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28 Cards in this Set

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What are carbohydrates?

Carbohydrates are polyhydroxylated compounds having at least 3 carbon atoms and a potentially active carbonyl group which may be an aldehyde or a keto group.

Carbohydrates are chemically characterised as

Polyhydroxyl aldehyde or ketone

Sugars that contain an aldehyde group are called

Aldoses


Eg; aldotriose aldohexose

Sugars that contain a ketone group are called

Ketose Eg; ketotriose ketohexose

All carbohydrates can be classified as

Monosaccharides; one unit of carbohydrate


Disaccharides; two units of Carbohydrates


Oligosaccharides; two to ten monosaccharide units


Polysaccharides; hundreds of monosaccharide units

What are isomers

Isomers are molecules that have the same molecular formula, but have a different arrangement of the atoms in space. E.g. fructose, glucose, mannose, and galactose are isomers of each other having formula C6H12O6.

What are epimers

EPIMERS are sugars that differ in configuration at ONLY 1 POSITION. Examples of epimers : D-glucose and D-galactose (epimeric at C4) D-glucose and D-mannose (epimeric at C2)

What are enantiomers

ENANTIOMERS: A special type of isomerism found in pairs of structures that are mirror images of each other. The mirror images are termed as enantiomers and the two members are designated as D- and L- sugar. The vast majority of sugars in humans are D-sugars. In D form the OH group on the asymmetric carbon is on the right. In L form the OH group is on the left side.

What is a chiral carbon

A carbon linked to four different atoms or groups farthest from the carbonyl carbon.

Describe cyclization

It involves the reaction of C-5 OH group with the C-1 aldehyde group or C-2 of keto group. Six membered ring structures are called Pyranoses while five membered ring structures are called Furanoses.

What is an anomeric carbon and what does it create

The carbonyl carbon after cyclization becomes the anomeric carbon.This creates α and β configuration.In α configuration the OH is on the same of the ring in fischer projection. In Haworths it is on the trans side of CH2OH.

What is a mutarotation

The spontaneous interconversion of α and β anomers in solution.

What are amino sugars

Sugars in which a hydroxyl group (common on carbon 2) is replaced by an amino group e.g. D-glucosamine and D-galactosamine.

What are deoxysugars

Monosaccharides in which an -H has replaced an – OH group

Describe L- fucose

(formed from D-mannose by reduction reactions). It is found among carbohydrate components of glycoproteins, such as those of the ABO blood group determinates on the surface of red blood cells

Describe 2-deoxyribose

The pentose sugar component of DNA.

What are mucopolysaccharides

Mucopolysaccharides are protective polysaccharides. They are attached to proteins. They are gel like substances known to fill the space of most tissues

Give 6 examples of mucopolysaccharides

connective tissue


Skin


bone


cartilage body cells


mucous secretions


synovial fluids

What are proteoglycans

Proteoglycans are glycosaminoglycans covalently linked to serine residues of specific core proteins. Protein (5%) + polysaccharide (95%)

What are Mucopolysaccharidosis

Mucopolysaccharidosis are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal enzymes needed to break down molecules called glycosaminoglycans.

Excess accumulation of Mucopolysaccharides in body tissues may cause

1. Serious physical disorders


2. Various genetic deformities including skeletal deformities (especially of the face), mental retardation and decreased life expectancy.

Give 7 signs of Mucopolysaccharidoses

Hepatomegaly


Splenomegaly


Enlarged tongue


Retinal pigmentation


Hip dislocation


Heart murmurs


Heart valve damage from thickening

What is glycosylation and state some of its characteristics

Glycosylation is the process or result of addition of saccharides to proteins and lipids.


The process plays an important role in the synthesis of membrane and secreted proteins.


Majority of proteins synthesized in the rough ER undergo glycosylation.


It is an enzyme -directed site-specific process.


Glycosylation may play a role in cell-cell adhesion (a mechanism employed by cells of the immune system), as well.

Describe the types of glycosylation

Two types of glycosylation exist: N-linked glycosylation to the amide nitrogen of asparagine side chains and O-linked glycosylation to the hydroxy oxygen of serine and threonine side chains.

Give 5 structural functions of glycoproteins and one other function

glycoproteins have structural functions: constituent of the cell wall; form connective tissues such as collagen; found in gastrointestinal mucus secretions; used as protective agents and lubricants ;found abundantly in the blood plasma.



The human blood groups A, B, AB, and O depend on the oligosaccharide part of the glycoprotein on the surface of erythrocyte cells. The terminal monosaccharide of the glycoprotein at the nonreducing end determines blood group.

Oligosaccharides are? And describe what it means

Oligosaccharides are antigenic determinants . Carbohydrates on cell surfaces are immunochemical markers. ABO blood group antigens are oligosaccharide components of glycoproteins and glycolipids on the surfaces of individual cells, besides blood cells.

Transfusion of type A blood group into a type B individual, results in

an anti-A antibody- A antigen reaction.

an anti-A antibody- A antigen reaction?

clumps together (agglutinates) the transfused erythrocytes, resulting in an often fatal blockage of blood vessels