Chapter 7 Definitions/Concepts Flashcards Preview

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Flashcards in Chapter 7 Definitions/Concepts Deck (45)
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1

Carbohydrates

Structural and protective unit of cell walls of bacteria and plants, connective tissue of animals, and participate in recognition and adhesion between cells. Can be covalently attached to proteins or lipids.

2

Polysaccharide

20 or more monosaccharide units.

3

Monosaccharide Characteristics

Soluble in water, taste sweet and form colorless crystalline structures. Contain an unbranched carbon chain that can be an open-chain or closed-cyclic.

4

Closed-cyclic bond

Carbon of the carbonyl forming a bond with one of the hydroxyl oxygens.

5

Aldose

Carbonyl group is found at the end of the unbranched carbon chain forming an aldehyde.

6

Ketose

Carbonyl found at any position other then the end, forming a ketone.

7

Monosaccharide Composition

Composed of at least three carbons. They all contain one or more asymmetric carbon except ketotriose.

8

Monosaccharide Stereoisomers

Determined by the hydroxyl group on the chiral carbon furthest away from the carbonyl. The D form is more common for carbohydrates.

9

L Stereoisomers

Are not as common among carbohydrates. Act more like fiber because in humans there is not was to facilitate transfer into cells.

10

D-Ketoses

Four and five carbon ketoses are named inserting a "-ul" into the name of the corresponding aldose. All carbonyls are on the 2 carbon.

11

Cyclic Monosaccharides

Aldotetroses and all monosaccharides with five or more carbons occur predominately as cyclic structures. Through aldolcondensation they form either a hemiacetal or hemiketal resulting in an additional chiral carbon.

12

Chiral Carbon Transformation Through Aldolcondensation

When a hemiketal or hemiacetal is formed it forms an additional chiral carbon that can be either alpha or beta. Alpha if the hydroxyl is pointing down and beta if it is pointing up.

13

Pyranoses

Six membered ring structure, can be formed by aldoses as well. Exists in two chair conformations. Boat conformation is not usually seen because of bulky substituents.

14

Furanoses

Aldohexoses form a furanose. A five membered ring. Not as stable as the pyranoses.

15

Monosaccharide Reducing Agents

Monosaccharides with a carbonyl carbon are capable of reducing other species at the same time as they are being oxidized.

16

Non-Reducing Sugars

Some disaccharides that form linkages at the anomeric carbon to prevent the interconversion to the linear form.

17

Glycosidic Bonds

Formed between the anomeric carbon and another atom from another molecule. In disaccharides the anomeric carbon is usually linked to an O from another sugar.

18

Polysaccharides

Can be homo or heater. Form linear branched chains. Don't have a definite molecular weight because there is no specific stoping signal to end synthesis.

19

Homopolysaccharides As Fuel Stores

Starch- fuel storage in plants, found in granules.
Glycogen- fuel storage in animals, found in granules in liver and muscle.
Dextrans -fuel storage in bacteria and yeast..

20

Strach

Two types, amylose and amylopectin.

21

Amylose

Long and unbranched, D-glucose connected by alpha 1-4 linkages

22

Amylopectin

Long and branched, D-glucose connected by alpha 1-4 linkages and alpha 1-6 linkages at branch points.

23

Dextrans

D-glucose chains connected by alpha 1-6 linkages and all have alpha 1-3 branches. Some also have alpha 1-2 or 1-4 branches.

24

Glycogen

More highly branched then amylopectin. When used one monosaccharide is removed from one of the branched non-reducing ends.

25

Homopolysaccharides As Structural Components

Cellulose and Chitin

26

Cellulose

Found in plant cell walls. Linear unbranched structures with beta 1-4 linkages. No enzyme to break bond, can't be used as fuel source.

27

Chitin

Found in exoskeletons from anthropoids composed of beta 1-4 linkages but no with D-glucose.

28

Polysaccharide Sterics

Free rotation around the glycosidic bonds hindered by hydroxyl groups. Hydrogen bonding on the hydroxyl groups direct the 3D structure.

29

Starch Structure

The most stable conformation of amylose is a tight helix stabilized by hydrogen bonds. Has 60 degree angles creating a left-handed helix with 6 residues per turn.

30

Heteropolysaccharides As Structure

Peptidoglycan and Agar