- How did Cajal use Golgi's own staining technique to argue against Golgi's theory of a continuous nerve network?
Cell Biology
The structure and function of the living cell.
- What did Camillo Golgi's silver-staining technique allow scientists to see for the first time?
- What later fields of research trace their foundation back to Harrison's tissue culture technique?
- How did Rous prove that something smaller than a cell was responsible for the hen's tumor?
- Which five nucleotide bases did Albrecht Kossel identify inside the cell nucleus?
- Why was Kossel's focus on the chemical contents of the nucleus unusual for physiologists of his era?
- What function does the phytol tail serve in anchoring chlorophyll within a cell membrane?
- How does tropomyosin physically block myosin from binding to actin in a relaxed muscle?
- Why did the 1918 influenza kill healthy young adults at unusually high rates instead of mainly the elderly?
- What is the respiratory enzyme that Otto Warburg identified, and why is it central to how cells extract energy?
- How does Langmuir's surface science help explain how cell membranes stay selectively permeable?
- Why were transparent cells nearly invisible under a conventional light microscope before phase contrast?
- Why did staining or fixing a specimen make it impossible to observe certain living processes?
- What sequence of reactions did Hans Krebs identify between glucose breakdown and the release of carbon dioxide?
- What is the 'yellow ferment' that Hugo Theorell studied, and what role does it play in cellular oxidation?
- What are the main stages of the Calvin cycle, from carbon dioxide fixation to sugar production and regeneration of the acceptor molecule?
- Why is cholesterol indispensable to the body despite its reputation for causing disease?
- What basic principle of viral oncology did Dulbecco and Rubin establish about how a virus alters a cell's hereditary programme?
- How did Nirenberg use synthetic RNA made of a single repeating nucleotide to crack the first genetic codon?
- Why does the second messenger concept apply to so many hormones and neurotransmitters beyond adrenaline?
- How did Albert Claude use a centrifuge to separate different structures inside a broken-open cell?
- What is a lysosome, and why would its enzymes destroy the cell if they escaped containment?
- What route does a newly made protein travel from the ribosome to the cell membrane, according to Palade's mapping?
- How did this cell-fractionation work change scientists' understanding of how drugs act on cells?
- What is the chemiosmotic hypothesis, and how does a proton gradient across a membrane drive ATP synthesis?
- What role does the electron transport chain play in pumping protons out of the mitochondrion?
- How does fusing a spleen cell with a myeloma cell produce a hybridoma that manufactures one antibody forever?
- What is a proto-oncogene's normal job in a healthy cell, and what makes it become dangerous?
- Why was it previously impossible to observe individual ion channels rather than population averages?
- What signalling protocol and infrastructure made the first SMS message possible?
- Why was Dolly's birth significant for the long-standing biological debate about whether adult cells retain full genetic instructions?
- How does ATP synthase use physical rotation, rather than ordinary chemistry, to build ATP?
- What long-standing assumption about adult cells did Dolly's birth overturn?
- What did having the complete cell lineage of C. elegans mapped since the 1980s make possible once its genome was sequenced?
- What are signal sequences, and how do they direct a newly made protein to its correct cellular compartment?
- How did Günter Blobel demonstrate that proteins carry built-in address labels?
- Why do mutations in signal sequences underlie certain inherited diseases?
- How does ubiquitin tag proteins for destruction inside a cell?
- How did James Rothman identify the protein machinery that lets vesicles fuse with their target membranes?
- What did Randy Schekman's work in yeast reveal about the genes controlling vesicle budding from the endoplasmic reticulum?
- Which human diseases are linked to disruptions in cellular vesicle trafficking?
- What did John Sulston's complete cell lineage map reveal about how a multicellular organism develops?
- How did Peter Agre's discovery of aquaporin-1 explain how water moves across cell membranes so quickly?
- Where in the body is aquaporin-1 found, and why is it essential in each location?
- Why is ubiquitin's near-universal presence in eukaryotic cells significant?
- What observation about spleen nodules led McCulloch and Till to the concept of the stem cell?
- Why do chromosomes lose a little bit of DNA every time a cell divides?
- What role do telomeres play in protecting the meaningful parts of a chromosome?
- How does the enzyme telomerase counteract the shortening of chromosome ends?
- How is telomerase implicated in both aging and cancer?
- Why did GFP tagging let biologists watch cellular processes happen live, rather than only in fixed, dead tissue?
- Why does a giant panda's digestive system host bacteria capable of breaking down tough cellulose fibre?
- Why was the scientific consensus before Gurdon's work that cell differentiation was a one-way process?
- What are telomeres and why do chromosomes need a protective structure at their ends?
- How did Blackburn and Greider discover the enzyme telomerase?
- What did Jack Szostak's artificial chromosome experiments prove about telomere function?
- What roles do the molecular motors myosin, kinesin, and dynein play in transporting material inside a cell?
- Why does a neuron extending down a metre-long axon depend on kinesin to survive?
- What did Gurdon's 1962 frog nucleus transplant prove about whether cell differentiation is reversible?
- What genes did Randy Schekman identify in yeast that control how vesicles are sorted to their destinations?
- What are SNARE proteins and how do they let a vesicle fuse with exactly the right membrane?
- What diseases result when the vesicle trafficking system fails?
- What kinds of cellular structures became visible for the first time once super-resolution microscopy existed?
- What is the unfolded protein response and how does it let a cell detect misfolded proteins?
- What is autophagy and why was it difficult to study before Ohsumi's experiments?
- How did starving yeast and screening mutants reveal the genes that control autophagy?
- Why is autophagy implicated in diseases like Parkinson's, Alzheimer's, and type 2 diabetes?
- What is the normal self-recognition advantage, and how was it tested in identical twins?
- Why did many twins fail to reliably distinguish photographs of themselves from photographs of their sibling?
- What does the twin study suggest about how facial distinctiveness underpins recognizing your own face?
- What are integrins, and how do they connect the extracellular matrix to a cell's internal cytoskeleton?
- Why does the presence of DNA in the cytoplasm, outside the nucleus, signal danger to a cell?
- Why did Lucy Shapiro choose Caulobacter crescentus to study how a single cell can produce two different daughter fates?
- What early warnings did Shapiro raise about antibiotic resistance, and how far ahead of the field were they?
- What did the prevailing biological consensus in the 1960s assume about differentiated cells and their genetic information?
- What did the 2026 ribozyme actually demonstrate about copying RNA templates and itself?
- Why has building an RNA molecule that can copy a version of itself proven so experimentally difficult?
- Why are morphogen gradients robust to changes in source and sink rates but highly sensitive to pore connectivity of the extracellular space?
- What causes individual plant cells to spontaneously polarize their PIN transporters without an external directional cue?
- How does flux sensing, rather than concentration sensing, explain how cells detect and respond to auxin transport?
- What role does molecular noise play in helping cells establish coordinated PIN polarization across a tissue?