DNA Think About NOWDNA Think About NOW

• When you hear the term DNA, what When you hear the term DNA, what comes to mind?comes to mind?

• What do you think DNA looks like What do you think DNA looks like (under the microscope of course)?(under the microscope of course)?

• What happens when something What happens when something goes wrong with DNA?goes wrong with DNA?

Where is DNA found in the Where is DNA found in the Cell??Cell??

Answer:

The Nucleus

Stores and passes on genetic information from one generation to another .

DNA DEOXYRIBONUCLEIC ACID

Every living thing has DNA. That means that you have something in common with

a zebra, a tree, a mushroom and a beetle!!!!

DNA stands for:D: DeoxyriboN: NucleicA: Acid

DNA is too small to see, but under a microscope it looks like a twisted up ladder!

DNA Who Done It?DNA Who Done It?

• James Watson, Francis Crick and James Watson, Francis Crick and Rosalind Franklin are credited with Rosalind Franklin are credited with discovering the double helix discovering the double helix structure of DNA.structure of DNA.

• Watson and Crick used Franklin’s x-Watson and Crick used Franklin’s x-ray data to write “The Double ray data to write “The Double Helix”Helix”

Watson Crick Franklin

DNA Dorks

X-Ray picture of DNAX-Ray picture of DNA

• X-ray X-ray crystallographycrystallography is a is a method of method of determining the determining the arrangement of arrangement of atoms within a atoms within a crystal, in which a crystal, in which a beam of X-rays beam of X-rays strikes a crystal and strikes a crystal and diffracts into many diffracts into many specific directions.specific directions.

DNA STRUCTURE

The DNA structure is shaped liked a spiral staircase, or twisted ladder.

DNA STRUCTURE

The outer parts of the ladder are made of sugars (deoxyribose) bonded to each other by phosphates.

DNA STRUCTURE

The steps of the ladder are made of pairs of nitrogen bases.

DNA is made up of steps and rails of a DNA is made up of steps and rails of a ladder.ladder.

This is a rail

This is a step

Green can only go with Red

Purple can only go with Yellow

Nitrogen Bases (Steps)

A T

A

A

A T

T

T

C

C

C

C

C

G

G

G

G

G

G

C

A T

G C

DNA STRUCTURE

1. ADENINE = A2. GUANINE = G3. CYTOSINE = C4. THYMINE = T

THE NITROGEN BASES ARE REPRESENTED BY THEIR CAPITAL LETTER.

DNA STRUCTURE

There is only one way the nitrogen bases can form

Adenine pairs with ThymineGuanine pairs with Cytosine

DNA STRUCTUREQUESTION ?

Can C join with A?

And G join with T?

DNA STRUCTURE

ACTCATGGTCATG

TGAGTACCAGTAC

This is an example of a genetic code that may be found in your body.

DNA STRUCTURE

The combinations of the nitrogen bases is the code that produces the genes for a particular trait.

DNA STRUCTURE

Because there can be so many different combinations of the bases the code can be limitless

DNA REPLICATION

Replication: is the process where DNA molecules form exact duplicates.

DNA REPLICATION STEPS

1.The ladder splits

2. Free floating nitrogen bases begin to pair with each strand

3. Two new DNA chains are formed

****DNA replication needs to happen before a cell divides.

DNA Replication Video