Carbohydrates
compounds composed of carbon, oxygen, and hydrogen arranged as monosaccharides or multiples of monosaccharides; most have a ratio of one carbon molecule to one water molecule (CH2O)
Sugars
monosaccharides and disaccharides
Monosaccharides
carbohydrates of the general formula that typically form a single ring
Glucose
a monosaccharide; sometimes known as blood sugar or dextrose
Fructose
a monosaccharide; sometimes known as fruit sugar or levulose; fructose is found abundantly in fruits, honey, and saps
Galactose
a monosaccharide; part of the disaccharide lactose
Disaccharides
pairs of monosaccharides linked together
Condensation
a chemical reaction in which water is released as two reactants combine to form one larger product
Maltose
a disaccharide composed of two glucose units; sometimes known as malt sugar
Sucrose
a disaccharide composed of glucose and fructose; commonly known as table sugar, beet sugar, or cane sugar; sucrose also occurs in many fruits and some vegetables and grains
Lactose
a disaccharide composed of glucose and galactose; commonly known as milk sugar
Polysaccharides
compounds composed of many monosaccharides linked together
Oligosaccharide
an intermediate string of three to ten monosaccharides
Glycogen
an animal polysaccharide composed of glucose; manufactured and stored in the liver and muscles as a storage form of glucose; glycogen is not a significant food source of carbohydrate and is not counted as a dietary carbohydrate in foods
Starches
plant polysaccharides composed of glucose
Dietary fibers
in plant foods, the nonstarch polysaccharides that are not digested by human digestive enzymes, although some are digested by GI tract bacteria; dietary fibers include cellulose, hemicelluloses, pectins, gums and mucilages as well as the nonpolysaccharide
Soluble fibers
nonstarch polysaccharides that dissolve in water to form a gel; ie is pectin from fruit which is used to thicken jellies; can be used in reduction of cholesterol
Viscous
a gel-like consistency
Fermentable
the extent to which bacteria in the GI tract can break down fibers to fragments that the body can use
Insoluble fibers
nonstarch polysaccharides that do not dissolve in water; examples include the tough, fibrous structures found in the strings of celery and the skins of corn kernels
Resistant starches
starches that escape digestion and absorption in the small intestine of healthy people
Phytic acid/phytate
a nonnutrient component of plant seeds; occurs in the husks of grains, legumes, and seeds and is capable of binding minerals such as zinc, iron, calcium, magnesium and copper in insoluble complexes in the intestine, which the body excretes unused
Amylase
an enzyme that hydrolyzes amylose (a form of starch); a carbohydrase, an enzyme that breaks down carbohydrates
Satiety
the feeling of fullness and satisfaction
Maltase
an enzyme that hydrolyzes maltose
Sucrase
an enzyme that hydrolyzes sucrose
Lactase
an enzyme that hydrolyzes lactose
Lactose intolerance
a condition that results from inability to digest the milk sugar lactose; characterized by bloating, gas, abdominal discomfort, and diarrhea; lactose intolerance differs from milk allergy, which is caused by an immune reaction to the protein in milk
Lactase deficiency
a lack of the enzyme required to digest the disaccharide lactose into its component monosaccharides (glucose and galactose)
Kefir
a fermented milk created by adding Lactobacillus acidophilus and other bacteria that break down lactose to glucose and galactose, producing a sweet, lactose-free product
Gluconeogenesis
the making of glucose from a noncarbohydrate source
Protein-sparing action
the action of carbohydrate (and fat) in providing energy that allows protein to be used for other purposes
Ketone bodies
the metabolic products of the incomplete breakdown of fat when glucose is not available in the cells
Ketosis
an undesirably high concentration of ketone bodies in the blood and urine
Acid-base balance
the equilibrium in the body between acid and base concentrations
Insulin
a hormone secreted by special cells in the pancreas in response to (among other things) increased blood glucose concentration; the primary role of insulin is to control the transport of glucose from the bloodstream into the muscle and fat cells
Glucagon
a hormone that is secreted by special cells in the pancreas response to low blood glucose concentration and elicits release of glucose from liver glycogen stores
Epinephrine
a hormone of the adrenal gland that modulates the stress response; formerly called adrenaline; when administered by injection, epinephrine counteracts anaphylactic shock by opening the airways and maintaining heartbeat and blood pressure
Diabetes
a chronic disorder of carbohydrate metabolism, usually resulting from insufficient or ineffective insulin
Type 1 diabetes
the less common type of diabetes in which the pancreas fails to produce insulin
Type 2 diabetes
the more common type of diabetes in which the cells fail to respond to insulin
Hypoglycemia
an abnormally low blood glucose concentration
Glycemic response
the extent to which a food raises the blood glucose concentration and elicits an insulin response
Glycemic index
a method of classifying foods according to their potential for raising blood glucose
Added sugars
sugars and syrups used as an ingredient in the processing and preparation of foods such as breads, cakes, beverages, jellies, and ice cream as well as sugars eaten separately or added to foods at the table
Dental caries
decay of teeth
Dental plaque
a gummy mass of bacteria
Artificial sweeteners
sugar substitutes that provide negligible, if any, energy; sometimes called nonnutritive sweeteners
Nonnutritive sweeteners
sweeteners that yield no energy (or insignificant energy in the case of aspartame)
Sugar alcohols
sugar-like compounds that can be derived from fruits or commercially produced from dextrose; also called polyols; sugar alcohols are absorbed more slowly than other sugars and metabolized differently in the human body; they are not readily utilized by ord
Nutritive sweeteners
sweeteners that yield energy, including both sugars and sugar alcohols
A monosaccharide is:
a carbohydrate with a general structure of a ring composed of carbon, hydrogen, and oxygen atoms
Monosaccharides important in nutrition are:
glucose
fructose
galactose
Disaccharides important in nutrition are:
sucrose (fructose + glucose)
lactose (galactose + glucose)
maltose (glucose +glucose)
Nearly all plant foods contain:
glucose
Most plants (especially fruits and saps) contain:
fructose
What happens in a condensation reaction?
