Jan21 Carbs Lipids
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Transcript of Jan21 Carbs Lipids
© 2014 Pearson Education, Inc.
Biol 1306
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
• His body mass index went from 28.8,
considered overweight, to 24.9, which
is normal. He now weighs 174 pounds.
• Haub's "bad" cholesterol, or LDL,
dropped 20 percent and his "good"
cholesterol, or HDL, increased by 20
percent. He reduced the level of
triglycerides, which are a form of fat,
by 39 percent.
• He also took a multivitamin pill and
drank a protein shake daily. And he
ate vegetables, typically a can of green
beans or three to four celery stalks.
• Before his Twinkie diet, he tried to eat
a healthy diet that included whole
grains, dietary fiber, berries and
bananas, vegetables and occasional
treats like pizza.
• "There seems to be a disconnect
between eating healthy and being
healthy," Haub said. "It may not be the
same. I was eating healthier, but I
wasn't healthy. I was eating too much."
• Mark Haub, professor of human
nutrition at Kansas State University
• A man of Haub's pre-dieting size
usually consumes about 2,600
calories daily
• For 10 weeks, he limited himself to
less than 1,800 calories a day
• Ate one of these sugary cakelets
every three hours, instead of meals
• To add variety in his steady stream
of Hostess and Little Debbie snacks,
Haub munched on Doritos chips,
sugary cereals and Oreos
http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/
© 2014 Pearson Education, Inc.
• Observation/question?
• Haub’s hypothesis?
• Prediction?
• Experiment?
• Conclusion?
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Carbon can bond with _______ atom(s).
a. 1
b. 2
c. 3
d. 4
© 2014 Pearson Education, Inc.
Carbon can bond with _______ atom(s).
a. 1
b. 2
c. 3
d. 4
© 2014 Pearson Education, Inc.
Carbon’s ability to bond with up to four other atoms is significant because ___________.
a. it enables the synthesis of inorganic molecules
b. it allows molecules to assume complex shapes,
and form long chains, rings, and helices
c. all biological molecules have four covalent bonds
d. it leads to the creation of large monomers from
smaller polymers
© 2014 Pearson Education, Inc.
Carbon’s ability to bond with up to four other atoms is significant because ___________.
a. it enables the synthesis of inorganic molecules
b. it allows molecules to assume complex shapes,
and form long chains, rings, and helices
c. all biological molecules have four covalent bonds
d. it leads to the creation of large monomers from
smaller polymers
© 2014 Pearson Education, Inc.
3.3 What Are Carbohydrates?
Where do you find carbohydrates?
What are carbohydrates?
– Sugars and polymers of sugars
– So then….what is a sugar?
What functions/purposes do carbohydrates serve?
– Energy
– Storage of energy
– A structural part of nucleic acids
– A structural part of some organisms
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3.3 What Are Carbohydrates?
What is a sugar? Some examples…
– Glucose
– Most common sugar in living organisms
– monosaccharide
– Sucrose
– Table sugar
– Disaccharide (glucose-fructose)
– Fructose
– Fruit, honey, corn syrup
– monosaccharide
– Lactose
– Milk
– Disaccharide (glucose-galactose)
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
3.3 What Are Carbohydrates?
Polysaccharides are chains of monosaccharides
– Storage polysaccharides include
– Starch, an energy-storage molecule in plants, formed in roots and
seeds
– Glycogen, an energy-storage molecule in animals, found in the
liver and muscles
– Both starch and glycogen are polymers of glucose
molecules
© 2014 Pearson Education, Inc.
3.3 What Are Carbohydrates?
Polysaccharides as a structural material
Cellulose (polymer of glucose) is one of the most important structural
polysaccharides
– It is found in the cell walls of plants
– It is indigestible for most animals
© 2014 Pearson Education, Inc.
3.3 What Are Carbohydrates?
Polysaccharides as a structural material
Chitin (a polymer of modified glucose units) is found in
– The outer coverings of insects, crabs, and spiders
– The cell walls of many fungi
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Why is it so hard for most animals to break down cellulose?
a. The lipid monomers of this polymer are connected by bonds with unique orientations.
b. It must be eaten with large amounts of fiber.
c. Most animals lack the enzymes that break the bonds between the glucose molecules of this polymer.
d. The high pH of cellulose denatures the digestive enzymes of most animals.
© 2014 Pearson Education, Inc.
Why is it so hard for most animals to break down cellulose?
a. The lipid monomers of this polymer are connected by bonds with unique orientations.
b. It must be eaten with large amounts of fiber.
c. Most animals lack the enzymes that break the bonds between the glucose molecules of this polymer.
d. The high pH of cellulose denatures the digestive enzymes of most animals.
© 2014 Pearson Education, Inc.
Examples
carrot spinach apple banana
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Examples carrot
spinach
apple
banana
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© 2014 Pearson Education, Inc.
