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OpenStem
@openstem · Joined Jul 2026
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Flashcards10 cards
What is a blood type based on?1 / 10
A blood type is based on which antigens — marker molecules — are present on the surface of a person's red blood cells. The ABO system and the Rh system are the two most medically important classification systems.
Biology · L3 · The ABO and Rh Blood Group Systems
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Biology · L3 · The ABO and Rh Blood Group SystemsFlashcards9 cards
What happens if a person receives blood with an antigen their plasma has antibodies against?1 / 9
The recipient's antibodies bind to the foreign antigens on the donated red blood cells and cause them to clump together (agglutinate) and rupture. This transfusion reaction can block blood vessels, damage the kidneys, and be life-threatening.
Biology · L3 · Transfusion Compatibility and Reactions
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Biology · L3 · Transfusion Compatibility and ReactionsFlashcards10 cards
What are the three main layers of the skin (from outermost to innermost)?1 / 10
Biology · L3 · Skin Structure: The Three Layers
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Biology · L3 · Skin Structure: The Three LayersFlashcards10 cards
What are the five main functions of the integumentary system?1 / 10
Biology · L3 · Skin Functions, Hair, Nails, and Wound Healing
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Biology · L3 · Skin Functions, Hair, Nails, and Wound HealingFlashcards10 cards
What is the lymphatic system, in one sentence?1 / 10
A network of vessels and organs that collects excess fluid from body tissues, filters it for pathogens, and returns it to the bloodstream — while also playing a central role in immune defense.
Biology · L3 · Lymphatic Vessels and Fluid Return
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Biology · L3 · Lymphatic Vessels and Fluid ReturnFlashcards10 cards
What is a lymph node?1 / 10
A lymph node is a small, bean-shaped structure found at intervals along lymphatic vessels. Lymph flows through nodes on its way back to the blood, and each node is packed with immune cells that filter out pathogens and debris.
Biology · L3 · Lymph Nodes, the Spleen, and Immune Defense
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Biology · L3 · Lymph Nodes, the Spleen, and Immune DefenseFlashcards10 cards
What is a genetic disorder?1 / 10
A health condition caused, at least in part, by a change (mutation) in an organism's DNA or by an abnormal number of chromosomes. Some genetic disorders are inherited from parents; others arise from a new mutation.
Biology · L3 · Genetic Disorders Vocabulary
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Biology · L3 · Genetic Disorders VocabularyFlashcards10 cards
What causes sickle cell anemia?1 / 10
A mutation in the gene for hemoglobin, the protein in red blood cells that carries oxygen. The mutated hemoglobin can cause red blood cells to become rigid and curved into a sickle (crescent) shape, especially when oxygen levels are low.
Biology · L3 · Sickle Cell Anemia, Cystic Fibrosis, and Down Syndrome
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Biology · L3 · Sickle Cell Anemia, Cystic Fibrosis, and Down SyndromeFlashcards10 cards
Why do plants need defenses at all, since they cannot run away from a hungry animal?1 / 10
Because a plant is rooted in place, it cannot flee a herbivore the way an animal can run from a predator. Instead, plants rely on structural and chemical defenses built into their tissues, along with occasional help from animal partners, to discourage or survive being eaten.
Biology · L3 · Physical and Chemical Plant Defenses
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Biology · L3 · Physical and Chemical Plant DefensesFlashcards10 cards
What is defensive mutualism?1 / 10
Defensive mutualism is a relationship between two species in which one partner provides food or shelter, and in return the other partner actively defends it against enemies. Both species benefit: one gains protection, the other gains a resource, such as food.
Biology · L3 · Defensive Mutualism: The Ant-Acacia Relationship
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Biology · L3 · Defensive Mutualism: The Ant-Acacia RelationshipFlashcards10 cards
What is innate behavior?1 / 10
Innate behavior (also called instinctive behavior) is behavior an animal performs correctly the very first time, without ever having been taught or having practiced it. It is inherited, genetically programmed, and shows up in every normal member of a species.
