CARBOHYDRATES Flashcards
Are aldehyde or ketone derivatives of polyhydric alcohols consisting of carbon, hydrogen, and oxygen
CARBOHYDRATES
carbohydrates consists of
carbon, hydrogen, oxygen
carbohydrates are ____ and ____ derivatives
aldehyde & ketone
carbohydrates can be classified as ____ and ____
aldoses & ketoses
have many OH in their structure
polyhydric alcohol
general formula for carbohydrates
(CnH2O)n
carbohydrates that are found in foods such as fruits, milk, and vegetables
simple carbohydrates
carbohydrates that provide vitamins, minerals, and fiber.
foods such as bread, legumes, rice, pasta, and starchy vegetables
complex carbohydrates
IMPORTANCE OF CARBOHYDATES
Provide a significant fraction of the ____ in the diet of most organisms
ENERGY
IMPORTANCE OF CARBOHYDATES
____ form of energy in the body
STORAGE
storage form of carbohydrates in plants
STARCH
storage form of carbohydrates in humans
GLYCOGEN
glycogen is stored in what organs
liver, muscle
IMPORTANCE OF CARBOHYDATES
Cell membrane components that mediate some forms of ____
intercellular communication
IMPORTANCE OF CARBOHYDATES
carbohydrate in the CELL WALLS OF BACTERIA
PEPTIDOGLYCAN
IMPORTANCE OF CARBOHYDATES
carbohydrate in the EXOSKELETON OF MANY INSECTS
CHITIN
IMPORTANCE OF CARBOHYDATES
carbohydrate that is the FIBROUS component of the PLANT CELL WALL
CELLULOSE
a structural polysaccharide
CELLULOSE
IMPORTANCE OF CARBOHYDATES
Serves as ____ of many organisms
STRUCTURAL COMPONENT
IMPORTANCE OF CARBOHYDATES
____ contains sugar as an essential features of their structure;
plant metabolites
beside a sugar
glycoside
non sugar component of glycoside
AGLYCONE
sugar component of glycoside
GLYCONE
IMPORTANCE OF CARBOHYDATES
Play an ____ in plant-animal interaction, protection from wound and infection and detoxification of foreign substances
ECOLOGICAL ROLE
IMPORTANCE OF CARBOHYDATES
____ and ____ are used as food and pharmaceutical.
SUGAR & STARCH
- The most important carbohydrate;
- Dietary carbohydrate absorbed into the bloodstream;
- Major metabolic fuel of mammals and universal fuel of the fetus.
GLUCOSE
Glucose is classified/categorized as ____
ALDOHEXOSE
synonym of glucose
blood sugar
Glucose is a precursor for the synthesis of what nucleic acids
DNA & RNA
Glucose is a precursor for the synthesis of ____ – in lactose of milk, in glycolipids, and in combination with protein in glycoproteins and
proteoglycans
GALACTOSE
Disease associated with Carbohydrate Metabolism
disease that cannot digest & lacks β-1,4 enzymes
lactose intolerant
Disease associated with Carbohydrate Metabolism
previously considered as a hereditary disease, but now a lifestyle disease
DIABETES MELLITUS
Disease associated with Carbohydrate Metabolism
- has galactose in the bloodstream instead of glucose
- a metabolic disorder that can lead to lens opacity and cataract formation
GALACTOSEMIA
CARBOHYDRATES
ratio of carbon molecule to water molecule
1:1
in every carbon, there is 1 water molecule
the 1:1 ratio of carbon & water in carbohydrates is only applicable to ____
monosaccharides
carbohydrate is also known as
hydrate of carbon
- “simple sugars”
- Cannot be hydrolyzed into simpler carbohydrates;
- Contains a single polyhydroxy aldehyde or ketone unit
MONOSACCHARIDE
glucose, fructose
MONOSACCHARIDE
MONOSACCHARIDE
Cannot be hydrolyzed into ____
SIMPLE CARBOHYDRATES
MONOSACCHARIDE
Contains a ____ polyhydroxy aldehyde or ketone unit
SINGLE
MONOSACCHARIDE
classification is based on:
- number of C
- whether they have aldehyde or ketone group
classification of glucose
aldohexose
classification of fructose
ketohexose
simplest aldose
glycerose / glyceraldehyde
simplest ketose
dihydroacetone
Most monosaccharides have a ____ taste;
sweet
solubility of monosaccharides
very soluble in water
monosaccharides are ____ at room temperature
solid
