Transcript Chapter 15 Lipids 15.6 Steroids: Cholesterol, and Steroid Hormones CH3 CH3 CH3 CH3 CH3 HO Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings.

Chapter 15
Lipids
15.6
Steroids: Cholesterol, and Steroid
Hormones
CH3
CH3
CH3
CH3
CH3
HO
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings
1
Steroid Nucleus
A steroid nucleus
consists of
• 3 cyclohexane rings.
• 1 cyclopentane ring.
• no fatty acids.
steroid nucleus
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Cholesterol
Cholesterol
• is the most abundant steroid in the body.
• has methyl CH3- groups, alkyl chain, and -OH
attached to the steroid nucleus.
CH3
CH3
CH3
CH3
CH3
HO
3
Cholesterol in the Body
Cholesterol
• 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.
An artery clogged
by cholesterol
plaque
4
Cholesterol in Foods
Cholesterol
• is considered
elevated if
plasma
cholesterol
exceeds 200
mg/dL.
• is synthesized in
the liver and
obtained from
foods.
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Learning Check
Match the components of the cholesterol molecule with
the following:
___ carbon chain
___hydroxyl group
___ steroid nucleus
___methyl group
CH3
CH3
B
D
CH3
CH3
CH3
A
HO
C
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Solution
Match the components of the cholesterol molecule with
the following:
_D carbon chain
_A_hydroxyl group
_C steroid nucleus
_B_methyl group
CH3
CH3
B
D
CH3
CH3
CH3
A
HO
C
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Lipoproteins
Lipoproteins
• combine lipids
with proteins
and
phospholipids.
• are soluble in
water because
the surface
consists of
polar lipids.
8
Types of Lipoproteins
Lipoproteins
• differ in density, composition, and function.
• include low-density lipoprotein (LDLs) and high-density
lipoprotein (HDLs).
9
Transport of Lipoproteins in the
Body
10
Steroid Hormones
Steroid hormones are
• chemical messengers in cells.
• sex hormones.
Androgens in males (testosterone)
Estrogens in females (estradiol)
• Adrenocortical hormones from adrenal glands.
mineralocorticoids (electrolyte balance)
glucocorticoids regulate glucose level
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Steroid Hormones
Steroid hormones
• are produced from
cholesterol.
• include sex
hormones such as
androgens
(testosterone) in
males and estrogens
(estradiol) in
females.
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Adrenal Corticosteroids
Steroid hormones called adrenal corticosteroids
• are produced by the adrenal glands located on the top
of each kidney.
• include aldosterone, which regulates electrolytes and
water balance by the kidneys.
• include cortisone, a glucocorticoid, which increases
blood glucose level and stimulates the synthesis of
glycogen in the liver.
13
Anabolic Steroids
Anabolic steroids
• are derivatives of testosterone.
• are used illegally to increase muscle mass.
• have side effects including fluid retention, hair growth,
sleep disturbance, and liver damage.
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Adrenal Corticosteroids
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Learning Check
Identify each lipid as
(1) fatty acid
(2) steroid
A.
B.
C.
D.
E.
(3) triacylglycerol.
Cholesterol
Stearic acid
Glyceryl tristearate
Estradiol
Contains no fatty acids.
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Solution
Identify each lipid as:
(1) fatty acid
(2) steroid
A. 2 Cholesterol
B. 1 Stearic acid
C. 3 Glyceryl tristearate
D. 2 Estradiol
E. 2 Contains no fatty acids.
.
(3) triacylglycerol
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