Announcements & Agenda (04/16/07)
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Transcript of Announcements & Agenda (04/16/07)
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AnnouncementsAnnouncements & Agenda& Agenda (04/16/07)(04/16/07)
Pick up QuizzesPick up QuizzesExtra Credit Assignment Due NOW!Extra Credit Assignment Due NOW!Exam Fri 04/20 (Ch 13,14,15)Exam Fri 04/20 (Ch 13,14,15) REVIEW @ 5 pm Wed!!!REVIEW @ 5 pm Wed!!! exam exam will notwill not include pp. 520-524 include pp. 520-524 BTW, “Forms of Carbohydrates” tutorial on CD good for BTW, “Forms of Carbohydrates” tutorial on CD good for
looking at carbohydrate structureslooking at carbohydrate structures
TodayToday Finish fatty acids (15.2)Finish fatty acids (15.2) Triglycerides & reactions (15.3, 15.4)Triglycerides & reactions (15.3, 15.4) Glycerophospholipids (15.5)Glycerophospholipids (15.5) Cholesterol (15.6)Cholesterol (15.6)
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Last Time: PolysaccharidesLast Time: Polysaccharides
• often polymers of D-glucose.often polymers of D-glucose.• include amylose & amylopectin, include amylose & amylopectin,
starchesstarches made of made of αα-D-glucose.-D-glucose.• include include glycogenglycogen (animal starch (animal starch
in muscle), which is made of in muscle), which is made of αα--D-glucose.D-glucose.
• include include cellulosecellulose (plants and (plants and wood), which is made of wood), which is made of ββ-D--D-glucose.glucose.
α-D-Glucose
O
CH2OH
OHOH
OH
OH
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The monosacharides in glycogen in The monosacharides in glycogen in are linked by…are linked by…
0%
0%
0%
0%
0%1.1. -1, 4 glycosidic bonds only-1, 4 glycosidic bonds only
2.2. -1, 4 glycosidic bonds only-1, 4 glycosidic bonds only
3.3. -1, 6 glycosidic bonds only-1, 6 glycosidic bonds only
4.4. Contain both Contain both and and glycosidic bonds glycosidic bonds
5.5. None of the aboveNone of the above
11 22 33 44 55
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Last Time: Intro to Lipids (Fat!)Last Time: Intro to Lipids (Fat!)
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24 Good Practice Problems (Ch 15)24 Good Practice Problems (Ch 15)
15.05, 15.11, 15.13, 15.19, 15.21, 15.05, 15.11, 15.13, 15.19, 15.21, 15.27, 15.29, 15.31, 15.37, 15.39, 15.27, 15.29, 15.31, 15.37, 15.39, 15.41, 15.43, 15.45, 15.49, 15.51,15.41, 15.43, 15.45, 15.49, 15.51,
15.57, 15.65, 15.67, 15.69, 15.71,15.57, 15.65, 15.67, 15.69, 15.71,
15.73, 15.77, 15.78, 15.81 15.73, 15.77, 15.78, 15.81
Turn in your work for 15 of these by Wed @ 11 am Turn in your work for 15 of these by Wed @ 11 am to receive 1 pt extra creditto receive 1 pt extra credit
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Last Time: Lipids w/ Fatty AcidsLast Time: Lipids w/ Fatty Acids
• saturated:saturated: all all single Csingle C–C –C bonds.bonds.
• unsaturated:unsaturated: with one or with one or more double more double C=C bonds.C=C bonds.
palmitic acid, a saturated acid
palmitoleic acid, an unsaturated acid
O
C OH
O
C OH
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Last Time: Unsaturated vs. Last Time: Unsaturated vs. Saturated Fatty AcidsSaturated Fatty Acids
• Unsaturated: contain one or Unsaturated: contain one or more more ciscis double C= double C=C bonds.C bonds.
• have “kinks” in the fatty acid have “kinks” in the fatty acid chains.chains.
