How is DNA packaged within Eukaryotic Cell nucleosomes

DNA is wrapped around proteins called histones, to form nucleosomes. Each nucleosome is a histone octomer composed of (H2A, H2B, H3, and H4) subunits with a 1.65 helical turn of 147 nucleotide bases. Nucleosomes then fold upon themselves to form chromatin. 

Loosely packed Chromatin called euchromatin is assoicated with high gene expression whereas densely packed chromatin called heterochromatin is associated with transcriptional repression (gene silencing). 

During metaphase stage of mitosis and meiosis chromatin becomes supercoilded resulting in the ability to see chromosomes under a microscrope. This is essential for the seperation of DNA between daughter cells. 

Answered by Rosewan A. Biology tutor

3373 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

What are the four stages of mitosis and what characteristic events occur within the cell at each stage?


Please could you explain Oxidative Phosphorylation?


Draw a diagram of a human cell, include; the Nucleus, the Golgi Apparatus, Lysosomes, Ribosomes and Mitochondria, annotating your diagram with the general functions of each component and of the cell membrane.


How does sexual selection lead to the evolution of elaborate male traits?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences