genotype

Genetic makeup (DNA).

phenotype

Observable traits (e.g., antibiotic resistance, pigment).

lac operon

• A set of genes involved in lactose metabolism in E. coli.
• Regulated by presence/absence of lactose and glucose

Transcription

Rifampin (inhibits bacterial RNA polymerase)

Translation

Tetracyclines, Streptomycin, Chloramphenicol (target bacterial ribosomes)

Horizontal Gene Transfer Types

• Transformation
• Transduction
• Conjugation

• Transformation

Uptake of naked DNA

• Transduction

Via bacteriophages (viruses)

• Conjugation

Direct cell-to-cell contact using a pilus

Ames Test

Detects mutagenic potential of chemicals using bacteria.

Mutation Categories

• Point mutations
• Frameshift

• Point mutations

Silent, Missense, Nonsense

Frameshift

Insertions or deletions

anaerobic fermentation

regenerates NAD⁺; produces acids/gases/alcohol

Allows ATP production without oxygen

Photosynthesis in Bacteria

Involves light reactions and carbon fixation (e.g., cyanobacteria)

Catabolism

Breaks down molecules release energy

anabolism

builds molecules req energy

enzymes

• Biological catalysts; affected by temp, pH, inhibitors

Functions: Lower activation energy

aerobic respiration

Uses O₂, most ATP

Anaerobic respiration

Uses other terminal electron acceptors

cardio defenses

Blood-borne immune cells, clotting, complement

lymphatic defenses

Lymph nodes, WBCs, spleen

Sepsis

Body-wide inflammatory response to infection

Endocarditis

Inflammation of heart lining

Endotoxic shock:

Caused by Gram-negative LPS

Hemorrhagic fever

Internal bleeding (e.g., Ebola)

Nonhemorrhagic fever

High fever without bleeding (e.g., Q fever)

GI system defenses

Stomach acid, mucus, GALT, microbiota

Helminth Life Cycles

Involve ingestion, migration through tissues, reproduction

acute gi disease

sudden onset

chronic gi disease

long term

intoxication gi disease

toxins, not infection

Genitourinary Tract Defenses

Urine flow, low pH, mucous membranes

UTIs

Caused by E. coli, Staph saprophyticus

Vaginosis

Overgrowth, little inflammation (e.g., Gardnerella)

Vaginitis

Inflammation, itching, discharge (e.g., Candida)

Prostatitis

Inflammation of prostate, often bacterial

Fever

Raises body temp to inhibit microbes and enhance immunity

Helper T

Activate immune response

Cytotoxic T

kill infected cells

b cells

produce antibodies

Inflammation

Redness, heat, swelling, pain – recruits immune cells

Vaccines

Train immune system for future exposure (active immunity)

MHC class I

All cells, present to cytotoxic T cells

MHC class II

• APCs (like dendritic cells), present to helper T cells

Bacillus anthracis

Causes anthrax, which can manifest as cutaneous, inhalational, or gastrointestinal forms. Inhalational anthrax is particularly severe and can be fatal if not treated promptly.

Staphylococcus aureus:

A versatile pathogen causing skin infections, pneumonia, endocarditis, and sepsis. Methicillin-resistant Staphylococcus aureus (MRSA) strains are notable for their antibiotic resistance

Streptococcus pneumoniae:

Responsible for pneumococcal diseases such as pneumonia, meningitis, and bacteremia. It is a leading cause of community-acquired pneumonia

Yersinia pestis:

The causative agent of plague, including bubonic, septicemic, and pneumonic forms. Transmitted primarily through flea bites

Borrelia burgdorferi:

Causes Lyme disease, transmitted by blacklegged ticks. Early symptoms include a characteristic "bull's-eye" rash

Bartonella henselae:

Leads to cat scratch disease, characterized by swollen lymph nodes near the site of a cat scratch or bite.​

Rickettsia species:

Responsible for diseases like Rocky Mountain spotted fever and typhus, transmitted by ticks, fleas, or lice.​

Epstein–Barr virus:

A herpesvirus causing infectious mononucleosis ("mono") and associated with certain cancers like Burkitt's lymphoma.​

Yellow fever virus:

A flavivirus transmitted by mosquitoes, causing symptoms ranging from fever to severe liver disease with bleeding.​

HIV:

Human Immunodeficiency Virus attacks the immune system, leading to AIDS if untreated. Transmitted through blood, sexual contact, and from mother to child.​

Streptococcus mutans:

A primary bacterium involved in dental caries (tooth decay) due to its acid-producing capability.

Escherichia coli:

While many strains are harmless, pathogenic E. coli can cause diarrhea, urinary tract infections, and other illnesses.

Helicobacter pylori

Infects the stomach lining, leading to ulcers and potentially increasing the risk of stomach cancer. Mayo Clinic​

Salmonella

Causes salmonellosis, a common foodborne illness resulting in diarrhea, fever, and abdominal cramps. Mayo Clinic​

Clostridium perfringens

Produces toxins leading to food poisoning, characterized by abdominal cramps and diarrhea. CDC​

Hepatitis A virus

Transmitted via the fecal-oral route, leading to liver inflammation. Often associated with contaminated food or water. Mayo Clinic​

Hepatitis B virus

Spread through blood and bodily fluids, it can cause both acute and chronic liver infections.​eatingwell.com

Hepatitis C virus

Primarily transmitted through blood, leading to chronic liver disease and potential liver cancer.​

Mumps virus

Causes mumps, characterized by swollen salivary glands, and can lead to complications like orchitis.​

Giardia duodenalis

A protozoan causing giardiasis, leading to diarrhea and gastrointestinal discomfort.​

Enterobius vermicularis

Also known as pinworm, it causes perianal itching, especially in children.​

Taenia solium

A pork tapeworm that can lead to cysticercosis if larvae invade body tissues.​

Fasciola hepatica

A liver fluke causing fascioliasis, leading to liver inflammation and bile duct obstruction.​

Chlamydia trachomatis

Causes chlamydia, a common sexually transmitted infection that can lead to reproductive complications if untreated. ​

Treponema pallidum

The bacterium responsible for syphilis, a disease with stages ranging from sores to systemic involvement. ​

Neisseria gonorrhoeae

Causes gonorrhea, a sexually transmitted infection affecting mucous membranes. ​Mayo Clinic

Haemophilus ducreyi

Leads to chancroid, characterized by painful genital ulcers. ​

Herpes simplex viruses 1 and 2

HSV-1 typically causes oral herpes, while HSV-2 is associated with genital herpes.​

Human papillomaviruses

A group of viruses causing warts and associated with cervical and other cancers.​

Candida albicans

A yeast causing candidiasis, including vaginal yeast infections and oral thrush.​

Trichomonas vaginalis

A protozoan causing trichomoniasis, a sexually transmitted infection leading to genital inflammation.​

Schistosoma haematobium

A parasitic worm causing urinary schistosom