Field
Biology
Life from the molecule up — the code, the machinery that reads it, and the cells it builds.
19 articles · 38 widgets
Epigenetics: The Marks Above the Genes
How chemical marks — DNA methylation and histone modifications — switch genes on and off without altering the DNA sequence, giving one genome the power to build hundreds of different cells.
The Microbiome: Your Body's Microbial Partners
The trillions of microbes living in and on you are mostly harmless or helpful — fermenting fiber, making vitamins, training immunity, and crowding out pathogens.
Stem Cells: The Body's Master Cells
What stem cells actually are — self-renewal, differentiation, and a potency hierarchy from totipotent to unipotent — plus iPSCs, real medical uses, and the hype to ignore.
CRISPR: Programmable Molecular Scissors
How CRISPR-Cas9 uses a guide RNA to find and cut a matching DNA sequence, why the cell's own repair machinery makes the actual edit, and where the risks and hype diverge.
Osmosis: Why Water Moves on Its Own
Osmosis is the passive diffusion of water — not solute — across a semipermeable membrane toward the more concentrated side, driven by chance and stopped only when water potential equalizes.
Viruses: Alive or Not?
What a virus actually is, why it is not a small bacterium, how it hijacks a host cell to copy itself, and why antibiotics do nothing to it.
Natural Selection
How three plain requirements — variation, heritability, and differential reproduction — force populations to change, why the algebra of allele frequencies makes it inevitable, and where random drift takes over from selection.
Photosynthesis
How a green pigment, a proton gradient, and one famously sloppy enzyme convert sunlight into the carbon in your body — and why the whole apparatus runs at about one percent efficiency.
Cellular Respiration
How your cells release the energy stored in glucose one small step at a time, run photosynthesis's own machinery in reverse, and pay for the privilege of not catching fire.
Enzymes: The Catalysts That Run Life
How enzymes accelerate biochemical reactions by lowering activation energy, why they are never used up, and why they can't change where a reaction ends.
Protein Folding
Levinthal's paradox, the hydrophobic effect that actually drives collapse, and the funnelled energy landscape that lets a protein find its native structure without ever searching for it.
Heredity and Mendelian Genetics
How Mendel's pea experiments overturned blending inheritance, why a monohybrid cross gives 3:1 and a dihybrid 9:3:3:1, and how the Punnett square is just a probability calculation over discrete alleles.
From DNA to Protein
The central dogma as information flow: transcription into messenger RNA, the triplet code and its built-in redundancy, translation at the ribosome, and why one genome can build hundreds of different cells.
Cell Membranes and Transport
How a self-assembling lipid bilayer becomes a selectively permeable barrier, why diffusion and osmosis move solutes for free while pumps spend ATP to push them uphill, and how those hard-won gradients power the rest of physiology.
The Synapse: How Neurons Talk
Why the spike can't jump the gap, how a chemical synapse relays it step by step, and why the receiving neuron sums many excitatory and inhibitory inputs before deciding to fire.
Cell Division and the Cell Cycle
The cell cycle from G1 through the M phase, mitosis stage by stage, the checkpoints that stop a cell from dividing at the wrong time, and how their failure becomes cancer.
The Adaptive Immune Response
How clonal selection, exponential expansion, and immunological memory turn a week-long illness into an infection you never notice — and how vaccines exploit the gap.
DNA Replication
The replication fork, the antiparallel problem that forces one strand to be built backwards in pieces, and the layered error correction that drives the final error rate down to one in a billion.
The Action Potential
The voltage spike that carries information through your nervous system, from ion channels to ECG.