ASC 378 EXAM 2 STUDY GUIDE
3 classes of nutrients that supply energy - Answers - 1. CHO: most important
2. fat (lipids): 2nd in importance
3. protein (amino acids): main function is building blocks for protein, but they do provide
energy
CHO are produced in nature by plants in a process called photosynthesis - Answers -
6CO2 + 6H2O -> C6H12O6 + 6O2
hexoses - Answers - play a significant role in nutrition both as food components and as
products of body metabolism C6H12O6
glucose, galactose, fructose, mannose
glucose - Answers - (hexose) occurs freely in nature; aka dextrose; by far the most
important hexose
-principle source of energy in blood
-principle energy source metabolized by body
-principle component of starch and cellulose
prepared commercially by the hydrolysis of cornstarch; used for various fermentations
(alcohol products)
galactose - Answers - doesn't occur freely in nature; only part of a disaccharide
(hexose)
fructose - Answers - (ketohexose); occurs in small amounts in fruits, honey, and plant
juices; sweetest of all the sugars
mannose - Answers - (hexose) occurs in plants as mannans (hexosans, gums)
pentoses - Answers - C5H10O5 very small amount in free form, they occur primarily as
pentosans (chains of pentoses); arabinose, zylose, ribose
arabinose - Answers - (pentose) little significance, in polymer form- a component of
gums (from trees); gum arabic
xylose - Answers - (pentose); trace amount in free form; major component of some
pentosans; hydrolysis of fibrous materials such as hay, oat hulls, corn cobs, woods yield
xylose in modest amounts
ribose - Answers - (pentose); little in free form, but very important in the animal; a
component of ATP, ADP, riboflavin, RNA, DNA; can be synthesized by animal for these
components, therefore it's not an essential nutrient
, trioses - Answers - important as intermediates in metabolism of CHO, but don't occur in
nature
disaccharides - Answers - C12H22O11/2[C6H12O6]-H2O; maltose, sucrose, lactose,
cellobiose
maltose - Answers - 2 molecules of glucose attached in alpha 1, 4
sucrose - Answers - glucose and fructose; table sugar, found in sugar cane and sugar
beets; also in ripe fruits and tree sap; in livestock feeds, used to improve palitability
(creep feeds) and to improve physical nature of diet (molasses)
lactose - Answers - galactose and glucose; milk sugar; the only occurrence in nature is
as a product of mammary gland; makes up 40% of solids of milk and is the main CHO
of the newborn and young-one of main energy sources, in addition to fat; young pig has
high amount of lactase, little sucrase or amylase
lactose has physiological functions that are important to the newborn - Answers - -more
slowly hydrolyzed in the GI tract, therefore, the peaks of glucose and galactose
absorption are not as pronounced, a more constant supply of nutrients is supplied at
tissue level
-less likely to undergo acid fermentation (lactic acid) in stomach; young tract not ready
for acid product irritation and digestive upsets (more acid environment in SI)
-favors the more desirable types of microbes
-favors the absorption of minerals, Ca, P in intestines
cellobiose - Answers - 2 glucose units (like maltose) but with beta 1,4 linkages; probably
not important nutritionally for nonruminants; it's an intermediate product of cellulose
digestion in ruminants
trisaccharide - Answers - 3 monomers; raffinose (glu, gal, fru); occurs in sugar beets,
cotton seeds and a few others; not important nutritionall
polysaccharides - Answers - (C6H12O6)n; most important group in nutrition from
standpoint of quantities; the main CHO in feedstuffs; complex CHOs are polymerized
monosaccharides with glycosidic linkage; high molecular weight compounds; therefore
many monomers, 100's and 1000's; glucoside link is hydrolyzed by enzymes to form
mono and di saccharides
starch (amylase, amylopectin), dextrin, glycogen, cellulose, inulin
starch - Answers - the reserve form of energy of most plants; plants concentrate it in
seeds, tubers, fruits, etc (cereal, legumes, potatoes)
-amylose: alpha 1,4 linkage (linear)
-amylopectin: same alpha 1,4 linkages, but with alpha 1,6 branches
20% amylose, 80% amylopectin in corn starch; polymers of glucose, complete
