Carbohydrates Flashcards
The most common source of energy is a biomolecule called what?
carbohydrate
Carbohydrates provide chemical energy in what forms?
3 carbs that provide energy?
- Glucose
- Starch
- Glycogen
Carbohydrates, in plants, are components of supportive structures. What do u call this carb?
present in plant cell walls
cellulose
What are the two carbohydrates present in nucleic acids?
- D-ribose
- 2-deoxy-D-ribose
Before, scientists thought of Carbohydrates as hydrates of what?
Carbon
What is the empirical formula of Carbohydrates?
Cn(H2O)m
Glucose or Galactose, for example, is a carbohydrate w/ a general formula C6H12O6. Divide these by a factor of 6 and you’ll be left w/ CH2O which is a “hydrate of carbon” (C w/ water)
At the molecular level, most carbohydrates are what?
poly + functional grp (2 ‘to)
- polyhydroxyaldehydes
- polyhydroxyketones
or compounds that yield them after hydrolysis
What do you call the carbohydrates w/ a single sugar molecule?
monomer of carbs
Monosaccharides
____ are monosaccharides containing an aldehyde group; whereas ____ are monosaccharides containing a ketone grp
Aldoses; Ketoses
In the naming of carbohydrates, the suffix -____ indicates that a molecule is a carbohydrate.
-ose
In the naming of carbohydrates, the prefixes tri-, tetr-, pent-, etc. indicate what?
no. of carbon atoms in the chain
What do you call the simplest monosaccharides that contain three carbon atoms?
Trioses
There are only two trioses, what are they?
- Dihydroxyacetone
- Glyceraldehyde
Among the two trioses, which of them does not contain a chiral carbon atom?
Dihydroxyacetone
since no chirality present, this molecule does not have nonsuperimposable mirror-image forms (enantiomers)
Among the two trioses, which of them has a chiral carbon?
Glyceraldehyde
since there is chirality at carbon number three, there are two possible enantiomers of Glyceraldehyde: L- & D-Glyceraldehyde
The possibility of ____ increases as the number of carbon items increases.
optical isomerism
stereoisomerism
What do you call the 2-D representations of the stereochemistry of 3-D molecules?
Fischer projections
In Fischer projections, the horizontal lines represent bonds directed ____ you. The vertical lines signify that bonds are directed ____ from you.
away or toward
towards; away
dark wedges = towards u (out of the page); broken lines = away (into the page)
Who proposed the Fischer projections?
Emil FIscher
in 1891 :ooo
The D in D-enantiomer means? While L is for?
Dextrorotary; Levorotatory
L- and D- refers to the direction of rotation of plane-polarized light (clockwise or counterclockwise). Glyceraldehyde has a specific rotation of how many degrees?
+-13.5o
What monosaccharide served as the reference point for the enantiomers of all the other aldoses and ketoses?
glyceraldehyde
What do you call the Carbon that is the reference point wherein it is the next-to-the-last carbon on the chain?
penultimate carbon
A monosaccharide that, when written as a Fischer projection, has the -OH group on its penultimate carbon to the right
D-Monosaccharide
A monosaccharide that, when written as a Fischer projection, has the -OH group on its penultimate carbon to the left.
L-Monosaccharide
What do you call the monosaccharide that have four possible stereoisomers due to two chiral carbons?
Aldotetroses
2 isomers are D; 2 are L. One of each two is an epimer
What do call the diastereomers that differ from each other in the configuration at only one chiral carbon?
Epimers
The D- and L- configuration may be determined by looking at the -OH group at the ____-numbered carbon
highest or lowest
highest
In naming carbohydates, remember that we start where the aldehyde or ketone grp is. Usually, the highest-numbered carbon is the one away from the aldehyde/ketone grp
The highest-numbered carbon may be also called as what carbon?
the orientation of this carbon determines the D or L configuration
penultimate carbon
What are the most important monosaccharides to us?
hexoses found prominently in our metabolism
- D-glucose
- D-galactose
- D-fructose
Also known as dextrose, what is the most common hexose that is an aldohexose?
D-glucose
found in honey, corn syrup, veggies, fruits and in our blood
normal glucose concentrations in the blood would be?
mg/dL
65 - 110 mg/dL
1mM=18mg/dL
hyper or hypoglycemia :oo
It is the sweetest of the carbohydrates, being twice as sweet as table sugar. What is this monosaccharide?
D-fructose
D-fructose is also called what?
- levulose
- fruit sugar
Like the most common hexose, this one is also an aldohexose and is found in milk and dairy products, what do u call this monosaccharide?
D-Galactose
What do you call the condition when a person is missing the enzyme that converts D-galactose to D-glucose?
Galactosemia
Galactoose accumulates in the blood & tissues, leading to cataracts, mental detardation, and liver disease.
With pentoses and hexoses, the most stable forms are actually ____ structures containing five or six atoms.
ring
What do you call the way of representing the cyclic structure of monosaccharides?
Haworth projection
A way to view furanose and pyranose; the ring is drawn flat and viewed through its edge, with the anomeric carbon on the right and the oxygen atom to the rear.
Haworth projection
What do you call the hemiacetal carbon of the cyclic form of a monosaccharide?
Anomeric carbon
What do you call the monosaccharides that differ in configuration only at their anomeric carbons?
Anomers
What do you call the new carbon stereocenter created in forming the cyclic structure that is based on FIscher projection?
Anomeric carbon
Stereoisomers that differ in configuration only at the anomeric carbon are called ____.
Anomers
The anomeric carbon of an aldose is carbon number what in haworth projections?
Carbon 1
The anomeric carbon of ketoses are carbon number what?
Carbon 2
Cyclization of sugars takes place because of interactions between functional groups on distant carbons.
The -OH grp in Carbon number what attacks the Carbon-1in fischer projections to form a cyclic hemiacetal in aldohexoses?
Carbon-5 or Carbon-4
nucleophilic attack ng -OH grp
C-4 hydroxyl attacking the carbonyl group will lead to the formation of a 5-membered ring, while the attack of C-5 hydroxyl at the carbonyl group will generate a 6-membered ring. In the case of glucose, a 6-membered ring is thermodynamically more stable than a 5-membered ring, thus favoring the formation of a 6-membered ring over a 5-membered ring.
Khan cyclic hemiacetals
On Fischer projections, the substituents of the stereocenters located right are pointing where in Haworth projections?
pointing down
only exemptions, if u’ll notice, are carbons 5 & 6. This is because the OH of the nucleophilic carbon needs to be in a desirable location (nearest the aldehyde or ketone). So the substituents of these groups rotate in a counterclockwise manner so that -OH of C-5 will easily attack the aldehyde.
Ochemtutor timestamp
On Fischer projections, the substituents of the stereocenters located left are pointing where in Haworth projections?
pointing up
only exemptions, if u’ll notice, are carbons 5 & 6. This is because the OH of the nucleophilic carbon needs to be in a desirable location (nearest the aldehyde or ketone). So the substituents of these groups rotate in a counterclockwise manner so that -OH of C-5 will easily attack the aldehyde.
Ochemtutor timestamp
What do you call a six-membered hemiacetal ring?
pyranose
indicated by -pyran-
corresponds to the shape of the heterocyclic compound pyran
What do you call a five-membered hemiacetal ring?
furanose
indicated by -furan-
corresponds to the shape of the heterocyclic compound furan
On Fischer projections, the -OH grp at the anomeric carbon that is located right are what types of anomers in Haworth projections?
α-anomer
In Fisher projections, the ones located on the right are pointing down. since we know that CH2OH is pointing up on Haworth, the α- designation means that the -OH is trans to CH2OH
On Fischer projections, the -OH grp at the anomeric carbon that is located left are what types of anomers in Haworth projections?
