From Gene to Protein

Proteins Review Accomplish most of the major cellular

functions Enzymes – catalyze reaction Structural fibers (cytoskeleton, muscle fibers etc.) Materials transport (hemoglobin carries oxygen,

carrier proteins or channels in cell membranes etc.)

Hormones or signals (insulin etc.) Pigments provide colors (chlorophyll, melanin) Immune function (antibodies)

Protein Structure Sequence of amino

acids Only 20 possibilities

The sequence is determined by genes (DNA)

Different proteins have different sequences and thus fold into very different 3-d shapes

From Gene to Protein DNA is transcribed

into RNA in the nucleus

RNA carries the code to ribosomes where the code is translated into a protein (polypeptide)

Where Ribosomes Are

Either in the cytosol (fluid of the cell) Makes proteins for inside the cell

Or attached to the rough endoplasmic reticulum Makes proteins to be shipped

Ribosomes in the Rough ER

Make proteins which then get wrapped in a membrane made by the ER

Known as a vesicle

Can be transported andkept separate from thecytosol

The Function of the Golgi

Vesicles from the ER usually go to the Golgi

Can be modified, tagged, sorted and shipped to a new location

Final Destination Vesicle can take protein to any

organelle or can form new organelle like a lysosome or vacuole

Can take protein to a membrane (organelle or plasma membrane)

Can expel protein outside of cell (i.e. into blood stream)

Chloroplast and Mitochondria Are thought to have once been free-living bacteria

Somehow got taken in by a cell and began living with it, eventually becoming a part of

Called endosymbiosis

So they make someof their ownproteins

Most genes haverelocated to nucleus

Evidence for Endosymbiosis

Chloroplasts and mitochondria are similar size to most bacteria

Contain their own DNA which has a similar structure to bacterial DNA

Contain their own ribosomes similar to bacterial ribosomes

Reproduce similarly to bacteria

Main Point

Genes code for traits by coding for proteins which have functions throughout the cell

Proteins go to different organelles and accomplish most functions of the cell

Cell Animation

http://www.youtube.com/watch?v=yKW4F0Nu-UY

Way more in depth- made for Med School students – but helps visualize dynamic nature of cell and see some major organelles/activities

R.A.F.T. Assignment - Individual Role: Functional protein

Audience: A newly made protein either in an organelle or in the blood

Format: A written method of your choice (story, poem, song, cartoon etc.)

Topic: “The Talk” – telling the protein where it came from and how it got there.