Flashcards in Carbohydrates 1 Deck (32)
Describe the covalent bond in a disaccharide
Hydroxyl group of one monosaccharide forms a covalent bond with an anomeric carbon of another monosaccharide
What is meant by anomeric?
Carbon 1 of one monosaccharide is the mirror image of the other carbon on the other monosaccharide (this is true I think for a beta glycosidic bond)
Name three important disaccharides
Maltose, lactose and sucrose
What is the direct breakdown product of starch?
Why is maltose considered a reducing sugar?
Anomeric Carbon 1 is available for oxidation
Where is sucrose made?
Is sucrose reducing or non-reducing?
Single monomeric species
What are heteropolysaccharides?
Have two or more monomer species
What are the two different forms of starch?
Amylopectin and Amylose
What proportion of starch is amylose?
What proportion of starch is amylopectin?
Describe the structure of amylose?
D-glucose units with alpha 1-4 linkage
Describe the structure of amylopectin
Branches occur every 24-30 monomers
Branches linked with alpha 1-6 glycosidic bonds
How many reducing ends does starch have in comparison to the non-reducing ends?
Not many reducing
Describe the overall shape of amylose and amilopectin
Form alpha helices
What is the difference in structure between amylopectin and glycogen?
In glycogen, branches occur much more frequently (every 8 to 12 units)
Where can you fin the glycogen in the body?
90% in the liver (replenishes blood sugar during starvation)
10% in the skeletal muscles (catabolism produces atp for contraction)
What effect does storing the glucose in the polymers have on compactness?
Makes them more compact
Amylopectin and glycogen are said to have many non-reducing ends, why might this be beneficial?
Synthesis and degradation to and from individual monomers becomes easier and therefore fast
What difference does storing polymers in the cell have on osmosis?
Polymers are osmotically inactive-
If free glucose were to be stored inside the cell then a lot of energy would be needed to keep the glucose inside the cell (since glucose concentration inside the cell would be much higher than glucose concentration outside the cell).
What are glycoproteins?
Proteins that have carbohydrates covalently attached
What is the range in carbohydrate content of eukaryotic extracellular protein?
Between 1 and 80 percent by mass
What is the possible effect of the carbohydrate on the protein?
Increase the proteins solubility
Influence protein folding and conformation
Protect it from degradation
Act as communication between cells
What are glycosaminoglycans ?
Unbranched polymers made from repeating units of hexuronic acid and an amino sugar - found in mucus and synovial fluid around the joints
What are proteoglycans?
A compound consisting of protein bonded to glycosaminoacid groups (mucopolysaccharide groups)
There is more protein than carbohydrate usually
Where can you find glycosamionglycans?
Found on the surface of cells or in between cells in the extracellular matrix
What type of tissue are proteglycans involved in?
Where can you find glycoproteins?
Outer plasma membrane and the extracellular matrix, in the blood and also within the secretory system
What type of proteins might be glycoproteins?
Cytoplasmic and nuclear proteins
What happens when glycosmainoglycans fail to get broken down?
Build up in connective tissue, leads to loss in cell architecture and function, leads to problems in endothelial structures as glycosaminoglycans can build up between the endothelial cells. Bones tend to be stunted, joints tend to be inflamed and severely damaged.