Microbial Genetics, Metabolism, Host Defenses, and Infectious Diseases (Pages 1–4)

Vocabulary-style flashcards covering genetics, metabolism, immune defense, and a range of pathogens and diseases mentioned in the notes.

Genotype

The sum of all genetic material (the genetic makeup) of an organism.

Phenotype

The observable characteristics or functions expressed by the genotype in a given environment.

Lac operon

A cluster of lactose-utilizing genes regulated as a single unit; typically off unless lactose is present, which induces transcription.

Rifamycin

Antibiotic that inhibits RNA synthesis by targeting RNA polymerase (transcription).

Actinomycin D

Antibiotic that inhibits transcription by intercalating into DNA and blocking RNA synthesis.

Erythromycin

Antibiotic that inhibits protein synthesis by binding to the 50S ribosomal subunit.

Spectinomycin

Antibiotic that interferes with protein synthesis by targeting the 30S ribosomal subunit.

Transduction

Horizontal gene transfer where a bacteriophage carries bacterial DNA from one cell to another.

Conjugation

Horizontal gene transfer via a pilus from one bacterium to another.

Transformation

Horizontal gene transfer involving uptake of free DNA from the environment by a bacterium.

Ames Test

A rapid assay used to detect chemicals with carcinogenic potential.

Missense mutation

DNA base change that results in a different amino acid in the protein.

Frameshift mutation

Insertion or deletion of bases that alters the reading frame, often producing a nonfunctional protein.

Silent mutation

Nucleotide change that does not alter the amino acid sequence of the protein.

Nonsense mutation

Mutation that creates a premature stop codon, truncating the protein.

Fermentation

Metabolic process converting glucose to fermentation products (e.g., lactic acid or ethanol) with regeneration of NAD+; does not require oxygen.

Photosynthesis

Process by which light energy is converted to chemical energy; may release oxygen (oxygenic) or not (anoxygenic) in bacteria.

Catabolism

Metabolic pathways that break down molecules to release energy.

Anabolism

Metabolic pathways that synthesize cellular components; consumes energy.

Enzyme

A mostly protein catalyst (often with nonprotein parts) that speeds up biochemical reactions and is not consumed in the reaction.

Competitive inhibition

Inhibitor competes with the substrate for the enzyme's active site, reducing reaction rate.

Noncompetitive inhibition

Inhibitor binds to a site other than the active site, altering enzyme activity regardless of substrate concentration.

Repression

Negative regulation of gene expression where a repressor prevents transcription.

Induction

Activation of gene expression where an inducer enables transcription.

Aerobic respiration

Glucose oxidation to CO2 with production of about 36–38 ATP per glucose in the presence of oxygen.

Anaerobic respiration

Glucose oxidation to CO2 with less ATP produced (2–36 ATP) in the absence of oxygen.

Fermentation (ATP yield)

ATP production from glucose without oxygen, yielding about 2 ATP per glucose.

Fevers (host defense)

Elevated body temperature to inhibit microbes and stimulate immune responses.

Helper T cell function

Activate macrophages, assist B cells, and help activate cytotoxic T cells.

Cytotoxic T cell function

Destroy infected host cells or foreign substances.

B cell function

Differentiate into plasma cells that secrete antibodies into tissues and blood.

Inflammation signs

Redness, heat, pain, swelling, and loss of function at infection sites.

Inflammation steps

Injury/initial response, vascular changes, edema with pus formation, and resolution or scarring.

Vaccination

Exposure to antigenic material to prime the immune system for faster secondary responses.

Major Histocompatibility Complex (MHC)

Genes encoding cell surface glycoproteins important for self-recognition and antigen presentation.

Class I MHC

MHC genes on all nucleated cells; present peptides to T cells and help with self-recognition.

Class II MHC

MHC genes on antigen-presenting cells (macrophages, dendritic cells, B cells); present antigens to T cells.

Class III MHC

Genes encoding components of the complement system.

Acute Endocarditis

Heart valve infection with signs like fever and abnormal heartbeat; commonly caused by Staphylococcus aureus or Streptococcus pneumoniae.

Bacillus anthracis

Cause of anthrax; black eschar in cutaneous form; transmitted via spores; detected by culture or PCR.

