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