ACT Membranes case studies
ACT Membranes · Put your knowledge to work in context.
The ACT Membranes credential is presented as a subject examination organized around five equally weighted domains: Membrane Structure and Composition, Membrane Transport, Membrane Signaling and Receptors, Membrane Bioenergetics, and Membrane Dynamics and Trafficking. Each domain carries a 20 percent share of the content outline, so the exam is designed to test breadth across the biology of membranes rather than depth in a single specialty. The ACT Membranes case studies are 5 cases and about 1,866 words.
1Cholesterol Tuning in a Cold-Adapted Membrane
A synthetic-biology team engineers a lipid vesicle to function at 4 degrees C. Their base membrane is made of pure 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC, 14:0 tails), which at 4 degrees C sits well below its gel-to-liquid-crystalline transition and is therefore rigid and leaky at the packing defects.
372 words, about 2 min2Driving Force Across a Leaky Epithelium
An investigator studies glucose uptake across an intestinal epithelial monolayer mounted in an Ussing chamber. The apical solution contains 5 mM glucose and 140 mM Na+; the basolateral solution contains 5 mM glucose and 140 mM Na+.
359 words, about 2 min3Desensitization in a Gs-Coupled Receptor Assay
A pharmacology lab measures cAMP in cells expressing a Gs-coupled receptor. Acute agonist (10 uM) raises cAMP 8-fold within 2 minutes.
374 words, about 2 min4Uncoupling and the Proton Circuit in a Respiring Vesicle
An investigator reconstitutes a bacterial respiratory chain into lipid vesicles: a NADH dehydrogenase, a quinone pool, and a terminal oxidase that reduces O2. NADH is added outside the vesicles.
372 words, about 2 min5Sorting a Cargo Receptor at the Golgi
A cell biologist studies a transmembrane cargo receptor that cycles between the trans-Golgi network (TGN) and endosomes. At 20 degrees C, cargo accumulates in the TGN and fails to reach endosomes; shifting to 37 degrees C releases the block.
389 words, about 2 min