announcements & agenda (04/18/07)
DESCRIPTION
Announcements & Agenda (04/18/07). Extra Credit Assignment Due NOW! Exam Fri 04/20 (Ch 13,14,15) REVIEW @ 3pm and 5 pm Today!!! exam will not include pp. 520-524 START at 10:30 am Today Cholesterol (15.6) More steroids (15.6)… Cell membranes (15.7). - PowerPoint PPT PresentationTRANSCRIPT
11
AnnouncementsAnnouncements & Agenda& Agenda (04/18/07)(04/18/07)Extra 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 @ 3pm and 5 pm Today!!!REVIEW @ 3pm and 5 pm Today!!! exam exam will notwill not include pp. 520-524 include pp. 520-524 START at 10:30 amSTART at 10:30 am
TodayToday Cholesterol (15.6)Cholesterol (15.6) More steroids (15.6)…More steroids (15.6)… Cell membranes (15.7)Cell membranes (15.7)
22
OHCH2
OH
OHCH2
CHO
(CH2)14CH3CHO
O
(CH2)14CH3CHO
O
(CH2)14CH3CHO
Last Time: Formation of Fats & Oils Last Time: Formation of Fats & Oils (Triacylglycerols)(Triacylglycerols)
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
+
33
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).
Last Time: 15.4 Chemical Properties of Last Time: 15.4 Chemical Properties of TriacylglycerolsTriacylglycerols
44
• 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
Last Time: 15.5 GlycerophospholipidsLast Time: 15.5 Glycerophospholipids
Fatty acid
Fatty acid
55
Last Time: Steroid NucleusLast Time: Steroid 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
66
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
77
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.
88
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.
99
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.
1010
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).
1111
Transport of Lipoproteins in the BodyTransport of Lipoproteins in the Body
1212
Steroid HormonesSteroid Hormones• chemical messengers in cells.chemical messengers in cells.• sex hormones. sex hormones.
Androgens in males (testosterone) Androgens in males (testosterone) Estrogens in females (estradiol)Estrogens in females (estradiol)
• Adrenocortical hormones from adrenal glands.Adrenocortical hormones from adrenal glands.-mineralocorticoids (electrolyte balance)-mineralocorticoids (electrolyte balance)-glucocorticoids regulate glucose level-glucocorticoids regulate glucose level
1313
Steroid HormonesSteroid Hormones• are produced from are produced from
cholesterol. cholesterol.
• include sex include sex hormones such as hormones such as androgens androgens (testosterone) in (testosterone) in males and males and estrogens (estradiol) estrogens (estradiol) in females.in females.
1414
Adrenal CorticosteroidsAdrenal Corticosteroids
1515
Anabolic SteroidsAnabolic Steroids
• are derivatives of testosterone.are derivatives of testosterone.• are used illegally to increase muscle mass.are used illegally to increase muscle mass.• have side effects including fluid retention, hair have side effects including fluid retention, hair
growth, sleep disturbance, and liver damage.growth, sleep disturbance, and liver damage.
1616
Cell MembranesCell Membranes• separate cellular contents from the separate cellular contents from the
external environment.external environment.• consist of a lipid bilayer made of two consist of a lipid bilayer made of two
rows of phospholipids.rows of phospholipids.• have an inner portion made of the have an inner portion made of the
nonpolar tails of phospholipids with the nonpolar tails of phospholipids with the polar heads at the outer and inner polar heads at the outer and inner surfaces.surfaces.
1717
Fluid Mosaic Model of Cell Fluid Mosaic Model of Cell MembranesMembranes
The The lipid bilayerlipid bilayer • contains proteins, carbohydrates, and contains proteins, carbohydrates, and
cholesterol.cholesterol.• has unsaturated fatty acids that make cell has unsaturated fatty acids that make cell
membranes fluid-like rather than rigid.membranes fluid-like rather than rigid.• has proteins and carbohydrates on the has proteins and carbohydrates on the
surface that communicate with hormones surface that communicate with hormones and neurotransmitters.and neurotransmitters.
1818
Fluid Mosaic Model of Cell Fluid Mosaic Model of Cell MembranesMembranes
1919
Transport Through Cell MembranesTransport Through Cell Membranes
The transport of substances through cell membranesThe transport of substances through cell membranesinvolvesinvolves• diffusion (passive transport),diffusion (passive transport), which moves which moves
particles from a higher to a lower concentration.particles from a higher to a lower concentration.• facilitated transportfacilitated transport,, which uses protein channels which uses protein channels
to increase the rate of diffusion.to increase the rate of diffusion.• active transportactive transport,, which moves ions against a which moves ions against a
concentration gradient.concentration gradient.
2020
Transport Pathways Through Cell Transport Pathways Through Cell MembranesMembranes