DNA: the blueprint of life

Where do you get your DNA?Where do you get your DNA?DNA is passed from parent to offspring.DNA is passed from parent to offspring.

Where do we find DNA?Where do we find DNA?DNA is in the nucleus of every cell.DNA is in the nucleus of every cell.

DNA makes up our chromosomes. Humans DNA makes up our chromosomes. Humans have 46 (23 pairs). have 46 (23 pairs).

What is DNA?What is DNA?DNA is the genetic code.DNA is the genetic code.

DNA is called theDNA is called the “blueprint” “blueprint” for for living things.living things.

What does the code “code for”?What does the code “code for”?

DNA DNA codes for the building of codes for the building of PROTEINSPROTEINS..

DNADNA ProteinProtein TraitsTraits

Gene – enough DNA to make 1 proteinGene – enough DNA to make 1 protein

Important NoteImportant Note

All cells carry out protein synthesis, each All cells carry out protein synthesis, each making their own proteins.making their own proteins.

Each organism makes its own specific Each organism makes its own specific proteins, those proteins make an organism proteins, those proteins make an organism different from other organisms.different from other organisms.

The “The “NANA” in D” in DNANA stands for ? stands for ?

NNucleic ucleic AAcidcid

DDeoxyriboeoxyribonnucleic ucleic AAcidcidDD NN AA

What is a What is a nucleic acidnucleic acid??

Nucleic acids may be Nucleic acids may be polymerspolymers made up of chains made up of chains of many of many nucleotidesnucleotides..

What is a What is a nucleotidenucleotide??

A A three part unitthree part unit composed of:composed of:

a sugara sugar

a phosphatea phosphate

a basea base

Nucleic acids are made of Nucleic acids are made of nucleotidesnucleotides..

Nucleic acids are named for the type of Nucleic acids are named for the type of sugar that they contain.sugar that they contain.DNA – Deoxyribose sugarDNA – Deoxyribose sugarRNA (which we will discuss later) – Ribose sugarRNA (which we will discuss later) – Ribose sugar

DNA’s shape? A double helixDNA’s shape? A double helixIt looks like It looks like a twisted laddera twisted ladder oror spiral staircase spiral staircase

** The structure of DNA was ** The structure of DNA was discovered by James Watson and discovered by James Watson and Francis CrickFrancis Crick

If DNA is If DNA is compared to a compared to a twisted ladder, twisted ladder, the sides of the the sides of the ladder are . . . ladder are . . .

The rungs (or The rungs (or steps) are . . . steps) are . . .

sugars and sugars and phosphatesphosphates

the basesthe bases

There are There are 4 4 basesbases . . . . . .

4 Base Nucleotides4 Base Nucleotides

Adenine - Adenine - AA Thymine – Thymine – T T

Guanine - Guanine - GG

Cytosine - Cytosine - CC

Each base can only pair with one other Each base can only pair with one other basebase

Adenine - Adenine - AA Thymine – Thymine – T T

Guanine - Guanine - GG

Cytosine - Cytosine - CC

The base pairing is:The base pairing is:

AA TT CC GGWhy? Why?

Bases will always pair this way Bases will always pair this way because:because:• Size (number of rings)Size (number of rings)

• Number of bondsNumber of bonds

*** The order of these *** The order of these bases codes for different bases codes for different proteins / traits. proteins / traits.