Lipids
1Lipids
Copyright 2007 by Pearson Education, Inc.Publishing as Benjamin
Cummings1Good Fats vs. Bad Fats
23LipidsLipids areMacromolecules that contain fatty
acidsInsoluble (will not dissolve in water) Named for the Greek
word lipos, which means fat.
34LipidsSix functions of lipids:1.Long term energy
storage2.Protection against heat loss (insulation)3.Protection
against physical shock4.Protection against water loss5.Chemical
messengers (hormones)6.Major component of membranes
(phospholipids)copyright cmassengale45Types of LipidsThe types of
lipids containing fatty acids areWaxes.FatsSteroids56 Fatty Acids
Copyright 2007 by Pearson Education, Inc.Publishing as Benjamin
Cummings
67Fatty AcidsFatty acids Are long-chain carboxylic
acids.Typically contain 12-18 carbon atoms.Are insoluble in
water.Can be saturated or unsaturated.
Copyright 2007 by Pearson Education, Inc.Publishing as Benjamin
Cummings
78LipidsTriglycerides:composed of 1 glycerol and 3 fatty acids.
H
H-C----O
H-C----O
H-C----O
HglycerolO
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3=fatty acidsO
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3=O
C-CH2-CH2-CH2-CH=CH-CH2-CH2-CH2-CH2-CH3=copyright
cmassengale----- Meeting Notes (8/26/14 13:19) ----- 8View
Presentation on the 2 types of FATTY ACIDS Discovery Ed Fatty Acids
Video 910Saturated fatty acids haveSingle CC bonds.High melting
points that make them solids at room temperature.The unhealthy fats
Saturated Fatty Acids BAD!
Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin
CummingsO
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3=saturated1011Unsaturated
Fatty Acids- GOOD!Unsaturated fatty acids Have one or more double
C=C bondLiquids at room temperatureThe healthy fats
O-C-CH2-CH2-CH2-CH=CH-CH2-CH2-CH2-CH2-CH3
Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin
Cummings11Dr. Thomas J. Montville12Summary of
FatsSaturatedUnsaturatedSingle bond (straight)Double
bondsSolidLiquidAnimal (cholesterol)Plants (cholesterol
free)UnhealthyEssential Fatty Acids and -3sCooling as
Solidliquid
ANOTHER GROUP OF LIPIDS ARE THE WAXES1314WaxesWaxes are
Coatings that prevent loss of water by leaves of plants.
TABLE 17.2Copyright 2007 by Pearson Education, Inc. Publishing
as Benjamin Cummings14ANOTHER GROUP OF LIPIDS ARE THE STEROIDS
1516CholesterolCholesterolIs the most abundant steroid in the
body.
16Cholesterol Explanation View Discovery Ed Video
1718Cholesterol in the BodyCholesterol in the body Is obtained from
meats, milk, and eggs. Is synthesized in the liver.Is needed for
cell membranes, brain and nerve tissue, steroid hormones, and
Vitamin D.Clogs arteries when high levels form plaque.
A normal, open artery.Copyright 2007 by Pearson Education,
Inc.Publishing as Benjamin CummingsAn artery clogged by cholesterol
plaque1819Cholesterol in FoodsCholesterol is Synthesized in the
liver. Obtained from foods. Considered elevated if plasma
cholesterol exceeds 200 mg/dL.
TABLE 17.4Copyright 2007 by Pearson Education, Inc. Publishing
as Benjamin Cummings19STOP2021Oils with Unsaturated Fatty
AcidsOilsHave more unsaturated fats.Have cis double bonds that
cause kinks in the fatty acid chains.Cannot pack triacylglycerol
molecules as close together as in fats.Have lower melting points
than saturated fats.Are liquids at room temperature.
2122Diagram of Triacylglycerol with Unsaturated Fatty Acids
Unsaturated fatty acid chains have kinks that do not allow close
packing.Copyright 2007 by Pearson Education, Inc. Publishing as
Benjamin Cummings2223Chemical Properties of Triacylglycerols
Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin
Cummings2324Cis and Trans Fatty AcidsUnsaturated fatty acids can be
Cis with bulky groups on same side of C=C. CH3 (CH2)5 (CH2)7 COOH
cis C=C H HTrans have bulky groups on opposite sides of C=C. CH3
(CH2)5 H C=C trans H (CH2)7 COOH
2425Trans Fatty Acids and Hydrogenation Trans fatty acidsAre
formed during hydrogenation when cis double bonds are converted to
trans double bonds.In the body behave like saturated fatty acids.
Are estimated to make up 2-4% of our total Calories. Are reported
in several studies reported to raise LDL-cholesterol and lower
HDL-cholesterol.
