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What is meiosis? Cell reproduction – Biology

By |2017-11-24T17:38:10-07:00May 29th, 2017|Biology|

At first all eukaryote cells divided using a process called mitosis. But about 1.4 billion years ago, some eukaryote cells developed the ability to reproduce using meiosis instead. Meiosis (my-OH-siss) is a way for cells to get more diversity while they are reproducing. A cell that reproduces by meiosis has twice as much DNA in its [...]

What are lysosomes? Parts of a cell – Biology

By |2018-04-15T17:01:41-07:00May 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 |2018-04-16T00:35:42-07:00May 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 a Golgi body? Parts of a cell – Biology

By |2017-05-28T23:20:56-07:00May 28th, 2017|Biology|

Taken with an electron microscope at the University of Melbourne, Australia When the RNA of a eukaryote cell has finished assembling new protein or lipid or sugar molecules in the endoplasmic reticulum, the molecules gradually pinch off a little piece of the endoplasmic reticulum around themselves. They seal themselves into a little bubble. [...]

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

By |2018-12-27T09:35:02-07:00May 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 [...]

What are eukaryotes? Cell biology

By |2017-05-28T22:37:27-07:00May 28th, 2017|Biology|

A eukaryote cell (seen through a microscope) full of chloroplasts Around two billion years ago, when all cells still lived in the ocean, a few of the earliest cells, or prokaryotes, evolved into more complicated cells called eukaryotes. They seem to have done this by enclosing several different kinds of prokaryotes inside another [...]

What is the endoplasmic reticulum? Parts of a cell

By |2017-05-28T22:26:46-07:00May 28th, 2017|Biology|

Endoplasmic reticulum inside a cell The endoplasmic reticulum is made out of a lipid membrane, just like the cell membrane around the outside of a cell, or like vacuoles, or like the membrane around the nucleus of a cell. Probably the endoplasmic reticulum evolved about two billion years ago out of the cell [...]

What is a sponge? Porifera, Evolution, and Biology

By |2018-04-13T14:35:53-07:00May 28th, 2017|Biology|

A group of brightly colored sponges in the ocean For almost three billion years, the only living things on earth were one-celled creatures, either prokaryotes or eukaryotes. Even today, the vast majority of the living things on earth are one-celled creatures, or microbes. But about 600 million years ago, a few one-celled creatures [...]

What is a hydra? Animal Biology and Evolution

By |2018-04-16T09:20:37-07:00May 28th, 2017|Biology|

Hydra evolution: a hydra budding new hydras For almost three billion years, the only living things on earth were one-celled creatures, either prokaryotes or eukaryotes. Early multi-cellular creatures Even today, the vast majority of the living things on earth are one-celled creatures - microbes. But about 600 million years ago, a few one-celled creatures began [...]