Anthrax vaccines and antibiotics

Vaccination and antibiotics such as ciprofloxacin or doxycycline are used for prevention and treatment.

Streptococcus mutans

Bacterium associated with dental caries (tooth decay) via acid production in dental plaque.

Escherichia coli (pathogenic)

Pathogenic strains cause diarrhea ranging from watery to bloody and cramps; stool culture or PCR used for diagnosis.

EHEC

Enterohemorrhagic E. coli; can cause bloody diarrhea and risk of kidney failure; managed with rehydration.

Staphylococcus aureus (clinical)**

Causes skin abscesses, pneumonia, and food poisoning.

Salmonella spp.

Pathogens causing diarrhea and fever from contaminated food; stool culture used for diagnosis.

Helicobacter pylori

Causes gastritis and peptic ulcers; diagnosed with urea breath test or stool antigen; treated with triple therapy.

Chlamydia trachomatis

Causes urethritis and PID; NAAT used for diagnosis; treated with azithromycin or doxycycline.

Streptococcus pneumoniae

Causes pneumonia, meningitis, and otitis media; diagnosed by culture or antigen testing; pneumococcal vaccine available.

Borrelia burgdorferi

Lyme disease agent; transmitted by Ixodes ticks; presents with erythema migrans; diagnosed by serology; treated with doxycycline.

Haemophilus ducreyi

Causes painful genital ulcers (chancroid); sexually transmitted; diagnosed by culture/NAAT; treated with azithromycin or ceftriaxone.

Streptococcus pneumoniae vaccine

Vaccine to prevent pneumococcal infections; reduces risk of pneumonia and meningitis.

Neisseria gonorrhoeae

Causes urethritis and PID; neonatal conjunctivitis; diagnosed by NAAT; treated with ceftriaxone plus azithromycin.

Treponema pallidum

Syphilis pathogen; phases include chancre, rashes, and gummas; diagnosed serologically; treated with penicillin G.

Rickettsia species

Rickettsial diseases with fever and rash; transmitted by arthropod vectors; treated with doxycycline.

Human papillomaviruses (HPV)

Warts and cervical dysplasia; detected by Pap smear and HPV DNA testing; vaccine available.

Bartonella henselae

Causes fever and lymphadenopathy (cat scratch disease); diagnosed by serology; treated with azithromycin.

Hepatitis A virus

Fecal–oral transmitted hepatitis; acute infection; prevented by vaccine and hygiene; diagnosed by serology.

Hepatitis B virus

Blood-borne hepatitis; can be acute or chronic; vaccinated; diagnosed by HBsAg/anti-HBc.

Herpes simplex viruses 1 & 2

Oral/genital vesicular infections; diagnosed by PCR or culture; treated with acyclovir.

HIV

Human immunodeficiency virus; causes flu-like symptoms then opportunistic infections; managed with safe-sex practices, PrEP, ART.

Enterobius vermicularis

Pinworm causing perianal itching; diagnosed by tape test; treated with albendazole; emphasizes hygiene.

Taenia solium

Tapeworm; causes intestinal infection and neurocysticercosis; acquired by ingesting eggs/larvae; stool O&P; cook pork; treated with praziquantel or albendazole.

Fasciola hepatica

Liver fluke causing RUQ pain; acquired from contaminated water or plants; diagnosed by stool O&P; treated with praziquantel.

Schistosoma haematobium

Blood fluke causing hematuria and bladder inflammation; contracted via infested water; diagnosed by urine microscopy; treated with praziquantel.

Giardia duodenalis

Protist causing diarrhea and greasy stools; diagnosed by stool antigen/O&P; treated with metronidazole.

SARS-CoV-2

Coronavirus causing COVID-19; transmitted via droplets/aerosols; diagnosed by PCR/antigen tests; prevented by vaccines; treated with supportive care/antivirals.

Trichomonas vaginalis

Protozoan causing vaginitis with frothy green discharge; sexually transmitted; treated with metronidazole.

Entamoeba histolytica

Protozoan causing dysentery (not explicitly listed but related to enteric pathogens listed); diagnosed by stool tests; treated accordingly.