Genetics 7/20/2020

What is DNA?

What is DNA?

In this course, you will learn about DNA and its role in the lives of all living things!

29 Cards

All living things use DNA.

You have DNA.
Trees have DNA.
Mushrooms have DNA.
Dinosaurs had DNA.

Like a blueprint, DNA carries
the instructions that make
a living creature.

It is a chemical recipe for life.

DNA stands for
deoxyribonucleic acid.

Say it with us!
Dee-ok-si-rahy-boh-noo-klay-ik a·suhd

DNA is a very long molecule
made of tiny things called atoms
that link together.

DNA looks like a long, spiral staircase.

The building blocks of DNA are called nucleotides and come in four flavors abbreviated as
A, G, C and T.

Each of your cells, the living units of your body, contains a full DNA blueprint of you.

This is your genome.

Every individual human, animal and plant has a unique genome.

Our genome is the starting point for what we look like and how our bodies work.

Living things that look similar usually have more similar DNA.

The platypus is a curious example of this.  It is a cute but very odd mammal with a strange genome.

A platypus has fur and a duck-like bill.  The female lays leathery eggs but nurses her young.  The male has venomous spurs on his hind feet!

How did the platypus come to look like a mash-up of other animals?

The platypus still has DNA from our reptile-like ancestors in its genome, such as egg-laying DNA!

Pieces of DNA called genes are recipes that cells use to make proteins, the “workers”
and building blocks of cells.

Cells within spurs on the platypus’ hind feet use snake-like venom genes as recipes to make toxic proteins!

But if all of the platypus’ cells have the same genome, why don’t they all make venom?

A platypus’ brain cells use (express) their DNA differently than venom cells do.  Its brain cells have their venom genes turned off.

In you or a platypus, cells with different expression of their DNA must work together.

We’ve learned that DNA makes proteins.  But it is also
hereditary material.

This is how the platypus got venom-producing DNA in the first place.  It got it from a reptile-like ancestor.

DNA can be copied.  When a cell divides into two new daughter cells, each gets a full DNA blueprint.

But DNA is not a perfect self-copying blueprint.  It can change from damage and copying errors.

These DNA changes can be helpful, neutral or bad, such as cancer-causing DNA mutations.

Helpful DNA changes that happen over time can drive evolution.

This is how there are so many crazy creatures today that seem to fit their environment…

like cave fish that have no eyes but have genes that help them feel tiny vibrations!

In summary, your DNA is a blueprint of you, but it is not written in stone.

You can even turn genes on or off with behaviors like diet and exercise!

So your DNA is important to how your body works, but it is not your destiny.

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