Genes are read and copied before use!

DNA: DeoxyriboNucleic Acid

RNA: RiboNucleic Acid

The instructions that are needed by the cell are copied from the DNA

into a similar molecule called RNA

The nucleus READS the genes and sends INSTRUCTIONS in the form of RNA “messages”

Nucleus Each gene is copied into RNA when it is needed by the cell

What Kind of Stuff Are You Made Of?

http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookAnimalTS.html

Cells lining a tubule

Fat cells

Muscle cells

Red blood cells

Cells lining the

small intestine

Cell types in the stomach

Nerve cells

Cells: The fundamental unit of life The building blocks of bodiesWe are each made of 100 trillion cells!

Different Cell Types Make Different Organs

http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookAnimalTS.html

Cells lining a tubuleFat cells

Muscle cells

Red blood cells

Cells lining the

small intestine

Cell types in the stomach

Nerve cells

What makes cells differentfrom each other?

Gene Expression

Each cell type does a different jobThey must not get “mixed up”!What makes these cells differentiate?

DNA(GENE)

PROTEINS

mRNA mRNA AAAAAAAAAA

DNA is copied into RNA:DNA letters copied into RNA code.

The RNA code specifies the order of amino acid building blocks in the protein.

The amino acid chain folds to make a functional 3D protein.

Messenger RNA

Flow of Genetic Information: DNA to RNA to Protein

A DNA Spelling Mistake Can Alter the Protein Chain

ATG TTC AGG CCA AAT TTT GTC GCG UAA GGA ATTSTART ADD ADD ADDADD ADDADD ADD STOP

TTC to TTT spelling change causes a different protein building block to be inserted in the second position. That is all it takes.

Spelling Mistake The DNA “word” TTC is changed to TTT

ATG TTT AGG CCA AAT TTT GTC GCG