Function and Structure of Proteins

how do proteins function as Blood proteins?

Albumin and other proteins in the blood are important in regulating the fluid concentration of the circulatory system and in forming blood clots to prevent bleeding. Hemoglobin is important in carrying oxygen to the cells and in regulating pH of the blood. Many other proteins are important carriers of materials such as those that bind with iron.

What are the different functions for proteins?

Support Hormones Blood proteins Receptor sites on membranes Movement Defense Enzymes

What kind of bond stabilizes secondary structure?

Hydrogen bonds: oxygen atoms have partial negative charge and hydrogen atoms attached to the nitrogens have a partial positive charge so hydrogen bonds can form between them

Which parts of amino acids are involved in peptide bonds?

The amino group on one amino acid and the carboxyl group on the other

What is secondary structure?

The coiling, bending or folding of the primary amino acid chain into a helix or into sheets. The coiling and bending is due to hydrogen bonds that form regularly between hydrogen regions of amino groups and oxygen regions of acid groups in the amino acids composing the polypeptide.

what is quaternary structure?

formed by bonding several polypeptides forms functional protein ex: hemoglobin or collagen in skin

What is an R-group?

proteins are repeating units of molecules which have an amino (NH2) group at one end and an acid (carboxyl) group at the other end. Between these there is a carbon atom which has a variable group attached to it. The letter R stands for the various units that can be substituted here.

what is tertiary structure?

3D structure of a polypeptide determined by interactions between amino acids

how do proteins function as Receptor sites on membranes?

Cells incorporate materials through protein channels. Information is transferred to nerve cells by protein receptors in the receiving cells.

What kind of bond connects monomers in a protein?

Peptide bond: the covalent bond b/w carboxyl group on one amino acid and the amino group on another, formed by a covalent bond

What type of bond stabilizes primary structure?

Peptide bonds hold the adjacent amino acids together in the polypeptide chain

how do proteins function as Enzymes?

Perhaps the most important function of proteins is their action as chemical mediators of reactions. Digestion of food and synthesis of important molecules occur in living cells only in the presence of these proteins. Life is impossible without them

what are proteins composed of?

amino acids

Alpha Helix

coil held together with hydrogen bonds ex: keratin in hair

Disulfide Bridges

covalent bonds that reinforce shape; 2 monomers with sulfhydryl (-SH) groups on side chains bond when brought close together

What is the basic building blocks of all proteins?

-amino acids -contains carbon bonded to an amino group, carboxyl group, hydrogen atom, and a varial group called R

what are amino acids composed of?

1) carbon backbone attached to hydrogen 2)amino acid group 3) Carboxyl group 4) R side chain

Beta pleated sheet

2 or more chains side by side connected by hydrogen bonds; ex: fibrous material like proteins in spider webs

2 types of secondary structure

Alpha Helix Beta Pleated Sheet

how do proteins provide Defense?

Antibodies, which fight invading viruses and bacteria, are proteins.

how do proteins provide Support?

Many structural materials are proteins such as the collagen that is the supporting framework in animal connective tissue. The matrix in which bone, cartilage and tendons form is protein.

how do proteins function as Hormones?

Some small hormones are proteins. These molecules carry information to various parts of the body.

how do proteins provide Movement?

The filaments which slide to cause the contraction of muscles are proteins. Other proteins cause cilia and flagella to move.

What is primary structure?

The name and location of each amino acid in the protein determines its primary structure. What is the first amino acid? the second? etc. When the name of each amino acid in the polypeptide chain or chains is known, the primary structure is known. Primary structure is fundamental to protein function, because the order of the amino acids in a protein determine the other levels of its structure and ultimately its function.

The biological activity of a protein is determined by its:

amino acid sequence

hydrophobic interactions in tertiary structures

hydrophobic (nonpolar) chains end up in clusters at core of protein; Van der Waal interactions hold them together

2 ways Tertiary structure held together

hydrophobic interactions and disulfide bridges

What is a polypeptide?

many amino acids (polymers) are joined together by peptide bonds.

denaturation

protein subject to changes in temperature, pH, or chemical exposure may change structure and lose its shape without losing primary sequence

In a folded protein, the nonpolar (hydrophobic) amino acids tend to be?

tucked away inside the protein