cell membrane structure. the cell membrane it is important to know the composition of the cell...
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Cell Membrane Structure
The Cell Membrane
• It is important to know the composition of the cell membrane because each part is responsible for bringing a type of nutrient into the cell.
Components of the cell membrane
• Phospholipids (Yes these are a type of lipid) • Proteins• Carbohydrates
Phospholipids
• Make up a majority of the cell membrane• Small molecules (such as water and oxygen)
can pass freely between phospholipids• Phospholipid structure:
Hydrophilic head (loves water) Faces towards water
Hydrophobic tail (Water fearing) Faces away from water
Phospholipids
• Exist in a bilayer – “2 layers”
• Heads face out of the cell and inside the cell• Tails cluster in the middle (see pictures)
Proteins
• Some are embedded on the inside of the cell membrane – Intrinsic proteins
• Some are embedded on the outside of the cell membrane – Extrinsic proteins
• Some pass through the cell membrane – Transmembrane Proteins
• All are involved in moving things into or out of the cell membrane
Proteins in the Cell MembraneTransmembrane Protein Goes through the cell membrane
Intrinsic Protein – Found on inside of cell membrane
Extrinsic ProteinFound on outside of cell membrane
Carbohydrates
• Made of Glycogen (Type of polysaccharide)• 2 types:– Glycoproteins
• Attached to proteins on the cell membrane• Used in cell to cell recognition
– Glycolipids• Attached to phospholipids on the cell membrane• Used to recognize foreign substances in the environment
• Both are found on outside of cell membrane
Carbohydrates
Protein
Phospholipids
Cell Membrane Structure Review
• Made mainly of Phospholipids– Exist in a bilayer– Hydrophilic head faces outside and inside of cell– Hydrophobic tail faces the middle of the membrane
• Proteins are embedded on the surface and through the membrane– Intrinsic – Inside of cell– Extrinsic – Outside of cell– Transmembrane – Extend through cell
Cell Membrane Structure Review
• Carbohydrates extend from the surface of the membrane to sense the environment– Glycolipids – Attach to phospholipids– Glycoproteins – Attach to proteins
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