AP Bio Review Part 1 - Biochemistry

1. All living matter made up of CHONPS

2. Bonds

a. covalent bonds are strong

b. hydrogen bonds are weak

c. polar molecules vs. non-polar molecules

d. reaction with water (cytoplasm & extracellular solution) vs. cell membrane

3. Reactions of life

a. dehydration synthesis

• releases water

• synthesis: builds covalent bonds

• anabolic, endergonic

b. hydrolysis

• uses water

• digestion: break covalent bonds

• catabolic, exergonic

4. Water

a. polar molecule leads to special properties

• cohesion, adhesion, high specific heat, less dense as solid

5. Macromolecules

a. carbohydrates

• sugar monomer

• energy, structure (cell wall, chitin)

b. lipids

• phospholipids (cell membrane)

• energy storage

• steroid hormones

c. proteins (amino acids)

• amino acid monomer

• 4 levels of structure

• bonding at each level: covalent, H bonds, hydrophobic interactions, van der Waals

forces, ionic bonds, disulfide bridges

Name _____________________________ AP Biology

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• many functions!: enzymes, structure, regulatory molecules

d. nucleic acids

• nucleotide monomers

• information storage

6. Enzyme function

a. proteins & RNA

b. bind to substrate

c. speed rate of reactions: reduce activation energy

d. induced fit (lock & key)

e. affected by temperature, pH, salinity, concentration of substrate & enzyme

a. Factors affecting enzyme function:

• Temperature: too high = denaturation

• pH: extreme values disrupt enzyme shape

• Substrate concentration: more substrate = faster reaction (until saturation)

• Enzyme concentration: more enzyme = faster reaction (if substrate is available)

b. Setting up a similar experiment:

• Use H₂O₂ and catalase (from liver or potato)

• Measure O₂ gas released as product

• Vary one factor (e.g., pH, temp), keep others constant

c. Controls vs. Experimental:

• Control: no enzyme or standard conditions

• Experimental: one variable altered (e.g., higher temp)

C. Sample Multiple Choice Answers

1. Hydrogen bond example
→ d. The attraction between a hydrogen of one water molecule and the oxygen of another

2. Feature of organic compounds
→ c. Carbon atoms covalently bonded to each other

3–7 Matching

8. Bonding amino acids (dehydration synthesis)
→ a. The release of a water molecule

9. A + B + energy → AB (requires energy)
→ e. Endergonic reaction

10. Measuring enzyme rate
→ b. Rate of disappearance of the substrate
(You could also use product formation)

1. 2003B:3 - Water’s Importance

a.

• Transpiration: Water’s cohesion (H-bonds) allows a continuous column of water to move up xylem. Adhesion helps water stick to vessel walls.

• Thermoregulation: High specific heat of water buffers body temp. Evaporation (sweating) cools due to high heat of vaporization.
  (Plasma membrane: Water’s polarity influences membrane formation; hydrophilic heads face out, hydrophobic tails inward.)

b.
Water is a reactant in photosynthesis (H₂O → O₂) and a product in cellular respiration (O₂ + glucose → CO₂ + H₂O). It cycles between biotic and abiotic reservoirs.

c.
Deforestation reduces transpiration, decreasing atmospheric moisture. Urbanization increases runoff, reducing infiltration and groundwater recharge.

2. 2002B:3 - Structural Polymers

Pair 1: Tubulin

• Structure: Globular protein forming microtubules.

• Role: Cell shape, chromosome movement in mitosis, cilia/flagella.

Pair 2: Chitin

• Structure: Polysaccharide with nitrogen groups.

• Role: Exoskeleton in arthropods, cell wall in fungi.

Pair 3: tRNA

• Structure: Single-stranded RNA, cloverleaf shape with anticodon.

• Role: Brings amino acids to ribosome during translation.

3. 2001:4 - Proteins

a.
Proteins = C, H, O, N (sometimes S); composed of amino acids.
Structures:

• Primary = AA sequence

• Secondary = α-helix, β-sheet (H-bonds)

• Tertiary = 3D shape (disulfide bridges, ionic, H-bonds, hydrophobic)

• Quaternary = Multiple polypeptides

b.
DNA codes proteins, mRNA carries message, tRNA brings AAs, ribosomes synthesize.

c.
Proteins form channels, pumps, receptors in membranes. Transport includes passive (facilitated) and active (ATP-driven) processes.

4. 2000:1 - Enzymes

a.

• Temperature: Increases activity to a point; too high denatures enzyme (disrupts structure → loss of function).

• pH: Each enzyme has optimal pH; extreme pH disrupts ionic/H-bonds → denaturation.

b.
Experiment:

• Hypothesis: Enzyme activity varies with pH.

• Control: Constant temp, enzyme, and substrate concentration.

• Test: Measure product formed at different pH values.

5. 2008:1 - Protein Structure & Function

a.

• Peptide bonds: Link AAs (primary)

• H-bonds: Stabilize α-helices and β-sheets (secondary)

• Disulfide bridges: Stabilize tertiary structure (S-S bonds)

b.

• Muscle contraction: Actin-myosin interaction depends on precise protein shape.

• Enzyme activity: Active site shape critical; wrong shape = no function.

c.
Sickle cell: Mutation in HBB gene (Glu → Val).
Selection: Heterozygotes resist malaria, giving evolutionary advantage in endemic regions.