The Cell Membrane
The Cell Membrane completely surrounds cells and keeps their interiors separate from their environment. It is composed of fat molecules with hydrophobic tails, meaning that they are repelled by water, and hydrophillic heads, meaning that they are attracted by water. This is called the Phospholipid bilayer. It is called a bilayer because it is formed out of two layers of fats, both with their hydrophobic ends facing inward towards each other and the hyrdophillic ends facing both towards the outside of the cell and into the interior of the cell with the cytoplasm.
Within the protein the membrane are many structures that extend throughout the lipid bilayer, including peripheral and integral proteins, carbohydrates, and transport proteins, aka protein channels.
The cell membrane is the only way that materials can enter or leave the cell. There are several ways for them to do this. One is through simple diffusion, and another way is through Active Transport using protein channels or other means. The Protein channels, including the Sodium-Potassium pump which is a form of Active Transport.
Substances within the membrane are free to move around within the membrane and change position within it. This allows the location of the proteins and other objects in the membrane to change.
During cell division, the cell membrane folds and pinches off to create two new cells, each surrounded by part of the same original membrane. A similar process takes place when a cell undergoes exocytosis. During exocytosis, a portion of the cell membrane pinches off from the cell to form a membrane-bound structure called a vesicle, filled with a compound being exported outside of the cell. These vesicles can then be Also, cells can take substances into their interior by merging their own membranes with the membranes of the vesicle they are absorbing. Then, the vesicles's contents are released into the cytoplasm of the cell.
Within the protein the membrane are many structures that extend throughout the lipid bilayer, including peripheral and integral proteins, carbohydrates, and transport proteins, aka protein channels.
The cell membrane is the only way that materials can enter or leave the cell. There are several ways for them to do this. One is through simple diffusion, and another way is through Active Transport using protein channels or other means. The Protein channels, including the Sodium-Potassium pump which is a form of Active Transport.
Substances within the membrane are free to move around within the membrane and change position within it. This allows the location of the proteins and other objects in the membrane to change.
During cell division, the cell membrane folds and pinches off to create two new cells, each surrounded by part of the same original membrane. A similar process takes place when a cell undergoes exocytosis. During exocytosis, a portion of the cell membrane pinches off from the cell to form a membrane-bound structure called a vesicle, filled with a compound being exported outside of the cell. These vesicles can then be Also, cells can take substances into their interior by merging their own membranes with the membranes of the vesicle they are absorbing. Then, the vesicles's contents are released into the cytoplasm of the cell.
All Cells:
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Plant only:
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