Biology · L3 · Innate Behavior and Fixed Action Patterns
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Biology · L3 · Innate Behavior and Fixed Action PatternsFlashcards10 cards
What is learned behavior?1 / 10
Learned behavior is behavior that changes as a result of experience. Unlike innate behavior, it is not fully present at birth — it develops or is modified through interactions with the environment.
Biology · L3 · Learned Behavior: Habituation, Imprinting, and Conditioning
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Biology · L3 · Learned Behavior: Habituation, Imprinting, and ConditioningFlashcards10 cards
What does it mean to "clone" a living thing?1 / 10
Making a clone means creating a genetic copy of an organism — a new individual with (almost) exactly the same DNA as the original. Cloning can happen naturally or be done deliberately in a lab.
Biology · L3 · What Is Cloning?
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Biology · L3 · What Is Cloning?Flashcards10 cards
What is a genetically modified organism (GMO)?1 / 10
A GMO is an organism whose genes have been deliberately changed by scientists — usually by adding a gene from another species — to give it a new trait it would not have developed on its own.
Biology · L3 · Genetically Modified Organisms (GMOs)
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Biology · L3 · Genetically Modified Organisms (GMOs)Flashcards10 cards
What is asthma?1 / 10
Asthma is a chronic condition in which the airways — mainly the bronchi and bronchioles — become inflamed and overly sensitive, periodically narrowing and making it harder for air to flow in and out of the lungs.
Biology · L3 · Asthma: Causes and Triggers
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Biology · L3 · Asthma: Causes and TriggersFlashcards10 cards
What are cilia, and how does smoking affect them?1 / 10
Cilia are tiny hair-like structures lining the airways that sweep mucus, dust, and pathogens up and out of the lungs. Chemicals in cigarette smoke paralyze and eventually destroy cilia, so debris and pathogens build up instead of being cleared.
Biology · L3 · Smoking, Chronic Lung Disease, and Pneumonia
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Biology · L3 · Smoking, Chronic Lung Disease, and PneumoniaFlashcards10 cards
How many heart chambers does a fish have, and what are they?1 / 10
A fish heart has 2 chambers — one atrium and one ventricle. Blood is pumped through the heart only once per full circuit around the body, called single circulation.
Biology · L3 · Circulatory System and Thermoregulation Across Vertebrate Classes
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Biology · L3 · Circulatory System and Thermoregulation Across Vertebrate ClassesFlashcards10 cards
What type of skin covering do fish have?1 / 10
Fish are covered in overlapping scales coated with a layer of mucus. The mucus reduces drag as they swim and offers some protection against infection.
Biology · L3 · Skin, Respiration, and Reproduction Across Vertebrate Classes
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Biology · L3 · Skin, Respiration, and Reproduction Across Vertebrate ClassesFlashcards10 cards
What is biodiversity?1 / 10
Biodiversity is the total variety of life in a given area, usually described at three levels: genetic diversity within a species, species diversity within a community, and ecosystem diversity across a landscape. High biodiversity generally signals a healthy, resilient environment.
Biology · L3 · What Biodiversity Is and Why It Matters
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Biology · L3 · What Biodiversity Is and Why It MattersFlashcards10 cards
What is habitat loss, and why is it considered the single greatest threat to biodiversity?1 / 10
Habitat loss is the destruction, fragmentation, or degradation of the natural environment a species depends on, usually through logging, agriculture, or urban development. It is the leading threat to biodiversity because a species that loses its habitat loses its food, shelter, and breeding grounds all at once.
Biology · L3 · Threats to Biodiversity and Conservation Strategies
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Biology · L3 · Threats to Biodiversity and Conservation StrategiesFlashcards10 cards
What is a hypha?1 / 10
A hypha (plural: hyphae) is a single thread-like filament that makes up the body of a multicellular fungus. Each hypha is a tube of cytoplasm surrounded by a rigid cell wall made of chitin, and it grows by extending at its tip.
