CH 7: Carbohydrates-monosaccharides, Disaccharides, & Polysaccharides

Chemicals that are sugars often have names ending in?

"-ose". For example, note the suffix "-ose" in fructose, glucose, galactose, sucrose, lactose, and maltose.

Definition of a sugar?

A carbohydrate that is soluble in water. Sugars are usually crystalline and have a sweet taste.

Monosaccharides are?

Monosaccharides are simple ("unit") sugars.

The simplest carbohydrates are?

Monosaccharides or single sugars

Cellulose is a?

Polysaccharide. •Chemically, consists of long chains of D-glucose (a monosaccharide ) molecules by *β (1→4)* glycosidic bonds •Forms the structure of some plants •Indigestible by humans but digestible by some other animals. •Valuable in the human diet as a source of dietary fiber.

Starch is a?

Polysaccharide. •Chemically, consists of long chains of glucose (a monosaccharide) molecules •Formed by plants during photosynthesis •Present in many plant-based food sources, such as root vegetables. e.g. potatoes, cereals e.g. and pulses. **Deposited into chloroplast of plant cells as insoluble granules: alpha-amylose and amylopectin.

Dextrin is a?

Polysaccharide. •Formed when starchy foods (i.e. foods that contain starch, such as bread or potatoes) are baked or toasted. Dextrin is formed as part of the dry "crust" •Dextrin is more soluble than starch

Glycogen is a?

Polysaccharide. •The stored form of glucose (glucose is a monosaccharide) present in animals including humans. •*α (1→4)* glyocosidic bonds branching points *α (1→6) every 8 to 14 glucose residues*. •Energy stored within the body, stored within muscles and the liver and brain •Humans store sufficient glycogen for 24 hours

Pectin is a?

Polysaccharide. •Present in the roots and/or fruits of certain plants e.g. types of plums and apples •Pectin forms a gel in water and has uses for setting jam and making various sweet foods. •Sometimes used as a vegan alternative to gelatin (also known as gelatine) in the preparation of "set" or glazed foods because the beef (cow) or pork (pig) origin of gelatin is not acceptable to some people. •Pectin forms a complex polysaccharide

Carbohydrate macromolecules are?

Polysaccharides, polymers, composed of many sugar building blocks.

Carbohydrates include?

Sugars & the polymers of sugars

Disaccharides consist of?

molecules whose form is that of two monosaccharide molecules joined together.

Agar

• A branched heteropolysaccharide composed of agarose and agaropectin. •Forms gel solutions used as a surface fro growing bacteria.

Selectin

• A family of plasma membrane *lectins* that mediate cell-cell recognition and adhesion in different cellular processes.

Lysozyme

• An enzyme that catalyzes the hydrolysis of the β (1→4) linked N-acetylmuramic acid and N-acetylglucosamine.

Glycoproteins

• Enzymes, transport proteins, receptors, hormones, and structural proteins.

Glycolipids

• Gangliosides are membrane lipids of eukaryotic cells where the carbohydrates form the outer surface of the membrane.

Hyaluronate

• Important glycosaminoglycan component of *connective tissue, synovial fluid, and vitreous humor of the eye.* • Composed of ~50,000 β (1→3) linked disaccharide units •In solution ~1000 times its dry volume.

Peptidoglycan

• Makes up bacterial cell walls • Covalently linked polysaccharide and polypeptide chains that enclose the cell. • Its polysaccharide component consists of linear chains of alternating β (1→4) linked GlcNAc and N-acetylmuramic acid. • The lactic acid group of N-acetylmuramic acid forms an amide bond with a D-amino acid-containing tetrapeptide (green) to form the peptidoglycan repeating unit.

Keratan Sulfate

• Most hetereogenouesof the major glycosaminoglycans: its sulfur content is variable, and it contains a small amount of fucose, mannose, GlcNAc, and salisilic acid. • Present in *cornea, cartilage, bone, and a variety of horny structure.*

Heparin and Coagulation

• Prevents blood clotting by activating protease inhibitor antithrombin.

Proteoglycans

• Proteins and glycosaminoglycans in the extracellular matrix of animal cells, rich in carbohydrate. • "Bottle like" molecular architecture with "bristles" noncovalently attached to a filamentous hyaluronate. • Highly hydrated complexes. • Varies in length, 400 to 40,000 Å, with up to 100 associated core proteins, each with ~ 50 keratan sulfate chains and ~ 100 chondroitin sulfate chains

Lectins

• Proteins that bind carbohydrates, which are *ubiquitous* in nature and frequently appear on the surface of cells. • They can recognize individual monosaccharides in a particular linkages to other sugars in an oligosaccharide.

Glycosaminoglycans

•A gel like matrix (extracellular spaces) where collagen can be found. • Forms solutions that are slimy (mucus like) which are have high viscosity and elasticity • Include: > Hyaluronate > Chondroitin 4-sulfate > Keratan Sulfate > Heparin

Fructose (Sugar)

•Also known as "Fruit Sugar" •Main sources are many kinds of fruits, as well as honey.

Agarose

•Forms gel solutions used for *separating DNA in electrophoresis*

Heparin

•Occurs almost exclusively in the intracellular granules of the mast cells that occur in the arterial walls. • Variably sulfated, *2.5 sulfate residue/dissacharide unit* • Most highly charged polymer in mammalian tissue. • Also regulates development and formation of blood vessels.

Galactose(sugar)

•Present in mammals' milk, hence associated with diary products •Provides mammilian infants with a source of energyR

Characteristics of monosaccharides?

•Soluble in water •Sweetness varies (with individual monosaccharide)

Types of Polysaccharides(5)

•Starch •Dextrin •Cellulose •Pectin •Glycogen

Chitin

•The principle component of the exoskeletons of invertebrate organisms; most fungi and many others. •β (1→4) linkages • Similar to cellulose except for the acetamido functional group.

Glucose(sugar)

•Very important in animal (including human) physiology, diet and nutrition •because GLUCOSE IS THE FORM OF SUGAR THAT IS USED BY THE BODY FOR ENERGY. •All other carbohydrates, including all other sugars, are converted into glucose within the digestive system (digestive processes) •Present in various forms of vegetation including many ripe fruits as well as onions and beetroot.

Ketoses

> The carbonyl carbon is a ketone > The smallest, with 3C, called ketotrioses > Hexoses/pentoses/etc.

Aldoses

> The carbonyl carbon is an aldehyde > The smallest, with 3C atoms, called aldotriose. > Aldohexoses/pentoses/etc.

The disaccharide LACTOSE (a sugar) is made up of which two monosaccharides?

Galactose & Glucose

5 Monosaccharides (Monomers of carbohydrates)

Glucose Fructose Galactose Deoxyribose Ribose

The disaccharide MALTOSE (a sugar) is made up of which two monosaccharides?

Glucose & Glucose

The disaccharide SUCROSE (a sugar)is made up of which two monosaccharides?

Glucose & fructose

Polysaccharides are

Long branching chains (polymers) of linked monosaccharides.

Mannose

Three letter code: MAN

Ribose

Three letter code: RIB