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Please direct newsletter questions and comments to: [email protected] Volume 9, Issue 14 Interesting Science Facts 1.) Fleas can jump 130 times higher than their own height. In human terms, this is equal to a 6 ft person jumping 780 ft into the air. Cells By the Number: Facts About the Building Blocks of Life By Chidinma Okparanta for the National Institutes of Health Cells are the basic unit of life — and the focus of much scientific study and classroom learning. Here are just a few of their fascinating facets. 3.8 billion That’s how many years ago scientists believe the first known cells originated on Earth. These were prokaryotes, single-celled organisms that do not have a nucleus or other internal structures called organelles. Bacteria are prokaryotes, while human cells are eukaryotes. 2.) There are no poisonous snakes in Maine. 3.) The smallest bone in the human body is the stapes or stirrup bone located in the middle ear. It is approximately .11 inches (.28cm) long. 4.) The longest cells in the human body are the motor neurons. They can be up to 4.5 ft (1.37 meters) long and run from the lower spinal cord to the big toe. 5.) The human eye blinks an average of 4,200,000 times a year. Follow us on Facebook December 1, 2014 Devloping nerve cells, with the nuclei shown in yellow Credit: Torsten Whittmann, University of California, San Francisco 0.001 to 0.003 This is the diameter in centimeters of most animal cells, making them invisible to the naked eye. There are some exceptions, such as nerve cells that can stretch from our hips to our toes, sending electrical signals throughout the body. 1665 In that year, British scientist Robert Hooke coined the term cell to describe the porous, grid-like structure he saw when viewing a thin slice of cork under a microscope. Today, scientists study cells using a variety of high-tech imaging equipment as well as rainbow-colored dyes and a green fluorescent protein derived from jellyfish. 200 That’s how many different types of cells are in the human body, including those in our skin, muscles, nerves, intestines, blood and bones. 3 to 5 Believe it or not, that’s the approximate number of pounds of bacteria you’re carrying around, depending on your size. Even though bacterial cells greatly outnumber ours, they’re much smaller than our cells and therefore account for less than 3 percent of our body mass. Scientists are learning more about how our body bacteria contribute to our health. 24 This is the typical length in hours of the animal cell cycle, the time from a cell’s formation to when it splits in two to make more cells. 120 That’s the approximate lifespan in days of a human red blood cell. Other cell types have different lifespans, from a few weeks for some skin cells to as long as the life of the organism for healthy neurons. 50 to 70 billion Each day, approximately this many cells die in the human body as part of a normal process that serves a healthy and protective role. Those that die in the largest numbers are skin cells, blood cells and some cells that line structures like organs and glands.