Survey of the Natural Sciences: Biology, General Chemistry, and Organic Chemistry
Scope and emphasis
The Natural Sciences survey pools first-year biology, general chemistry, and organic chemistry, with biology carrying the most questions. Biology leans on cell structure and organelles, cellular respiration and photosynthesis, DNA replication and gene expression, Mendelian and molecular genetics, and human systems (cardiovascular, respiratory, renal, endocrine, nervous, digestive). General chemistry stresses stoichiometry and limiting reagents, gas laws, solutions and colligative properties, equilibrium, acid–base chemistry, thermodynamics, and electrochemistry. Organic chemistry concentrates on functional groups, isomerism, nucleophilic substitution versus elimination, carbonyl reactivity, and aromaticity.
Traps that cost points
- Confusing competitive inhibition (raises Km, Vmax unchanged) with noncompetitive inhibition (lowers Vmax, Km unchanged).
- Treating pH as linear: a tenfold dilution shifts pH by one unit, not by a factor of ten.
- Mixing genotype frequencies with allele frequencies under Hardy–Weinberg.
- Selecting an answer that is true in general but does not resolve the specific stem - read the final clause first, since it dictates whether you need a calculation, a comparison, or a definition.
Worked example
What is the pH of 0.010 M HCl? Concentration equals 10⁻², so pH = 2. For 0.010 M acetic acid (Ka ≈ 1.8 × 10⁻⁵), [H⁺] ≈ √(Ka·C) ≈ √(1.8 × 10⁻⁷) ≈ 4.2 × 10⁻⁴, giving pH ≈ 3.4. A weak acid is never as acidic as the same concentration of a strong acid. If numeric answers span orders of magnitude, round aggressively rather than computing exactly.