Lipids Flashcards
are organic substances, relatively insoluble in water and soluble in organic solvents like alcohol, ether, etc. They are mainly compounds of C, H and O, but also carry P, N and S in some cases
Lipids
Functions of lipids
Source or storage of energy
Concentrated energy reserve (Adipose tissue)
Constituent of and regulate membrane permeability
Metabolic regulator
insulating materials against low temp
Source of fat-soluble vitamins and bile acids
Phospholipids, glycolipids and sterols are constituents of plasma lipoprotein, which transport fat
monocarboxylic acids with hydrocarbon side chain. They are the simplest form of lipids.
fatty acids
Do not contain double bonds in their hydrocarbon chain, e.g., palmitic and stearic aci
saturated FA
Contain one (monounsaturated aka MUFA) or more (polyunsaturated aka PUFA) double bonds in their hydrocarbon chain, e.g., oleic acid, linoleic acid, linolenic acid, arachidonic acid
Unsaturated FA
Common FA and their no. of carbons
lauric acid 12:0
myristic 14 :0
palmitic 16 :0
stearic 18 :0
palmitoleic 16:1
Oleic 18:1
linoleic 18:2
Linolenic 18:3
arachidonic 20:4
Not synthesized in the body, therefore should be taken in the diet,
essential FA
examples of essential FA
omega -6 FA
Linoleic acid
Arachidonic acid
omega-3 FA
Linolenic acid
Eicosapentanoic acid
Docohexaenoic acid
These FA can be synthesized in the body
non-essential FA
examples of non-essential FA
stearic
palmitic
TRUE or FALSE
Saturated fatty acids are usually solids at room temperature.
TRUE
TRUE or FALSE
Most unsaturated fats are liquid oils at room temperature.
TRUE
TRUE or FALSE
The longer the fatty acid chain, the higher the melting point of the fatty acids.
TRUE
TRUE or FALSE
Unsaturated FA has a higher melting point than saturated FA
FALSE
Unsaturated fatty acids have lower melting point than saturated fatty acids (degree of unsaturation).
aka fats, are esters of 3 fatty acids with 1 glycerol combined through esterification process; form of fatty acids for transport between tissues, storage of metabolic fuel, and storage as oils in seeds that provide energy for seed germination
TAGs
hydrogen gas is bubbled through the heated oil typically in the presence of a nickel catalyst resulting in H atoms added to one or more carbon-carbon double bonds to form carbon-carbon single bonds.
hydrogenation
Hydrolysis (split by water) in the presence of strong acids such as HCl or sulfuric acid or digestive enzymes called
lipases
occurs when a fat is heated with a strong base such as NaOH to form glycerol and the sodium salts of the fatty acids, which is soap.
saponification
esters of fatty acids with long-chain aliphatic alcohols each containing from 14 to 30 carbon atoms.
Waxes
It is used in candles, shoe polish, and wax paper
Beeswax
It is used as waxes for furniture, cars, floors, and shoes
Carnauba wax
It is used in candles, soaps, and cosmetics
Jojoba wax
esters of fatty acids with alcohol, carrying additional groups such as phosphate and nitrogenous group or carbohydrate
compound lipids
two fatty acids form ester bonds with the first and second hydroxyl groups of glycerol. The third hydroxyl group forms an ester with phosphoric acid, which forms another phosphoester bond with an amino alcohol.
glycerophospholipid
are two types of glycerophospholipids that are particularly abundant in brain and nerve tissues as well as in egg yolks, wheat germ, and yeast.
