Proteins

Multipurpose molecules Proteins: Multipurpose molecules 2006-2007

Proteins Examples muscle skin, hair, fingernails, claws pepsin insulin collagen, keratin pepsin digestive enzyme in stomach insulin hormone that controls blood sugar levels pepsin collagen (skin)

Proteins Function: many, many functions hormones movement signals from one body system to another insulin movement muscle immune system protect against germs enzymes Help speed up chemical reactions

Proteins —N— H | —C— C—OH || O Building block = amino acids – 20 different amino acids There’s 20 of us… like 20 different letters in an alphabet! Can make lots of different words —N— H | —C— C—OH || O variable group

Amino acid chains Proteins Each amino acid is different amino acids chained into a polymer amino acid Each amino acid is different some “like” water & dissolve in it some “fear” water & separate from it

Water-fearing amino acids Hydrophobic “water fearing” amino acids try to get away from water in cell the protein folds

Water-loving amino acids Hydrophillic “water loving” amino acids try to stay in water in cell the protein folds

For proteins: SHAPE matters! Proteins fold & twist into 3-D shape that’s what happens in the cell! Different shapes = different jobs growth hormone hemoglobin pepsin collagen

Protein Structures Primary Structures – it’s the amino acid sequence Determined by the genetic code in the mRNA. It is produced in the ribosome.

Protein Structures Secondary Structures – form as a result from hydrogen bonds between peptide groups. Planar or cylindrical

Protein Structures Tertiary Structures – Its 3 dimensional formation as a result of protein folding. Happens because of bonds between R groups of different amino acids.

Protein Structures Quaternary Structures – 2 or more polypeptide chains associate and form a single protein. Hemoglobin are 4 different amino acid chains.

It’s SHAPE that matters! Proteins do their jobs, because of their shape Unfolding a protein destroys its shape wrong shape = can’t do its job unfolding proteins = “denature” temperature pH (acidity) unfolded “denatured” In Biology, it’s not the size, it’s the SHAPE that matters! folded

Enzymes Catalyst –speeds up the rate of a chemical reaction Enzymes – proteins that act as biological catalysts Enzymes help lower the activation energy of a chemical reaction the energy needed to get a reaction started

Substrates bind to a site on the enzyme called the active site Enzymes Substrates bind to a site on the enzyme called the active site SHAPE MATTERS!!

Enzymes – Usually end in -ase Enzyme Substrate Lactase Lactose Amylase Carbohydrate Sucrase Sucrose Maltase Maltose

______________ ___________ Substrate Products Active Site Enzyme

Enzymes The fit between the active site and substrates is so precise that it is often compared to a lock and key

Factors that affect enzyme activity Temperature Concentration pH FGHGFH CONCENTRATION LOW CONCENTRATION

Let’s EAT some Proteins! 2006-2007

Activities demo raw egg vs. cooked egg drop raw egg into boiling water, like egg drop soup compare raw egg to hard-boiled egg demo cheese-making with heated milk & vinegar make yogurt