DNA and chromosomes may seem like completely separate things. Well, they’re not. In fact, all chromosomes are individual DNA molecules coiled and twisted around, because DNA is huge. At least in eukaryotes it is. That’s one of the first differences between eukaryotes and prokaryotes in their DNA – prokaryotes have less DNA.
Eukaryotic DNA is stored within the nucleus of each cell (apart from cells without one, e.g. red blood cells). Because of its sheer size, it must be organised well. Proteins called histones help do just that:
The S phase in the cell cycle involves the replication of DNA in chromosomes. Checkpoints ensure that all DNA is copied accurately, and once all chromosomes have been duplicated, they must be properly attached to the cell spindle fibres that will separate them during mitosis into the two new cells.
Thank you!! Your site is so helpful!
Hi! I have recently finished my first year doing biology at uni and I subscribed to you back when I was doing AQA A levels (glad I don’t live in Wales after watching this vid lol) and you and your website helped me so much. Just wanted to say it’s so nice to see you
Mr Peanutbutter YouTube
Just a huge thank you for spending your time helping others. I love your site and I'm seriously very grateful. No word of a lie
Neuron13 The Student Room
Thank you for the help, your website and videos are awesome
pika mart YouTube
You're such a G. Helped me so much, finally found someone who breaks biology down into something I can understand!!!
Alex Contact Form