Chemistry Final Exam Terms – Flashcards
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| Carbohydrates are composed of |
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| carbon, hydrogen, and oxygen, with the hydrogen and oxygen in the proportion of two to one, the same as water. |
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| General Carbohydrate Structure |
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| CxH2xOx |
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| As a class of compounds Carbs include |
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| simple sugars, starches, and cellulose |
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| fundamental role of carbs |
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| important source of energy |
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| structural role of carbs |
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| structural units in cell walls and membranes, and in cellular components responsible for function and growth |
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| stereoisomerism |
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| --the property of optical rotation of polarized light |
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| simplest carbohydrates are known as |
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| monosaccharides |
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| monosaccharides |
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| straight chain polyhydroxy alcohols |
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| Usual length of monosaccharides |
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| 3 to 8 carbon atoms |
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| How are monosaccharides classified |
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| according to the number of carbon atoms in the chain |
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| Carbohydrates are defined as derivatives of |
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| polyhydroxyaldehydes or polyhydroxyketones. |
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| aldose |
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| Sugar containing an aldehyde group |
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| ketose |
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| Sugar possessing a ketone group |
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| Trioses are derived from |
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| polyhydroxy alcohol glycerol |
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| oxidation on the central carbon of the triose yeilds |
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| a ketose |
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| pentoses |
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| sugars whose molecules contain five carbon atoms |
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| most pentoses contain _____asymmetric carbonds |
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| 3 |
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| How do pentoses occur in nature? |
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| combined in polysaccharides from which monosaccharides may be obtained by hydrolysis with acids. |
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| The Hexoses |
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| Glucose, fructose, and galactose |
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| by which physiological standpoint are hexoses the most important monosaccharides |
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| nutritional and physiological standpoint |
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| which carbs are used as food? |
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| hexoses |
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| Two ways haxoses can be found |
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| free or combined in disaccharides and polysaccharides |
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| Glucose |
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| normal sugar of the blood and tissue fluids and is utilized by cells as a source of energy |
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| Galactose |
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| constituent of milk sugar and is found in brain and nervous tissue |
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| Fructose |
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| keto sugar whereas the others are aldoses |
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| pyranoses |
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| The six member ring forms of sugar |
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| pyranoses are derivatives of |
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| heterocyclic compound pyran. |
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| D-glucose ring form = |
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| ?-D-glucopyranose |
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| what reaction forms a pyranose |
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| reaction between an aldehyde and an alcohol to form a hemiacetal. |
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| furnaose |
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| a derivative of furan. |
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| The formation of furnaose rings |
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| special case of a more general type of reaction between a ketone and an alcohol to form a hemiketal |
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| Derived Monosaccharaides formation |
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| reduction or oxidation of the carbonyl group |
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| Examples of Derived Monosaccharaides |
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| D-sorbitol or D-mannitol |
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| reduction products of derived monosaccharides |
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| polyols (polyalcohols) |
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| oxidation products of derived monosaccharides |
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| acids, ex. glucaronic acid |
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| Sialic Acid |
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| Important group of derived monosaccharide's resulting from the replacement of a hydroxyl group (OH) by an amino group. |
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| N-Acetylneuraminic Acid |
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| This negatively charged residue is found in complex glycans, mucins and glycoproteins in the cell membrane. Also found in glycolipids, such as gangliosides, a crucial component of neuronal membranes found in the brain. |
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| Complex Carbohydrates formation |
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| linking two or more monosaccharides whose combination involves the splitting out of a molecule of water. |
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| hemiacetal linkage |
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| always made from the aldehyde group of one sugar to the hydroxyl or ketone group of the second. |
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| simplest complex carbs |
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| diasaccharides |
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| Maltose |
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| diasaccharide, composed of two glucose molecules |
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| Lactose |
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| diasaccharide, composed of one molecule of galactose and one molecule of glucose |
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| Sucrose |
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| diasaccharide, composed of one molecule of fructose and one molecule of glucose |
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| Sucrose common name |
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| table sugar |
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| What is sucrose composed of? |
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| a molecule of glucose joined to a molecule of fructose in such a way that the linkage involves the reducing groups of each sugar (carbon 1 of glucose and carbon 2 of fructose). |
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| will sucrose reduce bendicts |
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| no |
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| What forms upon hydrolysis of sucrose |
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| molecule of glucose and a molecule of fructose are formed. |
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| What forms upon hydrolysis of Lactose |
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| forms a molecule of glucose and a galactose |
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| Where is lactose synthesized |
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| mammary glands |
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| will lacttose reduce bendicts |
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| yes |
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| polysaccharides |
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| complex carbohydrates that are made up of many monosaccharide molecules and therefore possess a high molecular weight. |
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| do polysaccharides reduce benedicts? |
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| no |
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| What do polysaccharides form? |
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| colloidal dispersions instead of simple solutions |
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| Polysaccharides can be formed |
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| pentoses or from hexoses and there are also mixed polysaccharides. |
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| Hexosans |
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| important polysaccharides, two hexoses combine and a water is split off |
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| Three most important polysaccharides |
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| cellulose, starch and glycogen |
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| Cellulose |
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| consist of glucose units linked in a ?(1-4) glycosidic linkage forming long unbranched chains |
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| Strach |
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| consists of glucose units linked in an ? (1-4) glycosididc linkage. Scattered throughout the molecule are ? (1-6) glycosididc linkages permitting branched chains to form. |
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| Glycogen |
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| – Resembles amylopectin, is highly branched, and represents the primary storage form of glucose. |
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| Two forms of starch |
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| Amylose -- straight chain Amylopectin -- and branched chain |
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| Monosaccharides undergo dehydration in the presence of mineral acids to form |
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| cyclic furfural derivatives |
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| Monosaccharides and redox reactions |
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| Can be oxidized or reduced or can serve as oxidizing or reducing agents. |
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| Schiff base |
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| Aldoses can react with primary amines |
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| Glucose's reaction with aromatic amines like o-toluidine |
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| Used as a method for measuring glucose concentrations |
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| Enzymatic methods represent |
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| principle means for determination today. |
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| Glycogen |
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| primary storage form of glucose occurring to the greatest extent in the liver and muscle tissue |
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| Complex carbohydrates (polysaccharides) are found in |
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| body fluids and connective tissues - i.e., synovial fluid |
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| Carbohydrate Metabolism |
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| energy production by conversion to carbon dioxide and water storage as glycogen in the liver or triglycerides in adipose tissue conversion to keto acids, amino acids, or protein |
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| once transported within the cell glucose is rapidly converted into |
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| glucose-6-phosphate |
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| Metabolic pathways available from G6P |
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| Glycolysis Tricarboxylic Acid Cycle Hexose Monophosphate Shunt Uronic Acid Pathway Glycogenesis |
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| glycogen synthetase |
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| catalyzes 1-4 glycosidic linkage |
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| What activates glycogen synthetase |
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| insulin --> cAMP levels --> PKA |
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| Glycogenolysis |
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| Conversion of Glycogen to Glucose |
