Proteins

Metabolism, support, transport, defense, regulation, motion

5 Functions of Proteins

Metabolism

Most proteins act as catalysts to accelerate chemical reactions within cells

Support

Keratin and collagen

Transport

Hemoglobin and membrane proteins

Defense

Antibodies

Regulation

Hormones are regulatory proteins that influence the metabolism of cells

Motion

Muscle proteins and microtubules

Carbon, hydrogen, oxygen, and nitrogen

Proteins are organic compounds that mostly consist of…

Amino acids

Proteins are formed by the linkage of monomers called…

Peptide bonds

Covalent bonds between amino acids are called…

Peptides

Two or more amino acids joined together

Polypeptides

Long chains of amino acids joined together

Protein

A polypeptide that has folded into a particular shape and has a particular function

20

How many different types of amino acids are there?

4

Amino acids contain a central carbon atom bonded to… other functional groups

Carboxyl group, amino group, R group

Every amino acid contains these three groups:

The type of amino acid

The R group of an amino acid determines…

shape

The R group gives the protein its…

Di-Peptides

Two amino acids that form a peptide bond and release a water molecule

By condensation (dehydration synthesis), monomer + monomer= polymer + water

How are di-peptides formed?

fold into their proper shape

Proteins cannot function properly unless they…

Denaturation

When a protein looses its proper shape

Chemicals, change in pH, or high temperature

What causes denaturation?

Primary, Secondary, Tertiary, Quaternary

4 Levels of Protein Structure

Primary Structure

The sequence of amino acids

DNA

What determined the primary structure of proteins?

Mutations

Changes that may lead to incorrect amino acid being made

Secondary Structure

Formation of complex shapes called alpha helices or beta pleated sheets

Hydrogen bonds

Alpha helices and beta pleated sheets are held within…

Alpha helices

Hydrogen bonding on every 4th amino acid (spiral shape)

Beta pleated sheet

Hydrogen bonding at extended lengths (folding)

Tertiary Structure

Final overal 3D shape of a polypeptide

Presence of hydrophobic interactions, hydrogen, ionic, and covalent bonding

What is tertiary structure stabilized by?

Tertiary structure

In order to function/for interactions to occur, what structure must proteins be at?

Globular proteins

Proteins that have all 4 protein structures

Quaternary Structure

Multiple polypeptide chains functioning together