2526Learning Check(1) True or (2) False
A. There are more unsaturated fats in vegetable oils.B.
Vegetable oils have higher melting points than fats. C.
Hydrogenation of oils converts some cis-double bonds to trans-
double bonds.D. Animal fats have more saturated fats.
2627Solution(1) True or (2) False
A. T There are more unsaturated fats in vegetable oils.B. F
Vegetable oils have higher melting points than fats. C. T
Hydrogenation of oils converts some cis-double bonds to trans-
double bonds.D. T Animal fats have more saturated fats.
2728SolutionWrite a fatty acid with 10 carbon atoms that is:A.
saturated CH3CH2CH2CH2CH2CH2CH2CH2CH2COOH
B. monounsaturated omega-3CH3CH2CH=CHCH2CH2CH2CH2CH2COOH
C. monounsaturated omega-6CH3CH2CH2CH2CH2CH=CHCH2CH2COOH
2829SolutionWrite a fatty acid with 10 carbon atoms that is:A.
saturated CH3CH2CH2CH2CH2CH2CH2CH2CH2COOH
B. monounsaturated omega-3CH3CH2CH=CHCH2CH2CH2CH2CH2COOH
C. monounsaturated omega-6CH3CH2CH2CH2CH2CH=CHCH2CH2COOH
2930Steroids: Cholesterol, Bile Salts, and Steroid Hormones
Copyright 2007 by Pearson Education, Inc.Publishing as Benjamin
Cummings3031Steroid NucleusA steroid nucleus consists of3
cyclohexane rings.1 cyclopentane ring.No fatty acids.
steroid nucleus3132CholesterolCholesterolIs the most abundant
steroid in the body. Has methyl CH3- groups, alkyl chain, and -OH
attached to the steroid nucleus.
3233Cholesterol in the BodyCholesterol in the body Is obtained
from meats, milk, and eggs. Is synthesized in the liver.Is needed
for cell membranes, brain and nerve tissue, steroid hormones, and
Vitamin D.Clogs arteries when high levels form plaque.
A normal, open artery.Copyright 2007 by Pearson Education,
Inc.Publishing as Benjamin CummingsAn artery clogged by cholesterol
plaque3334Cholesterol in FoodsCholesterol is Synthesized in the
liver. Obtained from foods. Considered elevated if plasma
cholesterol exceeds 200 mg/dL.
TABLE 17.4Copyright 2007 by Pearson Education, Inc. Publishing
as Benjamin Cummings3435Steroid HormonesSteroid hormonesAre
chemical messengers in cells.Are produced from cholesterol. Include
sex hormones such as androgens (testosterone) in males and
estrogens (estradiol) in females.
Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin
Cummings35Dr. Thomas J. Montville36Summary of
FatsSaturatedUnsaturatedSingle bond (straight)Double bond
(kinked)SolidLiquidAnimal (cholesterol)Plants (cholesterol
free)FlakyTenderizationUnhealthyEssential Fatty Acids and
-3sChemically stableD.B.s reactive, free radicalsCooling as
Solidliquid37SolutionWrite a fatty acid with 10 carbon atoms that
is:A. saturated CH3CH2CH2CH2CH2CH2CH2CH2CH2COOH
B. monounsaturated omega-3CH3CH2CH=CHCH2CH2CH2CH2CH2COOH
C. monounsaturated omega-6CH3CH2CH2CH2CH2CH=CHCH2CH2COOH
3738Cell Membranes
Copyright 2007 by Pearson Education, Inc.Publishing as Benjamin
Cummings3839Cell MembranesCell membranes Separate cellular contents
from the external environment.Consist of a lipid bilayer made of
two rows of phospholipids.Have an inner portion made of the
nonpolar tails of phospholipids with the polar heads at the outer
and inner surfaces.
3940Fluid Mosaic Model of Cell MembranesThe lipid bilayer
Contains proteins, carbohydrates, and cholesterol.Has unsaturated
fatty acids that make cell membranes fluid-like rather than
rigid.Has proteins and carbohydrates on the surface that
communicate with hormones and neurotransmitters.
4041Fluid Mosaic Model
Copyright 2007 by Pearson Education, Inc.Publishing as Benjamin
Cummings4142Transport Through Cell MembranesThe transport of
substances through cellMembranes involvesDiffusion (passive
transport), which moves particles from a higher to a lower
concentration.Facilitated transport, which uses protein channels to
increase the rate of diffusion.Active transport, which moves ions
against a concentration gradient.4243Transport Pathways Through
Cell Membranes
Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin
Cummings4344Learning CheckThe transport of particles across a cell
membrane fromhigh concentration to low concentration is called
1. Facilitated transport2. Diffusion3. Active transport
4445SolutionThe transport of particles across a cell membrane
fromhigh concentration to low concentration is called
2. Diffusion
45