hydrolysis yields glucose
3 classes of nutrients that supply energy - Answers - 1. CHO: most important
2. fat (lipids): 2nd in importance
3. protein (amino acids): main function is building blocks for protein, but they do provide
energy
CHO are produced in nature by plants in a process called photosynthesis - Answers -
6CO2 + 6H2O -> C6H12O6 + 6O2
hexoses - Answers - play a significant role in nutrition both as food components and as
products of body metabolism C6H12O6
glucose, galactose, fructose, mannose
glucose - Answers - (hexose) occurs freely in nature; aka dextrose; by far the most
important hexose
-principle source of energy in blood
-principle energy source metabolized by body
-principle component of starch and cellulose
prepared commercially by the hydrolysis of cornstarch; used for various fermentations
(alcohol products)
galactose - Answers - doesn't occur freely in nature; only part of a disaccharide
(hexose)
fructose - Answers - (ketohexose); occurs in small amounts in fruits, honey, and plant
juices; sweetest of all the sugars
mannose - Answers - (hexose) occurs in plants as mannans (hexosans, gums)
pentoses - Answers - C5H10O5 very small amount in free form, they occur primarily as
pentosans (chains of pentoses); arabinose, zylose, ribose
arabinose - Answers - (pentose) little significance, in polymer form- a component of
gums (from trees); gum arabic
xylose - Answers - (pentose); trace amount in free form; major component of some
pentosans; hydrolysis of fibrous materials such as hay, oat hulls, corn cobs, woods yield
xylose in modest amounts
ribose - Answers - (pentose); little in free form, but very important in the animal; a
component of ATP, ADP, riboflavin, RNA, DNA; can be synthesized by animal for these
components, therefore it's not an essential nutrient
, trioses - Answers - important as intermediates in metabolism of CHO, but don't occur in
nature
disaccharides - Answers - C12H22O11/2[C6H12O6]-H2O; maltose, sucrose, lactose,
cellobiose
maltose - Answers - 2 molecules of glucose attached in alpha 1, 4
sucrose - Answers - glucose and fructose; table sugar, found in sugar cane and sugar
beets; also in ripe fruits and tree sap; in livestock feeds, used to improve palitability
(creep feeds) and to improve physical nature of diet (molasses)
lactose - Answers - galactose and glucose; milk sugar; the only occurrence in nature is
as a product of mammary gland; makes up 40% of solids of milk and is the main CHO
of the newborn and young-one of main energy sources, in addition to fat; young pig has
high amount of lactase, little sucrase or amylase
lactose has physiological functions that are important to the newborn - Answers - -more
slowly hydrolyzed in the GI tract, therefore, the peaks of glucose and galactose
absorption are not as pronounced, a more constant supply of nutrients is supplied at
tissue level
-less likely to undergo acid fermentation (lactic acid) in stomach; young tract not ready
for acid product irritation and digestive upsets (more acid environment in SI)
-favors the more desirable types of microbes
-favors the absorption of minerals, Ca, P in intestines
cellobiose - Answers - 2 glucose units (like maltose) but with beta 1,4 linkages; probably
not important nutritionally for nonruminants; it's an intermediate product of cellulose
digestion in ruminants
trisaccharide - Answers - 3 monomers; raffinose (glu, gal, fru); occurs in sugar beets,
cotton seeds and a few others; not important nutritionall
polysaccharides - Answers - (C6H12O6)n; most important group in nutrition from
standpoint of quantities; the main CHO in feedstuffs; complex CHOs are polymerized
monosaccharides with glycosidic linkage; high molecular weight compounds; therefore
many monomers, 100's and 1000's; glucoside link is hydrolyzed by enzymes to form
mono and di saccharides
starch (amylase, amylopectin), dextrin, glycogen, cellulose, inulin
starch - Answers - the reserve form of energy of most plants; plants concentrate it in
seeds, tubers, fruits, etc (cereal, legumes, potatoes)
-amylose: alpha 1,4 linkage (linear)
-amylopectin: same alpha 1,4 linkages, but with alpha 1,6 branches
20% amylose, 80% amylopectin in corn starch; polymers of glucose, complete
hydrolysis yields glucose
