Biology and Human Concerns09/30/09 – 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 temperaturegets 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 bycollagen. 2 or more polypeptide subunits. 4connected 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 willbe read. Proteins do things to other proteins to give them function

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, uracilDNA – Deoxyribose = sugar. bases. Adenine, guanine, cytosine and thymine

Ribonucleic acid