Biology · L3 · Fungal Structure and Life Cycle
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Biology · L3 · Fungal Structure and Life CycleFlashcards10 cards
What is a decomposer, and why are fungi important decomposers in most ecosystems?1 / 10
A decomposer is an organism that breaks down dead organic matter into simpler substances. Fungi are especially important decomposers because their enzymes can break down tough materials like wood and leaf litter that few other organisms can digest, releasing the nutrients locked inside back into the ecosystem.
Biology · L3 · Fungal Roles: Decomposers, Partners, and Pathogens
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Biology · L3 · Fungal Roles: Decomposers, Partners, and PathogensFlashcards10 cards
What is an extremophile?1 / 10
An organism adapted to thrive in conditions that would kill or badly damage most other life — extreme heat, cold, salinity, pressure, or pH. Extremophiles are grouped into categories named for the specific extreme they tolerate, such as thermophiles (heat) or halophiles (salt).
Biology · L3 · Extremophile Categories: Heat, Salt, and Cold
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Biology · L3 · Extremophile Categories: Heat, Salt, and ColdFlashcards10 cards
Why do most ordinary proteins stop working in extreme heat?1 / 10
Heat makes molecules vibrate more violently, which can break the weak bonds (like hydrogen bonds) that hold a protein folded into its precise 3D shape. Once a protein unfolds, or "denatures," it usually stops working — this is the same reason a cooked egg white turns solid and opaque.
Biology · L3 · How Extremophiles Survive — Molecular Adaptations
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Biology · L3 · How Extremophiles Survive — Molecular AdaptationsFlashcards10 cards
What disease was Edward Jenner trying to protect people from in the 1790s?1 / 10
Smallpox — a severe, highly contagious viral disease that killed roughly 1 in 3 people it infected and left many survivors permanently scarred or blind. In 18th-century Europe it killed hundreds of thousands of people every year.
Biology · L3 · Edward Jenner and the Origin of Vaccination
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Biology · L3 · Edward Jenner and the Origin of VaccinationFlashcards9 cards
What is herd immunity?1 / 9
Herd immunity is protection at the level of a whole population, not just an individual. When enough people in a community are immune to a disease — through vaccination or past infection — the disease struggles to find new hosts to infect, so it stops spreading easily even to people who are not immune.
Biology · L3 · Herd Immunity
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Biology · L3 · Herd ImmunityFlashcards10 cards
What is coevolution?1 / 10
A pattern in which two species exert reciprocal selection pressure on each other over many generations, so that an evolutionary change in one species favors a counter-change in the other. Neither species evolves in isolation — each is responding to the other.
Biology · L3 · Coevolution Basics and the Red Queen Hypothesis
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Biology · L3 · Coevolution Basics and the Red Queen HypothesisFlashcards10 cards
What does host-parasite coevolution look like, in general terms?1 / 10
A host evolves defenses — such as a stronger immune response or a physical barrier — that reduce a parasite's ability to infect or exploit it. In response, the parasite evolves ways to get around those defenses, such as changing its surface proteins so the host's immune system no longer recognizes it. Each side is adapting to counter the other's latest adaptation.
Biology · L3 · Host-Parasite and Chemical Arms Races
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Biology · L3 · Host-Parasite and Chemical Arms RacesFlashcards9 cards
What is turgor pressure?1 / 9
Turgor pressure is the outward pressure that the cell's contents exert against the cell wall. It builds up as water enters the cell by osmosis — when the cell is in a hypotonic environment — and the wall pushes back with an equal and opposite force, keeping the cell firm.
Biology · L3 · Turgor Pressure and Plasmolysis
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Biology · L3 · Turgor Pressure and PlasmolysisFlashcards8 cards
What is wilting?1 / 8
Wilting is the drooping of leaves and stems that occurs when plant cells lose enough turgor pressure that they can no longer hold the plant's tissues rigid and upright.
Biology · L3 · Wilting and Whole-Plant Water Loss
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Biology · L3 · Wilting and Whole-Plant Water Loss