The Chemistry Book

Lesson: 86
Unit: 2
State Content Standard: 10a, 10c

Lesson Title: Proteins
Textbook page: Pages 684 - 690
Chemistry Passport: Page 100

Objectives
1. Students understand that proteins are one of the four macromolecules and makes up 20% of the body's weight.
2. Students know that proteins are made up of long chains of amino acids.
3. Students know that amino acids can be polar or nonpolar and the bonds that are formed between amino acids are called peptide bonds.

Lesson Content

Proteins

    -one of four macromolecules

    -20% of body weight

    -made up of long chains of monomers called amino acids

Building blocks of proteins: Amino Acids

    -made of central atom, hydrogen atom, amino group and a side chain or R group 

    -side chains can be polar or nonpolar

    -polar side is hydrophilic – loves water and will dissolve in water

    -nonpolar side is hydrophobic – hates water and will not dissolve in water

    -bonds between amino acids are called peptide bonds

    -when many amino acids form peptide bonds, a peptide chain is created

Structure: 4 levels

    -Primary: covalent bonds define structure; also called covalent structure

    -Secondary: hydrogen bonds that form spirals called alpha helixes or flat pleated sheets

    -Tertiary: interactions between polypeptide chains that cause complex coiling and folding

    -Quaternary: interactions between multiple polypeptide chains to form protein complexes

    -Some proteins do not have quaternary structures; they have more polypeptide chains and are called oligomeric proteins

1. What is the name of the chains that interact to form proteins?

A) Lipids

B) Peptide chains

C) Macromolecules

D) R chains

Correct answer: Peptide chains. When many amino acids form peptide bonds, they form peptide chains.

2. What is the name of the building blocks that bond together to make up those chains?

A) Sugars

B) Proteins

C) Amino acids

D) R chains

Correct answer: Amino acids. Proteins are made of monomers called amino acids.

3. What is the name of the bond between those building blocks?

A) Covalent bonds

B) Ionic bonds

C) Hydrogen bonds

D) Peptide bonds

Correct answer: Peptide bonds. Amino acids form bonds between them called peptide bonds.

4. Which two bonds are present in any given protein, not including the bond between amino acids?

A) Hydrogen and Covalent

B) Hydrogen and Ionic

C) Ionic and Covalent

D) Double and Triple

Correct answer: Hydrogen and Covalent. Amino acids are made of carbon chains containing only nonmetals. R chains contain hydrogen that bond to form the first structure.

5. What causes an amino acid to be either polar or nonpolar?

A) Peptide Bonds

B) Side Chains

C) R group

D) Hydrogen Bonds

Correct answer: Side Chains. An amino acid is made of an atom group and either an R group or a side chain, which is polar or nonpolar, making the amino acid polar or nonpolar as well.

Further Reading

Martini, Fredric H(2006)Protein. Martini, Fredric H(2006)Protein. Gorga, Frank R.(1998)Introduction to Protein Structure

http://webhost.bridgew.edu/fgorga/proteins/default.htm

http://www.cem.msu.edu/~cem252/sp97/ch24/ch24aa.html

http://www.callutheran.edu/Academic_Programs/Departments/BioDev/omm/aa/aa.htm

References