MCAT (Medical College Admission Test) Chemical and Physical Foundations of Biological Systems Flashcards

24 sample cards from the Chemical and Physical Foundations of Biological Systems deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. How do capacitors combine in series and in parallel?

   Parallel: C_total = C1 + C2 + ... (capacitances add). Series: 1/C_total = 1/C1 + 1/C2 + ... (total is less than the smallest). Opposite of resistors.

2. What is the magnetic force on a moving charge?

   F = qvB·sin(θ), where θ is the angle between velocity and the magnetic field B. The force is perpendicular to both v and B (direction by right-hand rule).

3. What is the resting membrane potential of a typical neuron, and what maintains it?

   About −70 mV (inside negative). Maintained by the Na⁺/K⁺ ATPase pump and selective ion permeability (mainly K⁺ leak channels).

4. Give the formula for the period of a simple pendulum and a mass-spring oscillator.

   Pendulum: T = 2π√(L/g). Mass-spring: T = 2π√(m/k). Note the pendulum period is independent of mass.

5. What is the relationship between frequency, period, and wave speed?

   f = 1/T, and v = fλ (wave speed equals frequency times wavelength).

6. What is the speed of sound in air and how does it depend on the medium?

   About 343 m/s in air at room temperature. Sound travels faster in liquids and fastest in solids; speed increases with medium stiffness and with temperature in gases.

7. State the Doppler effect qualitatively for sound.

   Observed frequency increases when source and observer approach each other and decreases when they move apart, because of compression/stretching of the wave fronts.

8. What is the relationship between intensity and the decibel sound level?

   β (dB) = 10·log10(I/I0), where I0 = 1×10⁻¹² W/m². Every 10 dB corresponds to a 10× change in intensity.

9. Order the electromagnetic spectrum from longest to shortest wavelength.

   Radio → microwave → infrared → visible → ultraviolet → X-ray → gamma. Shorter wavelength means higher frequency and higher energy.

10. Give the equation relating photon energy to frequency and wavelength.

    E = hf = hc/λ, where h = 6.626×10⁻³⁴ J·s (Planck's constant) and c = 3×10⁸ m/s.

11. State Snell's law of refraction.

    n1·sin(θ1) = n2·sin(θ2). Light bends toward the normal when entering a denser (higher n) medium, and the index of refraction n = c/v.

12. What is total internal reflection and when does it occur?

    All light reflects back into the denser medium when it strikes the boundary at an angle greater than the critical angle θ_c, where sin(θ_c) = n2/n1 (n1 > n2).

13. State the thin-lens / mirror equation and the sign conventions for image distance.

    1/f = 1/o + 1/i. Positive image distance (i) = real image; negative i = virtual image. Magnification m = −i/o.

14. Compare converging and diverging lenses by focal length and image type.

    Converging (convex) lens: positive focal length, can form real or virtual images. Diverging (concave) lens: negative focal length, always forms a virtual, upright, reduced image.

15. What are the four quantum numbers and what does each specify?

    n (principal, energy/shell), l (azimuthal, subshell shape s/p/d/f), m_l (magnetic, orbital orientation), m_s (spin, +½ or −½). No two electrons share all four (Pauli exclusion).

16. State Hund's rule and the Aufbau principle.

    Aufbau: electrons fill lowest-energy orbitals first. Hund's rule: within a subshell, electrons singly occupy each orbital with parallel spins before pairing.

17. How do atomic radius, ionization energy, and electronegativity trend across the periodic table?

    Across a period (left→right): radius decreases; ionization energy and electronegativity increase. Down a group: radius increases; ionization energy and electronegativity decrease.

18. Compare ionic, covalent, and metallic bonds.

    Ionic: electron transfer between metal and nonmetal (electrostatic attraction). Covalent: electron sharing between nonmetals. Metallic: delocalized 'sea' of electrons among metal cations.

19. How do you find the limiting reagent in a reaction?

    Convert each reactant to moles, divide by its stoichiometric coefficient; the reactant giving the smallest result is limiting and determines the maximum product yield.

20. Define molarity, molality, and how to calculate percent yield.

    Molarity = moles solute / L solution. Molality = moles solute / kg solvent. Percent yield = (actual yield / theoretical yield) × 100%.

21. What are the four colligative properties and what do they depend on?

    Vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure. They depend on the number (concentration) of solute particles, not their identity.

22. Write the rate law form and the Arrhenius relationship for reaction kinetics.

    Rate = k[A]^m[B]^n (orders from experiment). Arrhenius: k = A·e^(−Ea/RT); rate constant rises with temperature and falls with higher activation energy.

23. State Le Chatelier's principle and write the relationship between ΔG° and K.

    A system at equilibrium shifts to counteract an applied stress (change in concentration, pressure, or temperature). ΔG° = −RT·ln(K); negative ΔG° means K > 1 (products favored).

24. Define a buffer, give the Henderson-Hasselbalch equation, and state the Nernst-related cell potential sign for spontaneity.

    A buffer resists pH change; it contains a weak acid and its conjugate base. Henderson-Hasselbalch: pH = pKa + log([A⁻]/[HA]). For electrochemistry, a positive cell potential (E°cell > 0) indicates a spontaneous (galvanic) reaction; ΔG = −nFE.

What this deck covers

Chemical and Physical Foundations of Biological Systems flashcards FAQ