Monosaccharides
- A monomeric carbohydrate unit that cannot be degraded to simpler carbohydrate residues
- Often sweet tasting; includes glucose, galactose, fructose and ribose.
Disaccharides
- formed from two monosaccharides joined by a glycosidic bond.
- dissaccharides include lactose (glucose + galactose), and sucrose (glucose + fructose)
-They are simple sugars
-have alpha and beta configurations
Alpha vs. Beta configurations
- In the beta configuration, the bond emerging from C1 lies above the plane of the ring while in the alpha configuration, the bond emerging from C1 lies below the plane of the ring
Oligosaccharides
-Three to ten monosaccharides linked by glycosidic bonds constitute an oligosaccharide
-The majority are not digestible
Polysaccharides
- Important sugar/carbohydrate polymers consisting of many monosaccharides linked together by glycosidic bonds
-formed in condensation reactions. Biochemically, significant polysaccharides may be linear or branched and include; starch, glycogen, and cellu
Ketose
A simple sugar containing a ketone group, such as dihydroxyacetone and fructose.
Aldose
A monosaccharide such as glucose, galactose, ribose, and mannose with an aldehyde functional group.
Outline the structure of the disaccharides sucrose, lactose and maltose.
Sucrose lacks a free aldehyde or ketone group and is thus a nonreducing disaccharide while lactose and maltose are reducing disaccharides.
homopolysaccharide
-composed of a single monosaccharide monomer. Homopolysaccharides formed from glucose include glycogen, starch and cellulose.
Example: Glycogen, Starch, Cellulose
heteropolysaccharide
-composed of a variety of monomers and include the variety of glycosaminoglycans identified to date
-abundant in the extracellular matrix surrounding cells and have high viscosity and elasticity, often found in joints
Examples: Glycosaminoglycans
proteoglycan
-glycoproteins + glycosaminoglycan = proteoglycan
-resemble polysaccharides more than protein
-interact w/ growth factors
-continually turned over by lysozomal enzyme, defects could lead to huryley's syndrome
glycosaminoglycans
provide viscosity to cellular surfaces and the
extracellular matrix, and thus are found in abundance in joints, serving as lubricants
Chondroitin 4-Sulfate
(glycosaminoglycans)
found in connective tissue such as cartilage, tendons, and bone
Dermatan Sulfate
(glycosaminoglycans)
antithrombotic function
Heparin
(glycosaminoglycans)
Heparin- anticoagulant
Hyaluronate
(glycosaminoglycans)
in animals, not sulfated
glycoprotein
-Proteins found covalently attached to a variable carbohydrate oligosaccharide chain
- the carbohydrate is added post-translationally in the endoplasmic reticulum.
Glycogen
- deposited in the liver
- glycogen is utilized to provide energy during muscle contraction
- glucose monomers joined by alpha 1, 4-glycosidic linkages with alpha 1, 6-glycosidic linkages
Starch
major fuel reserve in plants, found in chloroplasts
- occurs as a mixture of linear amylose, composed of thousands of glucose residues linked by alpha 1, 4-glycosidic bonds, and branched, amylopectin.
cellulose
-long unbranched structural polysaccharide that is highly insoluble in water.
-major component of plant cell walls.
Cellulose is composed of up to 15,000 D-glucose monomers linked by beta 1,4-glycosidic bonds.
-cant be digested by humans
Review the major functions of carbohydrates
1. Structural elements in plants
2. Carbs store energy
3. Ribose and deoxyribose partly composed nucleic acid
4. Responsible for intracellular signaling and recognition processes
5. Some cells are completely covered by a protein coat others have carbohydr