Stem Cells

 
More Tags
 


Headline Tag: Science Rating: Amazing Hits: 1641 Comments: 0 Bill Nye: Greatest Discoveries : Biology Bill Nye: Greatest Discoveries : Biology Broadcast 2007. Hundreds of years before the DNA test, Micrographia championed the use of microscopes and set the stage for the first major discovery in biology: microorganisms. Learn how the secret of the cell was solved and how starfish led to the development of stem cell research. Where would we be today if it weren't for the scientists of the past? From the miniature world of genetics to the vast expanse of space, review the greatest discoveries of all time in this multi part series. Join host Bill Nye as he recounts the 100 most important discoveries and explains how each one has had a hand in shaping the modern world. Learn how the great discoveries were made, how they impacted the development of scientific knowledge. Discoveries Covered In This Episode: 1. Microorganisms (1674) Microscope lens grinder Anton Van Leeuwenhoek accidentally discovers microorganisms in a drop of water. Using his own microscopes, he observes sperm, bacteria and red blood cells. His observations lay the foundation for the sciences of bacteriology and microbiology. 2. The Cell Nucleus (1831) While studying an orchid, botanist Robert Brown identifies a structure within the cells that he terms the "nucleus." 3. Archaea (1977) Carl Woese discovers bacteria are not the only simple celled prokaryotes (unicellular organisms without a nucleus) on Earth. Many of the organisms classified in the new kingdom of Archaea are extremophiles. Some live at very high or low temperatures, others in highly saline, acidic or alkaline water. Some have been found in environments like marshland, sewage and soil. Archaea are usually harmless to other organisms and none are known to cause disease. 4. Cell Division (1879) Walther Flemming carefully observes that animal cells divide in stages and calls the process mitosis. Eduard Strasburger independently identifies a similar process in plant cells. 5. Sex Cells (1884) August Weismann identifies that sex cells must have divided differently to end up with only half of a chromosomal set. This very special division of sex cells is called meiosis. Weismann's experiments with reproduction in jellyfish lead him to the conclusion that variations in offspring result from the union of a substance from the parents. He refers to this substance as "germ plasm." 6. Cell Differentiation (late 19th century) Several scientists participate in the discovery of cell differentiation, eventually leading to the isolation of human embryonic stem cells. During differentiation, a cell turns into one of the many cell types that make up the body, such as a lung, skin or muscle cell. Certain genes are activated and others are inactivated, so the cell develops structures to perform a specific function. Cells that are not yet differentiated and have the potential to become any type of cell are called stem cells. 7. Mitochondria (late 19th century to the present) Scientists discover mitochondria, the powerhouses of the cell. These small structures within animal cells are responsible for metabolism and convert food into chemicals that cells can use. Scientists now believe they are specialized bacteria with their own DNA. 8. The Krebs Cycle (1937) Hans Krebs identifies the many steps the cell takes to convert sugars, fats and proteins into energy. Also known as the citric acid cycle, it is a series of chemical reactions using oxygen as part of cellular respiration. The cycle contributes to the breakdown of carbohydrates, fats and proteins into carbon dioxide and water. 9. Neurotransmission (late 19th to early 20th century) Discovery of neurotransmitters, how they tell the body what to do by passing signals from one nerve cell to another via chemical substances or electrical signals. 10. Hormones (1903) William H. Bayliss and Ernest H. Starling give hormones their name and reveal their role as chemical messengers. The team specifically describes secretin, a substance released into the blood from the duodenum (between the stomach and small intestine) that stimulates secretion of pancreatic digestive juice into the intestine. 11. Photosynthesis (1770s) Jan Ingenhousz discovers that plants react to sunlight differently than shade. The underpinnings of the understanding of photosynthesis are born. Photosynthesis is a process in which plants, algae and certain bacteria convert the energy of light into chemical energy. In plants, leaves take in carbon dioxide and roots absorb water. Sunlight runs a reaction that yields glucose (food for the plant) and oxygen (a waste product released into the environment). Nearly all living things on Earth are dependent on this process. User: spam_vigilante Sep 29, 2012 2:56 AM









Permanent Tag: Politics Rating: Amazing Hits: 526 Comments: 0 Give Us Liberty? Give Us Liberty? Q&A; with Dick Armey & Matt Kibbe of Freedom Works Sen. Lisa Murkowski (R-Alaska) is the latest victim of the Tea Party insurgency that's trying to take over the Republican Party. Tea Party favorite Joe Miller defeated Murkowski in The North Star State's primary by hammering away at (among other things) her support for TARP and lack of zeal for overturning Obamacare. Miller joins a new breed of anti-spending candidates such as Maine's Paul LePage, Kentucky's Rand Paul, Florida's Marco Rubio, and South Carolina's Nikki Haley, who promise to bring a new passion for shrinking government to D.C. and state capitals. Here's how Freedom Works' Dick Armey and Matt Kibbe sum up what the Tea Party stands for in their new book, GIVE US LIBERTY: A TEA PARTY MANIFESTO: "It doesn't take a lot of words to say that we just want to be free. Free to lead our lives as we please, so long as we don't infringe on the same freedom of others." Armey and Kibbe say that the Tea Party coheres around spending and that other issues are not central to its mission. Perhaps. Joe Miller is also pro-life, pro border fence, and wants to outlaw the use of embryonic stem cells in medical research. Maine gubernatorial hopeful LePage believes the "traditional definition of marriage should be preserved." Haley, who will probably be South Carolina's next governor, has campaigned on tough enforcement against illegal immigrants. And the closest thing to a Tea Party spokesperson is Sarah Palin, the former "Bridge to Nowhere" supporter who oversaw a 16 percent increase in spending during her time as governor of Alaska. Can this coalition stay together, stick to its anti-spending message, and actually change American politics? Or will it be co-opted by the very party upon which it seeks to perform a "hostile takeover?" Reason.tv's Nick Gillespie sat down with Armey and Kibbe to discuss these issues and more. The interview was shot by Jim Epstein and Meredith Bragg, and edited by Epstein and Joshua Swain. Approximately 9.30 minutes. User: Pantufas Sep 3, 2010 1:37 AM




 
Tags: Stem Cells, 1977, SciShow, Africa, Somalia, Egypt, Dick Armey, Bill Nye, Sam Harris, Winston Churchill, Tea Party Movement, Al-Jazeera, Jane Goodall, Fast Food, Bill Gates, Nobel Prize, Vegan or Vegetarian, Pakistan, Global Warming, Al Gore, Netherlands, Mosaic News, Marriage, TEDTalks, South Park, Israel, Link TV, Sarah Palin, Evolution, How To, National Geographic, Food, Iraq, BBC, Big Business, Japan, Cults and Religions, Science, Animals, Comedy Central, News, Politics, Humor, Television, Video Clips

The comments are property of their posters.

All logos and trademarks in this site are property of their respective owners.

Everything else © 2012 MilkandCookies.com.

[ DMCA | Privacy Policy ]