Oh, wow, oh, oh, oh, wow, oh, oh, man.

Oh, my.

And so, you're listening to The Science of Everything podcast, episode 44, cell division, and I'm your host, James Fodor.

So in this episode, we're going to talk about cell division. In particular, we're going to talk about

the cell cycle and the different phases in that, including interphase, synthesis, and mitosis.

We'll go through all the different phases of mitosis, prophase, prometaphase, metaphase, metaphase, and telephase. We'll look

at cytokinesis, and then we'll talk about some of the mechanisms of by which cells regulate the

cell cycle, including cyclone-dependent kinases, the cell checkpoints, and also the role of growth factors.

Recommended pre-listening for this episode, include episode 10, The Cell, Episode 18, Biochemistry Basics,

and Recommended is also episodes 34 and 35 about DNA structure and function, although that's not as crucial,

but it would be useful if you had that background. Let's get on to the episode. First of all,

just a short word on the structure of chromosomes. Again, this is where the previous knowledge about DNA structure and function would come in handy

because you'll understand more of the terms I'm using, but not essential.

So chromosomes are composed of chromatin, which is a complex of DNA, about 60% and about 40% proteins.

So it's DNA and protein sort of combined together.

Each chromosome is a single continuous

double strand of DNA, usually around like 150 million base pairs along, although it differs a lot

between the different chromosomes in humans. But we're talking, you know, hundreds of millions

of base pairs, so it's pretty long. It's double-stranded, so you know the DNA is the double helix

with the two strands bonded to each other.

So there are two actual individual strands of DNA on the chromosome. But when people

normally think about chromosomes, they think of these sort of roughly X-shaped structures.

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