How Does Your Nucleus Hold your DNA? – Secondary 11

Question: How Does Your Nucleus Hold your DNA?
- Keywords:
  cells,
  dna,
  genetics,
  nucleus
Asked by natrualme to Jemma, John, Lisa, Sam on 31 May 2012.
- Jemma Ransom answered on 31 May 2012:
  
  Hi @naturalme, blimey, you’re a curious person! Keep the questions coming.
  
  This is one of my favourite subjects. As you have probably already guessed, the double helix model of DNA that you often see in classrooms is too big to fit into a nucleus :-S Therefore cells have devised several clever structures that package the DNA into the nucleus. Thes are called Histones and they effectively wind up the DNA into a form that can fit easily inside the nucleus. The only problem with this is if the DNA is tightly wound p, nothing else in the cell can get to it and so the information that the DNA contains cannot be used by the cell. So cleverl, when the cell needs to get at a particular gene in the nucleus it can unwind that particular bit of DNA so that it can read the information on it. This is why all cells in your bory contain the same DNA, but only certain genes are expressed in each type of cell – that’s what makes your skin cells for example different from your brain cells.
  
  Hope that helps. More questions please!!
  Jemma

Question: How Does Your Nucleus Hold your DNA?