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94 Cards in this Set
- Front
- Back
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Sugars that contain aldehyde groups that are _____ to carboxylic acids are classified as _____ sugars.
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Oxidized
Reduced |
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What are examples of reduced sugars that are oxidized to carboxylic acids from aldehydes?
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Lactose
Maltose Glucose Galactose Fructose |
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Anomeric Carbon
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Oxygen on C1 available for redox reaction
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Type of sugar that contains a free anomeric carbon and can be oxidized, and can not be attached to any other structure.
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Reducing Sugar
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What test is used classically to screen for diabetes and other inborn errors involving the inability to metabolize other reducing sugars?
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Reducing-sugar test
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What are the most current tests that are used to identify blood glucose levels and diagnose diabetes?
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Glucose oxidase linked reactions
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Why is sucrose not a reducing sugar?
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No anomeric carbon
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What are common test reagents?
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Benedict's reagent (CuSO4/citrate) and Fehling's reagent (CuSO4/tartrate)
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What are the most abundant heteropolysaccaharides in the body?
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Glycosaminoglycans (GAGs)
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GAGs are molecules which are long unbranched polysaccharides that contain _____ _____ _____.
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Repeating Disaccharide Unit
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What is contained within the disaccharide unit of GAGs?
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1 of 2 modified sugars
Uronic acid (Glucuronate/Iduronate) |
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What are the 2 possible modified sugars found on a GAG?
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N-acetyl-galactosamine (GalNAc)
N-acetyl-glucosamine (GlcNAc) |
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GAGs are highly _____ charged molecules, with _____ conformation that imparts high _____ to the solution.
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Neg.
Extended Viscosity |
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Where are GAGs located primarily?
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Surface of cells or in the extracellular matrix
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Along with the high viscosity of GAGs comes low _____.
What does this make GAGs ideal for? |
Compressibility
Lubricating fluid joints |
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What does the rigidity of GAGs provide to the cell?
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Structural integrity
Passage between cell - cell migration |
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What are the most physiologically significant GAGs?
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Hyaluronic Acid
Dermatan Sulfate Chondroitin Sulfate Heparin Heparin Sulfate Keratan Sulfate |
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What GAG is used seen in synovial fluid, vitreous humor, ECM of loose connective tissue, and are large polymers that are shock absorbing
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Hyaluronate
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What GAG is seen in cartilage, bone, and heart valves and is the most abundant of the GAGs?
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Chondroitin Sulfate
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What GAG is seen in basement membranes and components of cell surfaces and contains a higher acetylated glucosamine than heparine?
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Heparin Sulfate
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What GAG is a component of intracellular granules of mast cells lining the arteries of the lung, liver, and skin and serves as an anticoagulant which is more sulfonated than heparin sulfate
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Heparin
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What GAG is seen in the skin, blood vessels, and heart valves?
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Dermatan Sulfate
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What GAG is seen in the cornea, bone, cartilage aggregated with chondroitin sulfates and is the most heterogenous of the GAGs?
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Keratin Sulfate
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Which intestinal enzyme breaks down the O-glycosidic bond between glucose and fructose?
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Sucrase
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Carbohydrate containing two sugar units
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Disaccharide
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Sugar consisting of two glucose molecules joined together by a reaction (condensation reaction) in which a molecule of water is removed. This reaction produces a bond between the two glucose molecules called a _____ _____.
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Maltose (Beer Sugar)
Glycosidic Bond |
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What is the intestinal enzyme which promotes the conversion of maltose to glucose?
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Maltase
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What Dissacharide consists of glucose and galactose?
What is its enzyme which breaks it down into glucose and galactose? |
Lactose (milk sugar)
Lactase |
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What dissacharides consists of glucose and fructose?
What is its enzyme which breaks it down into glucose and fructose? |
Sucrose (table sugar)
Sucrase (invertase) |
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What type of bond creates polysaccharides from monosaccharides?
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Glycosidic bonds
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How are glycosidic bonds formed?
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Hydroxyl group on anomeric carbon reacts with -OH or -NH group on another compound
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What is the most important of the aldohexoses?
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D-glucose
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What is the glycosidic bond called if it is involved with oxygen?
Nitgrogen? |
O-glycosidic
N-glycosidic |
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What are the simplest sugars?
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Monosacchardies
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What is a three carbon sugar?
4? 5? 6? |
Trioses (Glyceraldehyde)
Tetroses (Erythrose) Pentoses (Ribose) Hexoses (Glucose) |
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What are monosaccharides with aldehydes as their most oxidized functional group?
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Aldoses (glyceraldehysde)
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What are monosaccharides with a keto group as their most oxidized functional group?
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Ketoses (dihydroxyacetone)
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The naming of configurations of simple sugars and amino acids is based on the _____ _____ of glyceraldehyde.
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Absolute Configuration
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The symbols _____ and _____ refer to the absolute configuration of the four constituents around a specific _____ _____ in simple sugars and amino acids.
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L and D
Chiral Carbon |
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In a Fischer projection the D form has the hydroxyl group on the _____; the L form has the hydroxyl group on the _____.
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Right
Left |
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What are the sugars that are most common in nature?
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D-form sugars related to D-glyceraldehyde
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What polysaccharide requires the enzyme glucan transferase to breakdown?
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Glycogen
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Polysaccharides are large molecules and thus they are _____.
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Insoluble
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What are the main functions of polysaccharides in living organisms?
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Act as storage molecules (starch glycogen)
Act as structural materials (cellulose) |
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Polysaccharides which contain only a single monosaccharide species.
