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Biology 30 Diploma study materials
Biology 30 Diploma study resources

Biology 30 Diploma cheat sheet

Biology 30 Diploma · Keep the key ideas within reach.

Quick reference

Biology 30 - Core Concepts Reference

  • Neuron resting potential is about -70 mV, maintained by the Na+/K+ pump moving 3 Na+ out and 2 K+ in; threshold depolarization triggers an action potential that is all-or-none and refractory afterward.

  • Action potential sequence: depolarization (Na+ channels open, Na+ enters), repolarization (K+ channels open, K+ exits), then hyperpolarization and recovery; myelin sheaths allow saltatory conduction for faster transmission.

  • Synaptic transmission: an impulse opens Ca2+ channels, vesicles release neurotransmitter into the cleft, transmitter binds postsynaptic receptors, and acetylcholinesterase breaks it down to end the signal.

  • Hormone pathways: the hypothalamus releases factors to the anterior pituitary, which releases tropic hormones to target glands; negative feedback restores homeostasis, while positive feedback (oxytocin in labor) amplifies a change.

  • Insulin lowers blood glucose by promoting uptake and glycogen formation; glucagon raises it by promoting glycogen breakdown; thyroid hormones raise metabolic rate, and ADH increases water reabsorption in kidneys.

  • Mendelian ratios: a monohybrid cross of heterozygotes gives 3:1 phenotype and 1:2:1 genotype; a dihybrid cross of heterozygotes gives 9:3:3:1 when genes assort independently; a testcross with a homozygous recessive reveals an unknown genotype.

  • Non-Mendelian patterns: incomplete dominance blends phenotypes, codominance expresses both alleles, multiple alleles (ABO blood groups) create several phenotypes, and sex-linked traits appear more often in males because they carry one X chromosome.

  • DNA replication is semiconservative; transcription copies DNA into mRNA, and translation at ribosomes reads mRNA codons into amino acids using tRNA anticodons, with three bases coding for one amino acid.

  • Population genetics: the Hardy-Weinberg equation p^2 + 2pq + q^2 = 1 and p + q = 1 predicts allele and genotype frequencies when a population is large, random-mating, and free of selection, mutation, and migration.