Download Chapter 6: Carbohydrates

Chapter 6: Carbohydrates
Define the following terms.
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added sugars—sugars extracted from
plants and used to sweeten foods.
carbohydrates—nutrient that is a
person’s main source of energy; found
mostly in plant foods.
chlorophyll—green pigment in plants;
must be present for photosynthesis to
occur.
complex carbohydrates—
carbohydrates with complicated
structures; starches.
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dietary fiber—plant materials that are
eaten but can’t be digested by human
enzymes.
disaccharides—form when two
monosaccharides (single sugars)
combine chemically.
monosaccharides—sugars with singleunit chemical structure.
photosynthesis—chemical process by
which plants make carbohydrates.
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polysaccharides—complicated
chemical arrangements that plants form
by combining single glucose units to
build starches.
simple carbohydrates—sugars formed
from simple one- and two-unit structures.
starches—formed when plants combine
single glucose units into more
complicated chemical structures.
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sugars—simple carbohydrates
chemically formed from plants; made of
carbon, hydrogen, and oxygen.
sugar substitutes—artificial sweeteners
and sugar alcohols are
Answer the following questions.
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What kinds of foods provide
carbohydrates?
Some are in milk; most are in plant
foods, including fruits, vegetables, grain
products, dry beans, nuts, and seeds.
Describe photosynthesis.
Using the sun’s energy, plants convert
carbon dioxide and water into oxygen
and the sugar glucose.
What makes glucose and
sucrose different?
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Glucose is a monosaccharide, which has a
one-unit chemical structure. Sucrose is a
disaccharide, which has a two-unit chemical
structure.
If you saw the word dextrose on a food
label, what would you know about that
particular ingredient? Why?
You would know it is a sugar because it ends
in-ose.
What is the difference between
sugars and starches?
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Because their one- and two- unit structures are
chemically simple, sugars are called simple
carbohydrates. Starches combine single
glucose units into more complicated chemical
structures and are called complex
carbohydrates.
Why isn’t dietary fiber a nutrient?
Because it cannot be digested by human
enzymes
A teen had a long bike ride coming up the
next day, so he decided to get ready by
eating a big steak the night before.
• Explain you opinion of his decision.
• Since energy-producing glucose is only
available through plant foods, the steak
won’t help.
• During digestion, what happens to the
carbohydrates you have eaten?
• Most are converted back to glucose.
Fiber passes through the system
undigested.
How is the sugar in an apple
different from the sugar in a cookie?
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The apple has naturally occurring
sugars. The cookie has added sugar put
there for sweetening.
10. Since sugars are used to make
starch in a plant, why don’t such
starchy foods as potatoes taste
sweet?
The starch molecules are too large to fit
the taste buds receptors
Predict what might happen if a person
eliminated all carbohydrates from his or
her diet.
• Eliminating all carbohydrates would disrupt
many body processes and make the person
have less energy.
• Why might a lack of glycogen be a problem?
• Glycogen is extra glucose that has been stored
for times when the body needs extra energy. If
it’s not available, the body will use protein for
energy, taking it away from building and
repairing tissues.
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A friend says to you: “I’m supposed to cut
down on carbohydrates, so I don’t eat
many starchy foods now.” Thinking of
health, how might you respond?
This is not a good idea because health experts
suggest that your daily carbohydrate allowance
come mostly from complex carbohydrates and
naturally occurring sugars rather than added
sugars.
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If someone on a 2,000-calorie diet
drinks a 12-ounce soft drink, how
much more sugar could the person
eat during the day if following USDA
suggestions?
None; the drink probably has about 10
teaspoons of sugar, which is the daily
limit suggested fro a 2,000-calorie diet.
Suppose a cereal bar haws 16 g of
sugar. How many teaspoons of
sugar is that?
• 4 teaspoons ( 16 divided by 4)
• How can a food that replaces sugar
with a sugar substitute be high in
calories?
• It would still be high in calories if it’s high
in fat, which has 9 calories per gram.
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Why do some people think that
starchy foods make people gain
weight?
Because they are often eaten with high
fat spreads, sauces, and gravies.
If fiber is just eliminated as
waste, why is it needed?
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Fiber:
absorbs water and helps food move
through the large intestine at a normal
rate;
promotes regular bowel movements;
helps prevent constipation;
may help reduce cholesterol;
adds to feeling of fullness when eating.
What kinds of foods contribute
fiber to the diet?
– Whole-grain foods;
– Dry beans. peas, and lentils;
– Cooked vegetables.