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Transcript of Building Blocks of Life - d39smchmfovhlz.cloudfront.net fileAP Biology 2007-2008 Chemistry of Carbon...
AP Biology
Why study Carbon?
All of life is built on carbon
Cells
~72% H2O
~25% carbon compounds
carbohydrates
lipids
proteins
nucleic acids
~3% salts
Na, Cl, K…
AP Biology
Chemistry of Life
Organic chemistry is the study of
carbon compounds.
All living things have carbon in it!
Therefore…all living things are organic!
C atoms are versatile building blocks
Very reactive atom.
Outer most shell needs four more
electrons to be full or stable.
Can form up to 4 stable covalent bonds
AP Biology
Let’s review the hierarchy of life
Atom
Element
Molecule
Organelle
Cell
Tissue
Organ
Organ system
Organism
Population
Community
Ecosystem
Biosphere
Whew! Glad you
didn’t forget that!
Did I mention this
will be on your
final exam in May?
AP Biology
We are adding 3 more!
Atom
Element
Molecule
Monomers
Polymers
Macromolecule
Organelle
Cell
Tissue
Organ
Organ system
Organism
Population
Community
Ecosystem
Biosphere
AP Biology
What is a monomer?
What does the
prefix “mono”
mean?
ONE!
A single (one unit)
that are building
blocks of larger
molecules.
LEGO?
LETTERS of the
alphabet?
B
I
O
I
S
F
U
N
AP Biology
What is a polymer?
What does the
prefix “poly”
mean?
MANY!
Polymers are many
monomers joined
together
MONO+MONO+MONO+MONO=POLY
LETTERS of the
alphabet?
Consider the previous
slide…
B
I
O
I
S
F
U
N
AP Biology
H2O
HO
HO H
H H HO
Polymers
Long molecules built by linking repeating
building blocks in a chain
monomers
Think individual legos!
building blocks
repeated small units
Held together by
covalent bonds
Dehydration synthesis
AP Biology
H2O
HO
HO H
H H HO
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
enzyme Dehydration synthesis
Condensation reaction
You gotta be open to “bonding!
AP Biology
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
Breaking up is hard to do!
Hydrolysis
Digestion
enzyme
AP Biology
What is a macromolecule?
What does the prefix
“micro” mean?
SMALL
What does the prefix
“macro” mean?
LARGE!
Macromolecules are
many monomers and/or
polymers joined
together to form very
LARGE molecules.
AP Biology
BIO + IS + FUN = BIO IS FUN
Letters of the alphabet represent
monomers.
Letters combine to make words represent
monomers combining to make polymers.
Combing words to make sentences
represent combining polymers to make
macromolecules!
AP Biology
Macromolecules
Smaller organic molecules join together
to form larger molecules
macromolecules
4 major classes of
macromolecules:
carbohydrates
lipids
proteins
nucleic acids
AP Biology
Carbohydrates
Carbohydrates are composed of C, H, O
carbo - hydr - ate
CH2O
(CH2O)x C6H12O6
Monomers: simple sugars (single
sugars) or monosacharride (prefix
mono=one & suffix saccharide = sugar ).
3 monosaccharides :
Glucose, fructose and galactose
sugar sugar sugar sugar sugar sugar sugar sugar
C6H12O6 (CH2O)x
AP Biology
Function:
Dietary energy energy storage
raw materials structural materials
ex: sugars, starches, cellulose
AP Biology
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
H
H
H
OH
O
Glucose
H
OH
HO
O H
H HO
H
Ribose
CH2OH
Glyceraldehyde
H
H
H
H
OH
OH
O
C
C
C 6 5 3
AP Biology
More sugars!
Disaccharides = 2 sugars
Sucrose,
maltose,
lactose
Polysaccharides = many sugars
large polymers
Starch
Glycogen
Cellulose
Chitin
AP Biology
Building sugars
Dehydration synthesis
glycosidic linkage
The bond that joins
monosaccharides to create
polysaccharides
|
glucose
|
glucose
monosaccharides disaccharide
|
maltose
H2O
AP Biology
Building sugars
Dehydration synthesis
|
fructose
|
glucose
monosaccharides
| sucrose
(table sugar)
disaccharide
H2O
AP Biology
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)
AP Biology
Linear vs. branched polysaccharides
starch
(plant)
glycogen
(animal)
energy
storage
slow release
fast release
AP Biology
Polysaccharide diversity
Molecular structure determines function
isomers of glucose
structure determines function…
in starch in cellulose
AP Biology
Digesting starch vs. cellulose
starch easy to digest enzyme
enzyme
cellulose hard to digest
AP Biology
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
AP Biology
Cow can digest cellulose well; no need to eat other sugars
Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet
AP Biology
Helpful bacteria
How can herbivores digest cellulose so well?
BACTERIA live in their digestive systems & help digest
cellulose-rich (grass) meals