A cross-section of a cell showing organelles. Credit: Judith Stoffer.
Welcome to our tour of the cell! Imagine you’ve shrunk down to about 3 millionths of your normal size. You are now about 0.5 micrometers tall (a micrometer is 1/1,000th of a millimeter). At this scale, a medium-sized human cell looks as long, high, and wide as a football field. But you can’t see nearly that far. Clogging your view is a rich stew of molecules, fibers, and various cell structures called organelles. Like the internal organs in your body, organelles in the cell each have a unique biological role to play.
The Nucleus and Its Closest Neighbor
Our first stop is the somewhat spherical structure about 50 feet in diameter. It’s the nucleus—basically the cell’s brain. The nucleus is the most prominent organelle and can occupy up to 10 percent of the space inside a cell. It contains the equivalent of the cell’s genetic material, or DNA.
Continue reading “Take a Tour of Your Cells’ Organelles!”
Proteins play a role in virtually every activity in the body. They make up hair and nails, help muscles move, protect against infection, and more. Many NIGMS-funded researchers study the rich variety of proteins in humans and other organisms to shed light on their roles in health and disease.
Take our quiz to test how much you know about proteins. Afterward, find more quizzes and other fun learning tools on our activities and multimedia webpage, which includes an interactive protein alphabet.
Continue reading “Quiz: Prove Your Knowledge of Proteins!”
Although zinc may appear last on nutrition labels, it’s the second-most abundant trace element in our bodies, behind only iron. (Trace elements are molecules our bodies need in small amounts to stay healthy). Zinc is crucial for a well-functioning immune system, wound healing, physical growth, the senses of taste and smell, and the construction of proteins and DNA. It can also partner with oxygen to form zinc oxide, a compound that scatters ultraviolet light and can act as a protective barrier over inflamed skin. Many sunscreens, burn ointments, diaper creams, and other skin treatments contain zinc oxide.
Continue reading “Zinc: Zapping Invaders”
Zinc may help shorten colds, and it’s part of a compound that can protect skin from ultraviolet light. The element is also used to coat other metals and prevent rusting. Credit: Compound Interest. CC BY-NC-ND 4.0
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When someone mentions aging, you may think of visible changes, like graying hair. Scientists can see signs of aging in cells, too. Understanding how basic cell processes are involved in aging is a first step to help people lead longer, healthier lives. NIGMS-funded researchers are discovering how aging cells change and applying this knowledge to health care.
Discovering the Wisdom of Worms
with a ribosomal protein glowing red and muscle fibers glowing green. Credit: Hannah Somers, Mount Desert Island Biological Laboratory.
Aric Rogers, Ph.D., and Jarod Rollins, Ph.D., assistant professors of regenerative biology and medicine at Mount Desert Island (MDI) Biological Laboratory in Bar Harbor, Maine, are investigating aging by studying a tiny roundworm, Caenorhabditis elegans. Researchers often study C. elegans because, though it may seem drastically different from humans, it shares many genes and molecular pathways with us. Plus, its 2- to 3-week lifespan enables researchers to quickly see the effects of genetic or environmental factors on aging.
Drs. Rogers and Rollins investigate how C. elegans expresses genes differently under dietary restriction, enabling it to live longer. Understanding how genes are expressed when organisms live an extended life sheds light on the genetics underlying aging. This information could help researchers develop drugs or behavior modification programs that prolong life and delay the onset of age-related diseases such as heart disease, diabetes, cancer, and dementia.
Continue reading “Teaching Old Cells New Tricks: Insights Into Molecular-Level Aging”
Most of the mouthwatering dishes in a Thanksgiving feast share a vital ingredient: salt! Though the words “salt” and “sodium” are often used interchangeably, table salt is actually a compound combining the elements sodium and chloride. Table salt is the most common form that sodium takes on Earth. Many other sodium compounds are also useful to us. For instance, you might use baking soda, also known as sodium bicarbonate, in preparing Thanksgiving treats. Sodium compounds are also used in soaps and cosmetics and in producing paper, glass, metals, medicines, and more.
Continue reading “Pass the Salt: Sodium’s Role in Nerve Signaling and Stress on Blood Vessels”
The best-known sodium compound is table salt (sodium chloride). Sodium also gives traditional streetlights their yellow glow and is essential for muscle and nerve function. Credit: Compound Interest. CC BY-NC-ND 4.0
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Cells are the smallest units of life, providing structure and function for all living things, from microorganisms—like bacteria, algae, and yeast—to humans. They come in a wide range of sizes and shapes, and they’re complex machines with many smaller components that work together.
