Name: 【TED-Ed】Nature's smallest factory: The Calvin cycle - Cathy Symington
Uploaded: 2014-06-03T10:19:50.000Z
Duration: 5 min 38 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Soon, you're powered up by the energy surge

But how did that energy get into your bowl?

As you can see, carbon is the chemical backbone,

If you're thinking photosynthesis, you're right.

But photosynthesis is divided into two steps.

The first, which stores energy from the sun

in the form of adenosine triphosphate, or ATP.

And the second, the Calvin cycle, that captures carbon

This second phase represents one of nature's

And so with that, welcome to world's most miniscule factory.

The initiator? An industrious enzyme named rubisco

that welds one carbon atom from a CO2 molecule

That rapidly splits into two shorter chains

and called phosphoglycerates, or PGAs, for short.

nicotinamide adenine dinucleotide phosphate,

ATP, working like a lubricant, delivers energy,

while NADPH affixes one hydrogen to each of the PGA chains,

which incidentally have six carbons between them.

So, sugar has just been manufactured, right?

The Calvin cycle works like a sustainable production line,

need to be recreated by reusing materials

and manufacturing glucose takes a whole six.

While we've been focusing on this single production line,

five others have been happening at the same time.

With six conveyor belts moving in unison,

there isn't just one carbon that gets soldered

That creates 12 G3P chains instead of just two,

meaning that all together, 36 carbons exist:

the precise number needed to manufacture sugar,

that energy rich six carbon glucose chain.

The one fueling you via your breakfast. Success!

are swiftly assembled to recreate those six RuBPs.

the exact number contained by the remaining 10 G3PS.

By adding a third G3P, a nine carbon chain is built.

Those are soldered to a fourth G3P molecule,

So the Calvin cycle generates the precise number

required to keep this biochemical production line