How a single-celled organism almost wiped out life on Earth – Anusuya Willis

http://ed.ted.com/lessons/how-a-single-celled-organism-almost-wiped-out-life-on-earth-anusuya-willis

There’s an organism that changed the world. It caused the first mass extinction in Earth’s history … and also paved the way for complex life. How? Anusuya Willis explains how cyanobacteria, simple organisms that don’t even have nuclei or any other organelles, wrote a pivotal chapter in the story of life on Earth.

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The simple story of photosynthesis and food – Amanda Ooten

http://ed.ted.com/lessons/the-simple-but-fascinating-story-of-photosynthesis-and-food-amanda-ooten

Photosynthesis is an essential part of the exchange between humans and plants. Amanda Ooten walks us through the process of photosynthesis, also discussing the relationship between photosynthesis and carbohydrates, starch, and fiber — and how the air we breathe is related to the food we ingest.

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Nature’s smallest factory: The Calvin cycle – Cathy Symington

http://ed.ted.com/lessons/nature-s-smallest-factory-the-calvin-cycle-cathy-symington

A hearty bowl of cereal gives you the energy to start your day, but how exactly did that energy make its way into your bowl? It all begins with photosynthesis, the process that converts the air we breathe into energizing glucose. Cathy Symington details the highly efficient second phase of photosynthesis — called the Calvin cycle — which converts carbon dioxide into sugar with some clever mix-and-match math.

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Oxygen’s surprisingly complex journey through your body – Enda Butler

http://ed.ted.com/lessons/oxygen-s-surprisingly-complex-journey-through-your-body-enda-butler

Oxygen forms about 21% of the air around us. In your body, oxygen forms a vital role in the production of energy in most cells. But if gases can only efficiently diffuse across tiny distances, how does oxygen reach the cells deep inside your body? Enda Butler tracks the surprisingly complex journey of oxygen through your body.

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How do the lungs work? – Emma Bryce

http://ed.ted.com/lessons/what-do-the-lungs-do-emma-bryce

When you breathe, you transport oxygen to the body’s cells to keep them working, while also clearing your system of the carbon dioxide that this work generates. How do we accomplish this crucial and complex task without even thinking about it? Emma Bryce takes us into the lungs to investigate how they help keep us alive.

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How polarity makes water behave strangely – Christina Kleinberg

http://ed.ted.com/lessons/how-polarity-makes-water-behave-strangely-christina-kleinberg

Water is both essential and unique. Many of its particular qualities stem from the fact that it consists of two hydrogen atoms and one oxygen, therefore creating an unequal sharing of electrons. From fish in frozen lakes to ice floating on water, Christina Kleinberg describes the effects of polarity.