carbohydrates
DESCRIPTION
BIOLOGYTRANSCRIPT
”
“ CARBOHYDRATES
201139189CANDICE PIENAAR
REFERENCES
1) http://www.slideshare.net/kleppingerb/catrbohydrates?qid=674cbdcc-2c94-43fa-8f43-ffdb057f65aa&v=qf1&b=&from_search=5
2) http://www.slideshare.net/obanbrahma/carbohydrates-30770508?qid=674cbdcc-2c94-43fa-8f43-ffdb057f65aa&v=qf1&b=&from_search=6
3) http://www.slideshare.net/mazz4/carbohydrates-28729095?qid=674cbdcc-2c94-43fa-8f43-ffdb057f65aa&v=qf1&b=&from_search=9
4) http://www.slideshare.net/syed_ismail/carbohydrates-28872311?qid=674cbdcc-2c94-43fa-8f43-ffdb057f65aa&v=qf1&b=&from_search=8
5) http://www.slideshare.net/gangadharchatterjee/carbohydrate-chemistry-27717759
CARBOHYDRATESIs an organic compound
σακχαρωνGreek “sakcharon” = sugar
LETS LEARN SOME GREEK!!!!The name glucose comes from the Greek word glykys (γλυκύς), meaning "sweet", plus the suffix "-ose" which denotes a sugar
4 chiral centers give 24 = the 16 stereoisomer s of hexose sugars. Chirality, or "handedness", Greek, (χειρ), kheir: "hand” chiral carbons are enantiomers
Alpha α and Beta β are letters in the Greek alphabet
Carbohydrates • Carbohydrates, or saccharides (saccharo is Greek for ―sugar) are polyhydroxy aldehydes or ketones, or substances that yield such compounds on hydrolysis.
• Carbohydrates include not only sugar, but also the starches that we find in foods, such as bread, pasta, and rice.
• The term ―carbohydrate comes from the observation that when you heat sugars, you get carbon and water (hence, hydrate of carbon).
Carbohydrates and Biochemistry•Carbohydrates are compounds of tremendous biological importance:–they provide energy through oxidation–they supply carbon for the synthesis of cell components–they serve as a form of stored chemical energy–they form part of the structures of some cells and tissues•Carbohydrates, along with lipids, proteins, nucleic acids, and other compounds are known as biomolecules because they are closely associated with living organisms.
glucose
is the building blockof carbohydrates
Importance of carbohydrates:
CHIEF SOURCE OF ENERGY
Types of Carbohydrates:
monosaccharide
disaccharide
polysaccharide
monosaccharide
MONOSACCHARIDES
CLASSIFICATION OF MONOSACCHARIDES
1- According to the number of carbon atoms: .Trioses, contain 3 carbon atoms.• Tetroses, contain 4 carbon atoms.• Pentoses, contain 5 carbon atoms.• Hexoses, contain 6 carbon atoms.• Heptoses, contain 7 carbon atoms.• Octoses. contain 8 carbon atoms.
Glucose (a monosaccharide)
Plants:
photosynthesis chlorophyll
6 CO2 + 6 H2O C6H12O6 + 6 O2 sunlight (+)-glucose
(+)-glucose starch or cellulose
respiration
C6H12O6 + 6 O2 6 CO2 + 6 H2O + energy
monosaccharide
C6H12O6
Simple sugars that consist s only one (1) sugar molecule
Under monosaccharide:1. Glucose2. Fructose3. Galactose
monosaccharide
1. Glucose
Blood sugar; most important sugar in the bodies of both vertebrates and invertebrates
monosaccharide
2. Fructose
Corn sugar; sweetest form of sugar commonly found in fruits
monosaccharide
3. Galactose
Simplest sugar found in milk
Animals
plant starch (+)-glucose
(+)-glucose glycogen
glycogen (+)-glucose
(+)-glucose fats or aminoacids
respiration
(+)-glucose + 6 O2 6 CO2 + 6 H2O + energy
2. MONOSACCHARIDES
• Examples
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2. MONOSACCHARIDES
• Once a monosaccharide has been named as an aldose or a ketose, and the number of carbons has been designated, there are still several different isomeric forms for each.
