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!”
Vern Schramm, professor of biochemistry at Albert Einstein College of Medicine, Bronx, New York. Credit: Albert Einstein College of Medicine.
Enzymes drive life. Without them, we couldn’t properly digest food, make brain chemicals, move—or complete myriad other vital tasks. Unfortunately, in certain cases, enzymes also can trigger a host of health problems, including cancer, bacterial infections, and hypertension (high blood pressure).
Understanding how enzymes work has been the research focus of Vern Schramm for more than 4 decades.
“When we started our work, we were driven not by the desire to find drugs, but to understand the nature of enzymes, which are critical to human life,” Schramm says. But his research already led to one drug, and promises many more.
Continue reading “Block an Enzyme, Save a Life”
DNA, with its double-helix shape, is the stuff of genes. But genes themselves are only “recipes” for protein molecules, which are molecules that do the real heavy lifting (or do much of the work) inside cells.
Artist interpretation of RNAP grasping and unwinding a DNA double helix. Credit: Wei Lin and Richard H. Ebright.
Here’s how it works. A molecular machine called RNA polymerase (RNAP) travels along DNA to find a place where a gene begins. RNAP uses a crab-claw-like structure to grasp and unwind the DNA double helix at that spot. RNAP then copies (“transcribes”) the gene into messenger RNA (mRNA), a molecule similar to DNA.
The mRNA molecule travels to one of the cell’s many protein-making factories (ribosomes), which use the mRNA message as instructions for making a specific protein.
Continue reading “RNA Polymerase: A Target for New Antibiotic Drugs?”
What do you have in common with rodents, birds, and reptiles? A lot more than you might think. These creatures have organs and body systems very similar to our own: a skeleton, digestive tract, brain, nervous system, heart, network of blood vessels, and more. Even so-called “simple” organisms such as insects and worms use essentially the same genetic and molecular pathways we do. Studying these organisms provides a deeper understanding of human biology in health and disease, and makes possible new ways to prevent, diagnose, and treat a wide range of conditions.
Historically, scientists have relied on a few key organisms, including bacteria, fruit flies, rats, and mice, to study the basic life processes that run bodily functions. In recent years, scientists have begun to add other organisms to their toolkits. Many of these newer research organisms are particularly well suited for a specific type of investigation. For example, the small, freshwater zebrafish grows quickly and has transparent embryos and see-through eggs, making it ideal for examining how organs develop. Organisms such as flatworms, salamanders, and sea urchins can regrow whole limbs, suggesting they hold clues about how to improve wound healing and tissue regeneration in humans.
Continue reading “Amazing Organisms and the Lessons They Can Teach Us”
Women have two X chromosomes (XX) and men have one X and one Y (XY), right? Not always, as you’ll learn from the quiz below. Men can be XX and women can be XY. And many other combinations of X and Y are possible.
Continue reading “Chromosomally speaking, what do you know about sex? Take a quiz to find out.”
Happy Fat Tuesday!
On this day, celebrated in many countries with lavish parties and high-fat foods, we’re recognizing the importance of fats in the body.
You’ve probably heard about different types of fat, such as saturated, trans, monounsaturated, omega-3, and omega-6. But fats aren’t just ingredients in food. Along with similar molecules, they fall under the broad term lipids and serve critical roles in the body. Lipids protect your vital organs. They help cells communicate. They launch chemical reactions needed for growth, immune function, and reproduction. They serve as the building blocks of your sex hormones (estrogen and testosterone).
Here we feature five of the hundreds of lipids that are essential to health.
Continue reading “Five Fabulous Fats”
When you think of blood, chances are you think of the color red. But blood actually comes in a variety of colors, including red, blue, green, and purple. This rainbow of colors can be traced to the protein molecules that carry oxygen in the blood. Different proteins produce different colors.
Continue reading “Roses are red and so is . . . blood?”
In a previous post, we highlighted two NIGMS-funded winners of the 2018 Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring (PAESMEM ). For January’s National Mentoring Month, we tell you about other awardees: J.K. Haynes, Virginia Shepherd, and Maria da Graça H. Vicente.
Continue reading “NIGMS Grantees Receive National STEM Mentoring Award”
Credit: Rommie Amaro, Jacob Durrant, Adam Gardner, and colleagues.
Ah, December—a month suffused with light-filled holidays, presents, parties . . . and the spread of colds and flu. This playful image uses a festive approach to the serious science of understanding and finding ways to combat the flu virus.
Continue reading “Festive Flu Virus Structure”
Quick quiz: Which organism . . .
- Can regrow a severed spinal cord?
- Is a culinary delicacy overseas but an invasive pest in the U.S.?
- Reveals insights about tissue regeneration, evolution, and cancer biology?
Continue reading “Extreme Healing, Weird Genomics, and Bloodsucking Invaders”