water and soil.

What type of infection is caused by Giardia lamblia?

A) Respiratory tract infection

B) Skin infection

C) Gastroenteritis

D) Urinary tract infection

C) Gastroenteritis

How is Trichomonas vaginalis primarily transmitted?

A) Airborne droplets

B) Sexual intercourse

C) Contaminated food

D) Mosquito bites

B) Sexual intercourse

What type of organism describes a helminth?

A) Unicellular prokaryotic bacteria

B) Multicellular eukaryotic parasitic worms

C) Obligate intracellular viruses

D) Single-celled fungi

B) Multicellular eukaryotic parasitic worms.

What are the two main host categories for parasites?

A) Definitive hosts (carry adult parasites) and intermediate hosts (carry developmental stages)

B) Direct hosts and indirect hosts

C) Primary hosts and secondary hosts

D) Temporary hosts and permanent hosts

A) Definitive hosts (carry adult parasites) and intermediate hosts (carry developmental stages)

Which of the following is an example of a nematode that affects humans?

A) Enterobius vermicularis (pinworm)

B) Schistosoma mansoni (blood fluke)

C) Fasciola hepatica (liver fluke)

D) Taenia solium (pork tapeworm)

A) Enterobius vermicularis (pinworm)

What is a key characteristic of viruses?

A) They are multicellular organisms.

B) They are obligate intracellular parasites that can cause a range of diseases.

C) They are free-living prokaryotes.

D) They reproduce through binary fission.

B) They are obligate intracellular parasites that can cause a range of diseases.

What is the basic structure of a virus?

A) A flagellum, pili, and a capsule.

B) Nucleic acid (DNA or RNA) and a protein coat.

C) Mitochondria, ribosomes, and endoplasmic reticulum.

D) A cell wall, cytoplasm, and nucleus.

B) Nucleic acid (DNA or RNA) and a protein coat, with some enclosed in an envelope.

What does the term 'oncogenic virus' refer to?

A) Viruses that can induce tumors in animals and humans.

B) Viruses that are used in cancer therapy.

C) Viruses that only infect bacteria.

D) Viruses that cause infections in plants.

A) Viruses that can induce tumors in animals and humans.

How do RNA viruses typically transmit diseases?

A) Exclusively through insect vectors.

B) Via respiratory droplets, fecal-oral routes, or through direct contact.

C) Only through contaminated surgical instruments.

D) Primarily through spores.

B) Via respiratory droplets, fecal-oral routes, or through direct contact.

What are prions?

A) Smallest known viruses.

B) Multicellular parasites.

C) Infectious proteins that cause neurodegenerative diseases.

D) A type of bacterium.

C) Infectious proteins that cause neurodegenerative diseases.

How do viroids differ from viruses?

A) Viroids are short stretches of circular single-stranded RNA without a protein coat.

B) Viroids have a complex protein coat, unlike viruses.

C) Viroids contain both DNA and RNA.

D) Viroids infect bacteria, while viruses infect eukaryotes.

A) Viroids are short stretches of circular single-stranded RNA without a protein coat.

What is one effective method for sterilizing prions?

A) Exposure to UV light for 30 minutes.

B) Freezing at -20^{\circ} C

C) Exposure to sodium hydroxide for 60 minutes.

D) Standard autoclaving at 121^{\circ} C for 15 minutes.

C) Exposure to sodium hydroxide for 60 minutes.

What is characteristic of the incubation period for prion diseases?

A) Their incubation period is always less than 24 hours.

B) They have very short incubation periods.

C) They do not have an incubation period.

D) They typically have long incubation periods.

D) They typically have long incubation periods.

Which of the following is an example of a viral disease caused by an oncogenic virus?

A) Measles (rubeola virus)

B) Cervical cancer caused by HPV

C) Influena (flu virus)

D) The common cold (rhinovirus)

B) Cervical cancer caused by HPV.

Which of the following can occur during the pathogenesis of a fungal infection?

A) Overgrowth of normal flora, inhalation of spores, or traumatic inoculation.

B) Replication inside bacterial cells.

C) Exclusive transmission through insect vectors.

D) Only direct contact with infected individuals.

A) Overgrowth of normal flora, inhalation of spores, or traumatic inoculation can occur.

What is the main role of arthropods when they act as vectors?

A) They synthesize vitamins for their hosts.

B) They produce antibiotics.

C) They decompose dead organic matter.

D) They act as vehicles for the transmission of infectious diseases.

D) They act as vehicles for the transmission of infectious diseases.