β-anomer
In Fisher projections, the ones located on the left are pointing up. since we know that CH2OH is pointing up on Haworth, the α- designation means that the -OH is cis to CH2OH
In Haworth projections, the α- designation means that the -OH of the anomeric carbon is ____ to CH2OH
cis or trans?
trans
CH2OH is pointing up while the -OH grp of the anomeric carbon is pointing down
In Haworth projections, the β- designation means that the -OH of the anomeric carbon is ____ to CH2OH
cis or trans?
cis
CH2OH is pointing up and the -OH grp of the anomeric carbon is pointing up too
Because the α- and β- forms of glucose are six-membered cyclic hemiacetals, they are named ____ & ____, respectively
α-d-glucopyranose; β–d-glucopyranose
The designations -furan- and -pyran- are sometimes omitted in monosaccharide. Thus, the glucopyranoses, for example, are often named simply as what?
α-d-glucose & β-d-glucose
The most prevalent forms of D-ribose and other pentoses in the biological world are ____.
furanoses or pyranoses
furanoses
remember that the sugar grps in nucleics are pentoses (aldopentoses) and are 5-membered rings ryt
What do you call the change in specific rotation that occurs when an α or β form of a carbohydrate is converted to an equilibrium mixture of the two forms?
Mutarotation
α-D-glucose has a specific rotation of how many degrees?
+112o
this is how much it rotates plane-polarized light
β-D-glucose has a specific rotation of how many degrees?
+18.7o
this is how much it rotates plane-polarized light
In water or aqeuous solutions, glucose (α-D-glucose & β-D-glucose) has now a rotation of how many degrees?
+52.7o
In equilibrium, the glucose mixture consists of how much (in %) α-D-glucose & β-D-glucose?
glucose is in equi when in water
- α-D-glucose = 36%
- β-D-glucose = 64%
iirc, this is because the +18.7o of β-D-glucose is much nearer the equilibrium rotation of +52.7o than the 112o rotation of α-D-glucose
mutarotation ochemtutor
The treatment of a monosaccharide—all forms of which exist almost exclusively as cyclic hemiacetals—with an alcohol yields a what?
hemiacetal (sabi natin sugars r hemiacetals) + alcohol
- CHO + alcohol forms RO-C-OH (hemiacetal/hemiketal)
- RO-C-OH + alcohol forms RO-C-OR (did not add the other two substituents pa ng C which is supposed to be another R and H)
an acetal
cyclic acetal
Formation of Glycosides (Acetals) - Treatment of an aldehyde or a ketone with one molecule of alcohol yields a hemiacetal and treatment of the hemiacetal with a molecule of alcohol yields an acetal.
click
2nd source
A cyclic acetal derived from a monosaccharide is called a what?
glycoside
What do you call the bond from the anomeric carbon to the -OR grp in cyclic acetals?
glycosidic bond
Condensation reactions between a hydroxyl oxygen atom on carbon on one sugar and the anomeric form of another sugar result in the formation of glycosidic bond. Then water is formed what is a glycosidic bond?
Unlike a hemiacetal, an acetal is no longer in equilibrium with the open-chain carbonyl-containing compound, mutarotation is ____.
possible or not possible
not possible
What is the name of the glycoside of β-D-glucose after reacting w/ methanol?
methyl β-D-glucoside
In naming glycosides, we add the alkyl or aryl grp bonded to the oxygen then the -e suffix is replaced with ide.
A variety of reducing agents, such as H in the presence of a transition metal catalyst and sodium borohydride (NaBH4) can reduce the ketone grp of a monosaccharide to a ____.
to what functional grp?
hydroxyl grp
-OH grp; 2ndary alcohol
What do you call the product after a carbonyl grp of a monosaccharide is reduced to a hydroxyl group?
carbonyl group = aldehyde (CHO)
alditol
After the carbonyl group (aldehyde) of D-glucose is reduced, the product is now called as?
what do u call d alditol
D-glucitol
more commonly known as D-sorbitol
We name alditols by dropping the -ose from the name of the monosaccharide and adding -itol
Since aldehydes may be oxidixed to form carboxylic acids, aldoses may also be oxidized under ____ conditions to form a carboxylate grp.
acidic or basic
basic
the cyclic form of the aldose is oxidized by the mild oxidizing agent. Therefore, the aldose is what type of agent and what reaction did it undergo?
reducing agent; oxidation
Under basic conditions, the cyclic form of the aldose is in equilibrium with the open-chain form, which is then oxidized by the mild oxidizing agent. C1 of D-Glucose, for example, is oxidized to what?
