Lecture 3: Polymerization and Proteins Flashcards
What is the carbon backbone?
Carbon and hydrogen atoms bonded together
Purpose of functional groups
Functional groups bind to the carbon backbone and give function to a molecule
What is a wet weight?
Shows what humans are made up of everything except teeth, bones or hair
Macromolecules
All occur in polymers
- Proteins
-Carbohydrates
-Nucleic Acids
Lipids
-Not macromolecules since they are never polymers
Biochemical Unity
Macromolecules are made the exact same way in all living things meaning we can eat each other to obtain necessary biochemicals
Polymerization
Monomers bonded together via covalent bonds
- Two monomers form a covalent bond and water is released
-Anabolic(requires energy)
-DNA replication, Protein Synthesis, Making of Starch
What are proteins in terms of amino acids?
Proteins are polymers of amino acids
Depolymerization
-Condensation reaction
-Bond between two monomers is broken with the help of a water molecule
- OH binds to one monomer and H bonds to O of other monomer (leaving to OH’s)
-Catabolic(releases energy)
Basic Structure of all amino acids
Starts with an amino group, then there is a central carbon group, attached to the central carbon group there is a side chain and then also attached to the central carbon is a carboxyl group
Nonionized Amino Acid Group
Amino Group is (NH2) and the carboxyl group is COOH
Ionized Amino Acid Group
-Amino Acids in the human body are ionized due to pH of 7
-Amino group is NH3+ and the carboxyl group is COO-
What would happen if pH decreased in the body?
-Carboxyl group would become COOH and amino group would become non-ionized leading to alterations of amino acids and future proteins
Types of side chains(3 Types)
- Non-polar side chains: mostly carbon and hydrogen
- Polar side chains: have polar covalent bonds
- Electrically charged side chains(NH3+ and COOH)
What is a peptide bond?
Bond between two amino acids
How does a peptide bond occur?
Occurs between nitrogen of amino group and carbon of carboxyl group. OH of carboxyl group is released and H of amino acid group is also released(water is released)
What prevents amino acids from rotating freely around their peptide bonds?
Partial double bond character
Are non-polar amino acids hydrophobic or hydrophilic?
Hydrophobic
Are polar amino acids hydrophobic or hydrophilic?
Hydrophilic
What is the primary structure and its function?
-The order of amino acids
-Determines the function and how proteins will fold
Beginning and end of a polypeptide chain
Starts with an amino group(N-terminus)
End with a carboxyl group (C-terminus)
Secondary Structure
-Does not include side chains
-Hydrogen bond forms between oxygen(from carboxyl) and hydrogen (from amino group)
-Forms either alpha-helix or beta-helix
Primary Structure
-Amino acids form polypeptide chain
-Peptide bonds between each amino acid
Alpha-Helix
- Side chains point outward
- hydrogen bonds form in the direction of the helix
Beta-pleated Sheet
-Side chains point away from the plane
What is special about the proline side chain?
-Its side chain is bonded to the nitrogen and therefore the nitrogen lacks a hydrogen needed to create the bond (O-H) bond within the polypeptide chains
-This creates a kink in the peptide chain and prevents the rotation of the N-C bond
-The hydrogen bond cannot be formed between the oxygen and hydrogen since the nitrogen now lacks an H
-The proline is thus most likely found at the end of the polypeptide chain