as the saccharide unit increases, the solubility in water ____
DECREASES
basis for the relative sweetness
SUCROSE - 1.00
found on caramelized sugar
invert sugar
fruit sugar
fructose
inverted sugar is brown due to
levulose
sweetest sugar
fructose
anomeric carbon for glucose
C1
most predominant form of glucose
β-D-glucose
monosaccharides form ____ ring
pyranose
how many stereoisomers are possible in the structure of glucose
2
fructose form ____ ring
furanose
D-glucose in solution
dextrose
anomeric carbon for fructose
C2
TESTS FOR CARBOHYDRATES
- aldehydes and ketones that have an OH group on the carbon next to the carbonyl group react with a basic solution of Cu+2 (Benedict’s reagent) to form a red-orange precipitate of copper(I) oxide (Cu2O)
- sugars that undergo this reaction are called reducing sugars
OXIDATION OF MONOSACCHARIDES
TESTS FOR CARBOHYDRATES
reagent used for the oxidation of monosaccharides
BENEDICT’S REAGENT
TESTS FOR CARBOHYDRATES
result for oxidation of monosaccharides
red-orange precipitate
TESTS FOR CARBOHYDRATES
sugars that undergo oxidation are called
reducing sugars
all of the ____ are reducing sugars
monosaccharides
____ can form at the 6-carbon of aldohexoses and aldoketoses
phosphate esters
found in the sugar-phosphate backbone of DNA & RNA, in ATP, and as intermediates in the metabolism of carbohydrtaes in the body
phosphate esters of monosaccharide
seven-carbon sugar
sedoheptulose
derivatives of trioses, tetroses, & pentoses & sedoheptulose
monosaccharides
monosaccharides are formed as ____ in glycolysis and pentose phosphate pathway
metabolic intermediates
MONOSACCHARIDES
are important in nucleotides, nucleic acids and several coenzymes
PENTOSES
MONOSACCHARIDES
glucose, galactose, fructose, and mannose
HEXOSES
monosaccharides are ____ derivatives of glucose
carboxylic acid
MONOSACCHARIDES
for glucuronide formation and in glycosaminoglycans
D-glucuronate
MONOSACCHARIDES
metabolic derivatives of D-glucuronate
(in glycosaminoglycans)
L-iduronate
MONOSACCHARIDES
an intermediate in the uronic acid pathway
L-gulonate
- Meaning “two sugars“
- Are commonly found in nature as sucrose, lactose and maltose (LSM)
- Formed by a condensation reaction where one molecule of water condenses or is released during the joining of two monosaccharides
DISACCHARIDES
disaccharides are formed by what reaction
condensation reaction
The type of bond that is formed between the two sugars is called
GLYCOSIDIC BOND
disaccharides are found commonly in nature as ____, ____, ____
lactose, sucrose, maltose
LSM
- An excellent preservative because it has no “reducing end” or reactive group like the other sugars
- Other natural sources are found in plants such as sugar cane, sugar beets, and maple syrup
- Hydrolysis yields mixtures of glucose and fructose called “invert sugars”
SUCROSE
SUCROSE
An excellent preservative because it has no ____ or ____ like the other sugars
reducing end or reactive group
SUCROSE
Hydrolysis of sucrose yields mixtures of glucose and fructose called
inverted sugars
- beta-glycosidic bonds are unable to be digested by some people
- Many people are lactose intolerant and suffer from intestinal cramping and bloating due to the incomplete digestion of the substance
LACTOSE
Isomaltose, maltose, lactose, lactulose, sucrose and trehalose
DISACCHARIDES
α-D-Glucopyranosyl-(1→2)-β-D-fructofuranose
SUCROSE
β-D-Galactopyranosyl-(1→4)-α-D-glucopyranose
LACTOSE
α-D-Glucopyranosyl-(1→4)-β-D-Glucopyranose
MALTOSE
oligo means
few
Important oligosaccharides are ____ and ____ which are found in beans and legumes
raffinose
stachyose
- Raffinose and stachyose, because of their unique glycosidic bonds, cannot be broken down into their simple sugars.
- Therefore, they cannot be absorbed by the small intestine and are often metabolized by bacteria in the large intestine to form unwanted gaseous by-products.