Condensation combines two reactants to yield one product with the release of water
What happens in a hydrolysis reaction?
Hydrolysis splits one reactant into two products with the addition of water
Disaccharides include:
Sucrose, maltose, and lactose
The making of a disaccharide from two monosaccharides is an example of:
Condensation
The significant difference between starch and cellulose is that:
Digestive enzymes can break the bonds in starch, but not in cellulose
The ultimate goal of carbohydrate digestion and absorption is to yield:
Glucose
The enzyme that breaks a disaccharide into glucose and galactose is:
Lactase
What are the possible fates of glucose in the body?
It can be stored as glycogen
It can be used for energy
It can be converted to fat
What is the protein-sparing action of carbohydrates?
Glucose can be used for energy, leaving protein available for its special functions
How does the body maintain its blood glucose concentration?
Hormones are secreted in response to fluctuations in blood glucose
What happens when the blood glucose concentration rises too high?
When blood glucose is too high, the pancreas releases insulin, resulting in the storage of glucose in the cells
What happens when the blood glucose concentration falls too low?
When blood glucose is too low, the pancreas releases glucagon, resulting in the release of glucose into the blood
The storage form of glucose in the body is:
Glycogen
With insufficient glucose in metabolism, fat fragments combine to form:
Ketone bodies
14. What does the pancreas secrete when blood glucose rises?
Insulin
What does the pancreas secrete when blood glucose falls?
glucagon
What foods provide starches and fibers?
� Fruits
� Vegetables
� Legumes
� Whole-grain breads
� Cereals
Carbohydrates are found in virtually all foods except:
Meats
What percentage of the daily energy intake should come from carbohydrates?
45% to 65%
Carbohydrates appear in virtually all __________ foods
Plant
Carbohydrates are made of the following 3 atoms:
Carbon, oxygen, hydrogen
Which of the following compounds is a monosaccharide?
sucrose lactose
fructose pectin
maltose
Fructose
Which of the following are disaccharides?
glucose, maltose
fructose, sucrose
galactose, lactose
maltose, sucrose
maltose, sucrose
Fructose is the sweetest of sugars because:
Its chemical structure delivers a sweet sensation
A hydrolysis reaction can:
Split a disaccharide to form two monosaccharides
This reaction links two monosaccharides together:
Condensation
Disaccharides include:
Maltose
Sucrose
The principal carbohydrate of milk is:
Lactose
Fruits are usually sweet because they contain:
Simple sugars
An animal polysaccharide composed of glucose is called:
Glycogen
The difference between glycogen and starch is:
The glucose units are arranged differently
Starch is made up of
many glucose units bonded together
Fibers that do not dissolve in water are:
Insoluble fibers
Which type of starches escapes digestion and absorption in the small intestine?
Resistant starches
Most carbohydrate absorption occurs in the:
Small intestine
An enzyme that hydrolyzes sucrose is:
Sucrase
Carbohydrate digestion occurs in:
The mouth and small intestine
A condition that results from an inability to digest lactose is called:
Lactose intolerance
The main function of carbohydrates in the body is to:
Furnish the body with energy
When blood glucose levels fall, the liver:
Dismantles stored glycogen
The conversion of protein to glucose is called:
Gluconeogenesis
Ketosis is:
a condition that disturbs the body's acid-base balance
This hormone signals the release of glucose out of storage:
Glucagon
What condition results in the body's cells failing to respond to insulin:
Type 2 diabetes
_____________ refers to how quickly glucose is absorbed after a person eats and how high blood
sugar rises.
Glycemic response
Sugar causes which of these harmful condition(s):
addictions dental caries
diabetes ulcers
all of the above
Dental caries
Taken with ample fluids, fibers can help prevent what disorders?
Hemorrhoids
Appendicitis
Dietary fiber:
Provides satiety and delays hunger
Excess fiber can result in:
abdominal discomfort
gas and diarrhea