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OpenStem
@openstem · Joined Jul 2026
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Flashcards10 cards
What is a joint?1 / 10
A joint is any point where two or more bones meet. Some joints move a lot, some move only a little, and some don't move at all — the type of joint decides which.
Biology · L2 · Types of Joints: The Basics
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Biology · L2 · Types of Joints: The BasicsFlashcards10 cards
Why can your shoulder swing your whole arm in a circle, but your elbow can't?1 / 10
The shoulder is a ball-and-socket joint that can move in almost any direction, while the elbow is a hinge joint that only bends and straightens in one direction.
Biology · L2 · Joints in Everyday Movement
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Biology · L2 · Joints in Everyday MovementFlashcards10 cards
What is a microscope?1 / 10
A microscope is an instrument that uses lenses to make small objects look much bigger, so scientists can study things too tiny to see with their eyes alone — like cells.
Biology · L2 · How a Microscope Magnifies the Tiny World
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Biology · L2 · How a Microscope Magnifies the Tiny WorldFlashcards10 cards
Who was Robert Hooke?1 / 10
Robert Hooke was an English scientist who, in 1665, used one of the first compound microscopes to examine a thin slice of cork cut from a tree.
Biology · L2 · The Discovery of Cells and Cell Theory
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Biology · L2 · The Discovery of Cells and Cell TheoryFlashcards9 cards
What is herd immunity?1 / 9
Herd immunity happens when enough people in a community are immune to a disease — usually through vaccination — that the disease has a hard time spreading, even to people who are not immune.
Biology · L2 · What Is Herd Immunity?
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Biology · L2 · What Is Herd Immunity?Flashcards9 cards
What is a vaccination rate?1 / 9
A vaccination rate (also called vaccination coverage) is the percentage of people in a community who are vaccinated against a particular disease.
Biology · L2 · Vaccination Rates and Outbreak Risk
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Biology · L2 · Vaccination Rates and Outbreak RiskFlashcards10 cards
What is transpiration?1 / 10
Transpiration is the loss of water vapor from a plant, mostly evaporating out through tiny pores in the leaves called stomata.
Biology · L2 · The Transpiration Process
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Biology · L2 · The Transpiration ProcessFlashcards10 cards
What is turgor pressure?1 / 10
Turgor pressure is the outward push of water inside a plant cell against its rigid cell wall. When cells are full of water, this pressure keeps them firm, which is what holds a plant upright.
Biology · L2 · Wilting and Water Balance
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Biology · L2 · Wilting and Water BalanceFlashcards10 cards
What is a mollusk?1 / 10
A mollusk is an invertebrate with a soft body, and in most species that soft body is protected by a hard shell. Snails, clams, and octopuses are all mollusks.
Biology · L2 · Major Invertebrate Groups
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Biology · L2 · Major Invertebrate GroupsFlashcards8 cards
Match each invertebrate group to its defining feature.1 / 8
Biology · L2 · Comparing Invertebrate Features
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Biology · L2 · Comparing Invertebrate FeaturesFlashcards10 cards
What is DNA?1 / 10
DNA (short for deoxyribonucleic acid) is a long molecule found inside the cells of living things. It carries the instructions — called genes — for building and running an organism.
Biology · L2 · What Is DNA? The Basics
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Biology · L2 · What Is DNA? The BasicsFlashcards9 cards
What is the nucleus, and why does it matter for DNA?1 / 9
The nucleus is a structure inside most plant and animal cells. It acts like the cell's control centre and is where a cell's DNA is safely stored.
Biology · L2 · DNA, Genes, and Chromosomes
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Biology · L2 · DNA, Genes, and ChromosomesFlashcards9 cards
What does "food preservation" mean?1 / 9
Food preservation means treating or storing food in ways that slow down or stop the growth of the microorganisms that cause it to spoil, so the food stays safe to eat for longer.
Biology · L2 · Why Food Spoils and How We Slow It Down
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Biology · L2 · Why Food Spoils and How We Slow It DownFlashcards9 cards
How does refrigeration slow food spoilage?1 / 9
Refrigerators keep food cold, usually around 4°C (40°F). That cold slows the chemical reactions microbes need to grow and multiply, so spoilage happens much more slowly.
Biology · L2 · Four Ways to Preserve Food
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Biology · L2 · Four Ways to Preserve FoodFlashcards9 cards
What does "lifespan" mean?1 / 9
Lifespan is the total length of time a living thing survives, from the moment it is born (or hatches) until it dies. It is different from how long an animal takes to grow up — lifespan covers its whole life.
Biology · L2 · How Long Do Animals Live?
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Biology · L2 · How Long Do Animals Live?Flashcards9 cards
What is one reason bigger animals tend to live longer than smaller ones?1 / 9
Larger bodies often have slower metabolisms, so their cells wear out more slowly over time. A whale's giant body ages far more slowly than a mouse's tiny one.
Biology · L2 · Why Do Lifespans Vary So Much?
