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BIOLOGYCONCEPTS & CONNECTIONS
Fourth Edition
Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor
From PowerPoint Lectures forBiology: Concepts & Connections
CHAPTER 3The Molecules of Cells
Modules 3.43.10
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Carbohydrates are a class of molecules They range from small sugars to large
polysaccharides
Polysaccharides are long polymers of monomers
CARBOHYDRATES
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Monosaccharides are single-unit sugars
These molecules typically have a formula that isa multiple of CH2O
Each molecule contains hydroxyl groupsand a carbonyl group
Monosaccharidesare the fuels forcellular work
3.4 Monosaccharides are the simplestcarbohydrates
Figure 3.4A
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The monosaccharides glucose and fructose areisomers
They contain the same atoms but in differentarrangements
Glucose FructoseFigure 3.4B
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Many monosaccharides form rings, as shown here
for glucose
Abbreviated
structure
Figure 3.4C
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Monosaccharides can join to formdisaccharides, such as sucrose (table sugar) andmaltose (brewing sugar)
3.5 Cells link single sugars to form disaccharides
Glucose Glucose
MaltoseFigure 3.5
Sucrose
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Various types of molecules, including non-
sugars, taste sweet because they bind to sweetreceptors on the tongue
3.6 Connection: How sweet is sweet?
Table 3.6
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These large molecules are polymers of
hundreds or thousands of monosaccharideslinked by dehydration synthesis
3.7 Polysaccharides are long chains of sugar units
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Starch and glycogen are polysaccharides thatstore sugar for later use
Cellulose is a polysaccharide in plant cell walls
Figure 3.7
Starch granules in
potato tuber cells
Glucose
monomer
STARCH
GLYCOGEN
CELLULOSE
Glycogen granules
in muscle tissue
Cellulose fibrils ina plant cell wall
Cellulose
molecules
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These compounds are composed largely ofcarbon and hydrogen
They are not true polymers
They are grouped togetherbecause they do not mixwith water
3.8 Lipids include fats, which are mostly energy-storage molecules
Figure 3.8A
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Fats are lipids whose main function is energystorage
They are also called triglycerides
A triglyceride molecule consists of one glycerolmolecule linked to three fatty acids
Figure 3.8B
Fatty acid
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The fatty acids of unsaturated fats (plant oils)contain double bonds
These prevent them from solidifying at roomtemperature
Saturated fats (lard) lack double bonds
They are solid at room temperature
Figure 3.8C
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Phospholipids are a major component of cellmembranes
Waxes form waterproof coatings
Steroidsare oftenhormones
3.9 Phospholipids, waxes, and steroids are lipidswith a variety of functions
Figure 3.9
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Anabolic steroids are usually synthetic variantsof testosterone
Use of these substances
can cause serious healthproblems
3.10 Connection: Anabolic steroids and relatedsubstances pose health risks
Figure 3.10