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 and kept separate from the cytosol
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 some of their own proteins Most genes have relocated 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 4F0Nu-UY 4F0Nu-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 R ole: Functional protein A udience: A newly made protein either in an organelle or in the blood F ormat: A written method of your choice (story, poem, song, cartoon etc.) T opic: “The Talk” – telling the protein where it came from and how it got there.