• Each specific monosaccharide has a unique name.
• A prefix (D- or L-) is added to designate which of two possible isomeric forms is being referred to.
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disaccharide
disaccharide
C12H22O11
Pair of monosaccharide unitsGlucose + monosaccharide unit = disaccharide
Under disaccharide:1. Sucrose2. Lactose3. Maltose
OOHOH
FORMING DISACCHARIDES
C C
C
C O
C
H
OH
OHOH
OH
HH
CH2OH
H
H
CH2OH
C C
C
C O
C
H
OH
OHOH
OH
HH
CH2OH
H
H
C C
C
C O
C
H
OH
OH
OH
HH
CH2OH
H
H
C C
C
C O
C
H
OH
OH
OH
HH
CH2OH
H
H O
H H
GlycosidicBond This is a CONDENSATION
reaction, where a water molecule is lost.
Glucose
Maltose
disaccharide
1. Sucrose
Table sugar; glucose + fructose
disaccharide
2. Lactose
Milk sugar; glucose + galactose
disaccharide
3. Maltose
Malt sugar; glucose + glucose
polysaccharide
polysaccharide
Consists of chains of monosaccharide and disaccharide
Under polysaccharide:1. Starch2. Glycogen3. Cellulose
polysaccharide
1. Starch
Storage of glucose for plants
polysaccharide
2. Glycogen
Storage of excess sugar in animals; stored in liver and muscles
polysaccharide
3. Cellulose
Structural support of plants; known as “fiber”
Additional info:
monomer: a molecule that may react chemically to another molecule to form polymer; the simplest unit; repeating unit of polymer
polymer: a compound made up of several repeating units (monomer)
enzyme: speeds up chemical reaction
CLASSIFICATION:
1- Monosaccharides (simple sugars): They can not be hydrolyzed into simpler units. E.g. glucose, galactose,ribose
2- Oligosaccharides (oligo = few): contain from two to ten monosaccharide units joined in glycosidic bonds. e.g.
• disaccharides (2 units) e.g. maltose and sucrose,• trisaccharides (3 units).....etc.
3-Polysaccharides (poly = many): Also known as glycans. They are composed of more than ten monosaccharide units e.g. starch, glycogen, cellulose.....etc.
2- According to the characteristic carbonyl group (aldehyde or ketone group):
- Aldo sugars: aldoses:
Contain aldehyde group e.g. glucose, ribose, erythrose and glyceraldehydes.
- Keto sugars: ketoses:
Contain ketone group e.g. fructose, ribulose and dihydroxy acetone.
GLUCOSE FORMS A RING STRUCTURE
Note: functional group is on carbon one
TWO TYPES OF RING STRUCTURES FOR GLUCOSE
OH on carbon one:
BELOW the ring ABOVE the ring
The existence of - and -isomers:- leads to greater chemical variety is of importance in for example in
forming starch and cellulose
NOTE DIFFERENCE:
The main difference between glucose and galactose is that glucose is much sweeter than galactose.
13.4. REACTIONS--ADDITION
• Addition of an alcohol to an aldehyde:
• The product is called a hemiacetal (-OH and –OR attached to the same carbon).
• Hemiacetals are very reactive.
• They react with an additional alcohol molecule, losing –OH and adding another –OR.
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H+
13.4. REACTIONS--ADDITION
• The final product is an acetal (2 –OR groups attached to one carbon).
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hemiacetal acetal
13.4. REACTIONS--ADDITION
• Ketones undergo analogous addition reactions with alcohols.
• The initial product is a reactive hemiketal (two –R groups, one –OH, and one –OR).
• An additional –OR group is added to the hemiketal to produce a ketal.
42hemiketal ketal
13.4. REACTIONS--ADDITION