D-gluconate
What do you call a carbohydrate that reacts with a mild oxidizing reagent under basic conditions to give an aldonic acid?
reducing sugars
the carbohydrate reduces the oxidizing agent
What test is used to detect the presence of reducing sugars?
Tollens test
Oxidation of a cyclic hemiacetal form gives a ____, which is a cyclic ester linking the carboxyl grp and one of the sugar alcohols.
lactone
What is the oxidizing agent used in Tollens test?
Ag(NH3)2+
If anomeric carbons are involved in a glycosidic linkage, then the result in Tollens will be ____.
(+) or (-)?
negative
i think this is because may naka-bond n sa carboxylate ion so Ag(NH3)2+ cannot bond n (ata) haha so walang silver mirror appearance s tube
If anomeric carbons is not bonded and is free, then the result in Tollens will be ____.
(+) or (-)?
positive
i think this is because Ag(NH3)2+ can bond n (ata) haha and Ag is responsible for its silver mirror appearance s tube
What do you call the reduced sugars in which a hydrogen atom is substituted for one of the hydroxyl groups of the sugar?
present in nucleic acids
Deoxy sugars
An enzyme-catalyzed oxidation of the primary alcohol at carbon 6 of a hexose yields a what?
uronic acid
The enzyme-catalyzed oxidation of D-glucose yields what?
D-glucuronic acid
D-Glucuronic acid is widely distributed in both the plant and animal worlds. In humans, it serves as an important component of the acidic polysaccharides of connective tissues
What is formed by transfer of a phosphate group from ATP to give the phosphorylated sugar and ADP?
the bond between the phosphate grp and d phosphorylated sugar?
A phosphate group is transferred from ATP to glucose, making glucose-6-phosphate, which is the first step in glycoslysis
from ATP to Gluc
Phosphate esters
these are intermediates in the breakdown of carbohydrates to provide energy
What do you call a glycoside involving a furanose?
furanoside
What do you call a glycoside involving a pyranose?
Pyranoside
The glycosidic bonds between monosaccharide units are the basis for the formation of what saccharides?
oligo and polysaccharides
the notation for the linkage specifies the bond between the anomeric carbon nd d other carbon where d glycosidic bond is attached to.
If the internal monosaccharide residues that are incorporated in a polysaccharide form only two glycosidic bonds, the polymer will be ____.
linear, cyclic, branched, or what?
linear
If the internal monosaccharide residues that are incorporated in a polysaccharide form three glycosidic bonds, the polymer will be ____.
linear, cyclic, branched, or what?
branched
What do you call sugars with a substituted amino grp (-NH2)?
Amino sugars
What do you call carbs that have two units?
disaccharides
3 units r trisaccharides
We use the general term ____ to describe carbohydrates that contain six to ten monosaccharide units.
Oligosaccharides
In a disaccharide, 2 monosaccharide units are joined by a glycosidic bond between the ____ of one unit and an ____ group of another unit.
anomeric carbon; -OH
Condensation reactions between a hydroxyl oxygen atom on carbon on one sugar and the anomeric form of another sugar result in the formation of glycosidic bond. Then water is formed
what is a glycosidic bond?
What is known as the most abundant disaccharide and is acquired from the juice of sugar cane and beets?
Sucrose
What are the two monosaccharide units involved in the formation of sucrose?
- α-D-glucopyranose
- β-D-fructofuranose
β-D-fructose & α-D-glucose
In sucrose, carbon 1 of α-D-glucopyranose bonds to carbon 2 of β-D-fructofuranose by what linkage notation?
