Chromosomes - Jenn Fitzgerald | Library

Our DNA is made up of tiny repeating subunits called nucleotides. These nucleotides are so tiny, if we lined up 140 million of them in a straight line they would only be about 5cm long. Our tiny cells are able to fit all of our DNA inside them because they tightly wrap the DNA and form chromosomes. 

Chromatin & Chromosomes

DNA is found in the nucleus of eukaryotic cells. DNA can take 2 forms inside our cell's nucleus. Chromatin is the relaxed form of DNA. However, the DNA is not relaxed at all times. Chromosomes are condensed structures that contain DNA and are visible during mitosis. Chromosomes are passed from generation to generation of our cells. 
Eukaryotic DNA is organized into individual chromosomes. The length of a human chromosomes ranges from 51 million to 245 million nucleotide pairs. The phosphate groups in DNA create a negative charge which attracts the DNA to positively charged histone proteins and forms a nucleosome. The nucleosome then groups together into chromatin fibers, which supercoil to make up the DNA structure recognized as a chromosome. 

1

A repeating subunit of fibers which consist of DNA coiled around histones are what?

1

The relaxed form of DNA is called what?

1

What are the condensed structures of DNA that are visible during mitosis called?

2

Chromatin fiber is made up of nucleosomes, which are made up of __________ wrapped around beadlike proteins called __________.