Describe the structure and functions of lipids in plants and animals

Lipids are organic compounds which consist of hydrogen oxygen and carbon. When fatty acids are combined together, they form lipids. The energy storage lipids, tri-glycerides, are formed when three fatty acids and bonded together with a molecule of glycerol. The energy for this process is usually undertaken by the body, which will bond together fatty acids and glycerol in order to make tri-glycerides for energy storage in the form of fat.
They release more energy per unit mass than carbohydrates as they are a concentrated source of energy and provide fuel for aerobic respiration, therefore humans can take part in high energy sports (football) and animals are able to hunt, so lipids act as energy storage. His can also be good because it can provide insulation. Increased body fat levels in winter reduce heat losses to the environment; this is good for wild animals. Also lipids are a source of metabolic water. During respiration stored lipids are metabolised for energy, producing water and carbon dioxide, so it acts as a buoyancy for aquatic animals. Phospholipids which are a class of lipids form the structural framework of cellular membranes. Also lipids can help animals and plants by waxes and oil secreted on to surfaces provide waterproofing in plants and animals. You would test for a presence of a lipid by The two main ways to test for lipids in a sample substance is through the Sudan Red test and the Grease Spot test. Sudan Red is a dye that is lipid soluble. Therefore, when Sudan Red is added to a sample that contains lipids, the dye will colour the lipids red. The Grease Spot test can also be used identify the presence of lipids in a sample. Lipids make unglazed paper, such as the outside of a paper bag, translucent. Phospholipids have a very similar structure to triglycerides. However, in phospholipids, an additional functional group containing a phosphate group replaces one of the fatty acids. They are the main component of the cell membranes of every cell in your body. State 2 differences between the structure of a triglyceride and a phospholipid
Triglycerides are composed of two types of molecules: glycerol and 3 fatty acids. Phospholipids are similar to triglycerides in that they contain glycerol and fatty acids, too. But, the big difference is that phospholipids are made up of 1 glycerol molecule and only 2 fatty acid molecules not 3. The purpose is to create a hydrophilic/hydrophobic layer when you put the phospholipids together. The fats are hydrophobic, and the phosphorous is hydrophilic.