We couldn’t survive without proteins. They’re essential molecules that provide cells with structure, aid in chemical reactions, support communication, and much more. Portion out protein numbers with us below!

10 Trillion

That’s how many proteins scientists estimate are in each human cell.

229,378

That’s how many structures researchers shared with the scientific community through the Protein Data Bank (PDB) from its establishment in 1971 to the end of 2024. The PDB is a global repository for 3D structural data of proteins, DNA, RNA, and even complexes these biological molecules form with medicines or other small molecules.

42

That’s the percent of your body weight (not counting water) that’s made up of proteins.

Cells rely on garbage and recycling systems to keep their interiors neat and tidy. If it weren't for these systems, cells could look like microscopic junkyards—and worse, they might not function properly. So constant cleaning is a crucial biological process, and if it goes wrong, accumulated trash can cause serious problems.

Proteasomes: Cellular Garbage Disposals

One of the cell's trash processors is called the proteasome. It breaks down proteins, the building blocks and mini-machines that make up many cell parts. The barrel-shaped proteasome disassembles damaged or unwanted proteins, breaking them into bits that the cell can reuse to make new proteins. In this way, the proteasome is just as much a recycling plant as it is a garbage disposal.

Cells are the basic unit of life—and the focus of much scientific study. They’re categorized based on whether or not they have a distinct nucleus. Prokaryotic cells, like some bacteria such as blue-green algae, don’t have distinct nuclei. Instead, their nuclear material is spread throughout the cytoplasm. Eukaryotic cells—or cells with nuclei—make up humans, animals, plants, and fungi. Here are just a few of cells’ fascinating facets.

30 Trillion

That's about how many human cells adults have in their bodies. Males are on the higher side with about 36 trillion cells, while females average about 28 trillion cells.

“I think it’s really an exciting time for science. Some people might think that everything out there to be discovered has already been discovered, but that’s far from the truth. There is still much, much more to discover,” says John Jimah, Ph.D., an assistant professor of molecular biology at Princeton University in Princeton, New Jersey. We talked with him about how he moved internationally to pursue his career, how his current research on cell membranes could help treat malaria, and how science holds space for everyone.

Have you wondered what controls the most basic functions of our bodies, like breathing, moving, and sleeping? Chemicals called neurotransmitters play a central role. Neurotransmitters pass messages from one nerve cell to another, and sometimes to muscles or glands. These messages may:

• Prompt the next nerve cell to pass on the message, prevent the message from going any further, or adjust how the message is passed on
• Cause a muscle to contract, like our intestines do when they digest food
• Tell a gland to secrete hormones, which are molecules that further pass on messages to tissues or organs

“In high school, one of my teachers encouraged me to take an advanced biology class, and I’m so glad I did,” says Yvon Woappi, Ph.D. “The class opened my eyes to the fact that there were other people who loved nature like I did—they’re called biologists!” Now, Dr. Woappi is an assistant professor of physiology and cellular biophysics at Columbia University in New York City. We talked with him about his early love of nature and the night sky, the support he received from NIGMS training programs, and his research on wound healing.

RNA is essential for life as we know it. Among other roles, this molecule helps translate the instructions of DNA into proteins, which perform a vast range of tasks to keep us alive and healthy. In past Biomedical Beat posts, we've discussed the basics of RNA and how researchers are using it to develop medicines, vaccines, and tests for certain diseases. This year, in honor of RNA Day on August 1, we've created a quiz all about this remarkable molecule. Test your knowledge with the questions below!

Hormones are chemical messengers in the body that glands form and release, or secrete, into the bloodstream, where they travel to various organs and tissues to change biological functions. Hormone levels fluctuate during a lifespan and even on a daily basis.

Growth spurts in toddlers or sudden changes in adolescents are directly related to large hormonal shifts during development and puberty. Smaller changes occur throughout each day to help maintain normal bodily functions, such as our sleep-wake cycle known as our circadian rhythm.

“Throughout my career, I’ve enjoyed studying topics that no one else seems to care about. I always tell people that I like searching through the scientific garbage bin for inspiration,” says Ahna Skop, Ph.D., a professor of genetics at the University of Wisconsin-Madison. We talked with her about the backyard experiment that helped her gain confidence in her scientific abilities, her career-long pursuit to better understand a detail about cell division that others had written off as unimportant, and her desire to build an accessible scientific community.

Q: How did you first become interested in science?

A: Middle school and high school science fairs had a big impact on me. I would develop my ideas, and with the help of my dad, build the experimental setup I needed to answer the scientific question. One of my experiments studied whether ants preferred to eat salt or sugar, so I poured small piles of both all over the backyard and took daily measurements of the height of the piles to figure out which type was shrinking faster. (Spoiler alert for those of you who might try this at home: They liked both but preferred the sugar to the salt.)