• Why is it thought that too much sugar is bad for
you?
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• Why is it thought that too much sugar is bad for
you? • Promotes tooth-decay
• Calorie-dense (contains a lot of calories)
• Displaces more nutritious food in your diet
• May increase risk of high blood pressure
• May increase risk of poor lipid (fat) profile
• Increases triglyceride level in blood
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
3.4 Where do you find Lipids?
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3.4 Where do you find Lipids?
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3.4 What Are Lipids?
Lipids are classified into three major groups
– Oils, fats, and waxes
– Phospholipids
– Steroids containing rings of carbon, hydrogen, and
oxygen
© 2014 Pearson Education, Inc.
3.4 What Are Lipids?
Lipids are a diverse group
of molecules that contain
regions composed almost
entirely of hydrogen and
carbon
– All lipids contain large
chains of nonpolar
hydrocarbons
– Most lipids are therefore
hydrophobic and water
insoluble
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3.4 What Are Lipids?
What are the functions of lipids?
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3.4 What Are Lipids?
Lipids are diverse in structure and serve a variety
of functions
– They are used for energy storage
– They form waterproof coverings on plant and animal
bodies
– They serve as the primary component of cellular
membranes
– Still others are hormones
© 2014 Pearson Education, Inc.
3.4 What Are Lipids?
Lipids are classified into three major groups
– Oils, fats, and waxes
– Phospholipids
– Steroids containing rings of carbon, hydrogen, and
oxygen
© 2014 Pearson Education, Inc.
3.4 What Are Lipids?
Oils, fats, and waxes are lipids containing only
carbon, hydrogen, and oxygen
– Oils, fats, and waxes are made of one or more fatty
acid subunits
© 2014 Pearson Education, Inc.
3.4 What Are Lipids?
Oils, fats, and waxes are lipids containing only
carbon, hydrogen, and oxygen (continued)
– Fats and oils
– Are used primarily as energy-storage molecules,
containing twice as many calories per gram as
carbohydrates and proteins
– Are formed by dehydration synthesis
– Three fatty acids glycerol triglyceride
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Figure 3-12 Synthesis of a triglyceride
triglyceride
fatty acids glycerol
© 2014 Pearson Education, Inc.
3.4 What Are Lipids?
Oils, fats, and waxes are lipids containing only carbon, hydrogen, and oxygen
– Fats that are solid at room temperature are saturated (the carbon chain has
as many hydrogen atoms as possible, and mostly or all C–C bonds)
– Examples?
– Fats that are liquid at room temperature are unsaturated (with fewer
hydrogen atoms, and many CC bonds)
– Examples?
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Omega-3 and Omega-6 fatty acids
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Olive oil
Oleic acid is also the primary fatty acid in avocado
© 2014 Pearson Education, Inc.
Trans fats
© 2014 Pearson Education, Inc.
3.4 What Are Lipids?
Oils, fats, and waxes are lipids containing only carbon, hydrogen, and oxygen (continued)
– Waxes are highly saturated and solid at room temperature
– Waxes form waterproof coatings such as on
– Leaves and stems in plants
– Fur in mammals
– Insect exoskeletons
– Waxes are also used to build honeycomb structures
© 2014 Pearson Education, Inc.
3.4 What Are Lipids?
Phospholipids have water-soluble “heads” and water-insoluble “tails”
– These form plasma membranes around all cells
– Phospholipids consist of two fatty acids glycerol a short polar functional group
– They have hydrophobic and hydrophilic portions
– The polar functional groups form the “head” and are water soluble
– The nonpolar fatty acids form the “tails” and are water insoluble
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
3.4 What Are Lipids?
Steroids contain four fused carbon rings
– Steroids are composed of four carbon rings fused together with various functional groups protruding from them
– Examples of steroids include cholesterol
– Found in the membranes of animal cells
– Component of male and female sex hormones
– Makes up 2% of human brain
– Excessive cholesterol contributes to cardiovascular disease
© 2014 Pearson Education, Inc.
Figure 3-16 Steroids
Estrogen
Testosterone Cholesterol
© 2014 Pearson Education, Inc.
Which is NOT a type of lipid?
a. Triglyceride
b. Wax
c. Oil
d. Peptide
© 2014 Pearson Education, Inc.
Which is NOT a type of lipid?
a. Triglyceride
b. Wax
c. Oil
d. Peptide
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
Assignment
• I will post this assignment and the due date (Mon, Jan 26)
on the “schedule of assignments” file on blackboard
• Find any news article, blog, or advertisement about how
carbohydrates or fat affect health (called article 1)
• Read it
• Find an article supporting or debunking the claim (called article 2)
• Must be from a credible, scientific source
• Turn in a hard copy that contains
• The date, source, article name, author(s) of article 1
• One to three bullet points describing the claim in article 1
• The date, source, article name, author(s) of article 2
• One to three bullet points about how article 2 supports or debunks the claim in article 1