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Homopolysaccharides (starch, glycogen, dextrans, glucans)
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Polysaccharides which contain a different number of monosaccharide species.
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Heteropolysaccharides
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What are the two most important storage polysaccharides?
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Starch and Glycogen
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Large, insoluble carbohydrate that forms an important energy store in plants.
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Starch
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What does a starch polymer consist of?
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Large # of A-glucose molecules joined by condensation reactions.
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What are the two main components of Starch?
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Amylose
Amylopectin |
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What kind of chains does Amylose form in starches?
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Long unbranched straight chains
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What kind of chains does Amylopectin form in starches?
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Highly branched chains w/ alpha-1,4 linkages
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What enzyme rapidly hydrolyzes both Amylose and Amylopectin?
Where is this enzyme made? |
Alpha Amylase
Parotid glands and Pancreas |
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What is a highly branched polymer similar to Amylopectin but with Alpha-1, 6 linkages and very compact?
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Glycogen
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Where is glycogen especially abundant?
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Liver
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How can the glucose units of glycogen enter the glycolytic pathway?
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Upon removal by the action of glycogen phosphorylase
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The cleaving of glycogen beyond a branching point requires the activity of what?
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Glucantransferase
mylo-alpha-1,6 glucosidase |
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The most common organic compound on earth, not digestible by humans and often referred to as Dietary Fiber or Roughage acting as a hydrophilic bulking agent for feces.
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Cellulose
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What does the term glycan refer to?
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Polysaccharide
Oligosaccharide |
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What are the most abundant heteropolysaccharides in the body?
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GAGs
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Long, linear carbohydrate chains that contain repeating disaccharide units, which usually contains _____ and a _____ acid. They also contain _____ groups.
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GAGs
Hexosamine Uronic Sulfate |
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What residues cause GAGs to be negatively charged?
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Uronic Acid
Sulfate |
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GAGs function as important structural components of what?
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Connective tissue
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GAGs act as _____ _____ and hold water in the extracellular matrix
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Molecular Sponges
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What GAG is unique in that it does not contain any sulfate and is not found covalently attached to proteins as are proteoglycans?
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Hyaluronic Acid
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The majority of GAGs in the body are linked to core proteins, forming what?
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Proteoglycans (muccopolysaccharides)
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The bacterial cell wall contains a heteropolysaccharide made up of alternating what?
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N-acetylglucosamine
N-acetylmuramic acid |
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What is the ground substance of the extracellular matrix made up of?
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Proteoglycan molecules
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What are the constituents of proteoglycan molecules?
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95% polysaccharide
5% protein |
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What causes the linkage of GAGs to the core protein of a proteoglycan?
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Specific trisaccharide
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What constitutes the specific trisaccharide that links a GAG to the core protein of the proteoglycan?
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2 galactose residues
1 xylose residue |
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What are a part of the core protein of the proteoglycan?
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Rich in serine and threonine (allows multiple GAG attachments)
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What are the major functions of GAGs?
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Lubricants
Extracellular Matrix Molecular Sieve |
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Proteins that have a carbohydrate covalently attached to them.
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Glycoproteins
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The carbohydrate portion of most glycoproteins differs from that of proteoglycans in that it is _____ and _____.
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Shorter
Branched |
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What do glycoproteins serve as in the body?
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Enzymes
Hormones Antibodies Structural Proteins |
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Glycoproteins are often components of _____ _____ and are involved in ____ _____ _____ interactions.
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Cell Membranes
Cell-to-cell |
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These are found in the cell membrane with the carbohydrate portion extending into the extracellular space.
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Glycolipids
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What are glycolipids derived from?
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Ceramide
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What is included in the glycolipid class of compounds?
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Cerebrosides
Globosides Ganglosides |
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What is the most abundant GAG in the body?
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Chondroitin Sulfate
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Chondroitin may work by acting as a _____ _____ for proteoglycan molecules, and may also have _____ _____ properties.
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Building Block
anti-inflammatory |
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What does chondroitin sulfate do for our joints?
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Strength
Flexibility Shock Absorption |
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What holds the cells of a tissue together and provides a porous pathway for the diffusion of nutrients and oxygen to individual cells.
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Ground Substance (ECM)
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What is the ground substance of cells composed of?
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Interlocking meshwork of heteropolysaccharides (GAGs) linked to protein
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What will promote depolymerization of the extracellular matrix (ground substance)?
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Hyaluronidase
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An enzyme that splits hyaluronic acid and so lowers its viscosity and increases the permeability of the connective tissue and the absorption of fluids.
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Hyaluronidase
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What GAG contians the largest proportion of Sulfate?
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Heparin
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What GAG contains the least proportion of Sulfate?
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Hyaluronic Acid
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Dextrans are _____ of _____ produced extracellularly by bacteria and yeast. The enzyme used to produce dextrans is _____, and the substrate is _____. A side product of Dextran production is _____, which is formed into _____ and stored intracellularly as reserve nutrients.
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Polysaccharides
Glucose Glucosyl Transferase (dextran transferase) Sucrose Fructose Levans (fructans) |
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What is the most noted bacteria to produce Dextrans?
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Streptococcus mutans
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The dextran is deposited as a thick _____ around the cell and seems to be essential for the _____ of Strep. Mutans.
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Glycocalyx
Cariogenicity |
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_____ also increase the adhesion of bacteria to surfaces of the teeth and promote the formation of dental plaque. It is formed from the _____ _____ of sucrose by the enzyme _____ _____.
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Levans (fructans)
Fructose moiety Levan sucrase |
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What are Levans considered to be for bacteria?
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Reserve nutrients
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