This document discusses the structure and function of proteins and nucleic acids. It explains that proteins are made up of amino acid monomers linked together by peptide bonds to form polypeptide chains. The specific sequence and three-dimensional folding of the polypeptide chains determines the type and function of the protein. Nucleic acids like DNA and RNA are composed of sugar, base, and phosphate groups linked into long chains that carry genetic information and help regulate cellular functions. Key protein functions include structural, transport, receptor, defensive, enzymatic, sensory, and gene regulation roles in the cell.

1. Biology and Human Concerns
09/30/09 – Notes
Proteins
-Polypeptides
-Amino acid monomers
(Diagram bottom of page 42 – amino group vs. carboxyl group)
Amino Acids
-Linked by dehydration synthesis
-Link formed by carbon and nitrogen – peptide bond
-polypeptide = protein = bond forms polypeptide chain
-Order of polypeptides determines what type of amino acid is formed,
fold into 3-Dimensional shape to do different jobs.
-Cells build proteins, programmed by genes
Protein Structure
-Primary structure: beginning of all of the shaping of the protein
sequence of amino acids forms correct proteins
-Secondary structure: (diagram page 45). Alpha helix forms weak
hydrogen bonds that hold spiral shapes
together.
-Denaturation occurs when body temperature
gets too high, because proteins begin unfolding
-Tertiary structure: Stronger bonding helps protein hold shape.
(Living cell in living thing = surrounded by water).
-Loops and folds give protein shape
-Hyrophobic ends cluster in the middle, hydrophilic
ends face the outside around water
-Quaternary Structure: tertiary structures “glued” together in the cell by
collagen. 2 or more polypeptide subunits. 4
connected form a haemoglobin molecule.
Protein function
- Structural proteins: attach things together (cells to cells, parts of the
body to other parts of the body.
-Transport proteins: control what gets into cell and what doesn’t.
regulate movement within cell.
-Receptor proteins.
-Defensive proteins: antibodies: bind to invaders (pathogens) and
mark them for destruction.
-Enzymes: changes the rate of another chemical reaction
-Sensory proteins: (“living things respond to change in environment”!).
-Gene regulatory proteins: bind to DNA and control whether genes will
be read. Proteins do things to other proteins to give them function

2. Nucleic Acids
-Nucleic acids are long chains of monomers.
-Made of three parts: sugar, nitrogen base (shape made of carbon and
nitrogen) and a phosphate group. (ex. Deoxyribonucleic acid, ribonucleic acid)
RNA – Ribose = sugar. bases. Adenine, guanine, cytosine, uracil
DNA – Deoxyribose = sugar. bases. Adenine, guanine, cytosine and thymine
Ribonucleic acid