- What was Mikhail Tsvet trying to separate when he invented chromatography?
Plant Biology
The physiology, growth, and biochemistry of plants.
- Why was nitrogen the limiting factor in feeding the world despite making up most of the atmosphere?
- What method did Willstätter use to work out the structure of chlorophyll without modern spectroscopy?
- How is chlorophyll's porphyrin ring structurally related to haemoglobin?
- Why does chlorophyll use magnesium at its centre instead of the iron that haemoglobin relies on?
- What is the difference between chlorophyll-a and chlorophyll-b?
- What experimental steps let Willstätter's team identify chlorophyll's porphyrin ring and central magnesium ion using only 1910s chemistry?
- What function does the phytol tail serve in anchoring chlorophyll within a cell membrane?
- Why do plants use magnesium to capture light while animals use iron to carry oxygen?
- How did Willstätter's structural map of chlorophyll enable later research into the electron transport chain of photosynthesis?
- How does the Haber-Bosch process turn atmospheric nitrogen into ammonia for fertiliser?
- Why was the world's nitrogen supply running out before Haber's process existed?
- How are haemoglobin and chlorophyll molecular cousins, and what actually differs between them?
- Why was nitrogen in the atmosphere unusable to crops despite making up eighty percent of the air?
- In what sense did the Haber-Bosch process end up inside the bodies of most people alive today?
- What did de Hevesy's tracer experiments with radioactive phosphorus in plants and red blood cells in humans actually reveal?
- What other areas of food chemistry did Virtanen work on alongside his silage research?
- How did Melvin Calvin use radioactive carbon-14 pulses in algae to trace the path of carbon through photosynthesis?
- What are the main stages of the Calvin cycle, from carbon dioxide fixation to sugar production and regeneration of the acceptor molecule?
- Why did stopping the reaction after fractions of a second matter for identifying the cycle's intermediate compounds?
- Why is understanding the Calvin cycle considered essential to thinking about atmospheric carbon and food supply today?
- Which complex natural molecules did Woodward succeed in synthesizing over his career, and why was each considered difficult?
- Why did Norman Borlaug breed wheat with shorter stems, and how did that prevent crop collapse?
- How did Borlaug's wheat varieties resist the rust fungi that had historically devastated harvests?
- How much did wheat production in India and Pakistan change after adopting Borlaug's varieties in the late 1960s?
- How did Barbara McClintock use kernel pigmentation patterns in maize to detect transposons?
- What are transposable elements, and how did Barbara McClintock first notice them in maize kernels?
- Why are standard commercial tomatoes harvested green and then gassed with ethylene?
- Why does capsaicin deter mammals from eating peppers while leaving birds unaffected?
- How did Paul Bosland selectively breed capsaicin out of the jalapeño while keeping its shape and flavour?
- Why did plant biologists choose Arabidopsis thaliana as a model organism?
- What made Arabidopsis the first plant genome to be fully sequenced, in December 2000?
- How did sequencing Arabidopsis open the door to studying traits like drought tolerance?
- What does the Swiss constitutional clause on the 'dignity of living things' actually require regarding plants?
- How did the Swiss Federal Ethics Committee reason through what it might mean to morally wrong a plant?
- How did David Baulcombe find a similar RNA-silencing mechanism operating as a plant antiviral defence?
- What is lachrymatory-factor synthase and what did discovering it reveal about the onion's biochemistry?
- How does Boquila trifoliolata normally mimic the leaves of the living host plants it grows near?
- What happened when researchers presented the vine with artificial plastic plants instead of real ones?
- Why is the mechanism behind the vine's mimicry of plastic leaves still unexplained?
- What research did Ehrlich conduct on the coevolution of plants and their insect herbivores?
- How can a graph-based model of auxin transport, with non-polar (undirected) membrane edges, still produce directional vein patterns in a leaf?
- What is the role of positive feedback between auxin flux and transport capacity in stabilizing vein channels during leaf venation?
- How does modeling cells as graph nodes and intercellular membranes as unoriented edges allow branching vein patterns to emerge from a single auxin source-sink pair?
- How does feedback between PIN transporter regulation and auxin-responsive ARF-Aux/IAA signalling drive the switch between passage and spot patterns of auxin distribution?
- What mathematical mechanism produces the 'reverse-fountain' auxin flow pattern observed at plant root tips?
- How does cell growth interact with PIN polarisation to shape auxin distribution patterns in plant tissue?
- What causes isolated cells to exhibit oscillatory dynamics in auxin signalling pathway components, and how does this relate to observed oscillations in ARF target gene expression?
- How does treating plant tissue as a poromorphoelastic medium explain the coupling between water absorption and cell wall expansion during growth?
- Why do growing regions of a plant tissue behave as hydraulic sinks, and what non-local effects does this create across the tissue?
- 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?
- Why can ordered, tissue-wide auxin transport patterns emerge without a pre-existing auxin concentration gradient?
- What role does molecular noise play in helping cells establish coordinated PIN polarization across a tissue?
- How does the WUS-CLV feedback system generate the overlapping molecular gradients that define distinct zones within the shoot apical meristem?
- What mechanism allows the shoot apical meristem to maintain a stable size over time despite developmental perturbations?
- Why do the authors argue that reaction-diffusion dynamics are indispensable, rather than merely one possible explanation, for shoot apical meristem development?
- What kinds of root architecture changes, such as branching patterns, root angles, and growth rates, can be predictably engineered using synthetic genetic circuits?
- How could engineering root systems with programmable genetic circuits improve crop water and nutrient uptake under climate change?
- How do changes in the diffusion rates of activator and substrate molecules alter the number and size of simulated vascular bundles?
- Why does vascular bundle formation fail below a threshold width of parenchymatous tissue, and what does this imply about the evolutionary loss of vascular features in smaller tissue geometries?