Van leen

Galen

Ancient physician who dominated medical ideology with the "humoral theory" of four bodily fluids.

Robert Hooke

Coined the term "cell" in 1665 after observing cork under a primitive microscope.

Antonie van Leeuwenhoek

Father of Microbiology; first to observe live moving microorganisms ("animalcules").

Matthias Schleiden

Botanist who concluded that all plants are made of cells.

Theodor Schwann

Zoologist who concluded that all animals are made of cells.

Rudolf Virchow

Popularized "Omnis cellula e cellula" (all cells arise from pre-existing cells).

Louis Pasteur

Disproved spontaneous generation using his famous swan-neck flask experiment.

Robert Koch

Formulated postulates to definitively link a specific microorganism to a specific disease.

Joseph Lister

Pioneered antiseptic surgery by using carbolic acid (phenol) to sterilize instruments.

George Palade

Discovered ribosomes and mapped out the secretory pathway of the cell.

Christian de Duve

Discovered lysosomes and peroxisomes using differential centrifugation.

Lynn Margulis

Championed the Endosymbiotic Theory of mitochondrial and chloroplast evolution.

Leland Hartwell

Discovered CDC genes in yeast

Paul Nurse

Isolated the cdc2 gene

Tim Hunt

Discovered cyclins

Hans Spemann & Hilde Mangold

Discovered the embryonic organizer that directs the developmental fate of surrounding cells.

Frederick Banting & Charles Best

Successfully isolated insulin from pancreatic islet cells to treat diabetes.

Élie Metchnikoff

Discovered phagocytosis and pioneered the concept of innate/cellular immunity.

Paul Ehrlich

Proposed the Side-Chain Theory and developed the "magic bullet" concept for targeted treatments.

César Milstein

Co-developed hybridoma technology to produce monoclonal antibodies.

Steven Rosenberg

Pioneer of cancer immunotherapy; developed adoptive T-cell transfer using TILs.

James Allison

Discovered that CTLA-4 acts as an immune checkpoint brake on T cells.

Tasuku Honjo

Discovered PD-1

Siddhartha Mukherjee

Oncologist and author of the cancer history book "The Emperor of All Maladies."

Frances Kelsey

FDA reviewer who blocked thalidomide in the US

He Jiankui

Created the first CRISPR gene-edited babies

Landrum Shettles

Pioneer in IVF history whose unauthorized early human attempts sparked regulatory battles.

Linus Pauling

Legendary chemist who infamously proposed an incorrect triple-helix model for DNA.

James Thomson

Isolated the first human embryonic stem cells in 1998.

Refraction

The bending of light as it passes through media with different refractive indices.

Focal Point

The point where parallel light rays converge after passing through a lens.

Diffraction Limit

The physical barrier to resolution (~200 nm for visible light) caused by light-wave bending.

Point Spread Function (PSF)

The characteristic three-dimensional blur pattern of a sub-microscopic point source of light.

Electron Microscopy Resolution

Superior to light microscopy because moving electrons have a much shorter wavelength than photons.

Negative Staining

Heavy metal stain coats the background

Cryo-EM

Flash-freezes biological samples in vitreous ice to preserve native structures at near-atomic resolution.

X-ray Crystallography

Determines 3D molecular structure by analyzing the diffraction pattern of fired X-rays.

Synchrotrons

Particle accelerators generating intense X-rays to capture data from tiny or difficult crystals.

RPM vs. RCF

RPM is rotational speed; RCF is the actual relative centrifugal force exerted.

Differential Centrifugation

Separates organelles by size and density through sequential spins at progressively higher speeds.

Density Gradient Centrifugation

Separates particles of similar size but different densities along a continuous density medium.

Cyclins vs. CDKs

Cyclins oscillate in concentration; CDKs remain constant but require cyclins to become active.

Thalidomide Stereochemistry

The (R)-enantiomer is a safe sedative; the (S)-enantiomer causes severe birth defects.

Thalidomide in vivo conversion

The body naturally interconverts (R) and (S) enantiomers

Innate vs. Adaptive Immunity

Innate is immediate and non-specific; adaptive is delayed

Phagocytosis

The process where macrophages and neutrophils engulf and digest pathogens or debris.

Cytokines vs. Chemokines

Cytokines coordinate overall immune responses; chemokines specifically guide cell migration (chemotaxis).

B Cells vs. Plasma Cells

B cells display membrane-bound receptors; plasma cells secrete massive volumes of soluble antibodies.

Helper (CD4+) vs. Cytotoxic (CD8+) T Cells

CD4+ cells coordinate immune responses; CD8+ cells directly kill infected or mutated cells.

MHC I vs. MHC II

MHC I displays internal peptides on all nucleated cells; MHC II displays external peptides on APCs.

Thymus & Central Tolerance

Immature T cells binding self-antigens too strongly in the thymus are destroyed to prevent autoimmunity.

Regulatory T Cells (T-regs)

Specialized T cells that suppress immune responses to prevent over-activation.

Vaccination Mechanism

Mimics primary infection to train adaptive immunity and generate long-lived memory cells.

Reverse Transcription (HIV)

The process of copying single-stranded viral RNA into double-stranded DNA.

Integrase (HIV)

The viral enzyme that splices newly synthesized viral DNA directly into the host genome.

CCR5

A T-cell coreceptor; homozygous delta-32 mutation prevents HIV entry and confers immunity.

HIV CD4+ Targeting

Viral gp120 binds CD4

Checkpoint Inhibitors

Drugs that block cancer-hijacked "off-switches" to unleash T cells to destroy tumors.

CAR-T Therapy

Patient T cells are genetically engineered ex vivo to express tumor-targeting receptors.

Taxol

Chemotherapy drug that stabilizes microtubules

Reticular Theory vs. Neuron Doctrine

Golgi claimed a continuous physical mesh; Cajal proved neurons are discrete

Action Potential

All-or-nothing electrical impulse driven by sequential opening of voltage-gated Na+ and K+ channels.

Synaptic Transmission

Electrical signals trigger the release of chemical neurotransmitters across the synaptic gap.

Glial Cells

Supportive nervous system cells that form myelin

Hematopoietic Stem Cells

Rare

Graft-versus-Host Disease (GvHD)

Donor T cells in grafted marrow attack the recipient's body tissues.