Table of Contents
What is the structure of a chromosome like?
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
What does chromosomes consist of?
Chromosomes are made up of a DNA-protein complex called chromatin that is organized into subunits called nucleosomes. The way in which eukaryotes compact and arrange their chromatin not only allows a large amount of DNA to fit in a small space, but it also helps regulate gene expression.
What is a typical chromosome?
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females.
How are centromeres used to describe the shape of chromosomes?
The location of the centromere on each chromosome gives the chromosome its characteristic shape, and can be used to help describe the location of specific genes. DNA and histone proteins are packaged into structures called chromosomes. What is a cell?
What makes up the chromatin of a chromosome?
Chromosomes are made out of chromatin, which is a a collection of DNA, protein, and other large molecules. The chromatin helps change the shape of a chromosomes to help during replication (copying the DNA), and transcription (using the DNA). Structures called histones and nucleosomes are part of chromatin.
What makes up the thread like structure of a chromosome?
The thread-like structure in the chromosome is referred to as chromatin fibre and is arranged in the chromosome in such a manner that the chromosome looks like a spool of yarn. This chromatin fiber is a collection of protein molecules called histones that are wrapped with a string-like structure.
When are chromosomes not visible in the nucleus?
Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.