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Final Exam
Carbohydrates
73
Chemistry
Graduate
04/10/2013

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