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biochem
carbohydrates
193
Pharmacology
Professional
10/19/2009

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Term
Monosaccharides are simple sugars that consist of _____ and _____
Definition
aldoses and ketoses
Term
Aldoses are named for their ____
Definition
aldehydes
Term
Ketoses are named for their _____
Definition
ketones
Term
The simplest aldose is _____
Definition
glyceraldehyde
Term
The simplest ketose is _____
Definition
dihydroxyacetone
Term
___ and ____ are the most abundant monosaccharides
Definition
pentoses and hexoses
Term
Sugars have multiple ___ ____ ___
Definition
chiral carbon atoms
Term
Sugars are either __ or __ based on the chiral carbon furthest from the carbonyl carbon
Definition
D or L
Term
Most sugars in living organisms are the __ form
Definition
D form
Term
The chiral carbon is usually carbon #__
Definition
carbon #2
Term
Enantiomers are _____ images
Definition
mirror
Term
Diastereomers are ____ images
Definition
non-mirror
Term
____ are non-mirror images that differ in configuration at a single carbon (such as ribose and arabinose)
Definition
Epimers
Term
__________ primarily exist in ring forms by means of a rxn between a hydroxyl and carbonyl
Definition
Sugars with 4 or more carbons
Term
cyclic aldehydes are also known as ___
Definition
hemiacetals
Term
cyclic ketones are also known as ____
Definition
hemiketals
Term
Another name for a 5-membered ring
Definition
furan (furanose)
Term
another name for a 6-membered ring
Definition
pyran (pyranose)
Term
When sugars cyclize, the carbonyl carbon becomes a chiral center called the _____ _____
Definition
anomeric carbon
Term
There are two possible diastereomers that form from cyclization and they are called _____
Definition
anomers
Term
based on the stereochemistry, the anomeric carbon is either in ____ form or ____ form
Definition
alpha or beta
Term
What is mutarotation?
Definition
when sugar forms spontaneously interconvert when dissolved in water - usually more alpha-D-glucose than others
Term
6 reacions of monosaccharides
Definition
oxidation, reduction, esterification, isomerization, glycoside formation, and glycosylation
Term
what is an aldonic acid?
Definition
change from an aldehyde to a carboxylic acid
Term
what is a uronic acid?
Definition
change from terminal CH2OH to a carboxylic acid
Term
what is an aldaric acid?
Definition
when an aldehyde and the terminal CH2OH change to a carboxylic acid
Term
aldonic and uronic acids can cyclize to form a ______
Definition
lactone
Term
when can one use benedict's reagant?
Definition
to oxidize monosaccharides: used to detect a reducing sugar in urine
Term
which uronic acids are biologically important?
Definition
D-glucuronic acid and L-iduronic acid
Term
D-glucuronic acid and L-iduronic acid are _____
Definition
epimers
Term
glucuronic acid combines with other molecules in the liver to ______________
Definition
improve solubility to help remove wastes from the body
Term
Vitamin C is a form of _____ acid
Definition
uronic (derived from D-glucuronic acid)
Term
______ of aldehyde and ketone groups of sugars results in "sugar alcohols"
Definition
reduction
Term
"sugar alcohols" are also called _____
Definition
alditols
Term
_____ no longer have terminal aldehyde because it's been changed to a hydroxyl
Definition
alditols
Term
_______ (D-glucitol) is commonly found in candy
Definition
Sorbitol
Term
isomerization requires a(n) _______
Definition
intermediate
Term
glucose can convert to fructose and mannose in alkaline solution via _____
Definition
isomerization
Term
the intermediate required in isomerization is called a(n) ______
Definition
enediol (double bonded group and 2 alcohols)
Term
_____ are involved in some rxns during carb metabolism
Definition
enediols
Term
______ is when the free OH groups of carbs are converted to esters via reaction with acids
Definition
esterification
Term
what are the most common esters?
Definition
phosphate and sulfate esters
Term
______ esters are found in carb metabolism
Definition
phosphate esters
Term
_____ esters are found in proteoglycans
Definition
sulfate esters
Term
the reaction of an alcohol with a hemiacetal or hemiketal produces _____ or ____
Definition
acetal or ketal
Term
what is the bond between two sugars called?