Lecithin and cephalin
- Membrane component, nerve transmission
- Source of choline and methyl group
Lecithin
- Lung surfactant
- Deficiency causes respiratory distress syndrome
Dipalmitoyl lecithin
Structural component of membranes
cephalin
- Structural component of membranes in brain and muscle
plasmalogens
- Mediator of hypersensitivity, acute inflammatory reactions and anaphylactic shock
platelet-activating factor
Component of inner mitochondrial membrane has antigenic properties
cardiolipin
- Phosphatidylinositol 4,5-biphosphate is second messenger for hormone action
- Anchors the glycoproteins to membranes
phosphotidylinositol
present in plasma membranes of animal cells and prominent in myelin. Sphingosine molecule replaces glycerol. Sphingosine is a long-chain amino alcohol.
sphingolipids
structural parent of all sphingolipids
ceramide
contain phosphocholine or phosphoethanolamine as their polar head group. These are major component of membranes of nervous tissue
sphingomyelin
composition: Ceramide (sphingosine + fatty acid) + phosphoric acid + choline
sphingomyelin
Due to excessive accumulation of sphingomyelin as a result of deficiency of enzyme phingomyelinase causing mental retardation and early death.
Niemann-Pick disease:
are carbohydrates—lipid complexes having amphipathic nature. They are the important components of cell membrane and nervous tissue
glycolipids
2 types of cerobrosides
galactocerebroside
glucocerebroside
found in neural tissues
galactocerebroside
found in plasma membranes of cells
glucocerebroside
Ceramide + galactose + sulfate.
sulfatides
Ceramide + more than one hexose or hexosamine.
globosides
Ceramide + oligosaccharides + NANA (N-acetylneuraminic acid) – concentrated outside the cell membranes, recognition sites for extracellular molecules or neighboring cells.
gangliosides
lack of enzyme hexosaminidase A; gangliosides accumulate in brain & spleen; progressive developmental retardation, paralysis, blindness and death (at age 3 or 4)
Tay- Sachs disease
one or two D-galactose connected to a glycosidic linkage to C3 of glycerol. Predominate in plant cells; localized in the thylakoid membranes of chloroplasts; 70-80% of total membrane lipids of a vascular plants
galactolipids
sulfonated D-glucose residue attached to C3 of glycerol backbone
sulfolipids
spherical particles with an outer surface of polar proteins and phospholipids that surround hundreds of nonpolar molecules of triacylglycerols and cholesteryl esters. Two important lipoproteins are the LDL and HDL, which transport cholesterol.
lipoproteins
carries cholesterol to the tissues where it can be used for the synthesis of cell membranes and steroid hormones; can deposits cholesterol in arteries if in excess (bad cholesterol)
LDL
picks up cholesterol from the tissues and carries it to the liver, where it can be converted to bile salts, which are eliminated from the body.
HDL
carries the triacylglycerols synthesized in the liver to the adipose tissues for storage
VLDL
carry triacylglycerols from the intestines to the liver, muscle, and adipose tissues.
chylomicrons
obtained by hydrolysis of simple and compound lipids. Examples: steroids (cholesterol), prostaglandins, leukotrienes, etc.
Derived
are compounds containing the steroid nucleus, which consists of three cyclohexane rings and one cyclopentane ring fused together. They are almost planar and relatively rigid. Served as precursors for a variety of products.
steroids
most important and abundant steroids
cholesterol
synthesized from cholesterol in the liver and stored in the gallbladder. Act as detergents in the intestine, emulsifying dietary fats to make them more readily accessible to the digestive phase
bile acid
are chemical messengers that serve as a communication system from one part of the body to another. They are closely related in structure to cholesterol and depend on cholesterol for their synthesis.
steroid hormones
ovarian steroids with 18 carbon atoms. A group of female sex hormones, direct the development of female sexual characteristics:increasing size of uterus, fat is deposited in the breasts, and the pelvis broadens
estrogens
produced in the adrenal cortex and testes with 19 carbons atoms. Promote muscle growth and facial hair, and the maturation of the male sex organs and of sperm. e.g., testosterone with keto group at C3
androgens
produced in ovaries with 21 carbon atoms. Prepares the uterus for the implantation of a fertilized egg
progesterone
produced from adrenal glands on the kidneys
Adrenal Corticosteroids
increase the blood glucose level and stimulates the synthesis of glycogen in the liver.
cortisone
responsible for the regulation of electrolytes and water balance by the kidneys.
