SSC
BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Electron micrographs showed a light band sandwiched between 2 dark bands
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Freeze etched electron micrographs showed globular structures crossing the membranes
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Membrane proteins were shown to have hydrophobic sections.
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Fluorescent marking of membrane proteins showed they could move around within the membrane
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There were twice as many phospholipids in red blood cells than were needed to make a monolayer membrane.
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Detailed explanation-1: -What issues were found with the Davson-danelli model that meant the Singer-Nicholson model was eventually accepted? Membrane proteins were shown to have hydrophobic sections. There were twice as many phospholipids in red blood cells than were needed to make a monolayer membrane.
Detailed explanation-2: -Falsification Evidence for the Davson–Danielli Model Membrane proteins were discovered to be insoluble in water (indicating hydrophobic surfaces) and varied in size. Such proteins would not be able to form a uniform and continuous layer around the outer surface of a membrane.
Detailed explanation-3: -The Davson–Danielli model of membrane structure proposed that membranes were composed of a phospholipid bilayer that lies between two layers of globular proteins, as shown in this diagram.