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