Carbohydrates Flashcards
example of monosaccharides
glucose
example of disaccharides
sucrose, glu, fru
carbohydrates
produced from ____ and _____ via photosynthesis in plants
fulfill a variety of functions:
can be covalently linked with proteins to form _______ and _______
CO2, H2O
energy source, storage
structural component of cell walls and exoskeleton
informational molecules in cell signaling
glycoproteins, proteoglycans
examples of polysaccharides
cellulose, glycogen
classification of carbohydrates are by _____
number of carbons
carbohydrates are a large class of _____ and _____
poly hydroxy aldehydes and ketones
aldose contains an ______
ketose contains a a ________
aldehyde functionality
ketone functionality
glyceraldehyde and dihydroxy acetone are ______
same composition, different connectivity
structural isomers
glyceraldehyde is a _______
same connectivity, different arrangement
stereoisomer
have the same molecular formula but different structures
isomers
isomers that are not mirror images
diastereoisomers
isomers that differ at a new asymmetric carbon atom formed on ring closure
anomers
structural isomers that differ in the configuration around only one chiral center
epimers
nonsuperimposible mirror images
enantiomers
there are four different groups attached to the carbon atom and the carbon atom is sp3 hybridized
(asymmetric)
chiral carbon
______ is the smallest sugar that has a chiral carbon
the two basic configurations around the chiral carbon are named __ and __
glyceraldehyde
D, L
the D or L configuration is determined by the ________
asymmetric carbon most distant from the carbonyl carbon
what is more stable than linear forms of monosaccharides
ring structure
aldehyde and ketone carbons are ________
alcohol oxygen atom is ________
when aldehydes are attacked by alcohols, _______ form
when ketones are attacked by alcohols, _____ form
electrophilic
nucleophilic
hemiacetals
hemiketals
cyclization of monosaccharides
the former carbonyl carbon becomes a new chiral center called the __________
the former carbonyl oxygen becomes a _______
if the hydroxyl group is on the opposite side of the right as the CH2OH moiety, the configuration is ___
if the hydroxyl group is on the same side of the ring as CH2OH moiety, the configuration is __
anomeric carbon
a
b
the carbon bearing the two configurations is called the _______
the designation of a means the OH is __________
and B means ______
anomeric carbon
below the plane of the ring
above the plane of the ring
six membered oxygen-containing rings are called _______
pyranoses
five membered oxygen containing rings are called _______
furanoses
increasing the temperature shifts the equilibrium in the direction of the furnaces form ________
reducing the sweetness of the solution
the standard five carbon sugar
ribose
the standard six carbon sugar
glucose
the ketose form of glucose
fructose
in a solution, glucose interconverts between the linear form and four cyclic conformations. this process is known as _______
mutarotation
______ due to linear form behave like aldehydes and react with oxidizing agents
glucose
the enzyme that catalyzes the conversion of glucose to glucono lactone and hydrogen peroxide
glucose oxidase
______ oxidizes organic molecules into highly colored compounds
hydrogen peroxide
alcohols and amines with glucose
glycosidic bonds
when a hydroxyl group reacts with anomeric carbon
examples: maltose, lactose, sucrose
o-glycosidic
when nitrogen of an amine react with anomeric carbon
N-glycosidic bond
the disaccharide formed upon condensation of two glucose molecules via 1 to 4 bond is called
maltose
_______ linked through O-glycosidic bonds
disaccharides
enzymes responsible for linking monosaccharides are known as
glycosyltransferases
neither the fructose or glucose can be converted to aldehyde or kept group
a non reducing sugar
enzyme for cleavage of sucrose is called
sucrase
glucose + glucose
enzyme for hydrolyzing maltose is ______
maltose
maltase
galactose to glucose makes _______
enzyme for hydrolyzing lactose is _____
lactose
lactase
found in hemolymph
glucose-glucose
trehalose
natural carbohydrates are usually found as _______
these polysaccharides can be:
polymers homopolysaccharides heteropolysaccharides linear branched
polysaccharides do not have a _________
serve as energy reservoirs and structural components
defined molecular weight
the O-glycosidic bond connects sugar monomers to form _______ and _______o
oligomers and polymers
branched homopolysaccharide of glucose
functions as the __________
glycogen
main storage polysaccharide in animals
mixture of two homopolysaccharides of glucose
_______ is an unbranched polymer of a1-4 linked residues
_______ branched like glycogen but the branch points with a1-6 linkers occur every 24-30 residues
main storage polysaccharide in _____
starch
amylose
amylopectin
plants
glycogen and starch often form _____ in cells
______ contain enzymes that synthesize and degrade these polymers
__________ have one reducing end but many non reducing ends
enzymatic processing occurs simultaneously in many ________
granules
granules
glycogen and amylopectin
nonreducing ends
most abudant organic compound
____ sugar
B-glucose allows formation of long chains
_____ form between adjacent monomers
additional H bonds between chains
structure is now tough and water insoluble
cellulose
unbranched
hydrogen bonds
_____ has straight chains, suitable for structural parts
______, opitmal for storage
cellulose, straight chains
starch and glycogen, bent structure
the _____ and _____ make cellulose a difficult substrate to act on
fungi, bacteria, and protozoa secrete _____, which allows them to use wood as source of glucose
most animals cannot use cellulose a fuel source because _________
________ live symbiotically with microorganisms that produces cellulase
_____ hold promise in the fermentation of biomass into biofuel
fibrous structure, water-insolubility cellulase lack the enzyme to hydrolyze ruminants and termites cellulases
