Innate Immunity
Name two types of innate (non-specific) white blood cells that respond quickly to pathogens.
What are neutrophils, macrophages, natural killer cells, mast cells, dendritic cells.
What type of white blood cell makes antibodies?
What are B lymphocytes (B cells),
specifically, plasma B cells produce antibodies.
Define "pathogen" and give two examples.
Pathogen: organism that causes disease; examples: bacteria, viruses, parasites, fungi.
What kind of pathogen do antibiotics treat?
Bacteria only. Explanation: Antibiotics target bacteria, not viruses.
Define "biofilm" and explain two ways biofilms help bacteria survive antibiotics or environmental stress.
Microbiome: the collection of microorganisms and their genetic material living in and on the human body.
Which innate immune cell engulfs (phagocytoses) pathogens and helps clean up debris?
What are Macrophages (also neutrophil)
Explanation: Phagocytes engulf and digest pathogens.
Name two types of T lymphocytes and give one function for each.
Helper T cells (activate B cells and other immune cells); Killer (cytotoxic) T cells (destroy infected host cells).
Each has a role in killing
List three common transmission routes for infectious diseases.
Infectious: caused by pathogens and often contagious.
Non-infectious: not caused by pathogens and not contagious (e.g., genetic disorders, most cancers).
Briefly describe what a vaccine contains and how it helps prevent disease.
Vaccine: contains dead or weakened pathogen (or parts of it) so the body produces antibodies and memory cells without causing disease.
What is natural selection in one sentence?
A process where individuals better adapted to their environment survive and reproduce more, changing the population over time.
Explain why the innate immune response is called "non-specific."
Because it responds to general features of pathogens (not specific antigens) and acts the same way for many different invaders.
Memory cells are long-lived B or T cells that "remember" a pathogen so the immune system responds faster on re-exposure
List three common transmission routes for infectious diseases.
Direct contact, water, air (respiratory droplets), contaminated food; also vectors or bodily fluids.
What is antibiotic resistance, AND how can human behavior speed up its development?
Bacteria evolve the ability to survive antibiotics;
misuse/overuse (not finishing courses, using antibiotics for viral infections, over-prescription) speeds selection for resistant strains.
Explain how genetic variation helps a population survive environmental change.
Genetic variation provides different traits so some individuals may survive new conditions (disease, climate), allowing the population to persist.
Describe the role of inflammation in innate immunity. Give one sign of inflammation.
Role: brings immune cells to the infected area, increases blood flow and permeability so WBCs reach tissues. Sign: redness, swelling, heat, pain.
Explanation: Inflammation is a protective response that isolates and helps clear infection.
Explain how antibodies help the immune system remove pathogens (give two mechanisms).
Antibodies neutralize pathogens (block entry into cells) and opsonize pathogens (mark them for phagocytosis); they can also activate complement to lyse pathogens.
Give two human or environmental factors that increase the rate of disease transmission and explain how each increases spread.
Examples: Poverty/overcrowding — increases close contact and lowers sanitation; Contaminated water/food — provides a route for pathogens to enter many people.
Explain what bacteriophages are and one potential advantage they have over antibiotics.
Bacteriophages are viruses that infect and kill bacteria.
Advantage: they can target specific bacteria and replicate at infection sites, potentially reducing harm to beneficial bacteria
Describe quorum sensing and how it can contribute to antibiotic resistance.
Quorum sensing: bacterial communication that detects population density and triggers group behaviors (e.g., biofilm formation); this can coordinate defenses that reduce antibiotic effectiveness. Explanation: Coordinated behavior helps group survival under stress.
A student cut their finger and bacteria entered. Outline the first three innate immune actions that happen at the site of the cut (sequence).
First ...(1) Physical barrier broken; (2nd) Innate cells (neutrophils) rush in and phagocytose bacteria; (3rd) Macrophages clean debris and release signals to recruit more immune cells and start healing.
Compare and contrast primary immune response vs. secondary immune response (what differs in speed and antibody levels).
Primary - Slower, first exposure, lower, and later antibody production. Secondary- faster, stronger, and higher antibody levels due to memory cells.
Explanation: Memory cells produced after first exposure speed up later responses.
A disease spreads quickly in a crowded city after large gatherings and international travel. Identify and explain three contributing factors from the review sheet.
Contributing factors: high population density (urbanization), mass gatherings, global travel. Each increases contact rates or moves pathogens between regions.
Claim — "We should treat bacterial infections using bacteriophages instead of antibiotics." List one piece of evidence and one reasoning statement supporting this claim
Bacteriophages infect and destroy bacterial cell
Bacteriophages specifically target bacteria and can reduce bacterial populations where antibiotics fail due to resistance, using phages could control infections that antibiotics cannot.
Biofilm: a community of bacteria attached to surfaces embedded in a protective matrix. Ways biofilms help survival: (1) Physical barrier that reduces antibiotic penetration; (2) Slower-growing cells and shared resources make antibiotics less effective.