Week 7 Human Biology: Biology of Infectious Diseases

Vocabulary flashcards covering the biology of infectious diseases, including bacteria, viruses, HIV/AIDS, tuberculosis, malaria, and antibiotic resistance based on Chapter 8 of the lecture notes.

Microbes

Microscopic organisms, such as bacteria, viruses, and protists, that are widely distributed in the environment.

Pathogens

Disease-causing agents, including bacteria, viruses, and other microbes.

Bacteria

Single-celled, prokaryotic organisms that can be found in three common shapes: coccus, bacillus, and spirillum.

Coccus

A sphere-shaped bacterium.

Bacillus

A rod-shaped bacterium.

Spirillum

A curved, sometimes spiral-shaped bacterium.

Peptidoglycan

A disaccharide with an amino group that is a primary component of bacterial cell walls.

Gram-positive bacteria

Bacteria with cell walls that have a thick layer of peptidoglycan and stain purple with Gram stain.

Gram-negative bacteria

Bacteria that stain pink with Gram stain because they lack a thick peptidoglycan layer and possess an outer membrane with lipopolysaccharides.

Flagella

Long, thin appendages that provide motility to some bacteria.

Fimbriae

Stiff fibers on some bacteria that allow them to adhere to surfaces, such as host cells.

Pilus

An elongated, hollow appendage used to transfer DNA from one bacterial cell to another through conjugation.

Plasmids

Small, circular pieces of DNA in bacteria that often contain genes providing resistance to antibiotics.

Binary fission

The method by which bacteria reproduce, where a single chromosome is copied and the cell enlarges then separates into two cells.

Clostridium tetani

A bacterium that produces a toxin preventing the relaxation of muscles, leading to suffocation.

Viruses

Very small, acellular, intracellular parasites consisting of a capsid and a nucleic acid core (DNA or RNA).

Capsid

The outer protein coat of a virus.

Bacteriophage

A type of virus that specifically infects bacterial cells.

Lysogenic cycle

A viral life cycle stage where the virus becomes latent and its DNA is incorporated into the host DNA without immediately producing new viruses.

Prophage

Viral DNA that has been integrated into the host cell's genome.

Prions

Infectious protein particles that cause degenerative diseases of the nervous system by folding into abnormal shapes.

Epidemic

A classification for an infectious disease when there are more cases than expected in a certain area for a specific period of time.

Outbreak

An epidemic that is confined to a local geographic area.

Pandemic

A global epidemic, such as HIV/AIDS, tuberculosis, or SARS-CoV-2.

Reverse transcriptase

An HIV enzyme that converts single-stranded viral RNA into double-stranded viral DNA.

Integrase

An HIV enzyme that integrates viral DNA into the host cell's DNA.

Protease

An HIV enzyme that cleaves newly synthesized viral polypeptides into functional viral proteins.

gp120

Protein spikes in the HIV envelope that must bind to a CD4 receptor for the virus to enter target cells.

Retrovirus

A virus with an RNA genome that must use reverse transcription to convert its RNA into DNA before inserting it into the host genome.

Provirus

The term for HIV once its genetic material is integrated as part of the host cell's DNA.

Mycobacterium tuberculosis

The rod-shaped bacterium responsible for causing tuberculosis (TB).

Tubercles

Small, hard nodules in the lungs formed when white blood cells wall off an area infected with TB bacteria.

Latent TB

A condition where TB bacteria remain alive within tubercles but the patient does not feel sick and is not contagious.

Vector

A living organism, such as a mosquito, that transfers a pathogen from one host to another.

Plasmodium

The genus of protist parasites that cause malaria and are transmitted by female mosquitoes.

Emerging diseases

Diseases occurring for the first time in humans, rapidly becoming more common, or entering new geographic regions.

Reemerging diseases

Pathogens that reappear after a significant decline in incidence, such as Streptococcus or Helicobacter pylori.

SARS-CoV-2

A highly contagious coronavirus that emerged in the Wuhan province of China and causes the disease COVID-19.

Antibiotic resistance

A phenomenon where a population of pathogens becomes resistant to a drug because the drug kills only susceptible organisms, leaving resistant ones to multiply.

MRSA

Methicillin-resistant Staphylococcus aureus, a multidrug-resistant organism that causes "staph" infections.

XDR TB

Extensively drug-resistant tuberculosis, which is resistant to almost all first-line and second-line antibiotics used to treat TB.