Exam 2 lecture 14 Carbohydrates Flashcards
constitutional isomers: order of atoms changes or stays the same?
changes
tautomers are _ isomers?
constitutional
what are the carbohydrate tautomers?
aldose andketose
fisher projections are the _ versions of carbohydrates
linear
stereoisomers have the _ connectivity but _ spatial organizations
think about rotation
the same connectivity but different spatial organizations
configurational isomers have _ carbons
chiral carbons
enantiomers are mirror images at _ centers
all chiral centers
D-sugars are nonproteinogenic or proteinogenic?
nonproteinogenic
L-sugars are nonproteinogenic or proteinogenic?
proteinogenic
T/F: Diastereomers have multiple chiral centers. Not all chiral carbons are mirror images
true
alpha is _ betat is _ when converting from Fisher to Haworth
alpha is down beta is up
anomers differ at the anomeric carbon only! which means?
alpha vs beta
epimers differ at any OTHER carbon than the anomeric carbon. this means?
same alpha or beta but differ something else (left/right)
L side goes _ D side goes _ when converting from Fisher to Haworth
L side goes up D side goes down
conformational isomers have _ rotation changes
reversible rotation around our single bond. cannot change the order around the chiral carbon
example of a conformational isomer?
nucleotides as shown with sugars and the nitrogenous base. Sugar puckers exist
Endo, chair, boat, sugar pucker are what type of isomer?
conformational isomer
glycoside are formed when _
one or more hydroxyls are replaced
glycosides:
phosphorylation happens on:
esters
glycosides:
alcohols undergo
oxidation and reduction
glycosides:
amino sugars and nucleotides have _ linkages
N-linkages
glycosides:
methylation and toxins have _ linkages
O-linkages
glycosides:
fucose replaces OH with _
methyl group
fucose is a _ derivative
galactose
fucose is only _-monosaccharide made and used by mammals
L-monosaccharide
T/F: fucose is part of the A/B/O blood antigens
true
excess free fucose in blood =
liver damage, cancer, diabetes, heart disease
phosphorylation of monosaccarides adds _ charge important for?
negative charges that prevents sugars from spontaneously leaving the cell by crossing the lipid bilayer membranes and prevent from interacting with transporters of the unmodified sugar
phosphorylation of monosaccarides creates _ intermediates important for?
reactive intermediates that will more readily undergo metabolism
oxidation of monosaccardies creates _ sugars because they are oxidized at the carbonyl This also makes…
creates reducing sugars. creates acids and lactones
need free anomeric carbon
glucose is a reducing or non-reducing sugar?
reducing sugar
reduction of monosaccarides at the carbonyl makes _
alditols
alditols:
sorbitol can cause _ if it accumulates in the lens of the eye
cataracts
an O-glycosidic bond links:
anomeric carbon atom of a carbohydrate and oxygen atom of an alcohol
an N-glycosidic bond links:
anomeric carbon atom of a sugar linked to the nitrogen atom of an amine
an example of O-glycosidic bond:
carbohydrates are linked to form long polymers and when they are attached to proteins
an example of N-glycosidic bond?
when a nitrogenous bases are attached to ribose units to form nuclosides
T/F: some important toxins are N-linked glycosides
False. O-LINKED
sugars not proteins
what are the “regular” monosaccharides (4) of the essential monosaccarides
- D-glucose
- D-galactose
- D-Mannose
- D-Xylose
what is the “oddball” monosaccharide of the essential monosaccarides
L-fucose (only L-monosaccaride)
what are the amino sugars of the essential monosaccarides
- GlcNAc
- CalNAc
- Sialic acid
what are the 3 roles of polysaccarides?
- glucose storage
- structure
- protein diversity
branched connectivity of polysaccarides happens at:
1,6
unbranched connectivity of polysaccarides happens at:
1,4
glucose storage uses _ linkages
alpha
structural polysaccarides (ex chitin) uses _ linkages
beta
sugars in glycoproteins are attached to the amide nitrogen atom in the side chain of _ termed N-linkage
asparagine
3 common disaccharides
- sucrose
- lactose
- . maltose
disaccharide consists of 2 sugars joined by _-glycosidic bond
O-glycosidic bond
sugars in glycoprotiens are attached to the amide nitrogen atom in the side chain _ or _ termed O-linkaged
serine or threonine
_ is the storage form of glucose
glycogen
nutritional reservoir in plants is starch which there are 2 forms:
- amylose which is unbranched
2. amylopectin which is branched
T/F: the polysaccharide of glucose found in plants and plays a structural role is cellulose
true
a carbohydrate group covalently attached to a protein forms a
glycoprotein
Glycoprotiens:
1: glycoproteins, by weight have more _ than _
2. carbohydrates added on membrane proteins are for:
3. carbohydrates added on soluble proteins are for:
- glycoproteins have more protein than sugar by weight
- cell adhesion
- cell signaling
erythropoietin is a glycoprotein hormone that stimulates:
RBC production
GlcNAc is a glycoprotein whos presence is indicative of:
cellular energy stores
Glycoprotiens:
- glycosamminoglycans are more _ than _ by weight
- have repeating _ units
- their sugar component is _
- more sugar than protein by weight
- dissacharide units
- sugar component of proteoglycans
proteoglycans are proteins attached to glycosaminoglycans and have important structural roles. given that info, what are some examples of proteoglycans?
cartilge
blood clotting
chitin
Glycoproteins:
- mucins are more _ than _ by weight
- offer protection + hydration = _
- more sugar than protein by weight
2. lubrication
T/F: glycolipids decorate cell membranes and are used to recognize self from other
true
Type O/A/B:
O to B is addition of _
galactose (monsaccaride)
Type O/A/B:
O to A difference is a modified _
galactose (N-acetylgalactosamine)
Type O/A/B:
A to B difference on _
N-linked acetyl