α-D-glucose to β-D-fructose by what bond?
α, β-1,2-glycosidic bond
C-1 of α-D-glucose to C-2 of β-D-fructose
glu + fru = sucrose
Both anomeric carbons of sucrose are involved in the formation of a glycosidic bond, therefore, sucrose is what type of of sugar?
reducing or non-reducing
non-reducing sugar
____ derives its name from its presence in malt, the juice from sprouted barley and other cereal grains.
what disaccharide
Maltose
from starch
Maltose consists of two monosaccharide units. What are they?
D-glucopyranose
D-glucose (2 cla)
The 2 monosaccharide units of maltose are enjoined between carbon 1 of one units and carbon 4 of the other unit, thereby naming the linkage notation as?
α-D-glucopyranose to β-D-glucopyranose by what bond?
α-1,4-glycosidic bond
C-1 of α-D-glucose to C-4 β-D-glucose
If β-D-glucose to α-D-glucose, then the molecule is cellobiose and not maltose
In maltose, since the hemiacetal group β-D-glucose on the right of α-D-glucose is in equilibrium w/ the free aldehyde and can be oxidized to a carboxylic acid, maltose can be classified as what type of sugar?
reducing or nonreducing
reducing sugar
What is the disaccharide principally present in milk?
Lactose
What are the two monosaccharide units involved in the formation of lactose?
- β-D-Galactopyranose
- β-D-Glucopyranose
β-D-Galactose & β-D-Glucose
What do you call the linkage notation between the carbon 1 of β-D-Galactose and carbon 4 of β-D-Glucose?
this is d
β-1,4-Glycosidic bond
In lactose, since the hemiacetal group β-D-glucose on the right of β-D-galactose is in equilibrium w/ the free aldehyde and can be oxidized to a carboxylic acid, lactose can be classified as what type of sugar?
reducing or nonreducing
reducing sugar
Among the common sweetening agents, what tastes the sweetest?
even sweeter than table sugar?
D-fructose
What are the three important polysaccharides all made up of glucose?
starch, glycogen, and cellulose
homosaccharide din cla
What do you call the polysaccharide used for energy storage in plants?
Starch
found in all plant seeds and tubers & is d form in which glucose is stored for later use
Starch can be separated into two principal polysaccharides. What are they?
Amylose & Amylopectin
The complete hydrolysis of Amylose and Amylopectin yields to?
α-D-Glucose
Amylose is composed of continuous, unbranched chains of as many as 4000 D-glucose units joined by ____.
α-1,4-glycosidic bonds
Amylopectin is composed of continuous, branching chains of as many as 10,000 D-glucose units joined by ____.
α-1,4-glycosidic bonds
The branches of Amylopectin consists of 24-30 D-glucose units that start/are joined with an ____.
what linkage notation?
α-1,6-glycosidic bonds
What do you call the helix conformation that is characterized with six residues per turn and is the most usual conformation of amylose?
Starch-Iodine Complex
Iodine molecules fit into the helix to form the complex
What enzymes attack the α-1,4-glycosidic bonds of starch?
2 cla
- α-amylase
- β-amylase
Identify the type of amylase
an exoglycosidase that cleaves from the nonreducing end of the polymer
β-amylase
Identify the type of amylase
Maltose is the product of the reaction
β-amylase
Identify the type of amylase
an endoglycosidase that hydrolyzes glycosidic linkages anywhere along the chain
α-amylase
Identify the type of amylase
Glucose and maltose are the products of the reaction
α-amylase
____ enzymes degrade the α-1,6-glycosidic bonds of branches and they occur in both plants and animals.
Debranching enzymes
What do you call the energy-reserve carbohydrate for animals?
Glycogen
Like amylopectin, glycogen is a branched polysaccharide containing how many glucose units?
~106 glucose units
Like amylopectin, glycogen’s α-D-glucoses are joined by what linkage notation? what about its branches?
- α-1,4-glycosidic bonds (for α-D-glucose)
- α-1,6-glycosidic bonds (for branching)
What do you call the protein situated at the heart of every glycogen?
