AP Bio test 1 study guide
1. Differentiate between ionic, polar covalent, nonpolar covalent, and hydrogen bonds. Examples.
Ionic bond: transfer of electrons between atoms → attraction between oppositely charged ions. Example: NaCl.
Polar covalent bond: unequal sharing of electrons, causing partial charges. Example: H₂O.
Nonpolar covalent bond: equal sharing of electrons, no charge separation. Example: O₂, CH₄.
Hydrogen bond: weak attraction between a hydrogen atom (partially positive) and an electronegative atom (like O or N). Example: bonds between water molecules.
2. What is a salt?
A compound formed by the ionic bonding of a cation (positive ion) and an anion (negative ion). Example: NaCl.
3. Differentiate between a single and double bond.
Single bond: 1 pair of shared electrons (C–H).
Double bond: 2 pairs of shared electrons (C=C).
4. What subatomic particles make up the atom?
Protons (+), neutrons (neutral), electrons (–).
5. What is a valence electron?
Electrons in the outermost shell that participate in chemical bonding.
6. What does it mean for a substance to be polar? Nonpolar?
Polar: uneven distribution of charge, hydrophilic (dissolves in water).
Nonpolar: even charge distribution, hydrophobic (doesn’t dissolve in water).
7. How hydrogen bonding gives water life-sustaining properties.
Hydrogen bonds give water high cohesion, adhesion, high specific heat, density differences (ice floats), and solvent ability — all crucial for supporting life.
8. Properties of water important to life.
Cohesion/adhesion → transport in plants.
High specific heat → climate stability.
Ice less dense than liquid → aquatic life survives winter.
Universal solvent → supports biochemical reactions.
9. Adhesion vs. cohesion.
Adhesion: water sticks to other surfaces.
Cohesion: water molecules stick to each other.
10. Water’s high specific heat regulates climate.
It absorbs and stores heat without big temperature changes → stabilizes Earth’s climate.
11. Evaporative cooling.
When water evaporates, high-energy molecules leave, cooling the surface (ex: sweating).
12. Why water is a universal solvent.
It’s polar → dissolves many polar and ionic compounds.
13. Hydrophilic vs. hydrophobic.
Hydrophilic: water-loving, dissolves in water (salt, sugar).
Hydrophobic: water-fearing, doesn’t dissolve (oils, fats).
14. Acid vs. base.
Acid: increases [H⁺], pH < 7.
Base: decreases [H⁺] or increases [OH⁻], pH > 7.
15. How buffers work.
They resist pH changes by accepting or donating H⁺ (ex: bicarbonate in blood).
16. Structure of carbon.
Carbon has 4 valence electrons, forms 4 covalent bonds, allowing large complex molecules (chains, rings, branching).
17. Functional groups.
Examples: hydroxyl (–OH), carbonyl (C=O), carboxyl (–COOH), amino (–NH₂), sulfhydryl (–SH), phosphate (–PO₄), methyl (–CH₃).
18. ATP and energy.
ATP = adenosine triphosphate. Energy released when phosphate bonds are broken → powers cellular processes.
19. Dehydration synthesis vs. hydrolysis.
Dehydration synthesis (condensation): builds polymers by removing water.
Hydrolysis: breaks polymers by adding water.
20. Carbohydrate monomer.
Monosaccharide (simple sugar). Example: glucose.
21. Functions of carbohydrates.
Energy source, energy storage, structural roles.
22. Bond in carbohydrates.
Glycosidic linkage.
23. Mono-, di-, polysaccharides.
Monosaccharide: single sugar (glucose).
Disaccharide: 2 sugars (sucrose, lactose).
Polysaccharides: many sugars. Examples:
Starch (plants, energy storage).
Glycogen (animals, energy storage).
Cellulose (plants, structural).
Chitin (exoskeletons, fungi cell walls).
24. Functions of lipids.
Energy storage, insulation, membranes, hormones.
25. Structure of triacylglycerol.
1 glycerol + 3 fatty acids.
26. Structure of a phospholipid.
Glycerol backbone + 2 fatty acids + phosphate group → hydrophilic head, hydrophobic tails.
27. Saturated vs. unsaturated fatty acid.
Saturated: no double bonds, solid at room temp.
Unsaturated: at least one double bond, liquid at room temp.
28. Animal vs. plant/fish fats.
Animal fat: mostly saturated, solid (butter, lard).
Plant/fish fat: mostly unsaturated, liquid (olive oil, fish oil).
29. Steroid structure.
4 fused carbon rings with various functional groups. Example: cholesterol.
30. Why cholesterol is important.
Maintains cell membrane fluidity; precursor for steroid hormones and vitamin D.
31. Protein monomer.
Amino acid.
32. Bond that holds amino acids together.
Peptide bond.
33. Functions of proteins.
Enzymes, structure, transport, signaling, defense.
34. Differentiation of macromolecules.
Carbs: monosaccharides, glycosidic bonds, C/H/O.
Lipids: fatty acids, ester bonds, mostly C/H.
Proteins: amino acids, peptide bonds, C/H/O/N (sometimes S).
35. Four levels of protein structure.
Primary: amino acid sequence.
Secondary: α-helix/β-sheet (H-bonds).
Tertiary: 3D folding.
Quaternary: multiple polypeptides.
36. What happens when a protein denatures?
It loses shape (unfolds), function is destroyed.
37. How an enzyme works.
Lowers activation energy by binding substrates at active site → speeds reaction.
38. Activation energy.
The energy required to start a chemical reaction.
39. Free energy diagram.
(You’ll sketch: reactants → transition state → products, showing lower activation energy with enzyme.)
40. Effect of temperature/pH on enzymes.
Extreme temp/pH can denature enzymes, lowering activity.
41. Cofactors vs. coenzymes.
Cofactor: inorganic helper (metal ion).
Coenzyme: organic helper (vitamins).
42. Competitive vs. noncompetitive inhibition.
Competitive: inhibitor binds active site.
Noncompetitive: inhibitor binds elsewhere → changes enzyme shape.
43. Allosteric regulation.
Regulation by binding to a site other than the active site → enzyme shape changes.
44. Cooperativity.
Binding of one substrate increases enzyme’s affinity for more substrates (ex: hemoglobin and oxygen).
45. Feedback inhibition.
End product of a pathway inhibits an earlier enzyme in the pathway.