DNA vs Genes vs Chromosomes: An Overview (original) (raw)

What is DNA?

Deoxyribonucleic acid (DNA) is the material that exists in every cell in your body that holds your genetic code. It makes up your body’s instruction manual.

What is DNA made of?

DNA has a language that it uses to write your instruction manual (a code). Four chemical bases make up your DNA language including:

• Adenine (A).
• Cytosine (C).
• Thymine (T).
• Guanine (G).

These four bases arrange themselves in order to form “words” in your instruction manual.

DNA constantly replicates itself by making hand-written copies of your body’s instruction manual using the chunks of bases that form the words. There are an estimated 3 billion bases in a human’s body. About 99% of those bases are the same in every person. The remaining 1% is what makes you unique.

What are genes?

Genes are the building blocks for your body. Some genes give the instructions to make proteins. A protein’s job is to tell your body what types of physical characteristics you should have, like your hair and eye color. Some genes code for RNA, which does other jobs.

How do I get genes?

You can’t buy genes from a department store. You inherit your genes from your parents. You receive one copy of a gene from each parent (one from the egg and one from the sperm). Once you receive a pair, your genes divide and copy themselves until your body has enough genes to fill your instruction manual. There are approximately 20,000 to 25,000 genes in your body.

What are chromosomes?

Chromosomes are structures that look like thread, which live in the nucleus (center) of cells. Chromosomes contain DNA and protein, and they come in different sizes. Proteins called histones allow them to pack up small enough to fit in a nucleus. Without histones, our chromosomes would be as long (tall) as we are! Chromosomes give your cells the actual instructions to make you into a unique person.

How many chromosomes do humans have?

Humans should have 23 pairs of chromosomes (46 total). Chromosomes divide into 22 numbered pairs (autosomes) and one pair of sex chromosomes (X and Y). You receive one chromosome from each parent to make a pair.

Although rare, errors occur when cells divide and replicate, so people might have an additional chromosome attached to a pair (trisomy) or one less chromosome on a pair (monosomy).