biochem ch17
Terms
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- carbohydrates
- generally sugars and polymers of sugars; the primary source of energy for the cell
- monosaccharide
- the simplest type of carbohydrate consisting of a single saccharide unit
- disaccharide
- a sugar composed of 2 monosaccharides joined through an oxygen atom bridge
- glycosidic bond
- the bond between the hydroxyl group of the C-1 carbon of one sugar and a hydroxyl group of another sugar
- oligosaccharide
- an intermediate-sized carbohydrate composed of from 3 to 10 monosaccharides
- polysaccharide
- a large, complex carbohydrate composed of long chains of monosaccharides
- ketose
- a sugar that contains a ketone (carbonyl) group
- aldose
- a sugar that contains an aldehyde (carbonyl) group
- triose
- a 3-carbon monosaccharide
- stereoisomers
- a pair of molecules having the same structural formula and bonding pattern but differing in the arrangement of the atoms in space
- stereochemistry
- the study of the spatial arrangement of atoms in a molecule
- enantiomers
- stereoisomers that are nonsuperimposable mirror images of one another
- chiral molecule
- molecule capable of existing in mirror-image forms
- asymetric carbon
- a chiral carbon; a carbon bonded to four different groups
- glyceraldehyde
- triose
- Fischer Projection
- a two-dimensional drawing of a molecule, which shows a chiral carbon at the intersection of two lines and horizontal lines representing bonds projecting out of the page and vertical lines representing bonds that project into the page
- glucose
- hexose
- hemiacetal
- the family of organic compounds formed via the reaction of one molecule of alcohol with a ketone in the presence of an acid catalyst
- anomers
- isomers of cyclic monosaccharides that differ from one another in the arrangement of bonds around the hemiacetal carbon
- Haworth projection
- a means of representing the orientation of substituent groups around a cyclic sugar molecule
- fructose
-
1) Levulose
2) fruit sugar
- found in honey, corn syrup, and sweet fruites - hemiketal
- the family of organic compounds formed via the reaction of one molecule of alcohol with a ketone in the presence of an acid catalyst
- galactose
- 1) in lactose/milk sugar
- ribose
-
1) exists mainly in the cyclic form
2) backborn in DNA, RNA - Benedict's reagent
- a buffered solution of Cu2+ ions that can be used to test for reducing sugars or to distinguish between aldehydes and ketones
- reducing sugar
- a sugar that that can be oxidized by Benedict's or Tollens' reagents; includes all monosaccharides and most disaccharides
- maltose
- linking 2 alpha-D-glucose
- nonreducing sugar
- a sugar that cannot be oxidized by Benedict's or Tollens' reagent
- lactose
- beta-D-galactose and alpha-D-glucose
- galactosemia
- a human genetic disease caused by the inability to convert galactose to a phosphorylated form of glucose (glucose-1-phosphate) that can be used in cellular metabolic reactions
- lactose intolerance
- the inability to produce the degestive enzyme lactose, which degrades lactose to galactose and glucose
- sucrose
-
1) table sugar
2) linked to dental caries
3) nonreducing
4) glycosidic O is part of an acetal and ketal - amylose
- usually assumes a helical configuration with 6 glucose units per turn
- amylopectin
- a highly branched form of amylose; the branches are attached to the C-6 hydroxyl by alpha (1 to 6) glycosidic linkage; a component of starch
- glycogen
-
1) storage carbohydrates in animals
2) a branched chain polymer - cellulose
-
1) major structural polymer in plants
2) polysaccharide
3) a linear homopolymer - monosaccharides
-
1) glucose
2) fructose
- one sugar (saccharide) molecule - disaccharides
-
1) sucrose
2) lactose
- 2 monosaccharides linked - polysaccharides
-
1) starch
2) glycogen
3) cellulose
- chains of linked monosaccharide units - erythrose
- tetrose
- D-glyceraldehyde
- aldotriose
- dihydroxyacetone
- ketotriose
- stereoisomers, ex
-
1) D-glucose
2) D-mannose
3) D-galactose
- have the same chemical formula (C6H12O6) but differ in the positions of the hydroxyl groups on their asymmetric carbons - enantiomers are also called?
- optical isomers
- beta-D-galactoseamine
- a component of the blood group antigens
- reducing sugars
- all monosaccharides and the disaccharides except sucrose
- most important reduced sugar is?
- deoxyribose (in DNA)
- sucrose is formed by linking?
- alpha-D-glucose with beta-D-fructose
- glycosidic ling of sucrose
- 1,2
- glycosidic bond of lactose
- 1,4
- glycosidic bond of maltose
- 1,4
- maltose is formed when?
- starch is partly hydrolyzed
- cellobiose
- linking 2 beta-D-glucose
- glycosidic link of cellobiose
- 1,4
- cellobiose comes from?
- hydrolyzed cellulose
- cellulose is composed of?
- beta-D-glucose units linked beta-1,4
- the repeating disaccharide of cellulose is?
- beta-cellobiose
- starch
-
1) polysaccharide
2) storage form of glucose found in plants - starches are polymers of --- linked glucose?
- alpha
- starch with 1,4 link
-
1) polymer is linear
2) called "amylose" - starch with 1,4 and 1,6 links
-
1) polymer is branched
2) called "amylopectin" - glycogen is similar with?
- amylopectin, but it has more frequent branching (about every 10 residues)
- glycogen is stored in>
- liver and muscle cells
- glycoproteins
-
contain carbohydrate redisued on protein chains
ex. antibodies-chemicals - the carbohydrate part of the glycoprotein plays a role in determining?
- the part of the antigen molecule to which the antibody binds
- the human blood groups depend on the?
- oligosaccharide part of the glycoprotein on the surface of erythrocyte cells
- What determine blood group?
- the terminal monosaccharide of the glycoprotein at the nonreucing end
- terminal sugar for type A
- N-acetylgalactosamine
- terminal sugar for type B
- alpha-D-galactose
- terminal sugar for type AB
-
1) N-acetylgalactosamine
2) alpha-D-galactose - terminal sugar for type O
- none
- tooth decay is due to breakdown of?
- sucrose into glucose and fructose by enzyme
- What enzyme is responsible for breakdown of sucrose into glucose and fructose?
- glucosyl transferase
- glucosyl transferase is located on?
- cell membranes of bacteria, Streptococcus mutans
- the glucose molecules are then coupled together is large strands referred to as?
- dextrans
- frctose is used by the bacteria for?
- energy
- lactic acid is secreted as a?
- waste product
- this lactic acid secreted by bacteria in the plaque is kept in close contact with enamel, causing?
- erosion and cavities
- sucrose is composed of?
- alpha-D-glucose and beta-D-fructose