The element potassium plays a pivotal role in our bodies. It’s found in all our cells, where it regulates their volume and pressure. To do this, our bodies carefully control potassium levels so that the concentration is about 30 times higher inside cells than outside. Potassium works closely with sodium, which regulates the extracellular fluid volume and has a higher concentration outside cells than inside. These concentration differences create an electrochemical gradient, or a membrane potential.

Potassium is the primary regulator of the pressure and volume inside cells, and it’s important for nerve transmission, muscle contraction, and more. Credit: Compound Interest CC BY-NC-ND 4.0.

Some might think that protein is only important for weightlifters. In truth, all life relies on the activity of protein molecules. A single human cell contains thousands of different proteins with diverse roles, including:

• Providing structure. Proteins such as actin make up the three-dimensional cytoskeleton that gives cells structure and determines their shapes.
• Aiding chemical reactions. Many proteins are biological catalysts called enzymes that speed up the rate of chemical reactions by reducing the amount of energy needed for the reactions to proceed. For example, lactase is an enzyme that breaks down lactose, a sugar found in dairy products. Those with lactose intolerance don’t produce enough lactase to digest dairy.
• Supporting communication. Some proteins act as chemical messengers between cells. For example, cytokines are the protein messengers of the immune system and can increase or decrease the intensity of an immune response.

The element manganese is essential for human life. It’s aptly named after the Greek word for magic, and some mysteries surrounding its role in the body still exist today—like how our bodies absorb it, if very high or low levels can cause illness, or how it might play a role in certain diseases.

Manganese is necessary for metabolism, bone formation, antioxidation, and many other important functions in the body. The element is found in strong steel, bones and enzymes, and drink cans. Credit: Compound Interest CC BY-NC-ND 4.0.

You might first think about sports when you hear the word base, but not all bases are on the baseball diamond. In chemistry, a base is a molecule that reacts with an acid, often by accepting a proton from the acid or from water. Baking soda and dish soap are common bases.

Every year on March 14, many people eat pie in honor of Pi Day. Mathematically speaking, pi (π) is the ratio of a circle’s circumference (the distance around the outside) to its diameter (the length from one side of the circle to the other, straight through the center). That means if you divide the circumference of any circle by its diameter, the solution will always be pi, which is roughly 3.14—hence March 14, or 3/14. But pi is an irrational number, which means that the numbers after the decimal point never end. With the help of computers, mathematicians have determined trillions of digits of pi.

To celebrate Pi Day, check out this slideshow of circular microbes, research organisms, and laboratory tools (while you enjoy your pie, of course!). To explore more scientific photos, videos, and illustrations, visit our image and video gallery.

Someone’s hand moving to scroll through this blog post is possible because of a mineral that both gives bones their strength and allows muscles to move: calcium. As the most abundant mineral in our bodies, it’s essential for lots of important functions. It’s found in many foods, medicines, and dietary supplements.

Calcium keeps your bones strong, allows your muscles to move, and is important for many other bodily functions. The element is found in foods, medicines, and the world around us. Credit: Compound Interest CC BY-NC-ND 4.0.

You may know that antioxidants can help protect your cells from oxidative damage, but do you know about selenium—an element often found in special proteins called antioxidant enzymes? Selenium is essential to your body, which means you must get it from the food you eat. But it’s a trace element so you only need a small amount to benefit from its effects. In addition to its antioxidant properties, it’s also important for reproduction, DNA synthesis, and hormone metabolism.

Just as electricity powers almost every modern gadget, the tiny molecule adenosine triphosphate (ATP) is the major source of energy for organisms’ biochemical reactions. ATP stores energy in the chemical bonds that hold its three phosphate groups together—the triphosphate part of its name. In the human body, ATP powers processes such as cell signaling, muscle contraction, nerve firing, and DNA and RNA synthesis. Because our cells are constantly using and producing ATP, each of us turns over roughly our body weight in the molecule every day!

Our bodies can produce ATP in several ways, but the most common is cellular respiration—a multistep process in which glucose molecules from our diet and oxygen react to form water and carbon dioxide. The breakdown of a single molecule of glucose in this way releases energy, which the body captures and stores in around 32 ATP molecules. Along with oxygen, mitochondria are crucial for producing ATP through cellular respiration, which is why they’re sometimes called the powerhouses of cells.

Upgrading X-ray crystallography equipment at the University of Arkansas in Fayetteville has had an unexpected benefit: enabling analyses that could help art museums authenticate, restore, and learn more about their pieces.

Scientists use X-ray crystallography to determine the detailed 3D structures of molecules. In biomedical contexts, researchers often apply X-ray crystallography to map the structures of proteins and other biomolecules like DNA and RNA. A molecule’s structure can shed light on its function and help answer scientific questions. For example, knowing the structures of proteins involved in antibiotic resistance can help researchers determine how those molecules work and how to combat bacteria that produce them.

Protein Data Bank's 50 years logo. Credit: PDB website.

The Protein Data Bank (PDB), established in 1971, is the single global repository for 3D structural data of proteins, DNA, RNA, and even complexes these biological molecules form with drugs or other small molecules. More than 1 million people—including researchers, medical professionals, educators, and students—use the PDB each year. NIGMS and other parts of NIH have helped fund this free digital resource since 1978.