• do not pack as closely. do not pack as closely. • have fewer attractions between have fewer attractions between
chains.chains.• have lower melting points.have lower melting points.• are liquids at room temperature.are liquids at room temperature.
COOHH
H CC
HOOC
H
H
C
C
“kinks” in chain
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15.315.3Waxes, Fats, and Oils Waxes, Fats, and Oils
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WaxesWaxes• esters of saturated fatty acids and long-esters of saturated fatty acids and long-
chain alcohols.chain alcohols.• coatings that prevent loss of water by coatings that prevent loss of water by
leaves of plants. leaves of plants.
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Fats and Oils: TriacylglycerolsFats and Oils: Triacylglycerols
• also called triacylglycerols or also called triacylglycerols or triglyceridestriglycerides
• esters of glycerol.esters of glycerol.• produced by esterification.produced by esterification.• Formed when the hydroxyl Formed when the hydroxyl
groups of glycerol react with groups of glycerol react with the carboxyl groups of fatty the carboxyl groups of fatty acids.acids.
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OHCH2
OH
OHCH2
CHO
(CH2)14CH3CHO
O
(CH2)14CH3CHO
O
(CH2)14CH3CHO
Formation of a TriacylglycerolFormation of a Triacylglycerol
glycerol + three fatty acids triacylglycerolglycerol + three fatty acids triacylglycerol
+ 3H+ 3H22OO
O
O
C (CH2)14CH3
CH O
O
C (CH2)14CH3
CH2 O
O
C (CH2)14CH3
CH2
+
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(CH2)12CH3
O
C
CH(CH2)7CH3(CH2)7CH
O
C
O
(CH2)16CH3C
O
O
OCH2
CH2
CH
Different Fatty Acids Can Make Different Fatty Acids Can Make Up Triacylglycerols!Up Triacylglycerols!
Stearic acid
Oleic acid
Myristic acid
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Melting Points of Fats and OilsMelting Points of Fats and Oils
A A fatfat
• is solid at room temperature.is solid at room temperature.
• is prevalent in meats, whole milk, butter, is prevalent in meats, whole milk, butter, and cheese. (mmm… cheese)and cheese. (mmm… cheese)
An An oiloil
• is liquid at room temperature.is liquid at room temperature.
• is prevalent in plants such as olive and is prevalent in plants such as olive and safflower.safflower.
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Oils w/ Unsaturated Fatty AcidsOils w/ Unsaturated Fatty Acids
• have more unsaturated fatshave more unsaturated fats
• have have cis cis double bonds that cause double bonds that cause “kinks” in the fatty acid chains“kinks” in the fatty acid chains
• ““kinks” result in poor packingkinks” result in poor packing
• have lower melting points than have lower melting points than saturated fatty acids.saturated fatty acids.
• are liquids at room temperature.are liquids at room temperature.
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Diagram of Triacylglycerol with Diagram of Triacylglycerol with Unsaturated Fatty AcidsUnsaturated Fatty Acids
Unsaturated fatty acid Unsaturated fatty acid chains with kinks cannot chains with kinks cannot pack closelypack closely..
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Percent Saturated and Unsaturated Fatty Percent Saturated and Unsaturated Fatty Acids In Fats and OilsAcids In Fats and Oils
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The chemical reactions of triacylglycerols are The chemical reactions of triacylglycerols are similar to those of alkenes and esters. similar to those of alkenes and esters.
• HydrogenationHydrogenation of double bonds in unsaturated of double bonds in unsaturated fatty acids by Hfatty acids by H22 (compare to alkenes) (compare to alkenes)..
• HydrolysisHydrolysis of ester bonds by water in the of ester bonds by water in the presence of an acid, a base, or an enzyme presence of an acid, a base, or an enzyme (compare to esters).(compare to esters).
15.4 Chemical Properties of Triacylglycerols15.4 Chemical Properties of Triacylglycerols
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Hydrogenation of OilsHydrogenation of Oils
• adds Hadds H22 to the to the
carbon atoms of carbon atoms of double bonds.double bonds.
• increases the increases the melting point.melting point.
