The document discusses the key biomolecules that make up living cells: carbohydrates, lipids, and proteins. Carbohydrates include monosaccharides (simple sugars), disaccharides formed from two monosaccharides linked together, and polysaccharides which are long chains of monosaccharides. Lipids are molecules that do not dissolve in water and include fats, phospholipids, waxes, and steroids. Proteins are polymers of amino acids and perform most of the work in cells and as enzymes, hormones, and antibodies. These biomolecules are essential building blocks and fuels for cellular structure and function.

1. 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 for Biology: Concepts & Connections
CHAPTER 3
The Molecules of Cells
Modules 3.4 – 3.10

2. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Carbohydrates are a class of molecules
– They range from small sugars to large
polysaccharides
– Polysaccharides are long polymers of monomers
CARBOHYDRATES

3. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Monosaccharides are single-unit sugars
• These molecules typically have a formula that is
a multiple of CH2O
• Each molecule contains hydroxyl groups
and a carbonyl group
• Monosaccharides
are the fuels for
cellular work
3.4 Monosaccharides are the simplest
carbohydrates
Figure 3.4A

4. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The monosaccharides glucose and fructose are
isomers
– They contain the same atoms but in different
arrangements
Glucose FructoseFigure 3.4B

5. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Many monosaccharides form rings, as shown here
for glucose
Abbreviated
structure
Figure 3.4C

6. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Monosaccharides can join to form
disaccharides, such as sucrose (table sugar) and
maltose (brewing sugar)
3.5 Cells link single sugars to form disaccharides
Glucose Glucose
MaltoseFigure 3.5
Sucrose

7. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Various types of molecules, including non-
sugars, taste sweet because they bind to “sweet”
receptors on the tongue
3.6 Connection: How sweet is sweet?
Table 3.6

8. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• These large molecules are polymers of
hundreds or thousands of monosaccharides
linked by dehydration synthesis
3.7 Polysaccharides are long chains of sugar units

9. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Starch and glycogen are polysaccharides that
store 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 in
a plant cell wall
Cellulose
molecules

10. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• These compounds are composed largely of
carbon and hydrogen
– They are not true polymers
– They are grouped together
because they do not mix
with water
3.8 Lipids include fats, which are mostly energy-
storage molecules
Figure 3.8A

11. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Fats are lipids whose main function is energy
storage
– They are also called triglycerides
• A triglyceride molecule consists of one glycerol
molecule linked to three fatty acids
Figure 3.8B
Fatty acid

12. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The fatty acids of unsaturated fats (plant oils)
contain double bonds
– These prevent them from solidifying at room
temperature
• Saturated fats (lard) lack double bonds
– They are solid at room temperature
Figure 3.8C

13. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Phospholipids are a major component of cell
membranes
• Waxes form waterproof coatings
• Steroids
are often
hormones
3.9 Phospholipids, waxes, and steroids are lipids
with a variety of functions
Figure 3.9

14. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Anabolic steroids are usually synthetic variants
of testosterone
• Use of these substances
can cause serious health
problems
3.10 Connection: Anabolic steroids and related
substances pose health risks
Figure 3.10