Definition
glycosidic linkage
Term
when two molecules combine via glycosidic linkage, they are called a _____
Definition
disaccharide
Term
_____ are long chains of monosaccharides combined by a series of glycosidic linkages
Definition
polysaccharides
Term
the acetal form of glucose is a _____
Definition
glucoside
Term
the ketal form of glucose is _____
Definition
fructoside
Term
in glycoside naming, 5-membered rings form ____ and 6-membered rings form ____
Definition
furanosides and pyranosides
Term
the addition of methanol to glucose produces ____ ____
Definition
methyl glucoside (used in manufacturing)
Term
in methyl glucoside, there is a link between a ____ group and ____ group
Definition
methyl and hydroxyl
Term
_____ reactions attach sugars (monomers and polymers) to proteins or lipids
Definition
glycosylation
Term
what are N-glycosidic bonds?
Definition
bonds that involve a bond between oligosaccharides and the amino NITROGEN of asparagine residues and link sugar to it
Term
what are O-glycosidic bonds?
Definition
bonds that involve a bond between an oligosaccharide and the hydroxyl OXYGENS of serine or threonine and link a sugar to it
Term
______ was originally called dextrose
Definition
D-glucose
Term
_____is the primary fuel for living cells and is the preferred energy source for brain cells and also for cells that have few mitochondria
Definition
D-glucose
Term
_____ is one of the most abundant biomolecules
Definition
D-glucose
Term
dietary sources of glucose include:
Definition
plant starch, disaccharides (lactose, maltose, sucrose)
Term
liver cells can synthesize glucose via ______
Definition
gluconeogenesis
Term
________ is produced by plants during photosynthesis
Definition
alpha-D-glucose
Term
3 important kind of MONOsaccharides
Definition
glucose, fructose, and galactose
Term
_____ was originally called levulose - referred to as fruit sugar
Definition
fructose
Term
Is fructose an aldose or a ketose?
Definition
ketose
Term
____ is twice as sweet as sucrose and is used in food production
Definition
fructose
Term
___ is used in the male reproductive tract as an energy source for sperm
Definition
fructose
Term
____ is used in synthesizing numerous biomolecules used by cells
Definition
galactose
Term
cells can synthesize _____ from glucose-1-phosphate when the diet does not produce enough
Definition
galactose
Term
what is galactosemia?
Definition
when the enzyme needed to metabolize galactose is missing - can be a problem when it builds up (mental retardation)
Term
______ is involved in producing glycolipids and glycoproteins and lactose in breast milk
Definition
galactose
Term
in ____ sugars, a hydroxyl group is replaced by an amino group - often found in the complex carbs attached to proteins and lipids
Definition
amino sugars
Term
D-glucosamine and D-acetylglucosamine are examples of
Definition
amino sugars
Term
____ sugars are monosaccharide derivatives that have a -H in place of an -OH
Definition
deoxy sugars
Term
linkages occur between the _____ carbon of one sugar and a ______ on another sugar
Definition
anomeric carbon and hydroxyl
Term
alpha-1,4 linkage is:
Definition
linking between anomeric carbon (carbon#1) of one sugar and #4 carbon on another sugar
Term
always number carbons starting with the ____
Definition
anomeric carbon
Term
4 key disaccharides
Definition
lactose, maltose, cellobiose, and sucrose
Term
what is lactose?
Definition
disaccharide; milk sugar; a combination of galactose and glucose; has beta-1,4 linkage
Term
lactose requires ____ to digest
Definition
lactase
Term
what is maltose?
Definition
disaccharide; the intermediate of starch hydrolysis; has 2 D-glucose molecules; has alpha-1,4 linkage
Term
what is cellobiose?
Definition
disaccharide; the degradation product of cellulose; 2 D-glucose molecules; has beta-1,4 linkage
Term
what is sucrose?
Definition
disaccharide; table sugar; alpha-glucose and beta-fructose; beta-1,2 linkage
Term
what is unique about sucrose's linkage?
