Carbohydrates Flashcards
Name 3 monosaccharides
fructose, glucose, galactose
Name 3 disaccharides
sucrose, maltose, lactose
Where can oxidation occur in the carb. structure?
either terminal (CH2OH and/or aldehyde end)
Where can reduction happen in the carb. structure?
aldehyde end of straight chain
What is a reducing sugar? Common example?
a sugar that can reduce a wear oxidizing agent
glucose
What are any sugars capable of opening into the straight chain form?
reducing sugars
What has to be on the anomeric C1 carbon in order to be a reducing sugar?
Only an OH
In Benedict’s solution, what happens if reducing sugars are present in the urine?
the reagent turns reddish brown
What can sugar in the urine indicate?
presence of diabetes melitus
What does esterification typically involve?
the formation of phosphate or sulfate esters
What does adding a phosphate to a monosaccharide do for it?
Makes it more reactive
aid in trapping molecule in cell
Which monosaccharides are often found in the CT?
sulfated
What does the sulfated monosaccharide attract? What does this do?
attracts large amounts of water therefore,
makes CT less dense, occupies more space
What are sugars where the OH group on the anomeric carbon is replaced by an alcohol?
glycosides, forming a glycosidic link
What is a methylation reaction?
Methyl is added to either alpha or beta, locking hemiacetals into an acetal which is stable
What are 2 monosaccharide derivitives?
deoxy- sugars (ex. deoxyribose)
amino sugars (D- glucosamine)
What is a sugar that the OH group is replaced by an amino group, which may also be acetylated?
amino sugars (common in complex biomolecules)
What type of link joins a disaccharide?
glycosidic linkage
Where do the alpha and beta designations come from?
OH positions at C1 of the 1st and 2nd monosaccharide
Where does the numerical designation of a disaccharide come from?
the carbons associated with the glycosidic bond
A disaccharide is D- if what? L-?
If the hydroxyl group on the highest numbered chiral carbon is on the right side/ left side
_________ are small numbers (3-15) of monosaccharides linked by glycosidic bonds. __________ are larger.
oligosaccharides
polysaccharides
When oligosaccharides are linked to proteins and lipids, what are they called?
glycoconjugates
Reducing sugar?
1.) sucrose
2.) glucose
3.) fructose
1.) no
2.) yes
3.) yes
2 functions of homopolysaccharides? (chain of all the same monosaccharides) POLYsaccharides
1.) storage (starch, amylose, amylopectin, glycogen)
2.) structural ( cellulose)
1 function of heteropolysaccharides? (chain of 2 or more diff. monosacs.)
structural (GAGs)
Amylose in D-glucose in which linkage?
alpha (1,4)
Amylopectin is D-glucose in which combo of linkages?
alpha (1,4)
alpha (1,6)
Where is glucose released from amylose?
non-reducing ends
Are branches on a polysaccharide more or less efficeint?
more
Location of examples of heteropolysaccharides:
1.) chondroitin sulfate:
2.) dermatan sulfate:
3.) heparin
4.) keratan sulfate
5.) hyaluronic acid
1.) cartilage, tendons, bone
2.) skin, blood vessels, heart valves
3.) mast cells, liver
4.) cornea, cartilage, iv disks
5.) synovial fluid, eye fluid
In a GAG structure, what does the disaccharide unit composed of? (2)
1.) acidic sugar (usually glucuronic acid)
2.) amino sugar
What is the oxidized form of glucose?
glucuronic acid
What are the 2 amino sugar possibilities for a GAG?
1.) glucosamine
2.) galactosamine
True or false. the disaccharide units of GAGs are often acetylated and sulfated
true
In GAGs, which 2 groups have negative charges?
acid group
sulfates
What does the negative charge in a GAG do? (3)
1.) creates slippery texture and they slide past each other due to repulsion
2.) large volume
3.) resilience (can be squished or expanded)
What do you get when you add mono, di, oligo, or polysaccharides to other molecules?
glycoconjugates
How are carbs attached to proteins?
O- or N- glycosidic links
In a glycoconjugate, which would be stronger, ionic linkage or covalent?
covalent
Where are oligosaccarides often attached in a glycoconjugate?
OH of serine or threonine via N-Acetylgalactosamine (GalNAc)
A carb can attach to a protein on asparagine R-group, where exactly? Via what?
N
N-Acetylgalactosamine (GalNAc)
______________consist of various GAGs (except hyaluronic acid) attached to core proteins via an O-glycosidic link
proteoglycans
In proteoglycans where are the core proteins?
hyaluronic acid backbone
Which is minimal in a proteoglycan, protein or carb?
protein
If using a tree analogy of a proteoglycan,
1.) leaves
2.) branches
3.) trunk
1.) Gag chains
2.) core proteins
3.) hylauronic acid
Where are proteoglycans located?
ECM
What do PGs contribute to?
1.) support
2.) elasticity to tissues
What is mucopolysaccaridosis?
genetic disease associated with defective proteoglycan metabolism
What types of monosaccharides are commonly found in the mono, di, or oligosaccharide attachments?
N-acetylglucosamine, N-acetylgalactosamine, mannose, galactose
What type of carbohydrate is not found on glycoproteins?
glucuronic acid, fructose
Where are glycoproteins often found?
attached to membranes, projecting externally from the cell
D-Glucose is a/n aldose or ketose? why?
aldose, aldehyde on C1
D-fructose is a/n aldose or ketose? why?
ketose, ketone on C2
What is a stereoisomer? What must it have?
same atoms in same order, but different spatial arrangement
chiral carbon
What kind of isomer is a mirror image (D or L based on position of OH group attached to chiral carbon, furthest from ald. or ket.)?
enantiomer
What is a structural isomer?
Same atoms, but not in the same order
What is a diastereomer?
stereoisomer that is NOT mirror images
What is an epimer?
A diastereomer that differs at only 1 chiral carbon
Is a diastereomer a stereoisomer?
Yes
Is a diastereomer an epimer?
Can be, if it differs at only 1 chiral carbon
What kind of isomer are both glucose and fructose?
structural isomers
What kind of reaction is the conversion between glucose and fructose?
isomerization reaction
What kind of reaction is the intramolecular shifting of bonds?
isomerization
Can isomerization reactions create stereoisomers?
Yes
__________ and ___________ are epimers of glucose.
mannose and galactose
Stereoisomers can be _________ or ____________
diastereomers, enantiomers
Any stereoisomer that is not an enantiomer is a _______________.
diastereomer
When does a monosaccharide form cyclic structures?
When one of their alcohol (OH) groups reacts with teh aldehyde (or ketone) group
Linear monosaccharides are only found when? What is this called?
interconverting between various cyclic forms
mutarotation
How is sorbitol created?
reduction of glucose
What is the D-isomer of glucose?
dextrose
Lactose is formed from _____ and _____.
glucose and galactose
Maltose is formed from ____ and ______.
glucose and glucose
sucrose is formed from _____ and ______.
glucose and fructose
The D- isomer of fructose is what?
levulose
D-fructose (levulose) is a ketohexose isomer of _______.
glucose
What is the sweetest naturally occurring sugar?
fructose
Galactose is a/an ________ of glucose.
epimer
What is the structural difference between maltose and isomaltose?
glycosidic link
What is common table sugar called?
sucrose
Sucrose has a glycosidic bond linking the __________ carbons of both glucose and fructose. Sucrose has what glycosidic linkage?
anomeric
alpha, beta (1–> 2)
How many rings in furanose?
5
