Carbohydrates Flashcards
Describe the cause/effect of Hurler’s syndrome (iduronidase deficiency) and Hunter’s syndrome (X linked iduronidase suphatase deficiency)
GAGs are normally degraded by lysosomal hydrolases - these dereditary diseases lead to enzyme deficiencies. These complex carbohydrates, therefore, accumulate within the lysozome of the cell and the cell begins to bulge which leads to deformity and mental retardation.
Describe Glycoprotein storage disease - how do we test for it?
It is a clinically progressive hereditary disorder that causes a deficiency in lysosomal hydrolases - which cause accumulation of partially degraded structures in the lysosome
We test for oligosaccharides in the urine to diagnose this disease
What do you call a one, two, three
five, six or seven carbon carbohydrate?
1= monosaccharide
2= disaccharide
3= triose
5= pentose
6= hexose
7= heptose
What is the difference between an aldose/ketose carbohydrate?
aldose = aldehyde group
ketose = ketone group
Name a few common 6 carbon carbohydrates
Glucose
Fructose
Galactose
Mannose
Are the vast majority of sugars L or D sugars?
D sugars
What is an isomer?
same chemical formula but different structures
i.e) glucose and fructose have the same chemical formula, but they have different structures
What is an enantiomer?
Structures that are mirror images of eachother
D and L sugars
What is the difference between a D sugar and an L sugar?
D sugar= OH group on the asymmetric carbon farthest from carbonyl carbon on right
L sugar= OH group on the asymmetric carbon farthest from carbonyl carbon on left side
What do we call a 6 member ring that is a product of cyclisation?
a Pyranose
What is the difference structurally between an alpha conformation of an anomer and a beta conformation of an anomer?
alpha conformation has the hydrogen facing up and the beta conformation has the hydrogen facing down
Which carbon in a ring is the anomeric carbon?
the anomeric carbon is at C1 of an Aldose or C2 of a ketose - it is traditionally the carbon that has a carboxyl group attached to it
How does an anomer of a saccharide differ in structure?
It only differs in structure at the anomeric carbon
Sugar can act as what sort of agent?
it can act as a reducing agent - due to the OH group
Describe a glycosidic bond
It is a bond between two carbohydrates at the 1 and 4 carbons (usually)-
the name of the bond depends on the numbers of carbons, the position of the anomeric hydroxyl group (alpha or beta)
What is the general structure of GAGs?
they are a repeating disaccharide unit
with an acidic sugar and an amino sugar repeat units
What are the functions of proteoglycans?
They are found in connective tissue and cartilage (they contain the hyluronic acid GAG that makes up the extracellular structure in cartilage and connective tissue) They act as molecular sieves.
What are GAGs?
Glycosaminoglycans = large complexes of negatively charged unbranched heteropolysaccharide chaines - they bind large amounts of water and make up the extracellular matrix
What are glycoproteins used for? What are they?
Glycoproteins are proteins with attached oligosaccharides - they contain no glucose.
They serve to sort proteins into various compartments, acting as enzymes, hormones, antibodies and structural proteins.
What type GAGs are present in synovial fluid of joints, humor of eye, loose connective tissue and cartilage?
Hyaluronic acid which is a lubricant and shock absorber GAG found in all of these areas
Which type of GAG is found in the mast cells that line arteries in liver, lungs and skin?
Heparin = which acts as an intracellular anticoagulant GAG all of these places
What are the proteoglycans (PG) ?
They are glycosaminoglycan chains with protein cores and protein links attached to the hyaluronic acid backbone
What is a common example of glycoproteins in the body?
Mucins (80% carbohydrate) act as protective lubricants in the GI and GU tract
