specalsied carbohydrates Flashcards
what is important about specialsed carbohydrates?
they are modified carbohydrates
what are 2 examples of specaslied carbohydrates?
glycosaminoglyvans and proteoglycans
what specialsed carbohydrates is part of glyoclopids and glycoproteins
oligosaccharides
what makes a modified carbohydrate a modified carbohydrate?
replacement of a hydroxl group of a monosaccharide with another group
what is a modifed carbohydrate also known as?
amino sugar
if a MC is based on a glucose what is it called?
acetylglucosamine
if a modified carbohydrate is based on galactose what is it called?
acetylgalactosamine
what is GlcNAc
acetlyglucosamine
what is GalNAc
acetlygalactosamine
what is saalic acid
-nine-carbon sugars
-found at the terminal end of sugar chains
-roles in cell recognition, signaling, and adhesion
summarise glycoasminglycans
unbranched heteropolysaccharides composed of repeating disaccharide units
for each unit , 1 monosaccharide is always GlcNAc or GalNAc
most cases the other monosaccharide is a uronic acid
what is urnoic acid?
Uronic acids are a class of sugar acids derived from monosaccharides
where is keratan sulphate found?
bone, cartlige
where is chondroitin sulphate
cartlidge, bone
where is dermatan sulphate found
skin, blodd vessels
where is hyaluronate found
ECM of loose connective tissue
where is heparin found?
liver
where is heparan sulphae found?
cell surfaces
summarise proteoglycans
consist of a core protein and long chains of polysaccharides called glycosaminoglycans (GAGs).
-found in connective tissue
-GAG chains are composed of repeating disaccharide units and can be highly sulfated, making them negatively charged.
how are several carbohydrates linked?
linked together by O-glycosidic bonds
how are several carbohydrates lined together (enzyme)
(glycosyltransferases
what are the possible oligosaccharides on RBC surface?
3 possible oligosaccharides on RBC surface
what common antigen does ABO blood groups share?
0 antigen
why is A and B blood group different?
antigens differ in their additional monosaccharide
what additional monosaccharide does group A have?
galNAc
what additional monosaccharide does group b have?
Gal
what link holds the addtional monosaachidres together?
linked by an α-1,3 link to the O antigen structure
What does the A antigen have that the B antigen doesnt?
GalNAc
what are the blood groups?
a, b, ab and o
what happens in a non self blood group?
antibodies form against non self blood group?
what can A give blood to?
AB
what can AB give blood to?
none
what can B give blood to?
AB
what can O give blood to?
a, b ab
what are some other examples of other glycolipids?
cerebroside
gangliosides
what are the glycolipids with important roles in the nervous sytem?
cerebroside
ganglsioside
what is cerebroside made from?
ceremide+ galactose
what is ganglisodies made from>
ceremide+ oligosaccharide with 1+ sialic acid
what do cell surface glycoproteins play a role in?
roles in cellular recognition and communication
biosynthesis of glycosylated proteins
takes place in ER & Golgi complex
what happens in the ER
n linked glycosylation happens
what happens in the golgi?
in the Golgi-
N-linked glycosylation continues
O-linked glycosylation takes place
glycosylated haemoglobin?
carbohydrate attached to globin chains
N-terminal αα (valine) of β-globin
example of CHOs in food production?
pectin
carrageenan
alginate
summarise pectin?
variable structure plant polysaccharides
gelling agents & thickeners
consist mainly of partially methylated poly-α-(1→4)-D-galacturonic acid residues
summaruse carrageenan?
polysaccharides extracted from red seaweeds
variable structure - 3 & 4 linked β-D-galactose & α-D-galactose units (agar is similar)
units are often sulphated
binder, thickening agent, prevents separation
summarise alginate?
variable structure algal polysaccharides
thermally stable cold setting gelling agents (in presence of calcium ions)
linear unbranched polymers:β-(1 4)-D-mannuronic acid & α-(1 4)-L-guluronic acid
what are alginate/
heteropolymeric & homopolymeric blocks