Some NIGMS-funded researchers use imaging techniques to peer inside cells, examine their structures, and study how they divide, grow, communicate, and carry out basic functions. Others use biochemical and genetic tests to study how cells interact with their environments, including those that may be toxic. Understanding cells’ biological processes helps to keep us healthy and identify new methods for treating disease.
Take our quiz to test how well you know cells. Afterward, check out our Studying Cells fact sheet and other blog posts on cell biology.
Continue reading “Quiz: How Does Your Knowledge of Life’s Building Blocks Stack Up?”
To get a look at cell components that are too small to see with a normal light microscope, scientists often use cryo-electron microscopy (cryo-EM). As the prefix cryo- means “cold” or “freezing,” cryo-EM involves rapidly freezing a cell, virus, molecular complex, or other structure to prevent water molecules from forming crystals. This preserves the sample in its natural state and keeps it still so that it can be imaged with an electron microscope, which uses beams of electrons instead of light. Some electrons are scattered by the sample, while others pass through it and through magnetic lenses to land on a detector and form an image.
Typically, samples contain many copies of the object a scientist wants to study, frozen in a range of orientations. Researchers take images of these various positions and combine them into a detailed 3D model of the structure. Electron microscopes allow us to see much smaller structures than light microscopes do because the wavelengths of electrons are much shorter than the wavelength of light. NIGMS-funded researchers are using cryo-EM to investigate a range of scientific questions.
Caught in Translation
3D reconstructions of two stages in the assembly of the bacterial ribosome created from time-resolved cryo-EM images. Credit: Joachim Frank, Columbia University.
Joachim Frank, Ph.D., a professor of biochemistry and molecular biophysics and of biological sciences at Columbia University in New York, New York, along with two other researchers, won the 2017 Nobel Prize in Chemistry for developing cryo.
Dr. Frank’s lab focuses on the process of translation, where structures called ribosomes turn genetic instructions into proteins, which are needed for many chemical reactions that support life. Recently, Dr. Frank has adopted and further developed a technique called time-resolved cryo-EM. This method captures images of short-lived states in translation that disappear too quickly (after less than a second) for standard cryo-EM to capture. The ability to fully visualize translation could help researchers identify errors in the process that lead to disease and also to develop treatments.
Continue reading “Freezing a Moment in Time: Snapshots of Cryo-EM Research”
If you’re looking for ways to engage students in science this school year, NIGMS offers a range of free resources that can help. All of our STEM materials are online and print-friendly, making them easy to use for remote teaching.
Pathways , developed in collaboration with Scholastic, is aligned with STEM and ELA education standards for grades 6 through 12. Materials include:
- Student magazines with corresponding teaching guides
- Related lessons with interactives
- Vocabulary lists
Cover of Pathways
student magazine, third issue.
Available lessons examine basic science careers, regeneration, and circadian rhythms.
Continue reading “Explore Our STEM Education Resources for the New School Year”
Of the 118 known elements, scientists believe that 25 are essential for human biology. Four of these (hydrogen, oxygen, nitrogen, and carbon) make up a whopping 96 percent of our bodies. The other 21 elements, though needed in smaller quantities, perform fascinating and vital functions. Phosphorus is one such element. It has diverse uses outside of biology. For example, it can fuel festive Fourth of July fireworks! Inside our bodies, it’s crucial for a wide range of cell functions.
Continue reading “Phosphorus: Glowing, Flammable, and Essential to Our Cells”
Phosphorus plays a vital role in life as part of DNA’s backbone. Red phosphorus helps ignite matches, and white phosphorus glows in the presence of oxygen. Credit: Compound Interest. CC BY-NC-ND 4.0
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Mitochondria (purple) in a rodent heart muscle cell. Credit: Thomas Deerinck, National Center for Microscopy and Imaging Research.
Mitochondria (mitochondrion in singular) are indispensable. Every cell of our bodies, apart from mature red blood cells, contains the capsule-shaped organelles that generate more than 90 percent of our energy, which is why they’re often called “the powerhouse of the cell.” They produce this energy by forming adenosine triphosphate (ATP), our cells’ most common energy source. But mitochondria also support cells in other ways. For example, they help cells maintain the correct concentration of calcium ions, which are involved in blood clotting and muscle contraction. Mitochondria are also the only structure in our cells with their own unique DNA, which with rare exceptions, is inherited only from mothers. That’s why, in honor of Mother’s Day, we’re exploring this special cellular connection to moms.
Continue reading “The Maternal Magic of Mitochondria”