Category: Cells

Career Conversations: Q&A with Evolutionary Biologist William Ratcliff

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Dr. Ratcliff wearing a lab coat and safety goggles and sitting at a microscope.
Dr. William Ratcliff. Credit: Courtesy of Dr. William Ratcliff.

“Being a researcher is special because there aren’t many jobs that allow you to spend the majority of your time thinking about the things you find the most interesting in the whole world,” says William Ratcliff, Ph.D., an associate professor of biological sciences and the director of the interdisciplinary graduate program in quantitative biosciences at Georgia Institute of Technology (Georgia Tech) in Atlanta. We talked with Dr. Ratcliff about his career path, research on yeast, and advice to budding scientists.

Q: How did you first become interested in science?

A: My family owns land in Northern California that has been passed down for more than 100 years. When I was a child, my brother and I would spend summers on that land getting lost in the woods. We would really see the forest for its parts: seeing how organisms interacted with one other, tracking stages of development, and listening to birdcalls. My grandmother would identify plants by their scientific names, and we’d discuss their reproduction strategies. We became amateur natural historians during those summers. Perhaps it’s no surprise my brother and I both got Ph.Ds. in biology.

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Five Outstanding Stories From 2022

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Throughout 2022, we shared the stories of dozens of NIGMS-supported researchers, trainees, and programs. We also highlighted new STEM education resources, tested your knowledge with quizzes, showcased extraordinary scientific images, and more. To celebrate the upcoming new year, we’re highlighting five of our most popular posts from 2022. Check out the list below, and let us know in the comments section which of this year’s posts you liked best!

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Science Snippet: ATP’s Amazing Power

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A twisted, blue crystalline structure with a small yellow molecule inside it.
ATP (yellow) powering a protein (blue) that moves material within cells and helps them divide. Credit: Charles Sindelar, Yale University.

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.

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In Other Words: Not All Cultures Are Human

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The word culture may make you think of a flag, style of clothing, celebration, or some other tradition associated with a particular group of people. But in biomedical science, a culture is a group of cells grown in a lab. Scientists use cultures to learn about basic biological processes and to develop and test new medicines.

Below the title “Culture: In Other Words,” two images are separated by a jagged line. On the left are outlines of faces surrounding a globe of the Earth. On the right is a hand holding a Petri dish with cells growing in it. Under the images, text reads: “Did you know? In biomedical science, a culture is a group of cells grown in a lab.”
Credit: NIGMS.

The Birth of a Culture

Scientists can grow many types of cells as cultures, from bacteria to human cells. To create a culture, a researcher adds cells to a container such as a Petri dish along with a mix of nutrients the cells need to grow and divide. The exact recipe varies depending on the cell type. (Because many lab containers were historically made of glass, researchers sometimes refer to studies that use cultures as in vitro—Latin for “in glass.”) Once the cells multiply and fill their container, researchers split the culture into new containers to produce more.

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Science Snippet: Lipids in the Limelight

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A large blue oval surrounded by small yellow circles.
Spheres of lipids (yellow) inside a cell. The nucleus is shown in blue. Credit: James Olzmann, University of California, Berkeley.

Have you ever wondered why your cells don’t spill into each other or what keeps your skin separate from your blood? The answer to both is lipids—a diverse group of organic compounds that don’t dissolve in water. They’re one of the four major building blocks of our bodies, along with proteins, carbohydrates, and nucleic acids. Types of lipids include:

  • Fats, necessary for our bodies’ long-term energy storage and insulation. Some essential vitamins are fat soluble, meaning they must be associated with fat molecules to be effectively absorbed.
  • Phospholipids, which make up a large part of cell and organelle membranes.
  • Waxes, which help protect delicate surfaces. For instance, earwax protects the skin of the ear canal.
  • Steroids, including cholesterol, a precursor to many hormones, which helps maintain the fluidity of cell membranes.
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In Other Words: How Cells Express Themselves

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When you encounter the word expression, you may think of a smile, a grimace, or another look on someone’s face. But when biologists talk about expression, they typically mean the process of gene expression—when the information in a gene directs protein synthesis. Proteins are essential for virtually every process in the human body.

Below the title “Expression: In Other Words,” two images are separated by a jagged line. On the left are several cartoon representations of a man with different facial expressions. On the right is a cartoon depiction of DNA and an arrow pointing to a folded protein. Under the images, text reads: Did you know? When biologists talk about expression, they’re typically referring to gene expression, where the information in a gene directs the building of a protein.
Credit: NIGMS.
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Science Snippet: RNA’s Remarkable Roles

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RNA, though less well known than its cousin DNA, is equally integral to our bodies. RNA molecules are long, usually single-stranded chains of nucleotides. (DNA molecules are also made up of nucleotides but are typically double-stranded.) There are three major types of RNA, which are all involved in protein synthesis:

  • Messenger RNA (mRNA) is complementary to one of the DNA strands of a gene and carries genetic information for protein synthesis to the ribosome—the molecular complex in which proteins are made.
  • Transfer RNA (tRNA) works with mRNA to make sure the right amino acids are inserted into the forming protein.
  • Ribosomal RNA (rRNA), together with proteins, makes up ribosomes and functions to recognize the mRNA and tRNA that are presented to the ribosomal complex.
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Slideshow: Mitosis Masterpieces

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The intricate process of mitosis—a cell splitting into two identical daughter cells—plays a pivotal role in sustaining life. Many scientists study this process to understand what’s needed for it to progress normally and why it sometimes goes awry, such as in cancer. During their research, the scientists often create eye-catching images and videos, and we showcase some of those visuals here.

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Science Snippet: Get to Know Your Nerve Cells!

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Nerve cells, also known as neurons, carry information through our bodies using electrical impulses and chemical messengers called neurotransmitters. A nerve cell’s size and shape depend on its role and location, but nearly all nerve cells have three main parts:

  • Dendrites that extend like branches and receive signals
  • A cell body containing the nucleus that holds the genetic material of the cell and controls its actions
  • An axon, a long structure that transmits messages
An illustration of a nerve cell that shows a round cell body with dendrites and a long axon branching away from it.
A typical nerve cell. Credit: iStock.
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Photographing the Physics of Cells

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Dr. Lakadamyali sitting behind a large, complex microscope in a lab.
Dr. Melike Lakadamyali with a microscope. Credit: Courtesy of Dr. Lakadamyali.

“It would be a dream come true if I could look at a cell within a tissue and have a Google Maps view to zoom in until I saw individual molecules,” says Melike Lakadamyali, Ph.D., an associate professor of physiology at the University of Pennsylvania’s Perelman School of Medicine in Philadelphia. Her lab is helping make part of that dream a reality by developing super-resolution microscopy tools that visualize cells at a near-molecular level.

Blending Physics and Biology

Science and math fascinated Dr. Lakadamyali since childhood, and she felt especially drawn to physics because she enjoyed using logic to solve problems. After graduating high school in her native country of Cyprus, she chose to study physics at the University of Texas, Austin. She never gave much thought to applying physics methods to biological
questions—a field known as biophysics—until her third year as an undergraduate, when she gained her first research experience in the lab of Josef Käs, Ph.D.

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