We use cookies to personalize our website and to analyze web traffic to improve the user experience. You may decline these cookies although certain areas of the site may not function without them. Please refer to our privacy policy for more information.

Settings

Save and close

JAX Frontend Platform

Minute to Understanding: What is a chromosome?

What is a chromosome? Our cells contain many structures that are essential for living. One of these key structures is a chromosome.

Chromosomes are found in the nucleus of every cell of our body and are made up of DNA, tightly coiled around proteins. We have 23 pairs of chromosomes altogether, and they can only be easily observed during cell division.

So why is our DNA kept in this special packaging? The chromosomes unique structure allows our genetic data to be discreetly kept inside our nuclei. This is important because we have an abundance of genetic data. If the DNA molecules in a single cell were unwound, they would stretch out to six feet long.

The chromosomes unique structure has a few key parts. Each chromosome has two short arms called p arms and two long arms called q arms. These arms are held together at the center by the centromere. The tips of the chromosome are capped by sections of DNA called telomeres. Telomeres protect chromosomes during DNA replication. By keeping our DNA secure, chromosomes make daily activities possible. For an organism to function properly, certain cells must constantly divide and replace older worn out cells with new ones. Chromosomes allow DNA to be accurately copied during these cell divisions.

So one more time. Chromosomes are found in the nuclei of our cells and allow DNA to be accurately copied during cell division. This ensures that our inner workings proceed smoothly and efficiently.

Related Videos

What is Endometriosis?

What is Endometriosis?

Endometriosis is a painful condition that affects over two million people with uteruses worldwide, but what is it exactly? 

Watch video
Healthspan vs. Lifespan

Healthspan vs. Lifespan

Science can help extend our healthspan, but what does that mean?

Watch video
What is Cancer?

What is Cancer?

How does cancer arise and why is it so complex?

Watch video
What are Preprints?

What are Preprints?

Learn how to read cutting edge science papers before anyone else!

Watch video
What is the Skin Microbiome?

What is the Skin Microbiome?

Trillions of tiny living things inhabit our skin, but don't worry: that's good! Learn more about our skin microbiome to see why.

Watch video
Can Our Genetic Makeup Protect Us from Disease?

Can Our Genetic Makeup Protect Us from Disease?

Discover what "genetic resilience" is and how our genetic makeup can protect us from diseases like Alzheimer's and type 2 diabetes.

Watch video
What is Gene Therapy?

What is Gene Therapy?

How can you give therapy to a gene? Find out how gene therapy can help treat disease!

Watch video
What is Epigenetics?

What is Epigenetics?

How do epigenetic changes affect individuals without physically changing their DNA?

Watch video
Genetics vs. Genomics

Genetics vs. Genomics

Don't use these interchangeably! There is a difference between genetics and genomics.

Watch video
What are Genes?

What are Genes?

What are genes and why are they of such interest to science?

Watch video
What is DNA?

What is DNA?

The definition and key facts about deoxyribonucleic acid (DNA), the building block of genes.

Watch video
What are Telomeres?

What are Telomeres?

Learn all about telomeres, a part of the chromosome that changes with aging.

Watch video
What is an Allele?

What is an Allele?

Alleles genetically influence many parts of our life, such as how we look, risk factors for certain diseases, and much more.

Watch video
What are DNA Variants?

What are DNA Variants?

We are all mutants! Learn about DNA changes that make us unique.

Watch video
What is a Chromosome?

What is a Chromosome?

Responsible for cell division and many other functions, see why the chromosome is key to our everyday life.

Watch video

©2025 The Jackson Laboratory