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Biology · L2 · Why Do Lifespans Vary So Much?Flashcards10 cards
What is cellular respiration?1 / 10
Cellular respiration is the process cells use to release the energy stored in food (glucose) so they can power everything they do — moving, growing, and repairing themselves.
Biology · L2 · Cellular Respiration: The Word Equation
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Biology · L2 · Cellular Respiration: The Word EquationFlashcards9 cards
How is cellular respiration the reverse of photosynthesis?1 / 9
Photosynthesis takes in carbon dioxide and water to build glucose and release oxygen, storing energy along the way. Cellular respiration does the exact opposite: it takes in glucose and oxygen and releases carbon dioxide, water, and energy.
Biology · L2 · Respiration vs. Photosynthesis
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Biology · L2 · Respiration vs. PhotosynthesisFlashcards10 cards
What is a succulent plant?1 / 10
A succulent is a plant with thick, fleshy stems or leaves that store extra water inside, letting it survive long periods without rain.
Biology · L2 · Thick Stems and Leaves That Store Water
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Biology · L2 · Thick Stems and Leaves That Store WaterFlashcards10 cards
Why do many desert plants have roots that spread out wide instead of growing deep?1 / 10
Desert rain usually only wets the top layer of soil before it evaporates or drains away. A wide, shallow root system can reach out across a large area to soak up as much of that brief rainfall as possible.
Biology · L2 · Roots and Waxy Coatings in Desert Plants
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Biology · L2 · Roots and Waxy Coatings in Desert PlantsFlashcards10 cards
What is a trait?1 / 10
A trait is a feature of a living thing — like flower color — that can be passed down from parents to offspring.
Biology · L2 · Punnett Square Vocabulary: Allele, Dominant, and Recessive
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Biology · L2 · Punnett Square Vocabulary: Allele, Dominant, and RecessiveFlashcards10 cards
In our cross, both parent flowers have the alleles "Pp". What color are both parents?1 / 10
Both parents are purple, since the dominant "P" allele in each one covers up its hidden recessive "p" allele.
Biology · L2 · Crossing Pp × Pp: Building One Punnett Square
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Biology · L2 · Crossing Pp × Pp: Building One Punnett SquareFlashcards9 cards
Which two body systems work together to deliver oxygen to your muscles during exercise?1 / 9
The respiratory system (your lungs) and the circulatory system (your heart and blood) work as one connected chain to deliver oxygen to your muscles.
Biology · L2 · How Breathing and Circulation Connect
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Biology · L2 · How Breathing and Circulation ConnectFlashcards9 cards
What happens to your breathing rate during exercise, and why?1 / 9
Your breathing rate increases so your lungs can take in more oxygen and clear out carbon dioxide faster, keeping up with your muscles' higher demand for oxygen.
Biology · L2 · Exercise and the Oxygen Delivery Chain
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Biology · L2 · Exercise and the Oxygen Delivery ChainFlashcards10 cards
What is metamorphosis?1 / 10
Metamorphosis is the dramatic change in body shape that many insects go through as they grow from a newly hatched egg into an adult. Instead of just getting bigger, the insect's body is rebuilt along the way.
Biology · L2 · Complete vs. Incomplete Metamorphosis: The Basics
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Biology · L2 · Complete vs. Incomplete Metamorphosis: The BasicsFlashcards10 cards
Does a butterfly go through complete or incomplete metamorphosis?1 / 10
Complete metamorphosis. A butterfly egg hatches into a caterpillar (the larva), which forms a chrysalis (the pupa), and an adult butterfly emerges from the chrysalis.
Biology · L2 · Metamorphosis in Action: Insect Examples
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Biology · L2 · Metamorphosis in Action: Insect ExamplesFlashcards9 cards
What are the three basic shapes bacteria can have?1 / 9
Bacteria are usually sorted into three basic shapes: cocci (round), bacilli (rod-shaped), and spirilla (spiral-shaped).
Biology · L2 · The Three Basic Bacteria Shapes
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Biology · L2 · The Three Basic Bacteria ShapesFlashcards10 cards
Name two examples of coccus (round) shaped bacteria.1 / 10
Streptococcus, which can cause strep throat and often grows in chains, and Staphylococcus, which lives on skin and often grows in grape-like clusters.
Biology · L2 · Example Bacteria for Each Shape
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Biology · L2 · Example Bacteria for Each ShapeFlashcards10 cards
What is asexual (vegetative) plant propagation?1 / 10
Asexual propagation is growing a brand-new plant from a piece of a parent plant — a stem, root, or leaf — instead of from a seed. No pollen, egg cell, or fertilization is involved.
Biology · L2 · What Is Asexual Plant Propagation?
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Biology · L2 · What Is Asexual Plant Propagation?Flashcards10 cards
How does a strawberry plant use runners to spread?1 / 10
A strawberry plant sends out long, thin runners across the soil surface. Where a runner touches the ground, it can grow its own roots downward and a new shoot upward, becoming a separate strawberry plant.
Biology · L2 · Runners, Tubers, and Cuttings in Action
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Biology · L2 · Runners, Tubers, and Cuttings in Action