What is the Function of DNA in a Human Cell?

Daniel Liden

Deoxyribonucleic acid (DNA) serves a variety of purposes, including data storage and replication, in the human cell and in the cells of many other organisms. DNA in a human cell is primarily responsible for storing genetic information that is used to control almost every aspect of cellular expression. This genetic information is passed down from parents to offspring, resulting in offspring with some genetic traits of each parent. DNA is also replicated whenever the cell divides; this ensures that each cell in the body has and expresses the same genetic information. It is also the first element in the synthesis of proteins, which are responsible for most cellular activity.

The blueprints for an individual's physical development are encoded in their DNA.
The blueprints for an individual's physical development are encoded in their DNA.

DNA in a human cell serves an essential role in biological inheritance, through which a child possesses some genetic traits of each of his parents. Humans reproduce through sexual reproduction. Most human cells contain two copies of the human genome so that, after cell division, both daughter cells will contain the same genetic information. Reproductive cells, one of which comes from each parent, contain only one copy. Two reproductive cells — one egg and one sperm — combine to form a human embryo containing a random assortment of genetic information from each parent.

Sperm are the male reproductive cells.
Sperm are the male reproductive cells.

Data storage and replication is one of the major roles of DNA in a human cell. Accurate copies of the human genome must be stored within each cell so genes can be expressed correctly. Mutations in DNA can cause the stored genetic information to be altered; this can cause altered gene expression that may lead to cancer or other diseases. DNA replication, then, needs to be a high-fidelity process since it happens countless times over the course of a human life and even minor errors in replication can cause harmful mutations. There are, accordingly, a variety of error-checking mechanisms in the DNA replication process that prevent nearly all possible replication errors.

Much of the genetic information contained in human cells exists to be expressed as RNA or protein. In a process called transcription, double stranded DNA is converted to single-stranded RNA, or ribonucleic acid. Some forms of RNA can serve various cellular functions based on their molecular configurations, but most are translated into proteins. Proteins serve a tremendous variety of cellular functions, ranging from signaling to cellular regulation to the catalysis of biochemical reactions. DNA in a human cell, then, is responsible for the inheritance, replication, and expression of genetic information.

The parents' DNA determines the traits of their offspring, including physical appearance.
The parents' DNA determines the traits of their offspring, including physical appearance.

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Discussion Comments


@pastanaga - What makes me more excited and interested, is that they have finally worked out the entire human genome and are working on the genomes for lots of other creatures now too. This is going to have far more consequences on our ability to keep ourselves healthy and to understand ourselves than almost any other discovery made in the history of mankind.

I mean, we still don't know how all these genes relate to each other in human DNA, but we are gradually learning and that's going to lead to more and more discoveries.


It's so amazing how much can be expressed through the genetic code, which is essentially the same for all living creatures, from the smallest and simplest to the largest and most complex.

I mean, basically the same code can tell proteins to become a human baby, or a stalk of celery and, all things considered, the two actually have more things in common than you might think, when you are studying the code.


One of the coolest things I've ever read was a letter from one of the guys who discovered that DNA was formed in a helix, to his ten year old son, explaining the discovery.

Try to find it if you can, it has a really simple and interesting explanation of the function of DNA, as well as a head's up about the discovery, basically because the man knew it was an incredible find and he wanted his son to hear about it first.

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