FL1/5

Rf (retention factor) formula

distance traveled by compound ÷ distance traveled by solvent

Chromatography polarity rule

Higher affinity/H-bonding to stationary phase = slower movement. Most NON-polar compound travels fastest.

Amino acid bond to form peptide

Carboxyl + amine → amide (peptide bond), covalent

SN2 reaction stereochemistry

Inversion of configuration at the carbon

Radiolabeling rule

Need an isotopic label (e.g., O-18/C-13) on the specific atom you want to track — label the thing that moves

Thin lens equation

1/o + 1/i = S (or 1/f = 1/o + 1/i) — o = object distance, i = image distance, f = focal length

Lens sign convention

Diverging lens = negative power; Converging lens = positive power

Magnification ratio formula

m = hi/ho = -i/o

Common ion effect

Adding a product ion to a solution shifts equilibrium back toward reactants (decreases ionization/solubility)

Effect of electronegative atom on acid strength

Adding an electronegative atom (e.g., Cl) near the acidic group stabilizes the conjugate base → stronger acid, MORE ionization

Index of refraction formula

n = c/v (speed of light in vacuum ÷ speed of light in medium)

Photon energy equation

E = hc/λ = hf

Thiol oxidation

Oxidation of thiols (-SH) forms disulfide bonds (S-S), which are covalent

Amino acid "affinity for cells"

Driven by charge → electrostatic interactions

Cysteine's special role in proteins

Cross-linking (forms disulfide bonds)

Glycine's special role in proteins

Acts as a spacer (small side chain, adds flexibility)

Serine's special role in proteins

Site of phosphorylation

Lipases

Hydrolase enzymes — catalyze hydrolysis of fats

pH change of 1 = what concentration difference?

×10 difference in [H+] (e.g., pH 4 → 7 = 10^3 difference)

Branched glycosidic bond type

α-1,6 glycosidic bond

Heterogeneous catalyst rate dependency

Surface area dependent — more SA = more reaction sites = faster reaction

The more negatively charged the conjugate base is:

The HARDER it is to lose another H+ (less dissociation)

Why does diluting acetic acid NOT decrease % ionization?

Le Chatelier's principle — dilution actually increases % ionization (shifts equilibrium toward more dissociation)

Why does adding HCl decrease % ionization of acetic acid?

Common ion effect — HCl is a strong acid, raises [H+], shifts acetic acid equilibrium back toward unionized form

Thin lens: object at 3 focal lengths, find image height ratio

Use 1/f = 1/o + 1/i to solve for i, then m = -i/o

Solids and H20 in Keq

Excluded from the equilibrium constant expression

Interpolation

Estimating a value that falls BETWEEN your existing data points

Extrapolation

Estimating a value OUTSIDE your existing data range

Intermolecular force strength ranking

Ionic > Hydrogen bonding > Dipole-dipole > London dispersion (weakest)

1-chlorobutane vs 1-butanol boiling point

1-chlorobutane has LOWER bp than 1-butanol (no H-bonding in chlorobutane; H-bonding in butanol raises bp)

Ketone vs enol — which is more stable/favorable?

Ketone form is more favorable (more stable) than the enol tautomer

Aldol reaction product

Aldehyde + base → β-hydroxyaldehyde ⇌ α,β-unsaturated aldehyde

Myopia (nearsightedness) — eye problem & fix

Eye too strong/short focal length; image forms in front of retina. Fix: reduce power, flatten lens (increase radius)

Hyperopia (farsightedness) — eye problem & fix

Eye too weak/long focal length; image forms behind retina. Fix: increase power, decrease radius

Cornea curvature and light bending

More curved cornea = smaller radius = bends light MORE strongly. Less curved = larger radius = bends light less.

Frequency units

1/s, s⁻¹, Hz

Solubility rule (polarity)

Like dissolves like — polar dissolves polar, nonpolar dissolves nonpolar

Sublimation phase change

Solid → gas directly

Photon energy vs wavelength relationship

Inversely related — longer wavelength = lower energy

Amine functional group structure

R-N(R)(R) — N bonded only to C or H (×3 total), NO C=O anywhere

Amide functional group structure

R-C(=O)-N(R)(R) — N directly attached to a carbonyl carbon

Carbamate functional group structure

R-O-C(=O)-N(R)(R) — has both an ester linkage (O-C=O) AND a nitrogen attached to the carbonyl

Imine functional group structure

R2-C=N-R — nitrogen is DOUBLE bonded to carbon

Beer-Lambert Law

A = εbC (Absorbance = molar absorptivity × path length × concentration)

pH formula in relation to [H3O]

pH = -log[H3O+], so [H3O+] = 10^(-pH)

Kw relationship

[H3O+][OH-] = 1×10⁻¹⁴, and pH + pOH = 14

Refraction (optics)

Light bends when passing from one medium to another (e.g., air to water)

Polarization (optics)

A filter that only allows light waves vibrating in one direction to pass through

Reflection (optics)

Light bounces straight back off a surface

Diffraction (optics)

Light bends around the edge of an obstacle, or spreads/overlaps after passing through a small gap, creating interference patterns

Gravitational potential energy context clue

"Drops" or "height" in a question = think MGH (gravitational PE)

Conductors — electron type

have free (mobile) electrons, AND bound electrons

Dominant/recessive mutation outcome

When both alleles are present, think of it as a "tug of war" — the dominant effect wins

Cancer cell mutations — inherited?

