Carbs Flashcards
are the most abundant organic
compounds in the plant world
carbohydrates
storehouse of energy
glucose, starch
supportive structure in plants
cellulose
crustacean shells
chitin
connective tissues
acidic polysaccharide
essential components of nucleic acids
D-Ribose, 2-deoxy-D-Ribose
A polyhydroxyaldehyde or polyhydroxyketone, or a substance that gives these compounds on hydrolysis.
Carbohydrates
A carbohydrate that cannot be hydrolyzed to a simpler carbohydrate.
monosaccharide
Monosaccharides have the general formula
CnH2nOn, where n varies from 3 to 8
A monosaccharide containing an aldehyde group.
Aldose
A monosaccharide containing a ketone group.
Ketose
The suffix -ose indicates that a molecule is a
carbohydrate
The suffix -ose indicates that a molecule is a
carbohydrate
Those containing an aldehyde group are classified as
Aldoses
Those containing a ketone group are classified as
Ketoses
the simplest aldose, contains one stereocenter and exists as a pair of enantiomers
glyceraldehyde
A two-dimensional representation for
showing the configuration of tetrahedral stereocenters.
Fisher Projection
represent bonds projecting forward
from the stereocenter
Horizontal line
represent bonds projecting to the rear
vertical lines
the -OH on its penultimate carbon
is on the right in a Fischer projection
D- monosaccharide
the -OH on its penultimate carbon
is on the left in a Fischer projection
L- monosaccharide
contain an -NH2 group in place of an -OH
group
Amino Sugars
only 3 amino sugars are common in nature
D-glucosamine, D-mannosamine, and D-galactosamine
is an acetylated derivative of
D-glucosamine
N-acetyl-D-glucosamine
Aldehydes and ketones react with alcohols to form
hemiacetals
form readily when hydroxyl and
carbonyl groups are part of the same molecule and
their interaction can form a five- or six-membered ring
cyclic hemiacetal
A five- or six-membered cyclic hemiacetal is
represented as
planar ring
The new carbon stereocenter created in forming the cyclic structure is called
anomeric carbon
Stereoisomers that differ in configuration only at the anomeric carbon are called
anomers
The anomeric carbon of an aldose is
C2
means that the -OH on the anomeric carbon is on the same side of the ring as the terminal -CH2OH
beta
means that the -OH on the anomeric carbon is on the side of the ring opposite from the terminal -CH2OH
alpha
A six-membered hemiacetal ring is called
pyranose
a five-membered hemiacetal ring is called
furanose
The most prevalent forms of D-ribose and other pentoses in the biological world are
furanoses
also form cyclic hemiacetals
aldopentoses
The prefix “deoxy” means
without oxygen
also forms a five-membered cyclic hemiacetal
D- Fructose
For pyranoses, the six-membered ring is more accurately
represented as a
strain-free chair conformation
The change in specific rotation that
accompanies the equilibration of alpha- and beta-anomers in
aqueous solution.
Mutarotation
When either -D-glucose or -D-glucose is
dissolved in water, the specific rotation of the solution gradually changes to an equilibrium value of
+52.7°, which corresponds to 64% beta and 36% alpha forms
A cyclic acetal derived from a monosaccharide is
glycoside
The bond from the anomeric carbon to the -OR group is called a
glycosidic bond
Mutarotation is not possible for a glycoside because
an acetal, unlike a hemiacetal, is not in equilibrium with the open-chain carbonyl-containing compound
Glycosides are stable in water and aqueous base
but like other acetals, are hydrolyzed in aqueous acid to an alcohol and a monosaccharide
Glycosides are named by
listing the alkyl or aryl group bonded to oxygen followed by the name of the carbohydrate in which the ending -e is replaced by -ide
The carbonyl group of a monosaccharide can be reduced to an hydroxyl group by a variety of
reducing agents, including NaBH4 and H2
in the presence of a transition metal catalyst (H2/Pt)
The reduction product is called
Alditol
Alditols are named by
by changing the suffix -ose to -itol
is found in the plant world in many berries and in cherries, plums, pears, apples, seaweed, and algae
Sorbitol
It is about 60 percent as sweet as sucrose (table sugar)
Sorbitol
The aldehyde group of an aldose is oxidized under
basic conditions to a carboxylate anion
The oxidation product is called an
aldonic acid
A carbohydrate that reacts with an oxidizing agent to form an aldonic acid is classified as a
reducing sugar
(it reduces the oxidizing agent).