Definition
it is beta 1,2 linkage (linkage between both anomeric carbons)
Term
polysaccharides are also called ___
Definition
glycans
Term
_____ are glycans with up to 10-15 monomers
Definition
oligosaccharides
Term
two classes of polysaccharides
Definition
homoglycans and heteroglycans
Term
_____ are composed of a single type of monosaccharide
Definition
homoglycan
Term
____ are composed of two or more different TYPES of monosaccharides
Definition
heteroglycans
Term
3 important kinds of homoglycans
Definition
starch, glycogen, and cellulose
Term
polysaccharides like ____ and ____ have no fixed molecular weight
Definition
starch and glycogen
Term
____ is an energy reservoir in plant cells and a significant energy source in the human diet
Definition
starch
Term
starches are made of two different polysaccharides: ____ and ____
Definition
amylopectin and amylose
Term
_____ is part of starch that is made of unbranched chains of d-glucose with alpha(1,4) linkages - it's a single linear chain that becomes a helix
Definition
amylose
Term
_____ is made of branched chains of D-glucose with alpha(1,4) and alpha(1,6) linkages
Definition
amylopectin
Term
_____-_____ breaks down amylopectin into individual monomers so you can absorb glucose into digestive tract and get it circulating
Definition
alpha-amylase
Term
what are reducing ends?
Definition
any sugar that, in an alkaline solution, forms some aldehyde or ketone. This allows the sugar to act as a reducing agent (like in benedict's reaction) - ring opens and becomes aldehyde and has reducing properties
Term
what are non-reducing ends?
Definition
the end which does not have a reducing agent. It lacks a free glycosidic hydroxyl.
Term
____ is the carbohydrate storage form used by vertebrates
Definition
glycogen
Term
______ is most abundant in liver and muscle cells (8-10% of liver; 2-3% of muscle cells)
Definition
glycogen
Term
___ involves compact branched chains of D-glucose similar to the structure of amylopectin (branches have closer spacing than amylopectin and are VERY very branched)
Definition
glycogen
Term
glycogen has numerous _______ ends that allows cells to rapidly break it down and release glucose
Definition
non-reducing ends
Term
____ is the structural polysaccharide in plants made of D-glucopyranose with beta1,4 linkages
Definition
cellulose
Term
_____is probably the most abundant organic substance on earth
Definition
cellulose
Term
in ______, unbranched chains pair together via H-bonds into bundles (microfibril - 40 pairs combine to form the structure found in plant cells)
Definition
cellulose
Term
_____ digests cellulose
Definition
cellulase
Term
types of heteroglycans
Definition
N-glycans, O-glycans, glycosaminoglycans (GAGs), glycan components of glycolipids, GPI anchors (glycosylphophatidylinositol)
Term
in __-glycans, sugar groups are linked to the nitrogen of the side chain made of asparagine residue
Definition
N-glycans
Term
what is the bond between the nitrogen (on protein) and the anomeric carbon of the N-acetylglucosamine (sugar) in N-glycans?
Definition
beta-glycosidic bond
Term
chain polysaccharides have _____ linkages
Definition
alpha (1,4)
Term
branched polysaccharides have ____ linkages
Definition
alpha (1,6)
Term
GAGs is short for ____
Definition
glycosaminoglycans
Term
______ are linear polymers of repeating dissacharides (specific groups of two sugars linked together in a specific way - range from 10 to hundreds of disaccharides - unbranched
Definition
GAGs
Term
GAGs generally contain a __-_______ ______ ______
Definition
6-carbon uronic acid (CH2OH to carboxylic acid)
Term
repeating groups in GAGs contain both _____ and _____ groups with negative charges
Definition
carboxyl and sulfate
Term
____ _____ keeps chains separated and the hydrophilicity attracts and maintains large volumes of water - vastly increasing the volume of space occupied
Definition
charge repulsion
Term
5 classes of GAGs
Definition
hyaluronic acid, chondroitin sulfate, dermatan sulfate, heparin and heparan sulfate, keratan sulfate
Term
How are GAGs connected to protein?
Definition
via serine or threonine (except in hyaluronic acid - connects via asparagine)
Term
which GAG is a component of cartilage?
Definition
chondroitin sulfate (negatively charged)
Term
in chondroitin sulfate, ____ and _____ are linked together
Definition
glucose and galactose
Term
chondroitin sulfate has a(n) ___-linked sugar at the end
Definition
O-linked
Term
which GAG is found primarily in the skin?
Definition
dermatan sulfate
Term
____ is a GAG that is an anticoagulant and is found in mast cells
Definition
Heparin
Term
____ is similar to heparin but has fewer sulfate and more acetyl groups
Definition
Term
which GAG is found in the cornea, cartilage, and intervertebral discs?
