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THIS IS A STUDY GUIDE , NOT AN ALL INCLUSIVE REVIEW. THERE MIGHT BE THINGS NOT COVERED BY THIS STUDY GUIDE THAT MIGHT BE ASKED IN YOUR Q UIZZES and TESTS . STUDENTS ARE RESPONSIBLE FOR STUDYING THEIR TEXT BOOKS AS PER THE COURSE SYLLABUS. LESSON # 8. Lipids.
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THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW. • THERE MIGHT BE THINGS NOT COVERED BY THIS STUDY GUIDE THAT MIGHT BEASKED IN YOUR QUIZZES and TESTS. • STUDENTS ARE RESPONSIBLE FOR STUDYING THEIR TEXT BOOKS AS PER THE COURSE SYLLABUS
LESSON # 8 Lipids
ORGANIC COMPOUNDS 1- Carbohydrates 2- Lipids 3- Proteins 4- Nucleic acids They are compounds that have carbon as their central element
LIPIDS 2- Lipids 6 CARBONS 6 OXYGENS 12 HYDROGENS Lipids are made of the same elements that carbohydrates (carbon, oxygen and hydrogen), but they contain more hydrogen relative to oxygen than do carbohydrates. Fatty Acid 16 CARBONS 2 OXYGENS 32 HYDROGENS
LIPIDS Lipids arenotpolymers of simpler components (monomers)
LIPIDS GENERAL CHARACTERISTICS OF LIPIDS 1- Relatively insoluble in water 2- They are not polymers of simpler units 3- They are not readily break down in water
LIPIDS Different Types of Lipids GLYCERIDES STEROIDS PHOSPHOLIPIDS glycerol
GLYCERIDES GLYCERIDES They are the most common class of lipids. The molecule of glyceride consists of a head of glycerol and a tail of fatty acids
GLYCERIDES TRIGLYCERIDES DIGLYCERIDES MONOGLYCERIDES Different types of Glycerides R 2 R R 3 2 1 R R R 1 1 A molecule of lipid formed from ONE fatty acid bonded to glycerol A molecule of lipid formed from TWO fatty acids bonded to glycerol A molecule of lipid formed from THREE fatty acids bonded to glycerol
GLYCERIDES H H C = C H H Monounsaturated Polyunsaturated Saturated and Unsaturated Fatty Acids 1- Saturated fatty acids They have no double bonds (One double bound) 2- Unsaturated fatty acids They have double bonds (Two or more double bound)
GLYCERIDES a- Palmitic acid b- Oleic acid c- Linoleic acid Saturated (no double bonds) Monounsaturated (one double bond) Polyunsaturated (two double bonds)
Saturated fats are solid at room temperature Unsaturated fats are liquid at room temperature
H Food producers turn naturally occurring oils into fat by saturating them by bubbling hydrogen trough the oil in a process called hydrogenation. 2
GLYCERIDES Hydrogenation produces trans fatty acids Trans fats increase the concentration of cholesterol in blood. Therefore, they are also harmful for health.
GLYCERIDES 2 4 6 1 3 5 1 3 4 6 2 5 Omega-3-containing fatty acids Most unsaturated vegetal oils contain the first double bound in the carbon number 6. They are omega-6- containing fatty acids Omega-3-containing fatty acids are unsaturated fatty acid, which contain the first double bound in the carbon number 3
GLYCERIDES Fatty Acids and Health 1- Saturated fatty acids are harmful for health because they increase the concentration of cholesterol in blood atherosclerosis heart disease. 2- Trans fats also increase the concentration of cholesterol. Therefore, they are also harmful for health. 3- Monounsaturated and polyunsaturated fats have not negative impact on health. 4- Omega-3-containing fats are beneficial for health because decrease the possibility of heart diseases.
GLYCERIDES ADIPOSE TISSUE ADIPOSE TISSUE Functions of Glycerides Source and Storage of Energy 1- When we eat fat, it is broken down into glycerol and fatty acids that can serve as energy source 2- If the body does not need energy, the glycerol and fatty acids are converted into triglycerides, which are stored in fat cells for later use
STEROIDS STEROIDS Steroids are structurally very different from triglycerides. The central element of steroids are four carbon rings
STEROIDS Principal Steroids 1- Cholesterol 2- Steroids hormones a) Sex Hormones b) Corticosteroids cortisol aldosterone prednisone
STEROIDS Functions of Cholesterol 1- Precursor of other steroids (hormones) 2- Structural function as part of the outer membrane of all animal cells
Functions of Steroid Hormones Estrogen and testosterone are important in natural processes as reproduction Pharmaceutical steroids can be used in potential harmful ways to build muscle mass
PHOSPHOLIPIDS glycerol PHOSPHOLIPIDS They are charged lipid molecules composed of two fatty acids, glycerol, and a phosphate group. Fatty acid tail: Hydrophobic Phosphate head: Hydrophilic
PHOSPHOLIPIDS TRIGLYCERIDE PHOSPHOLIPID GLYCEROL GLYCEROL VARIABLE GROUP PHOSPHATE GROUP glycerol
PHOSPHOLIPIDS Functions of Phospholipids 1- Structural function on cell membranes. They are the most abundant lipids in cell membranes
WAXES A wax is a lipid composed of a single fatty acid linked to a long-chain alcohol Waxy cuticle Functions: Conserve water and protect the plants from outside invaders Mesophyll cells Epidermal cells