1. AP Bio Exam Review: Biochemistry & Cells

2. Elements of Life Hint: Remember CHNOPS 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:
Mass
(dalton or AMU)
Location
Charge
neutron 1
nucleus
proton +1
electron
negligible
shell -1

4. Bonds Covalent Ionic Hydrogen All important to life
Form cell’s molecules
Quick reactions/ responses
H bonds to other electronegative atoms
Strong bond
Weaker bond (esp. in H2O)
Even weaker
Made and broken by chemical reactions

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

7. Examples of Benefits to Life
H2O Property
Chemical Explanation
Examples of Benefits to Life
Cohesion
polar
H-bond
like-like
↑gravity plants, trees
transpiration
Adhesion
unlike-unlike
plants xylem
bloodveins
Surface Tension
diff. in stretch
break surface
bugswater
Specific Heat
Absorbs & retains E
oceanmoderates temps protect marine life (under ice)
Evaporation
liquidgas KE
Cooling
Homeostasis
Universal Substance
Polarityionic
Good dissolver
solvent

8. 4. Solvent of life “like dissolves like” Hydrophilic Hydrophobic
Affinity for H2O
Appears to repel
Polar, ions
Nonpolar
Cellulose, sugar, salt
Oils, lipids
Blood
Cell membrane

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. ie. amino acid  peptide  polypeptide  protein
Monomers
Polymers
Macromolecules
Small organic
Used for building blocks of polymers
Connects with condensation reaction (dehydration synthesis)
Long molecules of monomers
With many identical or similar blocks linked by covalent bonds
Giant molecules
2 or more polymers bonded together
ie. amino acid  peptide  polypeptide  protein
larger
smaller

12. Dehydration Synthesis (Condensation Reaction)
Hydrolysis
Make polymers
Breakdown polymers
Monomers  Polymers
Polymers  Monomers
A + B  AB
AB  A + B
+ H2O +
+ H2O +

13. Differ in position & orientation of glycosidic linkage
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)
Differ in position & orientation of glycosidic linkage

14. 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
Hydrophobic tail

15. 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

16. amino acids  polypeptides  protein

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

18. Nucleic Acids = Information Monomer: nucleotide
IV. Nucleic Acids
Nucleic Acids = Information Monomer: nucleotide
DNA
RNA
Double helix
Thymine
Carries genetic code
Longer/larger
Sugar = deoxyribose
Single strand
Uracil
Messenger (copies), translator
tRNA, rRNA, mRNA, RNAi
Work to make protein
Sugar = ribose

19. Prokaryote Vs. Eukaryote
“before” “kernel”
No nucleus
Cytosol
No organelles other than ribosomes
Small size
Primitive
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

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

22. 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

26. Cell Membrane

27. 6 types of membrane proteins

28. 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

29. hypotonic / isotonic / hypertonic

31. 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