Definition
keratan sulfate
Term
which GAG is found in the vitreous humor of the eye, backbone sugars, and synovial fluid of the joints
Definition
hyaluronic acid
Term
which GAG has two glucose molecules combined in a different way?
Definition
hyaluronic acid
Term
_____ are compounds that combine carbohydrates with either lipids or proteins
Definition
glycoconjugates
Term
3 types of glycoconjugates
Definition
glycolipids, proteoglycans, glycoproteins
Term
______ serve structural and functional roles generally on the surface of cells or in the extracellular matrix
Definition
glycoconjugates
Term
proteoglycans have higher _____ content and are generally proteins linked to GAGs
Definition
carbohydrate
Term
glycoproteins do not usually have _____, ____, and ______ - they also have lower ____ content and more _____
Definition
uronic acids, sulfate groups, and disulfide repeating groups; lower carb content, more protein content
Term
_____ are GAGs linked to proteins
Definition
proteoglycans
Term
_______ are present on the cell surface or secreted into the extracellular matrix - they aren't held within the cell, but generated within the cell, link to proteins, and secreted from cell or bound to cell surface
Definition
proteoglycans
Term
in proteoglycans, GAGs are linked to ___ ___
Definition
core proteins
Term
proteoglycans use ___ and ____ linkages
Definition
N-glycosidic (linked to nitrogen of asparagine) and O-glycosidic (linked to hydroxyl group of serine or threonine) linkages
Term
there is a large amount of diversity in proteoglycans due to:
Definition
number of different core proteins and variety of classes and lengths of carb chains
Term
______ ______ are a series of proteoglycans linked to a common central GAG backbone made of hyaluronic acid
Definition
proteoglycan aggregates
Term
_____ are a type of proteoglycan aggregate that includes a transmembrane core protein with a sugar linked to the outside of the cell (membrane-linked)
Definition
syndecans
Term
_____ are a type of proteoglycan aggregate that are linked to a membrane via GPI anchors (such a heperan sulfate)
Definition
glypicans
Term
____ is a type of proteoglycan aggregate that is found in cartilage; it is a combination of chondroitin sulfate and keratan sulfate attached to a core
Definition
aggrecan
Term
____ _____ has a sugar backbone made of hyaluronic acid with core proteins linked to it and then more proteins (proteoglycans) linked to those core proteins
Definition
proteoglycan aggregates
Term
in ______, N-linked carb chains are formed initially and then added to the protein during synthesis (sugars are added later)
Definition
glycoproteins
Term
in ______, O-linked chains are built directly on the protein in the Golgi (and sugars are added at the golgi)
Definition
glycoproteins
Term
examples of glycoproteins
Definition
immunoglobulins, hormones, metal transport proteins, membrane proteins, ABO blood group system, and antifreeze in antarctic
Term
_____ ______ is a short repeating tripeptide sequence that keeps water from forming ice crystals
Definition
antifreeze glycoprotein
Term
_____ and ______ residues attach to a threonine (O-linked) in antifreeze glycoproteins
Definition
galactose and N-acetylgalactosamine
Term
in antifreeze glycoproteins, sugar residues form ____bonds with _____ and retards ice crystal formation
Definition
H-bonds with water
Term
______ is the layer outside most eukaryotic cells containing a large number of carbs; they serve as structural, signaling, and recognition roles for cells and tissues
Definition
glycocalyx
Term
what are some ways to increase the diversity of biomolecules to accomplish the many tasks required in cells?
Definition
alternative splicing and covalent modification
Term
___-_____ _______ includes phosphorylation, acetylation, glycosylation, etc
Definition
post-translational modification
Term
there is no _____ for sugars in coding - our body knows how to put sugars together
Definition
template
Term
how does the cell recognize the vast array of different carbs?
Definition
proteins (lectins) are able to bind to specific carb groups
Term
lectins are also known as ______
Definition
translators
Term
____ are used in numerous types of interactions for recognition (especially cell-cell)
Definition
lectins
Term
what is a glycome?
Definition
all the different types of sugars in your body
Term
a ___ is a term used to refer to the set of sugar and glycans that can be produced - all the different combinations of sugars in our bodies
Definition
glycome
Term
what are glycoforms?
