Molecules A (phospholipids) and C (glycoproteins) both have polar and non-polar parts to them. The charge in H2O forces the polar ends of the phospholipids and glycoproteins to be attracted to it which then creates a non-polar interior where the ends of each molecule that don’t have a charge are attracted to (like the fatty acid tails of the phospholipids). The none polar interior of the membrane creates a barrier which gives it the ability to be selective with what it allows in and out of the cell. The sugars attached to the proteins are very hydrophilic and so make the proteins a lot more polar than they would be without them. They are arranged into what is known as the fluid mosaic model, which allows them to float around the membrane and gives it fluidity, (if it wasn't for this fluidity, molecules wouldn't be able to pass through). So just like when we go for a swim we like to orientate ourselves a certain way round with our heads out of the water so we can breath, in a similar way so do the phospholipids and glycoproteins (although quite obviously the ‘motives’
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This movement is passive and doesn't require energy
Water diffuses through the membrane via osmosis and also through facilitated diffusion with the help of channel proteins called ‘aquaporins’. Both forms of movement (osmosis and facilitated diffusion) are passive and don’t require energy.
Alcohol passes through the cell membrane through diffusion and dissolves the lipids within the membrane
Bacteria enters the cell via endocytosis. The bacteria will push into cell membrane which will wrap around it and break off inside the cell creating a vesicle containing the bacteria inside.
As well as being used to support the structure of the cell, they are used in the process of making and transporting proteins inside the
This movement is passive and doesn't require energy
Water diffuses through the membrane via osmosis and also through facilitated diffusion with the help of channel proteins called ‘aquaporins’. Both forms of movement (osmosis and facilitated diffusion) are passive and don’t require energy.
Alcohol passes through the cell membrane through diffusion and dissolves the lipids within the membrane
Bacteria enters the cell via endocytosis. The bacteria will push into cell membrane which will wrap around it and break off inside the cell creating a vesicle containing the bacteria inside.
As well as being used to support the structure of the cell, they are used in the process of making and transporting proteins inside the