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Biology: explore STEM content (page 13 of 50) · openstem
Explore STEM Content
Search the community's STEM library — free to study, yours to make your own.
Biology
Cells, genetics, ecology and physiology on openstem — flashcards, notes, quizzes, sketches and flowcharts shared by the community. Study free, or clone anything into your library.
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.
Photosynthesis: light reactions and the Calvin cycle Photosynthesis is the process by which photosynthetic organisms convert light energy into chemical energy stored in organic molecules. Overall equation: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O
Biology
Biology · L4 · Photosynthesis: light reactions and the Calvin cycle
Plant Structures and Reproduction A plant's body is built from organs that each do a different job. Roots, stems, and leaves keep the plant alive and growing, while flowers handle reproduction — making the seeds that will become the next ge
Biology
Biology · L2 · Plant Structures and Reproduction Overview
A newly hatched sea turtle crawls toward the ocean immediately after hatching, without any parent present to teach it. This is an example of what kind of behavior?
What is CRISPR-Cas9, and where did it come from biologically?1 / 9
CRISPR-Cas9 is a gene-editing system adapted from a natural bacterial and archaeal immune defence against viruses. Bacteria store short snippets of past viral DNA in their genome (the CRISPR array) and use them, together with the Cas9 nuclease, to recognise and destroy matching viral DNA on reinfection. Scientists repurposed this system to cut DNA at any chosen site in a genome.
Biology
Biology · L4 · Biotechnology — Modern Applications
Which of Darwin's postulates directly explains why beneficial traits become more common over generations?
AVariation exists among individualsBTraits are heritableCIndividuals with advantageous traits reproduce more (differential reproduction)DPopulations overproduce offspring
A behavioral adaptation is something an animal does — an action or behavior, rather than a body feature — that helps it survive or reproduce in its environment.
What does the oxygen-hemoglobin dissociation curve describe?1 / 10
The oxygen-hemoglobin dissociation curve plots the percent saturation of hemoglobin with oxygen against the partial pressure of oxygen in the surrounding blood. Its S-shape (sigmoidal) reflects cooperative binding: hemoglobin binds oxygen more readily once one subunit has already bound it, so saturation rises steeply over the partial pressure range found in respiring tissues.
Biology
Biology · L4 · Gas Transport and Chemoreceptor Control
Bird Beaks and Feet: Shaped for the Job Look closely at a bird and you will notice something amazing: its beak and feet are shaped just right for the way it lives. A bird's beak shape tells you a lot about what it eats, and its feet shape t
Biology
Biology · L1 · Bird Beaks and Feet: Shaped for the Job
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
Biology · L3 · Transfusion Compatibility and Reactions
What is diffusion, and why does it require no energy input from the cell?1 / 9
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, until the concentration is equal throughout (equilibrium). It is driven by the random, constant motion of particles, so it is a form of passive transport that needs no ATP from the cell.
Biology
Biology · L3 · Membrane Transport and the Cell Cycle
Tiny Living Things at a Glance Microorganisms are living things too small to see without a microscope. Bacteria, viruses, and fungi are three main types, and they are very different from one another — in size, in how they live, and in how t
How Plants Grow Plants are living things, just like animals. They grow, they need food, and they make new plants. But plants grow in their own special way. The Parts of a Plant Most plants have four main parts, and each part has its own job