Definition
variations of a specific glycoprotein
Term
____ is the breakdown of glycogen to produce energy
Definition
glycolysis
Term
____ is the production of glucose from specific precursors
Definition
gluconeogenesis
Term
____ ____ is involved in the production of ribose for nucleotides
Definition
pentose phosphate
Term
_____ _____ is the building (glycogenesis) or break down (glycogenolysis) of glucose
Definition
glycogen metabolism
Term
______ are found in many plant foods (fruits and veges) and in whole grain in foods; they cannot be broken down by the body, but are important in our diet
Definition
dietary fiber
Term
glycolysis is the breakdown of ____ to form __ ______
Definition
glucose; 2 pyruvates
Term
anaerobic organisms convert pyruvate to ___
Definition
waste products
Term
aerobic organisms use oxygen as an electron _____ and convert pyruvate into ___ and _____
Definition
acceptor; CO2 and H20
Term
What is the net reaction of glycolysis?
Definition
D-glucose + 2ADP + 2P + 2NAD -> 2 pyruvate + 2ATP + 2NADH + 2H + 2H20
Term
NAD+ is used as an electron acceptor for what reason?
Definition
used in electron transport chain (in mitochondria) to make more ATP
Term
glucose is phosphorylated to form _____ and needs what?
Definition
glucose-6-phosphate; requires ATP
Term
_____ converts glucose to G6P
Definition
hexokinase
Term
hexokinase 1,2,3 are saturated at ____ concentrations of glucose and are _____ by G6P
Definition
low; inhibited
Term
hexokinase 4 requires ____ glucose concentration and is ___ _____ by G6P
Definition
high; not inhibited
Term
glucose-6-phosphate is converted (rearranged) to _____ by ____ ______
Definition
fructose-6-phosphate (F6P) by phosphoglucose isomerase (PGI)
Term
which steps in glycolysis require/generate ATP?
Definition
glucose to G6P; F6P to DHAP and GAP; glycerate-1,3,-biphosphate to glycerate-3-phosphate; and PEP to pyruvate
Term
F6P is phosphorylated to ______ by _______ and requires ______
Definition
fructose-1,6-bisphosphate; phosphofructokinase-1; requires ATP
Term
_________ is a major regulator of glycolysis and is inhibited by ATP and stimulated by AMP and F2,6BP
Definition
phosphofructokinase-1
Term
____ is a bifunctional kinase and phosphatase
Definition
phosphofrucokinase-2
Term
______ cleaves fructose-1,6-bisphosphate to form _______ and _______
Definition
aldolase; glyceraldehyde-3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP)
Term
______ reaction is thermodynamically unfavorable but proceeds because products are rapidly used
Definition
F1,6P to DHAP and GAP
Term
___ is the production of glycogen
Definition
glycogenesis
Term
_____ converts DHAP to GAP
Definition
triose phosphate isomerase
Term
______ removes a hydride ion from GAP and adds a phosphate to form ________
Definition
glyceraldehyde-3-phosphate dehydrogenase; glycerate-1,3-bisphosphate (G1,3P)
Term
the oxidation of GAP process also involves conversion of ___ to ____
Definition
NAD+ to NADH (which also requires an inorganic phosphate)
Term
after converstion of GAP to G1,3P a ________kinase catalyzes the production of ____ from ____ and one of the phosphoryl groups on G1,3P, which then forms _______
Definition
phosphoglycerate kinase; ATP to ADP; creates glycerate-3-phosphate
Term
___-____ _____ involves the production of ATP from a molecule with higher phosphoryl transfer potential than ATP
Definition
substrate-level phosphorylation
Term
at what point is the net production of ATP equal to zero?
Definition
when ATP is converted to ADP due to phosphoglycerate kinase
Term
______ ____ interconverts 3-phosphoglycerate to ___________
Definition
phosphoglycerate mutase; to 2-phosphoglycerate
Term
the intermediate between 3PG and 2PG is ______
Definition
glycerate 2,3 bisphosphate
Term
_____ removes a water molecule from glycerate-2-phosphate (2-phosphoglycerate) or 2PG to form ___________
Definition
enolase; to form phosphoenolpyruvate (PEP)
Term
the enol in PEP refers to the _____ bond
Definition
carbon=carbon double bond
Term
___ ___ catalyzes the formation of ATP using the phosphate from PEP, also leaving ______
Definition
pyruvate kinase; pyruvate
Term
_______ step gives ATP net production of 2
Definition
PEP to pyruvate
Term
pyruvate is first in the ____ form and is quickly changed to the ____ form
Definition
enol; ketone
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