an aldose has only one terminal OH group

a ketose has two terminal OH group

In photosynthesis, rubisco grats both co2 and h2o and puts them into a reaction with catalysis.

this is one of the slowest enzymes known

it is the most abundant enzyme in the world

aerobic/ cellular resipration

o2 is involved in break down to products

this reaction is slow burning to trap and use energy on a step by step basis

the energy collected is used in new bond creation and molecule rearrangement

polymerization

each glucose unit flips allowing the creation of a long stretched linear chain, this chain allows the formation of lots of hydrogen bonds, creating a strong structural unit

created using glycogen

the bonds create a left handed helix- structures involving glycogen are always this configuration

1. monosaccharides glucose and fructose serve as fuel molecules

2. polysaccharides starch and clycogen serve as chemical energy stores

3. polysaccarides such as sellulose, chitin, peptidoglycoans (material the bact. cell wall is made of), etc serve as structural and protective structures

4. monosaccarides ribose and deoxyribose are used in nucleotides and sucleic acids RNA and DNA.

5. glycoproteins are used for recoginition

based on the number of carbon atoms present : trioses, tetroses, pentoses, and hexoses

must abundant in living cells are hexoses and pentoses

class names often combine information about the carbon number and functional group

a stereoisomer is a molecule that has a sterocenter- a carbon with four unique groups attached

example is glyceraldehyde, d isomer has the hydroxyl ont he right and l isomer has hydroxyl on the left

naturally occuring, they contain 5-7 carbons.

trioses include glyceraldeyde (an aldose) and dihydroxyacetone (a ketone)

they contain chiral centers and exist in sterioisomers called enantiomers.

finsher projections represent the chiral structures of monosaccharides

they are designated based on the postion of the hydroxl group on the most distal carbon when compared to the carbonyl group

d- oh is to the right

l- oh is to the left

stereoisomers that are not enantiomers

can have one or more chiral center

term generally applied to molecules that have more than one chiral center

a type of diastereomer that only differ at a single chiral center

ex. d-glucose compared to d-galactose

these are interchanged in form by an isomerase

most simple sugars of 4 or more C exist in cyclic forms (hemiacetal or hemiketal)

A hydroxy group in the sugar reacts with the carbonyl group

the new oh bearing carbon is now a stereocenter and is called an anomeric carbon or anomers- it is next to the O

if the oh is up the ring is in the beta formation

if the oh is down the ring is in the alpha formation

the cyclic forms aer in equilibrium with open chain forms allowing the alpha and beta anomers to be converted into each others.

this is refered to as mutarotation

what is more stable:

cyclic or chain

5 or 6 carbon rings

cyclic structures are more stable than chain conformation

6 c rings are more stable than the 5c due to steric stress

what is more accurate in showing ring sturctures

conformational or haworth

1. oxidation/reduction

2. isomerization

3. esterfication

4. amino derivatives

5. glycoside formation and disaccharides

cyclic ester, lactone

lactones are readily produced in nature

L ascorbis acid/ vitamin C

Vitamin C is a powerful reducing agent that protects cells from reactive oxygen species (ROS) and reactive nitrogen species (RNS)

reducing sugars - the aldehyde or ketone group is responsible

needs an open chain so all monosaccharides are reducing sugars

alditols are produced.

the most important sugar is deoxyribose (DNA)

d sorbitol and d xylitol are used to sweeten nonsugar gum

free oh groups of carbohydrates can be converted to esters by reactions wtih acids

esterification often dramatically changes a sugar's chemical and physical properties

carbohydrate molecules are found predominantly in the proteoglycan components of connective tissues - dehydration reactions connects them

participate in forming of salt bridges between carbohydrate chains

attach sugars or glycans (sugar polymers) to proteins or lipids

catalyzed by glycosyl transferases, glycosidic bonds are formed between anomeric carbons in certain glycans and oxygen or nitrogen of other types of molecules, resulting in N or O glycosidic bonds

glycation

the reaction of reducing sugars with nucleophilic nitrogen atoms in a nonenzymatic reaction

the Maillard reaction - this results in an Amadori product, the Schiff base that forms rearranges into a stable ketoamine

these Amadori products further react to form Advanced Glycation End products (AGEs) that promote inflammatory processes

alpha D glucose

alpha D galactose

beta D fructose

90% of biological world are one of these three types

originally called Dextrose (based on the name of the ring conformation)

found in large quantities throughout the natural world

primary fuel for living cells

prefered energy source for brain cells and cells without mitochondria (erythrocytes)

refered to as fruit sugar due to high content in fruit

on a per gram vasis it is twice as sweet as sucrose there fore it is often used as a sweeetening agen tin processed food

sperm use sugar as an energy source

the "fast sugar"

present in the diet, 50 % is lactose

necessary to synthesize a variety of important biomolecuels: lactose, glycolipids, phospholipids, proteoglycan, glycolipids

epimerase can interconvert glucose and galactose

galactosemia is a genetic disorder resulting from a missing enzyme in galactose metabolism

epimer of glucose!!!

