Unit 3 Macromolecules
2007 AP Question 1 A) Three macromolecules that are very important components of the Cell Membrane of Eukaryotic organisms include molecules such as phospholipids, cholesterol and Glycoproteins all of which contribute to the continued functioning of the cell membrane.
Phospholipids
Structure: form the majority of the cell membrane, two layers of phospholipids combine to form the phospholipid bilayer, the phospholipids are made of two fatty acid tails attached to a phosphate head, the phosphate heads are hydrophilic (Polar) while the fatty acid tails are hydrophobic (Non-Polar) because of this the fatty acid tails are sandwiched between the phosphate heads in the phospholipid bilayer.
Function: the phospholipid bilayer is selectively permeable and plays an important role in determining what molecules can enter or exit the cell, it also makes the membrane very fluid (fluid mosaic model) which is of use when the cell moves by cytoplasmic streaming or when ingesting a particle by endocytosis (or secreting wastes by exocytosis). It also plays a role in protecting the cell from the outer environment as it is a physical barrier.
Phospholipids
Structure: form the majority of the cell membrane, two layers of phospholipids combine to form the phospholipid bilayer, the phospholipids are made of two fatty acid tails attached to a phosphate head, the phosphate heads are hydrophilic (Polar) while the fatty acid tails are hydrophobic (Non-Polar) because of this the fatty acid tails are sandwiched between the phosphate heads in the phospholipid bilayer.
Function: the phospholipid bilayer is selectively permeable and plays an important role in determining what molecules can enter or exit the cell, it also makes the membrane very fluid (fluid mosaic model) which is of use when the cell moves by cytoplasmic streaming or when ingesting a particle by endocytosis (or secreting wastes by exocytosis). It also plays a role in protecting the cell from the outer environment as it is a physical barrier.