Tag: Science Snippet

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Science Snippet: Brush Up on Biofilms

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A biofilm is a highly organized community of microorganisms that develops naturally on certain surfaces. Typically, biofilms are made up of microbes and an extracellular matrix that they produce. This matrix can include polysaccharides (chains of sugars), proteins, lipids, DNA, and other molecules. The matrix gives the biofilm structure and helps it stick to a surface.

Formation of a biofilm often involves a process called quorum sensing. In this process, microbes detect when they reach a certain population density and change their behavior in ways that help them function as a community.

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Science Snippet: Apoptosis Explained

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Apoptosis is the process by which cells in the body die in a controlled and predictable way because they have DNA damage or are no longer needed. The term comes from a Greek word meaning “falling off,” as in leaves falling from a tree.

When a cell undergoes apoptosis, it shrinks and pulls away from its neighbors. As the cytoskeleton that gives it shape and structure collapses, the envelope around the cell’s nucleus breaks down, and its DNA breaks into pieces. Its surface changes, signaling its death to other cells and leading a healthy cell to engulf the dying one and recycle its components.

On the left, two large cells with clear, smooth edges. On the right, two smaller cells with ragged edges.
Two cells in a healthy state (left) and entering apoptosis (right). Credit: Hogan Tang of the Denise Montell Lab, Johns Hopkins School of Medicine.
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Science Snippet: Learn About the Cytoskeleton

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A treelike structure made up of red and green fibers.
A cow cell showing actin filaments (red) and microtubules (green). Credit: Tina Carvalho, University of Hawaii at Manoa.

The cytoskeleton is a collection of fibers that gives shape and support to cells, like the skeleton does for our bodies. It also allows movement within the cell and, in some cases, by the entire cell. Three different types of fibers make up the cytoskeleton: actin filaments, intermediate filaments, and microtubules.

Powering Muscles

Actin filaments contract or lengthen to give cells the flexibility to move and change shape. Along with the protein myosin, they’re responsible for muscle contraction, including voluntary movement and involuntary muscle contractions, such as our heartbeats. Actin filaments are the thinnest and most brittle of the cytoskeletal fibers, but they’re also the most versatile in terms of shape.

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