While getting into the early lessons, you simply need to know these molecules exist and that the molecules of all living things are some variant of those four basic macro molecules. It's not necessary to memorize the formulas behind Lipids, DNA, Protein and Fatty Acids, but internalizing that these four classifications are polymers (made up of repeating units that can form a variety of molecules) is a good start and will help you understand later units like DNA replication and protein synthesis.

It's fine if you don't understand 100% of the detail (Khan Academy is possibly around Senior High school/Freshman college level), but try to take away from of the big picture ideas: It's hydrophobic (water-repelling) properties prevent water from sticking to the surface.Khan Academy generally is reputable, it's just that Biology requires highly highly specific language (and a lot of it). Wax covers the feathers of some aquatic birds and leaf surfaces of some plants. Fats also provide an efficient way to step energy over long time periods, since they contain over twice as much energy per gram as carbs Role of fats: many vitamins are fat-soluble, meaning they must be associated with fat molecules in order to be effectively absorbed into the body. Omega fatty acids regulate inflation and reduce risk of heart attacks, lower blood pressure, prevent blood clots, and decrease triglycerides in blood Fats are made of hydroxyl (OH) groups and hydrocarbon chains Lipids store energy, provide insulation and make up cell membranes, form water repellant layers on leaves, and provide building block for hormones such as testosteroneįat molecules are called triglycerides and are stored in fat cells.

Khan academy biology a level