DNADNABiology – Mr. FemiaBiology – Mr. Femia

HeredityHeredity

The genetic information that makes you look the way you do

The genetic information that makes you look the way you do

                                    

                            

InheritInherit

You inherit information from your parents

You inherit information from your parents

Nucleic AcidNucleic Acid

Molecules that store information about heredity in cell

Molecules that store information about heredity in cell

Examples of nucleic acidExamples of nucleic acid

DNA Only in the nucleus

Phosphate Sugar –Deoxyribose Nitrogen bases

(ATCG)

A – adenineT – thymineG – guanineC- cytosine

DNA Only in the nucleus

Phosphate Sugar –Deoxyribose Nitrogen bases

(ATCG)

A – adenineT – thymineG – guanineC- cytosine

RNA From the nucleus to

the cytoplasm Phosphate Sugar- Ribose Nitrogen bases (AUCG)

AU – uracilCG

RNA From the nucleus to

the cytoplasm Phosphate Sugar- Ribose Nitrogen bases (AUCG)

AU – uracilCG

DNA RNA DNA RNA

phosphate

Sugar nitrogen base

phosphate

Sugar nitrogen base

phosphate

Sugar nitrogen base

phosphate

Sugar nitrogen base

Complimentary Base Pairing

Complimentary Base Pairing

Adenine always pairs with Thymine or Uracil

A---T or U

Guanine always pairs with Cytosine

G---C

Adenine always pairs with Thymine or Uracil

A---T or U

Guanine always pairs with Cytosine

G---C

A---T C---GA---T C---G

Shape - Double HelixShape - Double Helix

Nucleotides pair up and twist to form a spiral staircase

Nucleotides pair up and twist to form a spiral staircase

Discovered by Watson and Crick

Discovered by Watson and Crick

Genetic CodeGenetic Code

The sequence of different nitrogen bases along one strand of DNA is a code for protein.

The sequence of different nitrogen bases along one strand of DNA is a code for protein.

CodonCodon

Nucleotides are arranged into groups of three.

Also called triplets – 2 nitrogen bases

Nucleotides are arranged into groups of three.

Also called triplets – 2 nitrogen bases

Amino acidsAmino acids

Each codon represents one of the 20 different amino acidsAAA ATT AAT

Each codon represents one of the 20 different amino acidsAAA ATT AAT

So…So…

Every 3 nitrogen bases make up one codon

Every codon codes for a specific amino acid

Many amino acids bonded together make up a protein

Every 3 nitrogen bases make up one codon

Every codon codes for a specific amino acid

Many amino acids bonded together make up a protein

Amino Acids are put together to make proteins

Amino Acids are put together to make proteins

Examples FingernailsHairSkinMuscles

Examples FingernailsHairSkinMuscles

So…….So…….

DNA is important because it helps determine the proteins that you are made of!

DNA is important because it helps determine the proteins that you are made of!

Replication of DNAReplication of DNA

Remember….Heredity is the passing of information from parents to you

This information must also be passed form one cell to the next when new cells are made (during which process?)

So……DNA must be replicated.

Remember….Heredity is the passing of information from parents to you

This information must also be passed form one cell to the next when new cells are made (during which process?)

So……DNA must be replicated.

                     

The GoalThe Goal

DNA replication - must make sure each cell in the same organism has exactly the same copy of DNA

DNA replication - must make sure each cell in the same organism has exactly the same copy of DNA

MutationMutation

Is it possible for there to be a mistake when replicating DNA?

Is it possible for there to be a mistake when replicating DNA?

MutationMutation

Can result in CancerRetardationSterilityPhysical

alterations

Can result in CancerRetardationSterilityPhysical

alterations

Germ Cell Tumor

Germ Cell Tumor

CausesCauses

Exposure to SunRadiationChemicalsOr a simple

mistake

Exposure to SunRadiationChemicalsOr a simple

mistake

Replication of DNAthe process of copying DNA in a

cell

Replication of DNAthe process of copying DNA in a

cellWhy?

In order for a cell to divide, it must first have 2 copies of DNA

One for the original cell and one for the new cell

Why?In order for a cell

to divide, it must first have 2 copies of DNA

One for the original cell and one for the new cell

ReplicationReplication

Replication Fork

The point where the double helix opens or unzipsA enzyme

unzips the double helix

Replication Fork

The point where the double helix opens or unzipsA enzyme

unzips the double helix

ReplicationReplication

Another enzyme puts free nucleotides into the correct place

Another enzyme puts free nucleotides into the correct place

Semi Conservative Replication

Semi Conservative Replication

Each new double helix that is formed consists of one old strand of DNA and one new strand

Notice the old molecule was blue and a new molecule still has a blue strand

Each new double helix that is formed consists of one old strand of DNA and one new strand

Notice the old molecule was blue and a new molecule still has a blue strand

Let’s see this in action…Let’s see this in action…

http://www.johnkyrk.com/DNAreplication.html

http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf

http://www.dnai.org/

http://www.johnkyrk.com/DNAreplication.html

http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf

http://www.dnai.org/