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What is nitrogen? Atoms, Elements, Chemistry

By |2018-04-24T14:46:22+00:00June 2nd, 2017|Chemistry|

Diagram of a nitrogen atom Inside a red giant star, the star smashes lighter atoms together. Smashing atoms gets the star energy to burn, and also leaves extra heavier atoms. Nitrogen is one of these heavier atoms, left over when a star smashes together carbon atoms. Nitrogen is not very heavy, though, and a [...]

How do cells move around? Cell biology

By |2018-04-16T00:35:41+00:00May 29th, 2017|Biology|

Bacterium with a flagellum(under a microscope) The simplest cells, developing about four billion years ago, had no way to control their own movement. They lived in the oceans, and they floated wherever the water took them. Sometimes they found food there, and sometimes they didn't. Many cells still live this way. By around [...]

What is RNA? Cell biology and evolution

By |2018-04-16T00:39:56+00:00May 29th, 2017|Biology|

RNA molecule: A single strand of RNA, seen under an electron microscope The RNA molecule was probably one of the earliest steps towards life on Earth. RNA is short for "ribonucleic acid". That's a very long, complicated molecule made out of amino acids linked together. The amino acids are made out of atoms of [...]

What is a prokaryote – Cell biology

By |2018-09-11T05:51:18+00:00May 29th, 2017|Biology|

A prokaryote (seen through a microscope) What does "prokaryote" mean? The simplest living cells are called prokaryotes, which is Greek for "before the nucleus" - these are cells that were so simple that they didn't have a nucleus. When did the first prokaryotes evolve? The first prokaryotes probably evolved from even simpler cells [...]

What is photosynthesis? Plant Biology

By |2018-04-16T00:37:36+00:00May 29th, 2017|Biology|

Chloroplasts (seen through a microscope) Photosynthesis is the way some cells on Earth pull in light from the sun and use it to make energy to repair and reproduce themselves. The first cells could not photosynthesize (foe-toe-SIN-the-size). They got food by breaking apart hydrocarbon molecules. But a little more than three billion years ago, [...]

How did cells evolve? Cell biology and evolution

By |2018-04-16T00:35:42+00:00May 28th, 2017|Biology|

One cell of a plant (magnified 22,500 times) Thanks to Ohio State University A cell is the smallest living thing (unless you count viruses), and all bigger living things are made of cells. Both plants and animals are made of cells. We don't know yet whether there are cells on any other planet [...]

What is DNA? Genetics and Evolution – Biology

By |2018-04-16T10:18:53+00:00May 28th, 2017|Biology|

A strand of DNA (seen through an electron microscope) If the RNA theory of the origin of life is right, then after a short time, about four billion years ago, the oceans on Earth had a lot of these strands of RNA molecules floating around in them. RNA molecules made proteins, and they also made new [...]