Agbi ch7

• *simple sugars
• *aldehydes or keytones with 2+ hydroxyl groups
• *many carbons have chiral centers
•      *n chiral centers has 2ⁿ stereoisomer
• *backbone: 4-7 carbons
• *aldoses: carbonyl group at end
• *ketoses: carbonyl group in middle of chain

• COH
•       |
•   H-C-OH
•       |
• HO-C-H
•       |
• HO-C-H
•       |
•   H-C-OH
•       |
•      CH2OH

• COH
•       |
•   H-C-OH
•       |
• HO-C-H
•       |
•   H-C-OH
•       |
•   H-C-OH
•       |
•      CH2OH

• COH
•       |
• HO-C-H
•       |
• HO-C-H
•       |
•   H-C-OH
•       | 
•   H-C-OH
•       |
•     CH2OH

• CH2OH
•     |
•     C=O
•     |
• H-C-OH
•     |
• H-C-OH
•     |   
•     CH2OH

• COH
•     |
• H-C-OH
•     |
• H-C-OH
•     |
• H-C-OH
•     |
•    CH2OH

• hemiacetals/hemiketals
• 5 member ring: furanose
• 6 member ring: pyranose
• not planar
• D/L OH becomes ring member
• Dbl bonded O becomes α/β OH on right

2 monosac. joined covalently by O-glycosidic bond

• 1. name α or β at carbon on 1st monosac.
• 2. name first residue
• 3. ID carbon number at bond
• 4. name second residue

typical bond: 1⇒4, 1⇒6

state of O on anomeric C determines whether sugar can react with oxidized cmpd

when O on anomeric C not attached to another structure ⇒ reducing sugar

hemiacetal at one end & need to convert back to linear form

sugars that contain aldehyde groups that are oxidized to carboxylic acids ⇒ reducing sugars

short chain of monosac. residues liked with glycosidic bond

• 20+ monosac. residues
• most common
• dont have defining molecular weight

*contains single monomeric species

folding includes H-bonds, and hydrophobic, van der waals, and electrostatic interactions

• found in corn kernals
• form of energy in plants

amylose: long, unbranched chains of D-Glucose with α1⇒4 link

amylopectin: long, highly branched chains of D-glucose with α1⇒4 & α1⇒6 link

more amylose found in plants

constant repeating

long highly branched chains of D-Glucose with α1⇒4 and α1⇒6 links at branches

highly compact

more branching than amlopectin

found in liver and muscles

short term energy supply

bachterial and yeast polysacc

α1⇒6 linked D-glucose

α1⇒2, α1⇒3, & α1⇒4 branching

soluble fiber, cant be digested

in soda to help lose weight: drink give false full feeling

abundantly found in plants

linear chains of D-glucose with β1⇒4 links

most animals dont have enzymes to hydrolize this linkage

N-acetylglucosamine residues with β1⇒4 links

contains 2+ species of monosac

• β1⇒4 linkd NAM and NAG
• found in bacteria
• prevents osmotic swelling
• lysosomes can hydrolize this bond

• found in algae cell walls
• can trap water
• L- and D-glactose
• β1⇒4

used as gel in electrophoresis

structural framework for cells

nutrients and waste diffuse thru (CO2, O2)

contains fibrous proteins

• glycosaminoglycans: linear polymers composed of repeating disacc units
•    -high density of negative charge

β1⇒3

biologically active & bound to proteins or lipids

• *cell signaling molecules
• *label proteins
• *recognition sites for hormones
• *cell identity

type of glycoconjugates

oligosacc covalently joined to a protein

~50% all proteins are glycosylated =>modifies protein activity

membrane sphingolipics, hydrophillic head groups are oligosacc.

gangliosides: used to determine blood groups, found on outter surface of plasma membrane

lipopolysaccharidse: fatty acids bound to glucosamine, targets for antibodies