smaller organic molecules join together to form larger molecules macromolecules 4 major classes of...
TRANSCRIPT
Organic Macromolecules
MacromoleculesSmaller organic molecules join
together to form larger moleculesmacromolecules
4 major classes of macromolecules:carbohydrateslipidsproteinsnucleic acids
PolymersLong molecules covalently bonded by linking
chains of repeating smaller units polymers monomers = repeated small units each cell has millionsof diff macromoleculesThink: 26 letters of alphabet for all possiblecombinations
How to break down a polymerHydrolysis
use H2O to break apart monomers reverse of condensation reactionH2O is split into H and OHH & OH group attach where the
covalent bond used to beex: digestion is
hydrolysis
http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html
So what’s all this talk about carbs??Atkin’s Diet & South Beach Diet
Carbohydrates
1. contain C, H, O2. 1:2:1 ratio3. provide energy or storage4. many end in “ose”5. three main groups – monosaccharides, disaccharides, polysaccharides
CarbohydratesCarbohydrates are composed of C, H, O
carbo - hydr - ateCH2O
(CH2O)x C6H12O6
Function:energy u energy storageraw materials u structural materials
Monomer: single sugar molecules (monosaccharides)
ex: sugars & starches
Sugars Most names for sugars end in -ose
Classified by number of carbons6C = hexose (glucose)5C = pentose (fructose, ribose)
3C = triose (glyceraldehyde): imp intermediate in metabolic process of cell respiration (burning glucose for energy)
2005-2006
What functional groups?
carbonyl
ketone
aldehyde
hydroxyl
Sugar structure5C & 6C sugars form rings in aqueous
solutions in cells!
Carbons are numbered
Numbered carbons
C
CC
C
CC
1'
2'3'
4'
5'
6'
O
Simple & complex sugarsMonosaccharides
simple 1 monomer sugarsglucose
Disaccharides2 monomerssucrose
Polysaccharides large polymersstarch
a. Monosaccharides: simplest form of carbohydrates building blocks for larger carbohydrates
(also called monomers)
usually contain molecular formula C6H12O6
isomers: glucose, fructose, galactose glucose (blood sugar), fructose &
galactose (fruit sugars) can occur as straight (open) chains or
as rings numbering of carbon atoms in ring
depends on the straight chain (always # the carbon atoms so that the carbon attached to the functional group is the smallest number possible)
Glucose in the open chain and ring form
Building sugarsDehydration synthesis: putting together
monomers by taking out water (req’s energy & enzymes)
|fructose
|glucose
glycosidic linkage: can be alpha or beta which changes the orientation of the 2 monosaccharides to each other
monosaccharides disaccharide
|sucrose
structural isomers
“Let’s go to the video tape!”(play movie here)
Isomers of Glucose
Lactose: β-1,4 linkage (the 1,4 tells you where the 2 molecules are bonded to each other)
b. Disaccharides: C12H22O11 (molecular formula) 2 monosaccharides joined twice the energy sucrose (table sugar) = 1 glucose + 1
fructose maltose (found in sugar cane) =
1 glucose + 1 glucose lactose (milk sugar) = 1 glucose + 1
galactose maltose has alpha linkage (bottom to
bottom) sucrose has alpha linkage (bottom to
bottom) lactose has beta linkage (top to bottom) 1,4 or 1,2 numbering tells you what
carbon numbers the linkage is being formed at
Polysaccharides (polymers of hundreds to thousands of monosaccharides)
Polymers of sugars costs little energy to buildeasily reversible = release
energyFunction:
energy storage starch (plants)glycogen (animals)
building materials = structurecellulose (plants)chitin (arthropods & fungi)
c. Polysaccharides: (C6H10O5)n [molecular formula] N= 5-5,000 monosaccharides Form chains of polymers
(repeating monomer units) 2 main functions: food storage and
structure Food storage
Structure
cellulosechitin
plant starches animal starches
amylose amylopectin glycogen
2005-2006
Branched v linear polysaccharides(made of repeating glucose monomers) Q: can you see the difference between starch & glycogen? Which is easier to digest?
Glycogen
α -1,4 linkage on the straight chain α -1,6 linkage at the branch points (every 10 glucose molecules)
Polysaccharide diversity
Molecular structure determines function
isomers of glucose How does structure influence
function…
Amylose v Amylopectin
Amylose: straight chain with α -1,4 linkageAmylopectin: - α -1,4 linkage on the straight chain with α -1,6 linkage at the branch points (every 30 glucose molecules)
Comparison of Cellulose vs. Amylose
Amylose straight chain that
forms a helical structure in water
uses α glucose α-1,4 linkage used for storage
(starch) in plants soluble in water Cellulose straight chain uses β glucose β-1,4 linkage (every
other glucose subunit is inverted)
cannot be digested by animals (lack the enzyme cellulase)
used for support makes up plant cell
walls insoluble in water
Cellulose in Plant Cell Walls
Parallel cellulose molecules are held together by hydrogen bonds.
Cellulose Most abundant
organic compound on Earth
Cross-linking between
polysaccharidechains: rigid & hard to digestThink herbivores:
spend a lot of time digesting food w/help of microbes
Digesting starch vs. cellulose (starch: all the glycosidic linkages are on same side: molecule lies flat)
2005-2006
Cowcan digest cellulose well; no need to eat supplemental sugars
Gorillacan’t digest cellulose well; must supplement with sugar source, like fruit
Chitinforms the
exoskeletons of arthropods
used to make a strong and flexible surgical thread that decomposes after the wound or incision heals
makes up the cell walls of some fungi
The structure of the chitin monomer
2005-2006
Glycemic indexWhich food will get into your
blood more quickly?applerice cakescorn flakesbagelpeanut M&M
2005-2006
Glycemic indexRanking of carbohydrates based on their
immediate effect on blood glucose (blood sugar) levels
Carbohydrate foods that breakdown quickly during digestion have the highest glycemic indices. Their blood sugar response is fast & high.
2005-2006
Glycemic indexWhich food will get into your
blood more quickly?apple 36rice cakes 82corn flakes 84bagel 72peanut M&M 33
Let’s build some
Carbohydrates!