systems
54 concepts carry this thread across the degree.
Cell theory
All living things are made of cells, and cells arise only from pre-existing cells.
Prokaryotic and eukaryotic cells
Two fundamentally different cellular architectures.
Organelles and the structure-function principle
Each organelle's form is matched to its role.
The fluid mosaic membrane
A dynamic lipid bilayer studded with mobile proteins.
The cell cycle and mitosis
How a cell duplicates and divides its contents faithfully.
The endosymbiotic theory
Mitochondria and chloroplasts descend from engulfed bacteria.
Trophic levels and energy flow
Energy dissipates as it passes up a food chain.
Logistic population growth
Growth slows as a population nears carrying capacity.
Competition and the niche
Two species cannot occupy the same niche indefinitely.
Predator-prey dynamics
Coupled cycles of predator and prey abundance.
Biogeochemical cycles
How carbon and nitrogen move through ecosystems.
Homeostasis and negative feedback
Stabilising the internal environment against disturbance.
Diffusion and osmosis
Passive movement of molecules down a gradient.
Gas exchange surfaces
Why exchange surfaces are thin, moist and large.
The principle of mass transport
Why large organisms need circulatory systems.
The bacterial growth curve
Lag, exponential, stationary and death phases.
Antibiotic resistance
Evolution in action under drug selection.
Horizontal gene transfer
Sharing genes between unrelated lineages.
Viral replication
The lytic and lysogenic strategies.
Microbial metabolic diversity
The many ways microbes extract energy.
The action potential
The all-or-nothing electrical impulse of a neuron.
The oxygen dissociation curve
Cooperative oxygen binding by haemoglobin.
Osmoregulation in the kidney
The countercurrent multiplier concentrates urine.
Muscle contraction
The sliding-filament mechanism of the sarcomere.
Hormonal regulation
Endocrine control of physiological state.
Innate and adaptive immunity
Two coordinated layers of defence.
Clonal selection
How lymphocytes specific to a pathogen are amplified.
Antibody structure and diversity
Generating a near-limitless repertoire from limited genes.
MHC and antigen presentation
Displaying cellular contents to T cells.
Immunological memory
The basis of long-lasting immunity and vaccines.
Synaptic transmission
Chemical communication across the synapse.
Neural integration
Summing excitatory and inhibitory inputs.
Long-term potentiation
A cellular mechanism of learning and memory.
Sensory transduction
Converting physical stimuli into neural signals.
Neural coding
How spikes represent information.
Metapopulation dynamics
Colonisation and extinction across habitat patches.
Island biogeography
Species richness from area and isolation.
Ecological succession
How communities assemble and change over time.
Keystone species
Species with outsized effects on community structure.
r- and K-selection
Contrasting life-history strategies.
Gene regulatory networks
The logic of cellular decision-making.
Feedback loops in biology
Sources of robustness and oscillation.
Metabolic flux analysis
Tracing material flow through a metabolic network.
Emergent properties
Behaviour arising from interactions, not parts.
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.
The SIR model
Compartmental modelling of an epidemic.
The basic reproduction number
R0 sets the threshold for an outbreak.
Herd immunity
The immune fraction that halts transmission.
Transmission dynamics
Contact rate, infectiousness and spread.
Vaccination strategy
Controlling disease at the population level.