[Music] lipids are next they are a large diverse group of organic compounds mostly they have carbon and hydrogen in them they have very little oxygen this makes them insoluble in water making them hydrophobic phobic means fearing which is in contrast to filic in this cont things to use the terms terms as opposites hydrophilic versus hydrophobic a molecules either water loving or water fearing or separating out from water is what that means since most of us is water H2O this describes an important quality of a molecule lipids separate out triglycerides are our neutral fats they are fat deposits they are insulation that's a good energy source or they're also building blocks for other lipid substances chemically they have a glycerol backbone and Three fatty acid chains coming off of them making them like an e shape looking structure fatty acids are chains of carbons with hydrogens attached to them they vary in length and in what type of coent bonds the carbons are attached to one another they are either mostly single or they have some doubles single balls are nice and straight they make saturated fats double bonds make Kinks or bend in the chain they create unsaturated fats or Oils the single Bonds in the saturated fats making them straight lines those fatty acids they can be packed very closely and that makes them solid at room temperature these are our animal fats like butter or lard on the other hand in unsaturated fats the molecules cannot pack that closely because they have these kinks in them from the double bonds they are liquid at room temperature good example of that is olive oil now let's get to trans fats they originated as margin and auto baked goods but are now in most processed foods they are partially hydrogenated plant oils making them solid at room temperature hydrogenated means we put more hydrogens onto the fatty acids this removes the double bonds making them fatty acid chains straighter which then makes them behave like saturated fats more than oils so they become solid at room temperature but we can call them they originate from vegetable oils so we think that's not that bad but don't be fooled both saturated and trans fats have been labeled as bad fats because they can cause cardiovascular disease we now know that trans fats are the really bad ones and should be avoided at all costs saturated fats just need to be more balanced in most of our diets let's go a little deeper on that prosto glands are chemicals that our cells make they influence other cells functions on a local level so they are kind of like hormones but they don't go into the bloodstream and get circulated through the whole body they just act locally in the neighborhood we have three basic families of them they are derived from fatty acids prostag gland and families control many functions like blood clotting or blood pressure they control inflammation for examples plant oils make prostag gland family one red meats Dairy as well as trans fats make the Prost glandon family two and then cold WEA boils and cold water fish make The Prost glandon family three Prost glin the families need to be mostly balanced but they are not in us the ones and three we need more of because they decrease inflammation and blood pressure for example and the prostag gland 2 family we need a little bit less of because they enhance inflammation leading to many degenerative diseases like cancer diabetes heart disease but also autoimmune diseases trans fats are really diverse because they don't just lead to a build up of pranin 2 but they also inhibit the production of the prandin one and the pranin 3 they build up in the body and then they can create an environment for a disease with a sudden onset like a heart attack so be cautious with that limit your Cheetos all right next next we need to look at a fat that makes up our cell walls a phospholipid is composed of a glycerol back bone with two fatty acid chains on one side and a phosphate containing molecule on the other side this makes it both fatty like as well as watery like the fatty acid gives you a nonpolar or a hydrophobic end and the phosphate containing molecule gives it a polar or a hydrophilic this molecule is said to have polar heads and non-polar Tails this makes the fosho lipid a great cell membrane because it sets up a boundary between the inside and the outside of a cell making two rows of phospholipids with the nonpolar Tails pointing at each other creates a little hydrophobic oil film on the inside the hydrophilic polar head molecules are on the outside making it soluble in water as a whole structure this oil film cannot be crossed by hydrophilic or water loving molecules and so therefore we can set up a distinct inside to the outside of a cell this cell membrane is also or phospholipid bilayer is also referred to as an elementary membrane it is a very very versatile structure in our body the next in our final fat category is the is the one of steroids steroids are flat molecules formed from four interlocking Rings steroids are different from other fats however they are carbon and hydrogen making them hydrophobic and soluble in fat but not in water cholesterol is the most important steroid we have it is the building block for many of the molecules like vitamin D our sex hormones or cortisol or the hormone aldosterone and we also find it in cell membranes we measure blood cholesterol as those cholesterols can be associated with cardiovascular disease the ones we measure are ldls and those are low density lipoproteins they carry fat molecules from the liver to the body so we know them therefore as bad cholesterol and then we have htl and that's known as the good cholesterol those are high density lipoproteins and they bring fat molecules from the body back to the liver for processing so they're like vacuum cleaners picking up the fat in the body so that makes them good the balance of HDL and LDL is very important and we measure that as the total 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