1. Molecules of Life Chapter 2

2. Protein Functions  Act as enzymes  Structural- cytoskeleton (actin, tubulin, others)  Mechanical- actin and myosin in muscle  Cell signaling  Immune responses  Cell adhesion  Cell cycle  transport

3. The 20 amino acids You don’t Have to memorize these

4. Proteins  Built from 20 common monomers called amino acids (aa) polypeptide=polymer Amino acid = monomer Peptide bond aa Polypeptide- A chain of amino acids bonded together by peptide bonds in a condensation reaction

5. Fig. 3-16a, p. 44 A DNA encodes the order of amino acids in a new polypeptide chain. Methionine (met) is typically the first amino acid. B In a condensation reaction, a peptide bond forms between the methionine and the next amino acid, alanine (ala) in this example. Leucine (leu) will be next. Think about polarity, charge, and other properties of functional groups that become neighbors in the growing chain. Peptide Bond Formation

6. Fig. 3-16b, p. 45 D The sequence of amino acid subunits in this newly forming peptide chain is now met–ala–leu–trp. The process may continue until there are hundreds or thousands of amino acids in the chain. C A peptide bond forms between the alanine and leucine. Tryptophan (trp) will be next. The chain is starting to twist and fold as atoms swivel around some bonds and attract or repel their neighbors. Stepped Art

9. Globin Chains in Hemoglobin

10. Fig. 3-19a, p. 47 valinehistidineleucinethreonineproline glutamic acid A Normal amino acid sequence at the start of the hemoglobin beta chain. glutamic acid Molecular Basis of Sickle Cell Anemia

11. Fig. 3-19b, p. 47 valinehistidineleucinethreonineprolinevalineglutamic acid B One amino acid substitution results in the abnormal beta chain of HbS molecules. The sixth amino acid in such chains is valine, not glutamic acid. Molecular Basis of Sickle Cell Anemia

22. Nucleotides Nucleotide (the monomer of nucleic acid) Monomer Two kinds of nucleic acids: RNA DNA

23. Four Nucleotides of DNA

24. Fig. 3-22, p. 49 covalent bonding in sugar– phosphate backbone hydrogen bonding between bases The DNA Molecule

25. Nucleic Acids- Informational Polymers Nucleic acids Proteins Lipids

26. Summary: Organic Molecules in Living Things