NOT inherited (somatic mutations)

Introns — function in mature mRNA

Useless/removed — never part of the mature transcript

Nuclear localization sequence

Tags a protein to be transported INTO the nucleus

Signal sequence

Directs a protein to the membrane or for secretion

NAD+ → NADH

This is a REDUCTION (NAD+ gains electrons/H to become NADH)

NADH → NAD+

This is an OXIDATION (NADH loses electrons/H to become NAD+)

Glycolysis net yield

2 NADH, 2 ATP (net), 2 pyruvate

Pyruvate oxidation yield (per pyruvate)

1 NADH (so 2 total per glucose, since 2 pyruvates made)

TCA cycle yield (per cycle, ×2 per glucose)

3 NADH, 1 FADH2, 1 GTP/ATP per turn (6 NADH, 2 FADH2, 2 GTP total per glucose)

Electron transport chain (ETC) ATP yield

~26-28 ATP total (oxidative phosphorylation)

Nephron pathway order

Glomerulus → PCT → Loop of Henle → DCT → Collecting duct (cortical → medullary) → out as urine

PCT (proximal tubule) function

Reabsorbs most filtered solutes — Na+, glucose, amino acids

Loop of Henle function

Fine adjustment of concentration gradient (countercurrent multiplier)

DCT (distal tubule) function

Hormone-regulated reabsorption (aldosterone acts here on Na+)

Collecting duct function

ADH acts here — last chance for water reabsorption, makes urine more concentrated

Transcription factors — where do they bind?

Promoter/enhancer regions of DNA

Simple diffusion across membrane — molecule type

Nonpolar, hydrophobic, small molecules

Active/passive transport via carrier — molecule type

Charged, large, or polar molecules that need a protein carrier

Cells in interphase — actively dividing?

NOT actively dividing (interphase = growth/DNA synthesis, not division)

Erythrocytes (mature RBCs) and DNA

Mature erythrocytes do NOT have DNA (no nucleus)

Phosphodiester bond direction

5' phosphate group of one sugar bonds to 3' hydroxyl (OH) group of the next sugar

CRH-ACTH-Cortisol negative feedback

Cortisol inhibits ("tells to chill") CRH and ACTH release — classic negative feedback loop

Cytochrome P450 (monooxygenase) — function & location

Mostly in liver; inserts an oxygen atom into a drug molecule = oxidation (Phase I metabolism)

Fatty acid oxidation — location

Occurs in the mitochondria

Muscle contraction → anaerobic shift sequence

1) Uses lots of ATP, needs O2. 2) If O2 insufficient, switches to anaerobic respiration. 3) Produces lactic acid, which LOWERS pH. 4) Muscles also produce CO2.

Henry's Law

C = kH × P (concentration of dissolved gas is directly proportional to its partial pressure) kH is a constant

Genetic code length rule

1 amino acid = 3 nucleotides (1 codon) + translation ends with a STOP codon

Prokaryotic (bacterial) ribosome subunits

30S + 50S = 70S total

Eukaryotic ribosome subunits

40S + 60S = 80S total

tRNA path through ribosome

A site → P site → E site (exit)

PCR vs RT-PCR — what each measures

PCR measures DNA; RT-PCR measures mRNA (reverse-transcribed to cDNA first)

X-inactivation in females (XX)

One X is randomly inactivated to prevent gene dose duplication; inactive X is last to replicate in mitosis

Lipases / Peptidases / Nucleases / Carbohydrases — what each digests

Lipases: fats. Peptidases: proteins. Nucleases: nucleotides. Carbohydrases: carbohydrates.

Water balance example (intake vs urine output)

Some water is lost via skin/lungs even if not urinated out — e.g., drink 1L, only excrete 400mL urine

High urine osmolarity + normal/low blood osmolarity means?

Kidneys are conserving water (ADH active, concentrating urine)

Cardiac output formula

CO = HR × SV (heart rate × stroke volume)

log10 shortcut rule

log10(10^x) = x — "how many times do I multiply 10 to get to this number"

Desmosomes

Mechanically hold cells together; strong, but other substances can still pass between cells

Gap junctions

Allow direct communication/signaling between adjacent cells

Intercalated discs

Combination of desmosomes + gap junctions, unique to cardiac muscle

Tight junctions

Form a seal — little to nothing can pass through (e.g., blood-brain barrier)

Amber codon

A stop codon (UAG in mRNA)

DNA template → mRNA codon conversion

DNA: TAC → mRNA: AUG (remember T→A, A→U, C→G, G→C, and DNA T becomes mRNA U)

Piaget — Sensorimotor stage (0-2)

Key milestone: object permanence

Piaget — Preoperational stage (2-7)

Key feature: symbolic thinking

Piaget — Concrete operational stage (7-11)

Key feature: conservation; reasoning still appearance-based in earlier stages

Piaget — Formal operational stage (11+)

Key feature: abstract, hypothetical thinking