Fluid mosaic model - Edexcel Watch
The only part I don't understand is the interpretations of data part, and I was wondering if anyone on here could clear it up a bit, and give me a general idea of what it is I'm supposed to know? Thanks
Sorry for the late reply
Hiya there! I know it's super late~ But the exam's around the corner and I stumbled upon this thread. What they mean by data interpretations is that what's the effect of temperature on membranes (this then leads to the beetroot practical). Here are the relationships, hope it helps! Oh and by any chance, would you be able to explain channel and carrier proteins?
Temperature and its effect on the phospholipid bilayer:
1.Temperature below 0 C
Phospholipids don’t have much energy, they don’t move much, are rigid. They’re packed closely together. The channel and carrier proteins deform, increasing permeability. Ice crystals may form and pierce through the membrane making it highly permeable when it thaws.
2.Temperatures between 0 and 45 C
The phospholipids can move around and aren’t as tightly packed – the membrane is partially permeable. As the temperature increases, the phospholipids move more as they have more energy, tis also increases permeability.
3.Temperatures above 45 C
Bilayer starts to melt (break down) and membrane become more permeable. Water inside the cell expands, putting pressure on membranes. Channel and carrier proteins deform and can’t control what enters or leaves – increasing permeability.
One way of resisting heat is to increase cholesterol levels in the membranes. (that’s why some cholesterol is good for you but too much isn’t)
You can search up a graph regarding the effects, basically, permeability is super high when temp is below 0 C, and lowest at temperatures like 25 C to 30-ish C. Then it gradually, but slowly increases as temp increases.