• produces solids produces solids such as margarine such as margarine and shortening. and shortening.
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CH(CH2)7CH3(CH2)5CH
O
C
CH(CH2)7CH3(CH2)5CH
O
C
CH(CH2)7CH3(CH2)5CH
O
C
O
O
OCH2
CH2
CH
HydrogenationHydrogenation
+ 3H+ 3H2 2 NiNi
glyceryl tripalmitoleateglyceryl tripalmitoleate (tripalmitolean)(tripalmitolean)
glyceryl tripalmitateglyceryl tripalmitate(tripalmitin)(tripalmitin)
O
(CH2)14CH3C
O
(CH2)14CH3C
O
(CH2)14CH3C
O
O
OCH2
CH2
CH
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Olestra, A Fat SubstituteOlestra, A Fat Substitute
• used in foods as an artificial fat.used in foods as an artificial fat.• sucrose linked by ester bonds to several sucrose linked by ester bonds to several
long-chain fatty chains.long-chain fatty chains.• not broken down in the intestinal tract.not broken down in the intestinal tract.
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Olestra (WOW or Light)Olestra (WOW or Light)
http://en.wikipedia.org/wiki/Olestrahttp://en.wikipedia.org/wiki/Olestra
Launched in 1996 as WOW potato chips ($400 Launched in 1996 as WOW potato chips ($400 mil in 1998). Fell to $200 mil when FDA mil in 1998). Fell to $200 mil when FDA restricted the label to state “may cause restricted the label to state “may cause abdominal cramping and loose stools”. It also abdominal cramping and loose stools”. It also inhibited absorption of Vitamins A, D, E and Kinhibited absorption of Vitamins A, D, E and K
It is made from one sucrose and 8 oleic acid It is made from one sucrose and 8 oleic acid molecules. The molecule is so large that it could molecules. The molecule is so large that it could not migrate past the intestinal wallnot migrate past the intestinal wall
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CisCis and and TransTrans Fatty Acids Fatty Acids
Unsaturated fatty acids can be Unsaturated fatty acids can be • ciscis with bulky groups on same side of C=C. with bulky groups on same side of C=C.CHCH33─ (CH─ (CH22))55 (CH(CH22))77── COOH COOH ciscis
C=CC=C H HH H
• transtrans have bulky groups on opposite sides of C=C. have bulky groups on opposite sides of C=C.
CHCH33─ (CH─ (CH22))55 HH
C=C C=C transtrans
H H (CH(CH22))77── COOHCOOH
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Hydrogenation & Trans Fatty AcidsHydrogenation & Trans Fatty Acids
Most naturally occurring fatty acids have Most naturally occurring fatty acids have cis double bonds!cis double bonds!
• However, during hydrogenation, some However, during hydrogenation, some cis cis double double bonds are converted to bonds are converted to trans trans double bonds.double bonds.
• In the body, In the body, trans trans fatty acids behave like saturated fatty acids behave like saturated fatty acids. Why? fatty acids. Why?
• It is estimated that 2-4% of our total Calories is in It is estimated that 2-4% of our total Calories is in the form of the form of transtrans fatty acid. fatty acid.
• Several studies reported that Several studies reported that transtrans fatty acids raise fatty acids raise LDL-cholesterol and lower HDL-cholesterol.LDL-cholesterol and lower HDL-cholesterol.
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HydrolysisHydrolysis
• triacylglycerols split into glycerol and three fatty triacylglycerols split into glycerol and three fatty acids.acids.
• an acid or enzyme catalyst is required.an acid or enzyme catalyst is required.
