eukaryote

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Proterozoic Eon – eukaryotes to worms

By |2018-04-21T11:56:39+00:00June 24th, 2017|Biology, Geology|

Two and a half billion years ago, the Archaean Eon ended and the Proterozoic Eon began. Trillions of prokaryote cells lived in Earth's oceans. Some of these cells could photosynthesize their energy from sunlight, water, and carbon dioxide. These photosynthesizing cells pooped out a lot of oxygen. By about 2.3 billion years ago, the iron [...]

How do eukaryote cells move? Cell biology

By |2017-05-29T10:30:48+00:00May 29th, 2017|Biology|

Human sperm cells with flagella (under a microscope) About two billion years ago, the first eukaryote cells evolved from the earlier prokaryote cells. These eukaryote cells also evolved a new way to move themselves around. Even though some eukaryote cells have flagella that look like the ones in prokaryote cells, they don't work the same [...]

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 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, [...]

What is a nucleus – Parts of a cell – Biology

By |2017-05-29T00:35:47+00:00May 29th, 2017|Biology|

An onion skin cell (seen through a microscope) You can see the nucleus inside each cell The earliest cells, and all prokaryote cells, don't have a nucleus. Inside these simple cells, the DNA molecules just float around in the cytoplasm. This is a nice simple arrangement, but it's risky - the DNA often [...]

What are mitochondria? Parts of a cell – Biology

By |2017-05-29T00:26:07+00:00May 29th, 2017|Biology|

A mitochondrion (seen through a microscope) About two billion years ago, in the Proterozoic, there were only prokaryotic cells on Earth. Mitochondria probably started out as independent cells that were especially good at digesting food. These cells were extra good at digesting because they had evolved to have two membranes. The inside membrane, [...]

What are lysosomes? Parts of a cell – Biology

By |2018-04-15T17:01:41+00:00May 28th, 2017|Biology|

Lysosomes (under an electron microscope) Prokaryote cells don't have lysosomes, so the first lysosomes probably evolved about the same time as the other pieces of eukaryote cells. That was about two billion years ago. Like the vacuoles and the Golgi bodies and the other parts of a cell, lysosomes (LIE-sew-somes (like HOMES)) are [...]

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 [...]

How do cells get rid of waste? Excretion and cell biology

By |2017-12-26T16:46:37+00:00May 28th, 2017|Biology|

Cell waste: A cell with a vacuole Cell waste and vacuoles Soon after eukaryote cells began to make vacuoles to help them catch their food and store it, about 600 million years ago, the cells also began to use the vacuoles to get rid of garbage in the cell - molecules that the [...]