IB Biology Exam 2024 with 100% correct answers

How do you calculate the magnification of a drawing/image? - correct answer Magnification=Image size(with ruler) / Actual size(according to scale bar) How do you calculate the actual size of a magnified specimen? - correct answer Actual size=Image size(with ruler) / magnification By which process do potassium ions move through potassium channels in axons? - correct answer Facilitated diffusion -at rest, the Na-K+ pump expels Na+ ions out of cell, while K+ are put within -when the neuron fires--> the ions swap locations via facilitated diffusion via Na-K+ channels What is the theory of endosymbiosis? - correct answer -eukaryotic cells are believed to have evolved from early prokaryotes that were engulfed by phagocytosis -the engulfed prokaryotic cell remained undigested -contributed new functionality to the engulfing cell -over generations, the engulfed cell lost some of its independent utility and became a supplemental organelle What general evidence supports the theory of endosymbiosis? - correct answer -membranes have a double me