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Lipids. Store Energy in a Fat Cell Part of membranes Serve as chemical messengers. Energy Storage. Humans store Energy in the form of fats Some Energy storage is in the form of the carbohydrate glycogen – fast energy Fats produce 50% more energy per gram than carbohydrates

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Lipids l.jpg
Lipids

  • Store Energy in a Fat Cell

  • Part of membranes

  • Serve as chemical messengers


Energy storage l.jpg
Energy Storage

  • Humans store Energy in the form of fats

  • Some Energy storage is in the form of the carbohydrate glycogen – fast energy

  • Fats produce 50% more energy per gram than carbohydrates

  • 9 kcal/gram compared to 4 kcal/gram


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Membrane Components

  • Because lipids are insoluble in water, they work well as membranes to separate compartments in the body

  • The structure of lipids makes them water repellent or hydrophobic


Messengers l.jpg
Messengers

  • Primary messengers like steroids

  • Secondary messengers like prostaglandins or thromboxanes


Classification of lipids l.jpg
Classification of Lipids

  • Classified into four groups

    1) Fats and waxes

    2) Complex Lipids

    3) Steroids

    4) Prostaglandins


Structure of fats l.jpg
Structure of Fats

  • Fats are esters

  • Alcohol part is always glycerol

  • Acid part varies but is a “Fatty Acid”

also called “glycerin”

a typical “fatty acid”


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Structure of Fats

  • Fatty Acids (FA)

    1) Practically all straight chain with no branches

    2) 10 to 20 C in length

    3) Contain an even number of C

    The body builds FA from two carbon units of acetic acid (acetate ion)

    • Those with double bonds are usually in the cis isomer formation


Structure of fats9 l.jpg
Structure of Fats

  • Fatty Acids + Glycerol = FAT (an ester)

first FA

glycerol

second FA

third FA


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Structure of Fats

  • FATS

    • Triglycerides (three FA esterified with glycerol)

      • Also called Triacylglycerides

    • diglycerides (two FA esterified w/ glycerol)

    • Monoglycerides (one FA esterified w/ glycerol)

    • Fats are insoluble in water

    • Exist as both saturated and unsaturated FA


Structure of fats11 l.jpg
Structure of Fats

  • FATS

    • Saturated Fatty Acids

      • Fit together well - close, parallel alignment

      • Regular pattern

    • Unsaturated Fatty Acids

      • cis/trans double bonds do not allow regular packing

      • LOWER mp and bp lower than the Sat’d. FA


Properties of fats l.jpg
Properties of Fats

  • Physical State - FATS

    • Animal fats

      • generally solids at RT

      • contain mostly saturated FA

    • Plant and Fish oils

      • generally liquids at RT

      • contain more unsaturated FA


Properties of fats13 l.jpg
Properties of Fats

  • PURE Fats

    • Colorless, odorless, and tasteless

    • Tastes, odors, colors are caused by substances dissolved in the fats

From Yahoo Images


Hydrogenation l.jpg
Hydrogenation

  • Treatment with hydrogen gas, H2

  • Catalyst required

  • NOT difficult to convert unsaturated FA to saturated FA

  • Called “hardening”

  • Margarine contains more unsaturation than hydrogenated shortenings

    • Crisco, Spry, etc.


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Hydrogenation

  • Unsaturated converted to saturated:


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Saponification

  • Triglycerides are subject to hydrolysis

    • Can be hydrolyzed with acid or base

    • Base hydrolysis is called “saponification”

    • Result of base hydrolysis is a SOAP

  • SOAP

    • The mixture of sodium salts of Fatty Acids produced by saponification is called SOAP.


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Saponification

  • Triglycerides are subject to hydrolysis

    • base hydrolysis is called “saponification”


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Soap Making

  • Pre-18th century soap making… It is said of Queen Elizabeth I that she bathed once a month, "whether she needed to or not". Whether she used soap is not recorded. But soap was a commodity only available to the wealthy before modern times.