aldosterone
released under stress to increase blood sugar and regulate carbohydrate, fat, and protein metabolism
cortisol
synthetic corticosteroid drugs that is derived from cortisone and used medically for reducing inflammation and treating asthma and rheumatoid arthritis
prednisone
are hormone-like substances produced in small amounts in most cells of the body. Substances that act only on cells near the point of hormone synthesis instead of being transported into the blood to act on cells in other tissues or organs. These are formed from arachidonic acid, the polyunsaturated fatty acid with 20 carbons
Eicosanoids
derived from prostate glands that stimulate contraction of smooth muscle of the uterus during menstruation and labor. These can affect wake-sleep cycle, elevate body temperature (fever) and cause inflammation and pain.
Prostaglandins
soluble in ether and has a ketone group at C9.
Prostaglandin E
soluble in phosphate buffer and has hydroxyl
group at C9.
Prostaglandin F
TRUE or FALSE
Production of prostaglandins can be inhibited using non-steroidal inflammatory drugs
(NSAID) thus the feeling of pain and the occurrence of inflammation can be prohibited.
TRUE
six membered ring containing an ether; produced by platelets; act in the information of blood clot & reduction of the blood flow to the site of a clot.
Thromboxanes
contain 3 conjugated double bonds; first found in leukocytes; powerful biological signals.
Leukotrienes
molecules can diffuse from a higher concentration to a lower concentration. For example, small molecules such as O2, CO2, urea, and water diffuse via passive transport through cell membranes. If their concentrations are greater outside the cell than inside, they diffuse into the cell. If their concentrations are higher within the cell, they diffuse out of the cell.
Passive transport
Certain ions such as K+, Na+, and Ca2+ move across a cell membrane against their concentration gradients. For example, the K+ concentration is greater inside a cell, and the Na+ concentration is greater outside. However, in the conduction of nerve impulses and contraction of muscles, K+ moves into the cell, and Na+ moves out by a process known as active transport.
Active transport
a proteins that extend from one side of the bilayer membrane to the other provide a channel through which certain substances can diffuse more rapidly than by passive diffusion to meet cellular needs. These protein channels allow transport of chloride ion, bicarbonate ion, and glucose molecules in and out of the cell.
facilitated transport
compounds that are essential to the health of humans and other vertebrates but cannot be synthesized and must therefore be obtained in the diet.
vitamins
Night blindness, xerophthalmia = keratinization of the cornea; keratinization of skin
Vitamin A (Retinol, (B-carotene)
Rickets = poor mineralization of bone; osteomalacia = bone demineralization
Excess: toxic, may lead to calcinosis (elevated Ca levels in blood, results to calcification of soft tissues.
Vitamin D (Calciferol)
Extremely rare–serious neurologic dysfunction
Vitamins E (Tocopherol, tocotrienols)
Impaired blood clotting (slow), hemorrhagic disease
vitamin K
Peripheral nerve damage (beriberi) or central nervous system lesions (Wernicke-Korsakoff syndrome)
Excess: Lactic acidosis results to acidification of blood.
Vitamin B1 (Thiamin)
Lesions of corner of mouth, lips, and tongue; seborrheic dermatitis
Vitamin B2 (Riboflavin)
Pellagra – photosensitive dermatitis, depressive psychosis
Excess: can lead to liver damage
VitaminB3 (Niacin)
Disorders of amino acid metabolism, convulsions.
Abnormalities in W and M metabolism, increased sensitivity of DNA to steroidal hormones which may lead to hormone-dependent cancer (breast, uterus and prostate)
Vitamin B6 (Pyridoxine, pyridoxal, pyridoxamine)
Megaloblastic anemia
VitaminB9 (Folic acid)
Pernicious anemia = megaloblastic anemia with degeneration of the spinal cord
Vitamin B12 (Cobalamin)
Impaired fat and carbohydrate metabolism, dermatitis
Vitamin H (Biotin)
Scurvy – impaired wound healing, loss of dental cement (gum decay and tooth loss), subcutaneous hemorrhage (fragility of blood capillaries)
vitamin C (ascorbic acid)
