Chromosomes are structures within cells that contain genetic material, also known as DNA. In this lesson, we will explore the basic concepts of chromosomes, their structure, and their function.
Structure of Chromosomes
Chromosomes are made up of DNA molecules that are tightly coiled around proteins called histones. This coiling helps to condense the DNA, allowing it to fit into the nucleus of a cell. The combination of DNA and histones forms a structure known as chromatin, which can be further condensed into visible chromosomes during cell division.
Each chromosome has a centromere, which is a specialized region that helps to hold the two copies of the chromosome together. The ends of chromosomes are known as telomeres, which help to protect the DNA from damage.
Types of Chromosomes
In humans, there are 23 pairs of chromosomes, for a total of 46 chromosomes. These chromosomes come in two types: autosomes and sex chromosomes. Autosomes are non-sex chromosomes, while sex chromosomes determine an individual’s sex. Females have two copies of the X chromosome, while males have one X and one Y chromosome.
Function of Chromosomes
The primary function of chromosomes is to carry genetic information from one generation to the next. This genetic information is stored in the sequence of nucleotides within the DNA molecule. During cell division, the chromosomes are replicated and then divided equally between the two new cells, ensuring that each cell receives a complete set of genetic information.
Chromosomes also play a role in gene expression, as the coiling and uncoiling of chromatin can affect whether or not genes are turned on or off.