OCH2
OCH
OCH2
OHCH2
OHCH
OHCH2
O
(CH2)14CH3CHO
H2OO
(CH2)14CH3C
O
(CH2)14CH3C
O
(CH2)14CH3C
H+
+
+
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OH
CH OH
CH2 OH
CH2
Saponification (Base Hydrolysis)Saponification (Base Hydrolysis)
O
O
C (CH2)14CH3
CH O
O
C (CH2)14CH3
CH2 O
O
C (CH2)14CH3
CH2
+ 3NaOH+ 3NaOH
Na+ -O
O
C (CH2)14CH333+
“soap”
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• the most abundant lipids in cell membranes. the most abundant lipids in cell membranes. • composed of glycerol, two fatty acids, composed of glycerol, two fatty acids,
phosphate, and an amino alcohol.phosphate, and an amino alcohol.
Glycerol
PO4Amino alcohol
15.5 Glycerophospholipids15.5 Glycerophospholipids
Fatty acid
Fatty acid
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Polarity of GlycerophospholipidsPolarity of Glycerophospholipids
A A glycerophospholipidglycerophospholipid has has • 2 nonpolar fatty acid chains.2 nonpolar fatty acid chains.• A phosphate group and a polar amino alcohol.A phosphate group and a polar amino alcohol. CHCH33
││+ ++ +
HOHO−CH−CH22−CH−CH22−N−CH−N−CH3 3 HOHO−CH−CH22−CH−CH22−NH−NH33
││ cholinecholine CH CH3 3 ethanolamineethanolamine
++
NHNH33
│ │ Amino alcoholsAmino alcohols HOHO−CH−CH22−CH−COO−CH−COO−−
serineserine
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Structure and Polarity of A Structure and Polarity of A GlycerophospholipidGlycerophospholipid
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LecithinLecithin and and cephalincephalin are glycerophospholipids are glycerophospholipids• abundant in brain and nerve tissues.abundant in brain and nerve tissues.• found in egg yolk, wheat germ, and yeast.found in egg yolk, wheat germ, and yeast.
Lecithin & CephalinLecithin & Cephalin
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CH3
CH3CH3
CH3
HO
CH3
15.6 Steroids: Cholesterol, & 15.6 Steroids: Cholesterol, & Steroid HormonesSteroid Hormones
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Steroid NucleusSteroid Nucleus
Consists of:Consists of:
• 3 cyclohexane rings.3 cyclohexane rings.
• 1 cyclopentane ring.1 cyclopentane ring.
• no fatty acids.no fatty acids.
steroid nucleussteroid nucleus
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CholesterolCholesterol
• is the most abundant steroid in the body. is the most abundant steroid in the body.
• has methyl CHhas methyl CH33- groups, alkyl chain, and -- groups, alkyl chain, and -
OH attached to the steroid nucleus.OH attached to the steroid nucleus.
CH3
CH3CH3
CH3
HO
CH3
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Cholesterol in the BodyCholesterol in the Body
• is obtained from meats, is obtained from meats, milk, and eggs. milk, and eggs.
• is synthesized in the liver.is synthesized in the liver.• is needed for cell is needed for cell
membranes, brain and membranes, brain and nerve tissue, steroid nerve tissue, steroid hormones, and Vitamin D.hormones, and Vitamin D.
• clogs arteries when high clogs arteries when high levels form plaque.levels form plaque.
An artery clogged by cholesterol plaque
A normal, open artery.
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Cholesterol in FoodsCholesterol in Foods
• is considered is considered elevated if elevated if plasma plasma cholesterol cholesterol exceeds 200 exceeds 200 mg/dL.mg/dL.
• is synthesized is synthesized in the liver and in the liver and obtained from obtained from foods.foods.
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Lipoproteins: LDL, HDL, Etc…Lipoproteins: LDL, HDL, Etc…
• combine lipids combine lipids with proteins & with proteins & phospholipids.phospholipids.
• are soluble in are soluble in water because water because the surface the surface consists of polar consists of polar lipids.lipids.
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Types of LipoproteinsTypes of Lipoproteins
• differ in density, composition, and function.differ in density, composition, and function.• include low-density lipoprotein (LDLs) and include low-density lipoprotein (LDLs) and
high-density lipoprotein (HDLs).high-density lipoprotein (HDLs).
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Transport of Lipoproteins in the BodyTransport of Lipoproteins in the Body