chloroplasts

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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 flowers reproduce – Plant Biology

By |2018-04-13T17:05:54+00:00May 30th, 2017|Biology|

Black-eyed Susan (the black in the middle is the seeds) The earliest flowers probably developed about 130 million years ago, in the Cretaceous period, as a way to attract newly evolved flying insects - mainly bees - and get them to help spread the plant's pollen far away from where the plant was [...]

What is moss? Plant Biology and Evolution

By |2017-05-29T22:55:45+00:00May 29th, 2017|Biology|

A moss-covered rock During the Cambrian period, about 540 million years ago, some early plants evolved from earlier algae that could live on land, outside of the water. These plants were like modern moss. All of the animals were still living in the water, so on land there was only moss and mushrooms. [...]

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, [...]

What is mitosis? Sexual reproduction – Biology

By |2017-05-29T00:31:28+00:00May 29th, 2017|Biology|

Eukaryote cells generally reproduce themselves using a method called mitosis. When a eukaryote cell senses that there is plenty of food around, it splits into two new cells that together can eat more food. But it's pretty complicated for eukaryote cells to divide. They have a lot of DNA molecules, to control all the different parts [...]

Leaf project – Chloroplasts and Cell Biology

By |2017-05-28T17:10:32+00:00May 28th, 2017|Biology|

Fall leaves from a maple tree You can see that leaves are only green because of the chloroplasts, because in the fall when the chloroplasts die, the leaves of the tree turn color and look yellow or orange to us. This is the color that the leaves are when they don't have any [...]

What is a chloroplast? Parts of a cell – Biology

By |2018-04-16T10:16:02+00:00May 28th, 2017|Biology|

Chloroplasts (seen through a microscope) The first cells that could make sugars out of sunlight and carbon dioxide and water by photosynthesis probably evolved around 3.8 billion years ago. They were prokaryotic cells that looked blue-green, because they needed to absorb all the warmer wavelengths of light and reflect the cooler blue and [...]