  • Source of “lye”… A large wooden hopper, which was large at the top and tapered down to a small bottom, was kept in the backyard near the kitchen door. The hopper was made of clapboards, which were arranged as a pyramid turned up side down. Dried grass or cornhusks were put into the bottom of the container to act as a strainer. In this the wood ashes from the hearth were stored. When the hopper was filled, many buckets of water had to be drawn from the well and poured over the ashes. Through a trough from the bottom of the hopper came the drops of strong brown lye, which was put in a large kettle over the fire to boil. As soon as the lye would float an egg, scraps of fat and grease were put in. everyone was careful not to touch the strong lye, for it would have eaten the skin off one’s fingers. (62) The grease was saved by the housewife from cooking during several months. Then it was put in the large round-bottomed iron kettle with the homemade lye. After boiling the mixture became a mass of jelly-like soap. Then it was allowed to cool, and from it were cut bars of brown soap, which were stored for household use. (63)



Classification of lipids20 l.jpg

FA

Glycerol

FA

FA

Classification of Lipids

Simple and complex lipids

Simple

Complex


Classification of lipids21 l.jpg

FA

Glycerol

FA

FA

Classification of Lipids

Simple and complex lipids

Simple

Complex

Glycerophospholipids

Glycolipids


Classification of lipids22 l.jpg

FA

GLUCOSE

GALACTOSE

Glycerol

FA

Sphingosine

FA

FA

Classification of Lipids

Simple and complex lipids

Simple

Complex

Glycolipids

Glycerophospholipids


Classification of lipids23 l.jpg

FA

GLUCOSE

GALACTOSE

Glycerol

FA

Sphingosine

FA

FA

Classification of Lipids

Simple and complex lipids

Simple

Complex

Glycerophospholipids

Glycolipids

Sphingolipids

Phosphoglycerides


Classification of lipids24 l.jpg

FA

FA

GLUCOSE

GALACTOSE

Glycerol

Glycerol

FA

FA

Sphingosine

FA

FA

PO43-

ALCOHOL

Classification of Lipids

Simple and complex lipids

Simple

Complex

Glycerophospholipids

Glycolipids

Sphingolipids

Phosphoglycerides


Classification of lipids25 l.jpg

FA

FA

GLUCOSE

GALACTOSE

Glycerol

Glycerol

FA

FA

Sphingosine

Sphingosine

FA

FA

PO43-

PO43-

ALCOHOL

CHOLINE

Classification of Lipids

Simple and complex lipids

Simple

Complex

Glycerophospholipids

Glycolipids

Sphingolipids

Phosphoglycerides

FA

Sphingosine


Membranes l.jpg
Membranes

  • Complex Lipids make up membranes

  • Hydrophilic vs. Hydrophobic


Cell membrane l.jpg
Cell Membrane

  • Lipid layers line up with alaphatic tails inward

  • Unsaturation allows for liquid like character of the membrane

  • Intergral and peripheral proteins are a part of the structure

  • Cholesteral is also a component of membranes



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Membranes

  • Youtube

  • http://www.youtube.com/watch?v=GW0lqf4Fqpg

  • http://www.youtube.com/watch?v=ULR79TiUj80

  • http://www.youtube.com/watch?v=vh5dhjXzbXc

  • http://www.youtube.com/watch?v=ooX9hHu5baM


Glycerophospholipids l.jpg

+

Glycerophospholipids

  • Glycerol is the alcohol

  • Two acids are Fatty Acids

  • Third is esterified to PO43- and choline

  • The Fatty Acid on carbon 2 is unsaturated


Glycerophospholipids32 l.jpg

+

Glycerophospholipids

Locate:

glycerol portion

stearic acid

choline

linoleic acid

phosphate

  • Phosphotidylcholines

  • Also called “lecithins”

  • Charged groups

  • Forms lipid bilayer with

  • Hydrophobic heads together


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Glycerophospholipids

  • Cephalins

    • another type of glycerophospholipids

    • alcohol is ethanolamine or serine instead of choline


Glycerophospholipids34 l.jpg
Glycerophospholipids

  • Phosphatidylinositols (PI)

  • Alcohol is inositol

  • Serve as signaling or

    Communication sites

inositol


Sphingolipids l.jpg
Sphingolipids

  • Coating of nerve axons (myelin)

  • Alcohol portion is sphingosine (not glycerol)

    • A long chain fatty acid is connected to the NH2

    • The End OH group is esterified by phosphorylcholine


Sphingolipids36 l.jpg
Sphingolipids

Can you find the sphingosine????


