Biochemistry: Unit Test 2 Proteins structure, polymerization and denaturation

What are Proteins made of?

Proteins are composed of amino acid monomers linked by covalent bonds

What are the roles of Proteins?

• catalyzing chemical reactions: speeding up reactions

• providing structural support: protein fibers provide support in bones, tendons, skin, nails

• transporting substances in the body: in the cell membrane, they aid in transporting in and out of the cell

• enabling organelles to move: through muscle contractions, which involves the interaction between the proteins, actin and myosin

• regulating cellular processes: proteins like hormones carry signals between cells, regulating cell processes

• provides defense from disease: antibodies are proteins which combat bacterial and viral infections

What is an Amino Acid?

An organic molecule made of a central carbon atom bonded to a hydrogen atom, amine group, carboxyl group, and R-group

What is Polypeptide?

A chain of amino acids linked by Peptide bonds. Formed by a Condensation (dehyration synthesis) reaction that is anabolic and exothermic

Name the 4 levels of Protein Organization

Primary Structure, Secondary Structure, Tertiary Structure, and Quaternary Structure

Describe EVERYTHING about the Primary Structure

• Linear sequence of amino acids, linked by peptide bonds, which are covalent bonds (backbone of polypeptide chain)

• polar due to C=O bonding of one amino acid and N-H of another amino acid

• amino acid sequence determines the function of a protein

Describe EVERYTHING about the Secondary Structure

Has can be TWO different structures:

• alpha helix: when polypeptide chain grows and coils

• beta pleated sheet: when polypeptide chain folds into a fan shape

• HYDROGEN BONDS are formed between amino acids at different locations in polypeptide chain to help maintain structure

Describe EVERYTHING about the Tertiary Structure

• the polypeptide chains are BENT BACK and FORTH into a 3-D STRUCTURE

• types of BONDING occur

  • Hydrogen Bonds

  • Ionic Bonds

  • Van Der Waals

  • Disulfide Bonds

• the interactions between R groups of amino acids cause the 3-D structure

Describe EVERYTHING about the Quaternary Structure

• QUATERNARY STRUCTURE occurs when multiple polypeptide chains assemble to form a larger protein

• example: hemoglobins are proteins within red blood cells and have a quaternary structure

What is polymerization?

Polymerization is a chemical process in which small molecules, known as monomers, combine to form a larger, more complex structure called a polymer.

What does the term Denaturation mean?

It refers to the process of proteins completely unfolding which is caused by the disruption of normal bonding of R groups. This causes intermolecular bonds to break which affects the secondary, tertiary, and quaternary structures.

This is usually caused by certain conditions such as exposure to extreme hot or cold and to certain chemicals. When a protein loses it’s 3D shape it cannot go back perform it’s function.

Examples: cooking eggs and meat, or using alcohol to disinfect.