alpha D glucuronatae and its epimer beta L iduronate an animals

involved largely in digestion

used in the liver to imorve water solubility to remove wast molecules

an emulsifying agent

the anomeric carbon in a carbohydrate can react with an alcohol to form a glycosidic bond

if the bond is formed between 2 monosaccharides, a disaccharide forms

linkage to the anomeric carbon can be either alpha or beta, creating isomers

the anomeric oh can react wtih another oh on an alcohol or sugar

wather is lost to form an acetal/ketal- condensation/dehydration reaction

results in 2 ether links next to each other to create an alpha orientation

formed by linking 2 alpha-D-glucose molecules to give an alpha 1,4 glycosidic link

the oh on the 4 carbon of the first molecule is the non reducing end, the oh on 1c on the second molecule is the reducing end

maltose is an intermediate product of starch hydrolysis

comes from industrially produced starch

formed by linking 2 betah d glucose molecules to give a beta 1,4 glycosidic link

it becomes hydrolyzed cellulose

fromed by joining beta d galactose to alpha d glucose to give a beta 1,4 glycoside

mutarotation gives an alpha or beta isomer

a milk sugar

lactose deficiency is common

lactose is a reducing sugar

formed by linking alpha D glucose with B D fructose to give a 1,2 glycosidic link

the glycosidic bond occurs between both anomeric carbons - a non reducing sugar wtih this

composed of many monosaccharide monomoers connected by glycosidic linkages

smaller glycans made of 10 to 15 monomers called oligosaccharides, most often attached to polypeptides as glycoproteins

two broad classes: N and O linked oligosaccharides

largely involved in cell recoginition

primairly made of oligosaccharides

attach glycans to the side chain of hydroxyl of serine or threonine residues or the hydroxyl oxygens of membrane lipids

this linkage also creates glycolipids

larger glycans may be hundreds or thousands of subunits, called polysaccharides

polysaccharides can be linear or branched

2 classes: honoglycans and heteroglycans (multiple subunits but generally alternate between 2 or 3 polysaccharides)

one type of monosaccharide present

found in starch, glycogen, cellulose, chitin

starch and glycogen are energy storage molecules while chitin and chellulose are structural

storage froms of glucose  found in plants

polumers of alpha linked glucose

if links are 1,4 the polymer is linear and called amylose (no branching here)

amylose usually assumes a helical configuration wtih 6 glucose per turn

if the links are both 1,4 and 1,6 the polymer is branched and is amylopectin (branched from of plant starch)

one starch molecule has some osmotif pressure as one glucose  molecule- must break sturcture to regain glucose

storage carbohydrate in animals is glycogen

it is a branched chain polymer like amylopectin but it has more frequent branching (every 10 residues)

stored in liver and muscle cells

animal equivalent of starch

the major structural polymer in plants

linear homopolymer composed of Beta D glucose units linked Beta 1,4

repeating disaccharide of cellulose is beta cellobiose- the digestion product of cellulose

animals lack the enzymes necessary to hydrolyze cellulose- bacteria in ruminants can digest cellulose so that they can eat grass

the betah 1,4 glycosidic bond causes each molecule to flip relative to each other- able to form a linear molecule

strands of bind together through h bonding

pairs of unbranched cellulose molecules (12,000 glucose units each) are held by h bonding to from sheet like strips- microfibrils

each microfibril bundle may contain 40 of these pairs

inmortant for dietary fiber, wood, paper, and textiles

linear homopolysaccharide of Nacetyl beta D glucosamine and provides structural support for the exoskeleton (shell) of invertebrates (ex insects, lobsters, shrimp)

the polymer is linked as beta 1,4 units

basically insect cellulose

extra carbonyl group on C2 creates opportunities form H bonding- more stability, esp. when compared to cellulose

high molecular weight carbohydrate polymers that contain more than one type of monosaccharide

major types : N and O glycosaminoglycans, glycan parts of glycolipidsand GPI anchors (glycosylphosphatidylinositol)

linear polymers with disaccharide repeating units

ex. chondroitin sulfate, a component of cartilage

bound with a Beta 1,3 bond

often also have acidic carboxyl groups

structrual heteroglycans that are involved in mucus production- outside cell, helps to create binding for tissues

sulfate allows molecule to bind to water then dehydrate to form a gel- forms salt bridges to create ECM

chondroitin sulfate

dermatan sulfate

heparin (blood clotting)

keratan sulfate

hyaluronic acid

compounds that are covalently link carbohydrates to proteins and lipids

2 types that contain protein: proteoglycans and glycoproteins

have a very high carbohydrate to protein ratio (95 to 50

found in the ECM

GAG chanis are linked to core proteins by N and O glycosidic links

have roles in organizing ECM

involved in signal transduction

metabolism of proteoglycans involved in many genetic disorders including Hurler's Syndrome

organization: Hyaluronic acid, core proteins and then proteoglycan

these materials contain carbohydrate residues on protein chans

very important examples of these materials are antibodies- chemicals which bind to antigens and immobilize them

the carbohydrate part of the glycoprotein plays a role in determining the part of the antigen molecule to which the antibody binds

may have other purpose besides just receptors

lots of these have redundancey of purpose

varies with different of cells

ex- RBC (metabolically inert) only carries o2 to cells- the glycocalyx has no receptors for proteins hormones etc

other cells have receptors that responds to very specific compounds- hormones

the glycoprotein that HIV has and binds to on a T cell, also attaches to brain cells

an example of a lectin and glycoprotein

living organisms require large coding capacities for information transfer

profound complexity of functioning systems

to succeed as a coding mechanism, a class of molecules must have a large capacity for VARIATION

glycosylation is the most important posttranslational modification in terms of coding capacity

barbohydrate binding proteins are involved in translating the sugar code

bind specifically to carbohydrates via h bond, van der waals forces, and hydrophobic interactions

lectins functions: binding to bacteria, viruses, toxins, leukocyte rolling, many others

the total set of sugars and glycans in a cell or organism in the glycome

constantly in flux depending on the cells response to environment

there is no template for glycan biosynthesis- it is done in a step wise process

glycoforms can result based upon slight variations in glycan composition of each glycoprotein