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How To Make Biological Molecules
Adapted from Kim Fogia and David Knuffke work
H2O
HO
HO H
H HHO
How to build a polymer• Synthesis
– joins monomers by “taking” H2O out• one monomer donates OH–
• other monomer donates H+ • together these form H2O
– requires energy & enzymes
enzymeDehydration synthesis
Condensation reaction
H2O
HO H
HO H HO H
How to break down a polymer• Digestion
– use H2O to breakdown polymers • reverse of dehydration synthesis• cleave off one monomer at a time
• H2O is split into H+ and OH–
– H+ & OH– attach to ends
– requires enzymes– releases energy
Hydrolysis
Digestion
enzyme
Dehydration and Hydrolysis
• http://www.youtube.com/watch?v=b7TdWLNhMtM&feature=related
OH
OH
H
H
HO
CH2OH
HH
H
OH
O
Carbohydratesenergy
molecules
Carbohydrates• Carbohydrates are composed of C, H, O
• Ratio of 1:2:1
• Function:– energy – energy storage– raw materials – structural materials
• Monomer: sugars• ex: sugars, starch, cellulose sugar sugar sugar sugar sugar sugarsugar
C6H12O6(CH2O)x
Sugars • Most names for sugars end in -ose• Classified by number of carbons
– 6C = hexose (glucose)– 5C = pentose (ribose)– 3C = triose (glyceraldehyde)
OH
OH
H
H
HO
CH2OH
HH
H
OH
O
Glucose
H
OH
HO
O H
HHO
H
Ribose
CH2OH
Glyceraldehyde
H
H
H
H
OH
OH
O
C
C
C6 5 3
Functional groups determine function
carbonyl
ketone
aldehyde
carbonyl
Sugar structure5C & 6C sugars form rings in solution
Carbons are numbered
Numbered carbons
C
CC
C
CC
1'
2'3'
4'
5'
6'
O
energy stored in C-C bonds
Simple & complex sugars• Monosaccharides
– simple 1 monomer sugars– glucose
• Disaccharides– 2 monomers– sucrose
• Polysaccharides – large polymers– starch
OH
OH
H
H
HO
CH2OH
H
H
H
OH
O
Glucose
main source of energy
• Formula: C6H12O6
• Sources: nectar, sap,
blood
Glucose vs. Fructose vs. Galactose Isomers?
• Formula:
C6H12O6
• Sources: Fruits
• Formula: C6H12O6
• Sources: Milk
Types of Isomers(examples can be found on page 35)
• Stereoisomers: differ in 3D orientation• Structural: same chemical formula but differ in the
order they are covalently bonded • Geometric (diastereomers): have same chemical
formula but differ in the way they are arranged on either side of double bond or ring.
• Optical: (enantiomers):same chemical formula but the arrangement around the Carbon that has four different groups around it (mirror images)
Building sugars• Dehydration synthesis
glycosidic linkage
|glucose
|glucose
monosaccharides disaccharide
|maltose
H2O
Building sugars• Dehydration synthesis
|fructose
|glucose
monosaccharides
|sucrose
(table sugar)
disaccharide
H2O
Building sugars• Dehydration synthesis
glycosidic linkage
|galactose
|glucose
monosaccharides disaccharide
|lactose
H2O
Polysaccharides • Polymers of sugars
– costs little energy to build– easily reversible = release energy
• Function:– energy storage
• starch (plants)• glycogen (animals)
– in liver & muscles
– structure• cellulose (plants)• chitin (arthropods & fungi)
Linear vs. branched polysaccharides
starch(plant)
glycogen(animal)energy
storage
slow release
fast release
Straight chain: amylose
Branched: amylopectin
Cellulose not digestible by us
http://cnx.org/content/m46008/latest/?collection=col11496/latest
http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit1/prostruct/images/u1fig8b.jpg http://academic.brooklyn.cuny.edu/biology/bio4fv/page/chitin.jpg
Bacteria cell wall
Fungi ,arthropods
Polysaccharide diversity
• Molecular structure determines function
isomers of glucose structure determines function…
in starch in cellulose
Digesting starch vs. cellulose
starcheasy todigest enzyme
enzyme
cellulosehard todigest
Chitin, a different structural polysaccharide
(a) The structure of the chitin monomer.
O
CH2OH
OHH
H OH
H
NH
C
CH3
O
H
H
(b) Chitin forms the exo- skeleton of arthropods. This
cicada is molting, shedding its old exoskeleton and emergingin adult form. It is also found in
Fungal Cell Walls.
(c) Chitin is used to make a strong and flexible surgical
thread that decomposes after the wound or incision heals.
OH
Cellulose • Most abundant organic
compound on Earth– herbivores have evolved a mechanism to digest
cellulose– most carnivores have not
• that’s why they eat meat to get their energy & nutrients
• cellulose = undigestible roughage
Cowcan digest cellulose well; no need to eat other sugars
Gorillacan’t digest cellulose well; must add another sugar source, like fruit to diet
Helpful bacteria• How can herbivores digest cellulose so well?
– BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals
Ruminants- 4 compartments
Longer digestion process
Ruminant: any even-toed, hoofed mammal of the suborder Ruminantia, being comprised of
cloven-hoofed, cud-chewing quadrupeds, and including,
besides domestic cattle, bison, buffalo, deer, antelopes, giraffes,
camels, and chevrotains. Dictionary.com
• What elements are Carbohydrates composed of?
• What are the functions of Carbohydrates?
• How are carbohydrates broken down in our bodies?
2. Which of the following is a polymer?
A. Simple sugar (aka monosaccharide)B. Carbon atomsC. GlucoseD. CelluloseE. deoxyribose
3. Starch and Glycogen bothI. Serve as energy storage for
organismsII. Provide structure and supportIII. Are structural isomers of glucose
A. I onlyB. II onlyC. I and II onlyD. I and III onlyE. I, II, and III