Basics of GeneticsIntro to Health Journalism

DNA: Deoxyribonucleic acid

The essence of life

DNA resides in the nucleus of each cell of

our bodies

DNA consists of four components that alternate and repeat, making

patterns

When a pattern of DNA “spells” something

comprehensible it is called a gene

Not all DNA makes genes

• Some of the DNA along the chromosome is “non-coding”

• It used to be called “junk DNA”

• Scientists now believe that this non-coding (non-gene) DNA has important signaling functions

Genes are the recipe for proteins

And proteins do almost everything in the body!

• Hair and nails (keratin)

• Enzymes that jumpstart chemical reactions in the body

• Hormones and other chemical messengers

• Antibodies that fight off invading viruses and bacteria

• There are hundreds of thousands of different proteins in the body

Let’s get this straight• DNA consists of long chains of four different

nucleotides

• Specific groupings of three nucleotides correspond to one amino acid

• There are 20 amino acids

• A protein is a chain made of specific pattern of amino acids

See any similarities?

• Genes are long strings of nucleotides. A total of four repeating nucleotides make distinct patterns—“spelling” genes

• Proteins are long strings of amino acids. A total of 20 repeating amino acids make distinct patterns—“spelling” proteins

Time to make the donuts!

How genes make proteins

The spiral staircase “unzips”

Stray nucleotides are attracted to these available

mates

And an identical complementary strand is

formed

This new strand contains all the

information from the original DNA

and can be used to churn out proteins

The DNA molecule zips back up and waits until it’s

needed again

How do four nucleotides and 20 amino acids spell

the instructions for making such a wide variety of differently

shaped proteins?

I’m glad you asked!

When a protein is spelled out it is a long chain of

amino acids

As soon as the protein chain is completed…

Due to innate attractions and

repulsions between these amino acids …

Voila!

• Each protein has a unique shape, perfectly designed to accomplish its specific task in the body

• So if there is even a tiny MUTATION in the DNA … i.e. if just one nucleotide out of thousands is mistakenly switched for another

• The entire protein shape will be DIFFERENT

• Which can lead to serious illness

And that’s why the body is so darn amazing!