Fats and oils are esters made up of glycerol and fatty acids. Fatty acids are hydrocarbon chains of differing lengths with various degrees of saturation that end with carboxylic acid groups. Additionally, fatty acid double bonds create many different types of fatty acids. Triglycerides store energy, provide insulation to cells, and aid in the absorption of fat-soluble vitamins. Fats are normally solid at room temperature, while oils are generally liquid.
1. Glycerol and fatty acids make up ____ and ____ .
2. Fatty acids are ______.
3. Cells receive insulation from ________.
Lipids are an essential component of the cell membrane. The structure is typically made of a glycerol backbone, 2 fatty acid tails (hydrophobic), and a phosphate group (hydrophilic). As such, phospholipids are amphipathic. In the cell membrane, phospholipids are arranged in a bilayer manner, providing cell protection and serving as a barrier to certain molecules. The hydrophilic part faces outward and the hydrophobic part faces inward. This arrangement helps monitor which molecules can enter and exit the cell. For example, nonpolar molecules and small polar molecules, such as oxygen and water, can easily diffuse in and out of the cell. Large, polar molecules, for example, glucose, cannot pass freely so they need the help of transport proteins.
4. The lipid structure is made up of ________ components.
5. Some constituents of lipids do not mix with ________.
6. The ________ manner of the phospholipids provide protection for the cells.
7. Oxygen and water have ________ molecules.
8. ________ needs the help of transport proteins.
Another type of lipid is wax. Waxes are esters made of long-chain alcohol and a fatty acid. They provide protection, especially to plants in which wax covers the leaves of plants. In humans, cerumen, also known as earwax, helps protect the skin of the ear canal. A further class includes steroids. One important type of steroid is cholesterol. Cholesterol is produced in the liver and is the forerunner to many other steroid hormones, such as estrogen, testosterone, and cortisol. It is also a part of cell membranes, inserting itself into the bilayer and influencing the membrane’s fluidity.
9. Wax is also a ________.
10. Wax provide protection for ________ and plants.
11. Cholesterol is a ________.
12. The ________ produces cholesterol.
13. Estrogen is a ____ ____.
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