31 results for “cell”
Life & Biology
What Is Life? The Cell
cells that contract, nerve cells that carry signals, red blood cells that ferry oxygen, skin cells
Article · 4 min read
The Human Body
The Immune System
cells. T cells are the commanders and assassins. Some coordinate the response, telling B cells to multiply
Article · 4 min read
The Human Body
The Heart and Blood
cells pass through in single file, with walls one cell thick. It is here, across those
Article · 4 min read
Life & Biology
DNA and Genes
cells, when, and how strongly. A liver cell and a brain cell carry identical DNA; they
Article · 4 min read
Life & Biology
Bacteria and Viruses
cell. A virus attaches to a cell whose surface it fits, slips its genes inside, and hijacks
Article · 4 min read
The Human Body
Skin, Hair and Nails
cells beneath from damage. Everyone has about the same number of pigment cells; people with darker
Article · 3 min read
Chemistry
The Chemistry of Life
cells burn to release energy. Plants make glucose by photosynthesis, then link thousands of them together
Article · 3 min read
The Human Body
Lungs and Breathing
cells burn for energy and carries away the carbon dioxide that burning produces. The journey of a breath
Article · 4 min read
Life & Biology
The Origin of Life
cell that could feed, grow and copy itself is one of the great unanswered questions in science
Article · 4 min read
Plants & Fungi
Photosynthesis: How Plants Eat Light
cell are their descendants, swallowed by a larger cell and kept as live-in food factories
Article · 3 min read
The Human Body
The Senses
cells. There are two kinds. About 120 million rods work in dim light and see only
Article · 4 min read
The Human Body
The Skeleton and Bones
cells a day: red blood cells to carry oxygen, white blood cells to fight infection, platelets
Article · 5 min read
The Human Body
Muscles
cells, about once a second, for a lifetime, without ever resting or tiring. It combines the strength
Article · 4 min read
The Human Body
The Brain
Cells that talk The brain is built from about 86 billion nerve cells, neurons, supported by a similar
Article · 4 min read
Chemistry
Water: The Strangest Ordinary Substance
cell happens in water. A heat store Water also soaks up a remarkable amount of heat
Article · 3 min read
Plants & Fungi
Seeds
cells that need damp conditions to grow. The seed, with its food store and waterproof coat
Article · 4 min read
The Human Body
Digestion
cell membrane, every molecule of energy you burn came in through this tube. Its health shapes
Article · 4 min read
Chemistry
Chemical Reactions
cells all release energy. If the reverse is true, the reaction absorbs heat and feels cold
Article · 3 min read
Planets & the Solar System
Comets, Asteroids and Pluto
cells, glaciers, possible ice volcanoes and a thin blue atmosphere, on a world at minus 230 degrees
Article · 4 min read
Chemistry
Acids and Bases
cells stop working properly. Why it matters pH shapes the natural world. Acid rain, caused by pollution
Article · 3 min read
Animals
Reptiles and Amphibians
cells, and thaws out alive in spring. Poison dart frogs of South America carry toxins in their
Article · 3 min read
Matter, Energy & Physics
Sound
cells in the inner ear. Echoes and sonar Sound bounces off hard surfaces, producing an echo
Article · 3 min read
Plants & Fungi
Fungi
celled fungi, turn sugar into alcohol and carbon dioxide, which is why bread rises and why beer
Article · 4 min read
Animals
The Octopus
cells that can produce blues and greens, and the skin itself can be raised into bumps
Article · 3 min read
Animals
Animal Migration
cells, and can read both its direction and its strength, which varies with latitude, giving them
Article · 4 min read
Plants & Fungi
Trees and Forests
cells, dead once mature, stacked end to end into pipes that carry water from the roots
Article · 4 min read
Matter, Energy & Physics
Light
cells in your retina. Light is how almost everything we know about the universe reaches us, from
Article · 4 min read
Plants & Fungi
Flowers and Pollination
cells, from one flower to the female part of another. Some plants simply release pollen into
Article · 4 min read
Space & the Universe
The Life of a Star
cells, the oxygen you breathe, the calcium in your bones and the iron in your blood
Article · 3 min read
Matter, Energy & Physics
The Quantum World
cells, MRI scanners, atomic clocks and the GPS that depends on them are all quantum devices
Article · 4 min read
The Human Body
Sleep and Dreams
cells that acts as a master clock. It runs on a cycle of about 24 hours
Article · 3 min read
