Transcript Document

BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 3
The Molecules of Cells
Modules 3.4 – 3.10
From PowerPoint® Lectures for Biology: Concepts & Connections
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Carbon Bonding
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Functional groups
influence the
characteristics of
the molecule and
the reactions
they undergo.
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Monomers, Polymers, and Macromolecules
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4 macromolecules
• Proteins ,
carbohydrates,
lipids and nucleic
acids.
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3.4 Monosaccharides are the simplest
carbohydrates. They are the monomers.
• Monosaccharides are single-unit sugars
• These molecules typically have a formula that is
a multiple of CH2O . Their formula is C6H12O6.
• Each molecule contains hydroxyl groups
and a carbonyl group as their functional group.
The hydroxyl group renders most sugars
hydrophillic or water loving.
• Monosaccharides
are the fuels for
cellular work
Figure 3.4A
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Polar and ionic molecules have positive and
negative charges associated with them and are
therefore attracted to water because water is a
polar molecule. They are said to be hydrophilic
because they interact with (dissolve in) water
forming hydrogen bonds.
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• The monosaccharides glucose, galactose and
fructose are isomers
– They contain the same atoms but in different
arrangements
Glucose
Fructose
Figure 3.4B
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Galactose
• Many monosaccharides form rings, as shown here
for glucose
Abbreviated
structure
Figure 3.4C
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Large carbon molecules are built from small
monomers.
The monomers, the polymers and the
macromolecules…….
• For each of the four macromolecules we will fill
in an organizer to study from. We will start
with the simple sugars which, when linked
together, form the carbohydrates.
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3.5 Cells link single sugars to form disaccharides
through dehydration synthesis.
• Monosaccharides can join to form disaccharides, such as
sucrose (table sugar) and maltose (brewing sugar) and
lactose (milk sugar)
Sucrose=fructose + glucose
Glucose
lactose
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Glucose
Maltose
3.6 Connection: How sweet is sweet?
• Various types of molecules, including nonsugars, taste sweet because they bind to “sweet”
receptors on the tongue. The tighter they bind
the receptors, the sweeter the taste.
Table 3.6
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Examples of some human
thresholds
TAS2R38 locus = bitter PTC locus
If sooo bitter = supertasters
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Taste
Substance
Threshold
for tasting
Salty
NaCl
0.01 M
Sour
HCl
0.0009 M
Sweet
Sucrose
0.01 M
Bitter
Quinine
0.000008
M
Umami
Glutamate
0.0007 M
CARBOHYDRATES
• Carbohydrates are a class of molecules
– They range from small sugars to large
polysaccharides
– Polysaccharides are long polymers of monomers
linked by dehydration synthesis.
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• Starch (plants) and glycogen (animals) are polysaccharides that store
sugar for later use
• Cellulose (plants) is a polysaccharide in plant cell walls. It passes as
“fiber” through our digestive tract for most animals can not hydrolyze
it. How do termites and cows get nutrients from plants???? Hum….
Starch granules in
potato tuber cells
Glycogen granules
in muscle tissue
Cellulose fibrils in
a plant cell wall
Cellulose
molecules
Figure 3.7
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Glucose
monomer
STARCH
GLYCOGEN
CELLULOSE
Carbohydrate morphology
• Starch- coils of branched glucose, plants use it
for energy.
• Cellulose-unbranched rods of glucose most
abundant organic compound. B-glycosidic
bonds prevent mammals from breaking it down
to obtain glucose.
• Glycogen-stored in liver more branched than
starch. Hydrolyzed in liver and digestive tract.
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3.8 Lipids include fats, which are mostly energystorage molecules
• 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. They are
hydrophobic.
– Fats, oils, phospholipids and
waxes are composed of glycerol
and fatty acids.
Figure 3.8A
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• Triglycerides= 3 fatty acid chains and a
glycerol. A triglyceride molecule consists of
one glycerol molecule linked to three fatty acids
• Fats are triglycerides whose main function is
energy storage in animals. Oils are analogous
in plants.
Fatty acid
Figure 3.8B
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• Unsaturated fatty acid chains (common in plant oils)
contain double bonds.
– These unsaturated fats form kinks which prevent them
from solidifying at room temperature as they can not
pack tightly together. They are better for you than
saturated fats.
• Saturated fatty acid chains (common in animal lard) lack
double bonds. They are solid at room temperature. They
should be limited in the diet as they can pack tightly
together and clog arteries and veins.
Figure 3.8C
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The Cis and Trans fats
Oleic acid
Elaidic acid
Stearic acid
Oleic acid is a cis
unsaturated fatty acid that
comprises 55–80% of
olive oil.
Elaidic acid is a trans
unsaturated fatty acid
often found in partially
hydrogenated vegetable
oils.
Stearic acid is a saturated
fatty acid found in animal
fats and is the intended
product in hydrogenation.
These fatty acids are geometric isomers(chemically
identical except for the arrangement of the double
bond).
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This fatty acid contains
more hydrogen and is not
isomeric with the
previous.
3.9 Phospholipids, waxes, and steroids are lipids
with a variety of functions
• Phospholipids are a major component of cell membranes.
They are composed of two fatty acid chains, a glycerol, and
phosphorus.
• Waxes form waterproof coatings. They are composed of one
fatty acid chain and a glycerol. Waxes are found on plants
and in your ears.
• Steroids
are often
hormones.
Figure 3.9
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3.10 Connection: Anabolic steroids and related
substances pose health risks
• Anabolic steroids are usually synthetic variants
of testosterone
• Use of these substances
can cause serious health
problems
• anadrol, oxandrin, dianabol
• winstrol, deca-durabolin
• equipoise.
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Figure 3.10
Anabolic steroids are similar to testosterone
• Anabolic steroids are synthetic derivatives of the male
hormone testosterone. The full name is androgenic
anabolic steroids and they promote growth of the
skeletal structure and increase lean body mass.
• Anabolic steroids are taken orally or injected. They are
taken in continuous patterns called "cycling," which
occur by starting, stopping and starting again over a
period of weeks or months and changing the dosages
of the steroids.
• Additionally, users will combine anabolic steroids
often times with other drugs (stimulants, depressants,
painkillers, anti-inflammatories) to maximize their
effectiveness while minimizing negative effects.
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More Negative Effects
• Arnolds, Asteroids, Ball Shrinkers, Gear, Gym
Candy, Iron Brew, Juice, Liquid Gold, Pumpup pills, Roids, Sted, Rocket fuel, Sloop,
Product, Stacking
• More serious dangers — including liver damage
and cancer — are linked to long-term, highdose use, which can be 100 times higher than
standard therapeutic doses.
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