Monosaccharides & polysaccharides

o What is the general structure and formula of a monosaccharide?

(CH20)n where n=3,4,5 or 6 -have two or more hydroxyl groups -either have an aldehyde or a ketone group

function of glycoproteins

(these have oligosaccharides)!- Glycoproteins are any of a group of conjugated proteins having a carbohydrate as the nonprotein component. have the following functions: a. cellular zip codes, these carbohydrate structures determine which proteins are exported (secreted), which are incorporated into the cell membrane, and which are destined for the lysosome. b. involved in cell-cell recognition and adhesion c. recognition of self vs. other by the immune system

§ What is a b-linkage? What is an a-linkage?

- Beta linkages point up and alpha linkages point down. If it is a monosaccharide, the OH will be pointing up in the beta formation and down in the alpha formation. Disaccharides have an ether pointing up in the beta conformation and an alpha linkage ether points down.

o Explain the joining of sugar monomers to make a polymer

-Condensation reaction (H2O is formed by breaking covalent bonds attached to the monosaccharide-creating a disaccharide -A glycosidic bond is formed

§ Explain how a branched polysaccharide becomes branched.

-Every hydroxyl group of a sugar can form a bond with the aldehyde of ketone carbon of another sugar! Because each monosaccharide has several free hydroxyl groups, it can form bonds with another monosaccharide multiple ways (through different positions)-which allows the polysaccharide to become branched. -This also allows the branched polysaccharide to rapidly release glucose molecules during times of need. Enzymes rapidly attack the end of the proteins, cutting one off at a time. The linkages in branched polysaccharides are 1,4 alpha linkages.

function of glucose

-Glucose- the monosaccharide glucose is the building block for many sugars, most importantly the energy storage monosaccharide for the polysaccharides starch and glycogen

§ What type of bond forms between them?

-Glycosidic linkage-covalent bond

§ Does the formula alone define a sugar?

-The formula alone does not define the sugar. The sugar can have isomers with the same formula and can be linear or in have a ring conformer. -the same number of atoms can be covalently bonded in a variety of ways, creating different structures and shapes

§ What atoms are joined together?

-The hydroxide groups of the monosaccharides react to join together, one losing an entire OH group while the other loses an H from the hydroxyl. The Oxygen that has lost the hydrogen will now bond with the carbocation of the monosaccharide.

§ Why does a linear polysaccharide remain linear (think linkages)?

-The linkages involved in linear polysaccharides are 1,4 beta linkages. This allows the conformation to be straight

function of cellulose

1,4- beta linkages, found in plant cell walls- the beta linkages allow the polysaccharide to make extra hydrogen bonds with other OH groups, giving the cell wall its rigid structure

function of chitin

1,4-beta linkages of N-acetoglucasmine- found in cell wals of fungi, and exoskeletons of crustacea.

function of glycolipids

A Glycolipid is a lipid that contains one or more carbohydrate groups and their role is to provide energy and also serve as markers for cellular recognition. These two make up the Glycocalyx which is basically the outer component of a cell surface, outside the plasmalemma; usually contains strongly acidic sugars, hence it carries a negative electric charge. This has the following functions: Protection: Cushions the plasma membrane and protects it from chemical injury Immunity to infection: Enables the immune system to recognize and selectively attack foreign organisms Defense against cancer: Changes in the glycocalyx of cancerous cells enable the immune system to recognize and destroy them Transplant compatibility: Forms the basis for compatibility of blood transfusions, tissue grafts, and organ transplants Cell adhesion: Binds cells together so that tissues do not fall apart Inflammation regulation: Glycocalyx coating on endothelial walls in blood vessels prevents leukocytes from rolling/binding in healthy states Fertilization: Enables sperm to recognize and bind to eggs Embryonic development: Guides embryonic cells to their destinations in the body

§ When are ring structures formed?

Aldehyde or ketone group of monosaccharide reacts with hydroxyl group

§ You should be able to identify a molecule as a monosaccharide based on its structure.

Must follow the forumal-can not exceed 6 carbons.

· Explain how oligosaccharides mediate interaction between neutrophils & cells lining blood vessels during inflammation response (rolling adhesion).

Specific carbohydrate on surface of white blood cells (neutrophils) is recognized by a lectin -Lectins are proteins found on cells lining the blood vessels. They are present when infection is present. -Recognition causes neutrophil to adhere to blood vessel & migrate into infected tissue where it can help remove bacteria

function of glycogen

glycogen is the primary storage of energy for animals- built simply by the monosaccharide glucose.