OLIGOSACCHARIDES
- Condensation products of more than ten monosaccharide units;
- not reducing sugars, since the anomeric carbons are connected through glycosidic linkages
POLYSACCHARIDES
not digested by human enzymes, and are major component of dietary fibers
non starch polysaccharides
a glucose polymer
cellulose
a fructose polymer
inulin
polysaccharides are classified as
homoglycan
heteroglycan
same set of monosaccharides
HOMOGLYCAN
different sets of monosaccharide
HETEROGLYCAN
HETEROGLYCAN or HOMOGLYCAN
glucan / glucosan
fructosan
HOMOGLYCAN
HETEROGLYCAN or HOMOGLYCAN
gums & mucilages
HETEROGLYCAN
- Homopolymer of D glucose units forming an α-glucosidic chain (called glucosan or glucan);
- ____ (and other glucose polymers) are usually insoluble in water because of high molecular weight;
- the major storage form of carbohydrates in plants and of two different forms: amylose and amylopectin
STARCH
STARCH
- consists of long, unbranched chains of glucose (from 1000 to 2000 molecules) connected by α(1→4) glycosidic linkages
- 10-20% of starch in plants is in this form
- its chain is flexible enough to allow the molecules to twist into the shape of a helix. Because it packs more tightly, it is slower to digest than other starches
AMYLOSE
amylose helices can ____ molecules of iodine, formaing a characteristic deep blue-purple color
TRAP
amylose helices can trap molecules of iodine, formaing a characteristic ____ color
deep blue-purple
often used as a test for the presence of starch
IODINE
amylose contains what glycosidic linkage
α(1→4)
STARCH
- consists of long chains of glucose (up to 10⁵ molecules) connected by α(1→4) glycosidic linkages, with α(1→6) branches every 24 to 30 glucose units along the chain
- 80-90% of the starch in plants is in this form
AMYLOPECTIN
glycosidic linkages found in amylopectin
α(1→4) & α(1→6)
color of amylopectin in iodine TS
blue-violet
- Measure of digestibility of starchy food
- Based on the extent to which it raises the blood concentration of glucose compared with an equivalent amount of glucose or a reference food such as white bread or boiled rice.
GLYCEMIC INDEX
- also known as animal starch, is structurally similar to amylopectin, containg both α(1→4) glycosidic linkages and & α(1→6) branch points
- even more highly branched, with branches occuring every 8 to 12 glucose units
- abundant in the liver and muscles
- on hydrolysis it forms D-glucose which maintains normal blood sugar level and provides energy
GLYCOGEN
the branching in amylopectin occurs every ____
24 to 30 glucose units
the branching in glycogen occurs every ____
8 to 12
Glycogen forms ____ in hydrolysis which maintains normal blood sugar level and provides energy
D-glucose
STARCH
unbranched
AMYLOSE
STARCH
branched
AMYLOPECTIN
highly branched
(animals)
GLYCOGEN
color of glycogen in iodine TS
reddish brown
- most abundant organic substance on earth
- a polymer consisting of long, unbranched chains of D-glucose connected by β(1→4) glycosidic linkagaes
- it may contain from 300 to 3000 glucose units in one molecule
CELLULOSE
glycosidic linkages of cellulose
β(1→4)
- a polymer of N-acetylglucosamine, an amide derivative of the amino sugar – glucosamine, in which one of the OH groups is converted to an amine (NH2) group.
- the polymer is extremely strong becasue of the increased hydrogen bonding provided by the amide groups
CHITIN
an amide derivative of the amino sugar – glucosamine
N-acetylglucosamine
- A polysaccharide of fructose found in tubers and roots of dahlias, artichokes, and dandelions
- Readily soluble in water
- Use to determine glomerular filtration
- Not hydrolyzed by intestinal enzymes
INULIN
Intermediates in the hydrolysis of starch
dextrins
GLYCOSAMINOGLYCANS is also known as
mucopolysaccharides
- Complex carbohydrates containing amino sugars and uronic acid;
- May be attached in protein molecule to form proteoglycan.
GLYCOSAMINOGLYCANS
or mucopolysaccharides
- provide the ground or packing substance of connective tissues;
- Hold large quantities & water supply, occupies space lubricating other structures.