Glycolipids l.jpg

a glucocerebroside

Glycolipids

  • Glycolipids contain carbohydrates

  • They also use sphingosine

  • One type is the cerebrosides

    • occur in the brain (7% of dry weight!)

    • present at nerve synapses


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Steroids

  • A third major class of lipids:

  • They are all based on this structure


Cholesterol l.jpg
Cholesterol

  • most abundant steroid in the body

  • cell membrane component

  • raw material for other steroids synthesis

  • Exists in both free and esterified forms

    • Esterifies with FA

    • Gallstones are almost pure cholesterol

    • Correlation between HI serum levels and atherosclerosis

    • Necessary for human life

    • Manufactured in the liver – body keeps a set amount


  • Lipoproteins l.jpg
    Lipoproteins

    • Transport cholesterol, and fats

    • Types of Lipoproteins

      • HDL = hi density lipoprotein (the good Kind)

        • 33% protein and 30% cholesterol

      • LDL = lo density lipoprotein (the not good kind)

        • 25% protein and 50 % cholesterol


    Steroid hormones l.jpg
    Steroid Hormones

    Cholesterol is starting material for synthesis of Progesterone:

    • Alcohol on C-3 converted to a ketone

    • Side chain on D ring modified

    • Precursor of sex hormones and adrenocorticoid hormones



    Steroid hormones43 l.jpg
    Steroid Hormones

    • Aldosterone

      • Product of the adrenal gland

      • Mineralocorticoid (regulates ion concentration)

      • Increased secretion enhances reabsorption of Na+ and Cl- ions in the kidney tubules


    Steroid hormones44 l.jpg
    Steroid Hormones

    • Sex Hormones - Testosterone

      • Promotes normal growth of male sex organs

      • Synthesized in testesfrom cholesterol

      • Secretion results in2nd sex characteristics


    Steroid hormones45 l.jpg
    Steroid Hormones

    • Sex Hormones - Estradiol

      • Regulates cyclic changes in the uterus

      • Synthesized from testosterone

      • Menstrual Cycle

        • increased estradiolat beginning of cycle

        • uterus thickens

        • Luteinizing hormonetriggers ovulation


    Youtube l.jpg
    YouTube

    http://www.youtube.com/watch?v=9oaFmKc3ll0

    http://www.youtube.com/watch?v=rBBWMRRWOrM

    http://www.youtube.com/watch?v=p_ewmP1L7ro


    Bile salts l.jpg
    Bile Salts

    • Bile Salts are oxidation products of Cholesterol – 3 OH’s and an Acid end

    • Charged salt is more soluble in solution

    • Bile salts help disperse dietary lipids inthe small intestine – increase digestion rate

    • Removes cholesterolin two ways – they are broken

      cholesterols and dissolve

      deposited cholesterol


    Prostaglandins l.jpg
    Prostaglandins

    • Fatty acid-like substances

    • Produced in prostate

      • small amounts producedin all tissue

    • Synthesized fromArachidonic Acid


    Prostaglandins51 l.jpg
    Prostaglandins

    • PGE2

      • induce labor

      • therapeutic abortion

      • lowers bp

      • used to treat asthma

    • PGE2

      • causes hypertension

    • PGE1

      • used as a nasal decongestant


    Thromboxanes l.jpg
    Thromboxanes

    • Induce Plaelet aggregation

    • When a blood vessel is ruptured,

    • platelets congregate and PGH2

    • causes Them to clot together

    • Aspirin blocks the effect and acts

    • A blood thinner

    PGH2


    Prostaglandins leukotriene l.jpg
    Prostaglandins / Leukotriene

    • Leukotrienes

      • Occur mainly in leukocytes (white blood cells)

      • Long lasting muscle contractions especially in the lungs where they cause Asthma-like attacks

    Leukotriene B4


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