Glycogenin
What enzymes assist in the breakdown of glycogen?
- Glycogen phosphorylase
- Debranching enzymes
What polysaccharide is the major structural component of plants, especially of wood and plant fibers?
Cellulose
Cotton is almost pure cellulose btw
Cellulose is a linear polysaccharide made up of what glucose anomer?
β-D-glucose
The β-D-glucose units of Cellulose are joined by what linkage notations?
β-1,4-glycosidic bonds
Cellulose form intermolecular ____ bonds which accounts for the polysaccharide’s water-insoluble and well-organized characteristic.
hydrogen bonds
Humans and other animals cannot use cellulose as food source because of the absence of what enzyme in our digestive system?
β-glucosidase
We only have α-glucosidase in our body that is why we can only use starch and glycogen as sources of glucose
____ are a group of polysaccharides that contain carboxyl groups and/or sulfuric ester groups
Acidic polysaccharides
Because acidic polysaccharides contain amino sugars, a more current name for these substances is?
glycosaminoglycans
one of the sugars is an amino sugar and at least one sugar has a negative charge due to the presence of a sulfate of carboxyl grp
____ is the simplest acidic polysaccharide present in connective tissue. It has a molecular weight between 105 and 107 g/mol
Hyaluronic acid
also has 300 to 100,000 repeating units and most abundant in embryonic tissues and other “fluid” tissues
Hyaluronic acid is joined by a ____ bond between D-glucuronic acid and N-acetyl-D-glucosamine.
β-1,3-glycosidic bond
N-acetyl-D-glucosamine, which is in turn linked to D-glucuronic acid by a B-1,4-glycosidic bond
____is a heterogeneous mixture of variably sulfonated polysaccharide chains, ranging in molecular weight from 6000 to 30,000 g/mol. This acidic polysaccharide is synthesized and stored in mast cells.
Heparin
Heparin binds strongly to a plasma protein called what to terminate the clotting process?
anticoagulant
antithrombin III
A heparin preparation with good anticoagulant activity contains a minimum of eight repeating units. The larger the molecule, the greater its anticoagulant activity
What do you call the linear homopolysaccharide with all the residues linked in β-1,4-glycosidic bonds?
Chitin
If the monomer of cellulose if β-D-glucose, the monomer of chitin is ____.
N-acetyl-β-D-glucosamine
What polysaccharide is present as the major structural component in the exoskeletons of invertebrates and occurs in cell walls of algae, fungi, and yeast?
Chitin
What do you call the polysaccharides that are major components of bacterial cell walls?
hetero or homo
heteropolysaccharides
Identify the heteropolysaccharide
- Polysaccharide that contains peptide crosslink
- found in bacterial cell wall
Peptidoglycan
Identify the heteropolysaccharide
- Polymer made up of D-galacturonic acid which is a derivative of galactose
- found in plant cell walls
Pectin
Identify the heteropolysaccharide
- Major nonpolysaccharide component in plant cell walls
- Polymer of coniferyl alcohol
kainis tlga c andrew naglalagay ng hindi nmn saccharides JUSME
Lignin
What do you call the molecules that contain residues that are covalently linked to the polypeptide chain?
Glycoproteins
What do you call the sugar chains present in glycoproteins?
oligosaccharide
The oligosaccharide in antibodies (which are glycoprotz) acts as ____, which are portions of molecules that antibodies recognize as foreign and to which they bind
antigenic determinants
What do you call the sugar chains present in proteoglycans?
glycosaminoglycans
The two monomers in heteropolysaccharides are held together by β-1,4-glycosidic bonds. What r the two monomers?
- N-acetyl-D-glucosamine
- N-acetylmuramic acid
Branched-chain polymer of A-D-glucose that is deposited in bodily tissues as a store of carbohydrates
Glycogen
Type of sugar where antibodies belong to
Glycoproteins
Polymer of D-galacturonic acid that is found in cell walls
Pectin