PROTEOGLYCANS
- Proteins containing branched & unbranched oligosaccharide chains;
- They occur in the cell membranes and many other situations;
GLYCOPROTEINS
example of glycoproteins / mucoproteins
serum albumin
GLYCOPROTEINS is also known as
mucoproteins
nine carbon sugar derived from mannosamine and pyruvate
NEURAMINIC ACID
- are N- or O-acyl derivatives of neuraminic acid
- Constituents of both glycoproteins & gangliosides (glycolipids)
- important in viruses (esp. those with influenza)
SIALIC ACID
Are formed by the condensation between the hydroxyl group of the anomeric carbon of monosaccharide (glycone), and a second compound that may not be another monosaccharide (aglycone)
GLYCOSIDES
GLYCOSIDES
- most stable glycoside
- resistant to hydrolysis
C-glycoside
GLYCOSIDES
- if the second group is a hydroxyl
- Acetal link (formed from an aldehyde and an –OH)
O-glycoside
GLYCOSIDES
- if the second group is amine
- Ex.: adenine and ribose in ATP
N-glycoside
GLYCOSIDE
If the hemiacetal (aldehyde + -OH) portion is glucose, the resulting compound is ____
GLUCOSIDE
GLYCOSIDE
If the hemiacetal (aldehyde + -OH) portion is galactose, the resulting compound is ____
GALACTOSIDE
GLYCOSIDES
may be methanol, glycerol, a sterol, a phenol, or a base such as adenine
AGLYCONE
MEDICINALLY IMPORTANT GLYCOSIDES
- Contain steroids as aglycone
- Include derivatives of digitalis (digoxin, digitoxin) and strophantus (ouabin)
CARDIAC GLYCOSIDE
derivatives of digitalis
digoxin, digitoxin
derivatives of strophantus
ouabin
MEDICINALLY IMPORTANT GLYCOSIDES
streptomycin
aminoglycoside antibiotics
- Lack an oxygen atom
- one hydroxyl group has been replaced by hydrogen
- deoxyribose in DNA
DEOXYSUGARS
DNA is deoxygenated at what carbon
C2
deoxysugar in glycoproteins
L-fructose
used experimentally as inhibitor of glucose metabolism
2-deoxyglucose
are components of glycoproteins, gangliosides, & glucosaminoglycosides
HEXOSAMINES
constituent of hyaluronic acid
D-glucosamine
constituent of chondroitin
D-galactosamine (chondrosamine)
AMINOSUGARS
D-glucosamine
D-galactosamine (chondrosamine)
D-mannosamine
Aminoglycosides antibiotics & macrolides
simplest carbohydrate that exists in two isomeric forms
GLYCERALDEHYDE
glyceraldehyde is a ____ molecule – it cannot be superimposed on its mirror imnage
CHIRAL
the two mirror-image forms of glyceraldehyde are ____ of each other
ENANTIOMERS
glucose can form ____ isomers
16
- Mirror images
- Determined by spatial relationship to the parent compound of the carbohydrates
D & L isomerism
OH group is on the right
D-isomer
OH group is on the left
L-isomer
Most monosaccharides in mammals are
D-sugars
Two possible structures for the pyranose and furanose forms of a monosaccharide
Alpha and beta anomers
OH down
alpha
OH up
beta
6 membered ring
5 carbon
1 oxygen
PYRANT
5 membered ring
4 carbon
1 oxygen
FURAN
- Sugars that differ in configuration at ONLY 1 POSITION
- Isomers differing as a result of variations in configuration of the –OH and –H on carbon atoms 2, 3, and 4 glucose (epimers of glucose)
- Examples:
▫ D-glucose & D-galactose (epimeric at C4)
▫ D-glucose & D-mannose (epimeric at C2)
▫ D-idose & L-glucose (epimeric at C5)
EPIMERS
EPIMERS
D-glucose & D-galactose
epimeric at ____
C4
EPIMERS
D-glucose & D-mannose
epimeric at ____
C2
EPIMERS
D-idose & D-glucose
epimeric at ____
C5
- The most important epimers of glucose
- Formed by epimerization at carbon 2 and 4, respectively
MANNOSE & GALACTOSE
- are a convenient way to represent mirror images in two dimensions
- place the carbonyl group at or near the top and the last achiral CH₂OH at the bottom
FISCHER PROJECTIONS
OPTICAL ACTIVITY
substance rotates polarized light to the left
LEVOROTATORY
OPTICAL ACTIVITY
substance rotatets polarized light to the right
DEXTROROTATORY
molecules that rotate the plane of polarized light
optically active
