CHEM 452 Lecture Outline 10 Lipids Part I PDF

CHEM452 Chapter 10 Chapter 10: Lipids Structure Read Chapter 10 Properties of Lipids _____________ to____________________polar biological molecules Highly _____________ Generally ____________________ Soluble in________________________ (e.g. chloroform and acetone) Fun...

CHEM452 Chapter 10 Chapter 10: Lipids Structure Read Chapter 10 Properties of Lipids _____________ to____________________polar biological molecules Highly _____________ Generally ____________________ Soluble in________________________ (e.g. chloroform and acetone) Functions of Lipids 1. 2. 3. 4. signaling molecules Some lipids are very______________________-lack polar head group Some are _____________________-contain polar head group Two main groups of lipids 1) ____________________________, O with a polar head and long chain C CH2 CH2 CH2 CH2 CH2 CH2 CH2 nonpolar HO tails CH 2 like CHfatty 2 acids CH2 CHor 2 CH2 CH2 CH2 CH3 2) _____________________________, such as cholesterol and steroids O C HO O C HO -O 1  CHEM452 Chapter 10 1. Fatty acids a. Function: b. General properties Contain a carboxyl head group ( polar) attached to a nonpolar hydrocarbon tail This makes it an _______________ molecule, _____________ water soluble Characteristics: 1)__________________ 2) _______________ 3) ____________(no double bonds), __________________ (one double bond) or polyunsaturated (multiple double bonds) The carboxyl group is_________ (ionized at neutral pH) gives fatty acids slight solubility in water c. Nomenclature of fatty acids Specify ____________ and _________________, separated by a colon Position of double bond are specified by _______________of followed by _ Examples: Palmitic acid (16 carbon saturated fatty acid) Oleic Acid (18 carbon monounsaturated fatty acid, db between C9 and C10) Linoleic Acid (18 carbon fatty acid polyunsaturated fatty acid, db between C9 and C10, C12 and C13) 2  CHEM452 Chapter 10 d. Number of carbons and double bonds i. Fatty acids have _____________ of carbon atoms (due to the way they are synthesized—uses _____________) ii. There is a common pattern of location of double bonds o The double bond is typically between (Δ9) for most __________________ fatty acids o In____________________fatty acids, additional double bonds are at (Δ12) and (Δ15) o ___________________: polyunsaturated fatty acids. “omega” designation refers to the position of the last double bond o iii. The length and saturation influences melting point and fluidity o The the fatty acid chain and the_________________ ___________________of it in water and __________________ 3  CHEM452 Chapter 10 This is because: o saturated chains will __________ versus unsaturated o Due to more van der Waals and ______________________ o In unsaturated fatty acids the stereochemistry of double are _______, rather than trans C C O C C C C C H H HO o This puts a kink in the hydrocarbon tail o This disrupts hydrophobic interactions o ___________________=adding hydrogen across double bond of unsaturated fatty acids to produce saturated fats § As a biproduct of the process, ___________ (fats with trans double bond) are created § Trans fats can pack more easily than cis fats § Trans fats increases LDL cholesterol, a positive correlator of heart disease 2. Triglycerides (Triacylglycerols) a. How triglycerides are made Recall how to make an ester O R O C R H H O 4  CHEM452 Chapter 10 O H C H C O H HO O H C O C H HO H C O H O H C HO O H C Fatty Acid H C O H C Fatty Acid C H C C Fatty Acid H O Monoglycerides are________________and Diglycerides are_______________ Functions: General properties: More_____________ (compared to free fatty acids) More _____________than sugars (more energy derived compared to sugar) Stored as in _________________ in adipose cells, unhydrated Not typically in membranes Fatty acyl tails can vary in chain length and saturations b. Hydrolysis of triglycerides 1. Enzymatic- ____________: adds water across ester bond to release fatty acid 2. Chemical-________________: NaOH and KOH hydrolyze bond to make fatty acid salts 5  CHEM452 Chapter 10 3. Membrane Lipids: Components of membranes (unlike triglycerides that are stored) Contain____________ or ________________ groups A. Phosphoglycerides (Phosphoacylglycerol or phospholipids or glycerophospholipid) 1. How they are made O H2C O O R O C R HC O H HH OO P OR O- O CH2 Fatty Acid Fatty Acid O X O P O H - O A phosphoglyceride is attached to (ester bond) and ____________________(phosphoester bond). The phosphate group can be attached to an additional group (X) where _________________, or group attached by phophoester bond 6  CHEM452 Chapter 10 2. Some example glycerophospholipids i. Phosphatidylcholine Phosphate is connected to ______________ The most common membrane lipid Net charge is_________ ii. Phosphatidylserine Phosphate is connected to ____________ Net ________________ Common on the __________________ of the plasma membrane 7  CHEM452 Chapter 10 iii. Phosphatidylethanolamine iv. Phosphate is connected to _______________ Net charge _________________ Small head group makes this a “cone shaped” lipid (creates negative membrane curvature) v. Phosphatidylinositol Net charge ______________ ________________: The inositol head group can be phosphorylated on multiple different positions. Each form serves a distinct signaling role in the cell. For example, PIP3 is phosphatidylinositol phosphorylated at positions________________ and is involving in ___________________ B. Sphingolipids Function: Found primarily in central nervous system 8  CHEM452 Chapter 10 Structure: _______________ (instead of glycerol) Attached to fatty acid via amide bond X=head group Some example sphingolipids 1. x=_____ 2. x=_______________________ Ceramide and Sphingomyelin are membrane components in the central nervous system c. Glycolipids ______________ (sugar) bound to ____ of lipid by _____________ (no phosphate). Backbone is usually _____________ Sugar is usually __________ or ________ Often found in nerve and brain membranes 9  CHEM452 Chapter 10 C. Archaeal Lipids Allow archaeal bacteria to survive in extreme condition Steroids Structure: Fused ring system containing _______________________ and ________________________rings Functions: Hormones, membrane components, some vitamins Cholesterol **do not have to be able to draw cholesterol. Be able to recognize structure. HO HO 10