AP Bio Exam Review: Biochemistry & Cells

1. AP Bio Exam Review:Biochemistry & Cells

2. Elements of Life • 25 elements • 96% : C, O, H, N • ~ 4% : P, S, Ca, K & trace elements (ex: Fe, I) Hint: Remember CHNOPS

3. II. Atomic Structure • Atom = smallest unit of matter that retains properties of an element • Subatomic particles:

4. Bonds

5. Weaker Bonds: Van der Waals Interactions: slight, fleeting attractions between atoms and molecules close together • Weakest bond • Eg. gecko toe hairs + wall surface

6. 1. Polarity of H2O • O- will bond with H+ on a different molecule of H2O = hydrogen bond • H2O can form up to 4 bonds

8. 4. Solvent of life • “like dissolves like”

9. Acids and Bases Acid: adds H+ (protons); pH<7 Bases: removes protons, adds OH-; pH>7 Buffers = substances which minimize changes in concentration of H+ and OH- in a solution (weak acids and bases) • Buffers keep blood at pH ~7.4 • Good buffer = bicarbonate

10. Figure 3.9 The pH of some aqueous solutions

11. Functional Groups

12. ie. amino acid  peptide  polypeptide  protein larger smaller

13. + H2O + + H2O +

14. I. Carbohydrates • Fuel and building • Sugars are the smallest carbs • Provide fuel and carbon • monosaccharide disaccharide  polysaccharide • Monosaccharides: simple sugars (ie. glucose) • Polysaccharides: • Storage (plants-starch, animals-glycogen) • Structure (plant-cellulose, arthropod-chitin) • On surface of cell membrane contribute to cell recognition, particularly in the immune response Differ in position & orientation of glycosidic linkage

15. II. Lipids • Fats: store large amounts of energy • saturated, unsaturated, polyunsaturated • Steroids: cholesterol and hormones • Phospholipids: cell membrane • hydrophilic head, hydrophobic tail • creates bilayer between cell and external environment Hydrophilic head (phospholipid) Hydrophobic tail (Fatty acid tail)

16. Four Levels of Protein Structure: • Primary • Amino acid sequence • 20 different amino acids • peptide bonds • Secondary • Gains 3-D shape (folds, coils) by H-bonding • α helix, β pleated sheet • Tertiary • Bonding between side chains (R groups) of amino acids • H & ionic bonds, disulfide bridges • Quaternary • 2+ polypeptides bond together

17. amino acids  polypeptides  protein

18. Protein structure and function are sensitive to chemical and physical conditions • Unfolds or denatures if pH and temperature are not optimal

19. IV. Nucleic Acids Nucleic Acids = Information Monomer: nucleotide

20. Comparisons of Scopes Light Electron Focuses a beam of electrons through specimen Magnify up to 1,000,000 times Specimen non-living and in vacuum Black and white • Visible light passes through specimen • Light refracts light so specimen is magnified • Magnify up to 1000X • Specimen can be alive/moving • color

21. Prokaryote Vs. Eukaryote • “before” “kernel” • No nucleus • DNA in a nucleoid • Circular plasmid • Cytosol • No organelles other than ribosomes • Small size • Primitive • Cell membrane/some cell wall • i.e. bacteria • “true” “kernel” • Has nucleus and nuclear membrane • Cytosol • Has organelles with specialized structure and function • Much larger in size • More complex • i.e. plant/animal cell

22. Parts of plant & animal cell p 108-109

24. Cells must remain small to maintain a large surface area to volume ratio • Large S.A. allows increased rates of chemical exchange between cell and environment

31. Animal cells have intercellular junctions: • Tight junction = prevent leakage • Desomosome = anchor cells together • Gap junction = allow passage of material

32. Cell Membrane

33. 6 types of membrane proteins

34. Passive vs. Active Transport • Little or no Energy • Moves from high to low concentrations • Moves down the concentration gradient • i.e. diffusion, osmosis, facilitated diffusion (with a transport protein) • Requires Energy (ATP) • Moves from a low concentration to high • Moves against the concentration gradient • i.e. pumps, exo/endocytosis

35. hypotonic / isotonic / hypertonic

37. Exocytosis and Endocytosis transport large molecules 3 Types of Endocytosis: • Phagocytosis (“cell eating” - solids) • Pinocytosis (“cell drinking” - fluids) • Receptor-mediated endocytosis • Very specific • Substances bind to receptors on cell surface