• 2-Ketoses (e.g. D-fructose) are also reducing sugars
The body uses _______to detoxify foreign alcohols
and phenols.
glucuronic acid
The intravenous anesthetic _____ is converted to the following water-soluble glucuronide and excreted.
Propofol
A carbohydrate containing
two monosaccharide units joined by a
glycosidic bond.
Disaccharide
A carbohydrate containing from six to ten monosaccharide units, each joined to the next by a glycosidic bond.
Oligosaccharide
A carbohydrate containing a large number of monosaccharide units, each joined to the next by one or more glycosidic bonds.
Polysaccharide
carbon 1 of α-D-glucopyranose bonds to carbon 2 of D- fructofuranose by an α-1,2-glycosidic bond
Sucrose
The principle sugar present in milk.
• About 5 - 8% in human milk, 4 - 5% in cow’s milk
Lactose
This disaccharide consists of D- galactopyranose bonded by a β-1,4-glycosidic bond to carbon 4 of Dglucopyranose.
Lactose
the juice of sprouted barley and other cereal grains.
Maltose
• It consists of two units of D- glucopyranose joined by a glycosidic bond between carbon 1 (the anomeric carbon) of one unit and carbon 4 of the other unit.
a-1,4-glosidic bond
Maltose
A carbohydrate consisting of large
numbers of monosaccharide units joined by glycosidic bonds.
Polysaccharide
A polymer of D-glucose and used for energy storage in plants.
Starch
Starch can be separated into
amylose and amylopectin
Amylose is composed of unbranched chains of up to
4000 D-glucose units joined by a-1,4-glycosidic bonds
Amylopectin contains chains up to
10,000 D-glucose
units also joined by a-1,4-glycosidic bonds. At branch points, new chains of 24 to 30 units are started by a-1,6-glycosidic bonds.
is a branched polymer of Dglucose units joined by a-1,4-glycosidic bonds. Branches consist of D-glucose units that start with an a-1,6-glycosidic bond.
amylopectin
is the energy-reserve carbohydrate for animals
Glycogen
Glycogen is a branched polysaccharide of
approximately
106 glucose units joined by a-1,4- and a-1,6-glycosidic bonds.
The total amount of glycogen in the body of a wellnourished adult human is about
350 g, divided almost
equally between liver and muscle.
is a linear polysaccharide of D-glucose units joined by b-1,4-glycosidic bonds.
Cellulose
It has an average molecular weight of 400,000 g/mol,
corresponding to approximately 2200 glucose units per
molecule.
Cellulose
It has an average molecular weight of 400,000 g/mol,
corresponding to approximately 2200 glucose units per
molecule.
Cellulose
Humans and other animals can not digest cellulose because their digestive systems do not contain
b-glycosidases, enzymes that catalyze the hydrolysis of b-glycosidic bonds.
Humans have only _____ ; hence, the polysaccharides we use as sources of glucose are starch and glycogen.
a-glucosidases
a group of polysaccharides that
contain carboxyl groups and/or sulfuric ester groups, and play important roles in the structure and function of connective tissues.
Acidic polysaccharide
is the simplest acidic polysaccharide
present in connective tissue.
hyaluronic acid
is synthesized and stored in mast cells of
various tissues, particularly the liver, lungs, and gut.
Heparin
The best known and understood of its biological
functions is its anticoagulant activity.
Heparin
is composed of D-glucuronic acid
joined by a b-1,3-glycosidic bond to N-acetyl-Dglucosamine, which is in turn linked to D-glucuronic
acid by a β-1,4-glycosidic bond.
Hyaluronic acid
is composed of D-glucuronic acid
joined by a b-1,3-glycosidic bond to N-acetyl-Dglucosamine, which is in turn linked to D-glucuronic
acid by a β-1,4-glycosidic bond.
Hyaluronic acid
