Big Idea
The work of each cell is done primarily by proteins. Since there are hundreds of thousands of “chores” for a cell to do, there are hundreds of thousands of proteins.
Proteins
What is a protein?
One of four types of macromolecule
Proteins fold in unique ways so that each one has a particular 3-D structure.
Building blocks of proteins
Amino acids
Amino acids bond together
Peptide bond:
How many different kinds of proteins?
Hundreds of thousands!20 amino acids – like 20 letters,
arranged in different orders to form words
In proteins, the sequence of amino acids (“words”) averages 300 amino acids (“letters”) long
Where do we get the amino acid building blocks?
Essential amino acids—
You must get them in your diet every day.
Animal products provide complete proteins (with all amino acids). Vegetarians have to make sure to eat foods that contain all amino acids: like rice or corn with beans.
Non-essential amino acids are made by the body.
What do all these proteins do?
Virtually every task in every cell of your body!
Structural
Hair, nails and skin
Structural
Muscle and nerves
Structural
Membranes
Enzymes
Enzymes catalyze chemical reactions in cells: make them happen more quickly and with less energy needed
http://www.youtube.com/watch?v=Pvgpk75us18
EnzymesEnzymes end in –aseExamples
lactase – breaks down lactose (milk sugars) diastase – digests vegetable starch sucrase – digests complex sugars and starches maltase – digests disaccharides to monosaccharides (malt sugars) glucoamylase – breaks down starch to glucose protease – breaks down proteins found in meats, nuts, eggs, and
cheese lipase – breaks down fats found in most dairy products, nuts, oils,
and meat cellulase – breaks down cellulose, plant fibre; not found in humans
Enzymes
Our cells could not function without thousands of enzymes—a major reason why protein is an all-important molecule
Transport molecules
Hemoglobin
Transport molecules
Cytochromes
Messenger proteins
Insulin
Antibodies
Proteins make you you!
http://learn.genetics.utah.edu/content/begin/dna/tour_protein.html