information
51 concepts carry this thread across the degree.
Mendel's law of segregation
Paired alleles separate into different gametes.
Mendel's law of independent assortment
Genes on different chromosomes are inherited independently.
The dihybrid cross
Predicting the 9:3:3:1 ratio of two traits.
Genetic linkage and recombination
Nearby genes tend to be inherited together.
Sex linkage
Inheritance of genes carried on the sex chromosomes.
The central dogma
Information flows DNA to RNA to protein.
Semiconservative DNA replication
Each old strand templates a new complementary one.
Transcription
Copying a gene into messenger RNA.
Translation and the genetic code
Reading codons to build a polypeptide.
Mutations
How changes in DNA sequence alter proteins.
Membrane transport
Passive, facilitated and active movement across membranes.
Signal transduction
Converting an external signal into a cellular response.
Receptor-ligand binding
Specificity and affinity in molecular recognition.
Second messengers
Amplifying and relaying signals inside the cell.
The resting membrane potential
The Nernst equation applied to ion gradients.
The Hardy-Weinberg principle
Allele and genotype frequencies in an idealised population.
Genetic drift
Random sampling changes allele frequencies.
Gene flow
Migration mixes alleles between populations.
Mutation-selection balance
Why harmful alleles persist at low frequency.
Inbreeding and heterozygosity
The genetic cost of mating with relatives.
Differential gene expression
One genome gives rise to many cell types.
Morphogen gradients
Concentration gradients supply positional information.
Hox genes and the body plan
Master genes that specify anatomy.
Induction
Cells directing the fate of their neighbours.
Apoptosis
Programmed cell death sculpts developing tissues.
The operon model
Coordinated regulation of bacterial genes.
Eukaryotic gene regulation
Enhancers, chromatin and transcription factors.
Epigenetic inheritance
Heritable change without altered DNA sequence.
The polymerase chain reaction
Exponential amplification of a DNA target.
DNA sequencing
Reading the order of bases in a genome.
CRISPR-Cas9
Programmable, targeted genome editing.
Oncogenes and tumour suppressors
The genetic accelerators and brakes of cancer.
The hallmarks of cancer
The capabilities a tumour must acquire.
Cell cycle checkpoints
Surveillance that guards against damaged division.
Angiogenesis and metastasis
How tumours secure a blood supply and spread.
Clonal evolution of tumours
Cancer progression as natural selection.
Sequence alignment
Detecting homology by dynamic programming.
Database searching with BLAST
Fast approximate matching against large databases.
Building phylogenetic trees
Distance and likelihood methods.
Hidden Markov models
Finding genes and motifs probabilistically.
Clustering gene expression
Finding structure in transcriptomic data.
Recombinant DNA technology
Cutting and joining DNA from different sources.
Cloning vectors
Carrying and replicating engineered DNA in cells.
Engineered genetic circuits
Switches and oscillators built from biological parts.
Gene therapy
Treating disease by correcting DNA.
The Nernst potential for a single ion
Let a membrane separate two well-stirred aqueous compartments, an inside and an outside, and let it be permeable to exactly one ionic species S of valence...
The Goldman-Hodgkin-Katz equation
Permeability-weighted concentrations set the membrane voltage: the log of the weighted sum ratio is the potential at which the net ionic current is zero.
Fick's law of diffusion in tissue
Flux runs downhill in proportion to the concentration gradient; the quadratic cost of distance is why exchange surfaces are thin, vast and near a vessel.
Starling forces and capillary exchange
Fluid crosses a capillary wall at a rate set by the hydrostatic pressure difference minus the oncotic difference discounted by the reflection coefficient.
The oxygen-haemoglobin dissociation curve
Four cooperating sites make oxygen binding sigmoid: saturation is the log-derivative of the Adair binding polynomial, and the Hill coefficient is its variance.
Renal clearance and glomerular filtration rate
Urine concentration times urine flow over plasma concentration gives the plasma volume cleared per minute; for a marker the tubule ignores, that is the GFR.