Transcript Macromolecules

Macromolecules
• Smaller organic molecules join together
to form larger molecules
– macromolecules
• 4 major classes of
macromolecules:
– carbohydrates
– lipids
– proteins
– nucleic acids
Polymers
• Long molecules built by linking repeating
building blocks in a chain
– monomers
• building blocks
• repeated small units
H 2O
– covalent bonds
HO
H
HO
H
Dehydration synthesis
HO
H
How to build a polymer
• Synthesis
– joins monomers by “taking” H2O out
• one monomer donates OH–
• other monomer donates H+
• together these form H2O
H 2O
– requires energy & enzymes
HO
H
Dehydration synthesis
HO
H
enzyme
Condensation reaction
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–
H2O
– H+ & OH– attach to ends
– requires enzymes
– releases energy
Hydrolysis
Digestion
HO
HO
enzyme
H
HO
H
H
Functional groups
• Parts of organic molecules that are
involved in chemical reactions
– give organic molecules distinctive properties
hydroxyl
amino
carbonyl
sulfhydryl
carboxyl
phosphate
Hydroxyl
• –OH
– organic compounds with OH = alcohols
– names typically end in -ol
• ethanol
Carbonyl
• C=O
– O double bonded to C
• if C=O at end molecule = aldehyde
• if C=O in middle of molecule = ketone
Carboxyl
• –COOH
– C double bonded to O & single bonded to OH
group
• compounds with COOH = acids
– fatty acids
– amino acids
Amino
• -NH2
– N attached to 2 H
• compounds with NH2 = amines
– amino acids
• NH2 acts as base
– ammonia picks up H+ from solution
Sulfhydryl
• –SH
– S bonded to H
• compounds with SH = thiols
• SH groups stabilize the structure of proteins
Phosphate
• –PO4
– P bound to 4 O
• connects to C through an O
• lots of O = lots of negative charge
– highly reactive
• transfers energy between organic molecules
– ATP, GTP, etc.
CH2OH
H
O
H
OH
H
H
OH
HO
H
OH
Carbohydrates
energy
molecules
Carbohydrates
• Carbohydrates are composed of Carbon,
Hydrogen, and Oxygen- usually at a 1:2:1
ratio….
carbo - hydrate
C H2O
(CH2O)x
C6H12O6
(CH2O)x
C6H12O6
Function:
– Fast energy (short term energy)
– Provides structural materials in cells (like cell
walls, receptors)
– Energy storage
Subunit / Building block / Monomer:
MONOSACCHARIDES!!!!
sugar
sugar
sugar
sugar
sugar
sugar
sugar
sugar
Sugars
• Most names for sugars end in -ose
• Classified by number of carbons
– 6C = hexose (glucose)
– 5C = pentose (ribose)
– 3C = triose (glyceraldehyde)
CH2OH
H
O
H
OH
6H
HO
H
OH
Glucose
H
CH2OH
OH
C
O
H
HO
H
5
OH
O
H
HO
H
Ribose
H
H
H
C
OH
C
3OH
H
Glyceraldehyde
Functional groups determine function
carbonyl
aldehyde
carbonyl
ketone
Sugar structure
5C & 6C sugars form rings in solution
Carbons are numbered
Numbered carbons
C 6'
5' C
O
4' C
C1'
energy stored in C-C bonds
harvested in cellular respiration
C3'
C2'
Sugar structure
5C & 6C sugars form rings in solution
Carbons are numbered
Carbohydrates include:
CH2OH
O H
H
H
OH H OH
HO
H
OH
Glucose
Simple sugars
(monosaccharides: such as glucose, ribose, and deoxyribose)
Short chain sugars
(disaccharides: such as sucrose, lactose, and maltose)
Complex carbs
(polysaccharides: such as starches, cellulose, and glycogen),
Building sugars
• Dehydration synthesis
monosaccharides
|
glucose
H2O
|
glucose
disaccharide
|
maltose
glycosidic linkage
A glycosidic link occurs when
two monosaccharides are
joined by dehydration
synthesis.
Building sugars
• Dehydration synthesis
monosaccharides
|
glucose
H2O
|
fructose
disaccharide
|
sucrose
(table sugar)
Polysaccharides are produced by adding more
monosaccharides to the chain. Some of the most important
polysaccharides are made of long polymers of glucose.
Polysaccharides
Chloroplast
Starch
• Starch
– Is a polymer
consisting entirely
of glucose
monomers
– Is the major
storage form of
glucose in plants
1 m
Amylose
Amylopectin
Glycogen is the storage form of glucose in animals and
humans which is analogous to the starch in plants. Glycogen
is synthesized and stored mainly in the liver and the muscles
Plants make glucose and cellulose
through the photosynthesis
processes, and store starch
primarily in their roots.
Animals and humans in
turn eat plant materials
and products.
Digestion is a process of hydrolysis
where the starch is broken down into
the various monosaccharides. A
major product is glucose, which can
be used immediately for metabolism
to make energy.
Mitochondria
Giycogen
granules
0.5 m
Glycogen
The glucose that is not used immediately is converted in
the liver and muscles into glycogen for storage. Any
glucose in excess of the needs for energy and storage as
glycogen is converted to fat.
Another polysaccharide, cellulose, has its glucose units
joined together, however, alternating glucose units are
'flip-flopped'.
Changes in the bond configuration cause changes in the
final shape and function of the molecules.
Cellulose is found in plant
cells, and forms the
structurally
strong framework in the cell
wall.
• Cellulose is difficult to digest
– Cows and other herbivores have microbes in
their stomachs to facilitate this process
Humans do not!
• Chitin, another important structural
polysaccharide
– Is found in the exoskeleton of
arthropods
– Can be used as surgical thread
CH2O
H
O OH
H
H
OH H
OH
H
H
NH
C
O
CH3
(b) Chitin forms the exoskeleton (c) Chitin is used to make a
(a) The structure of the
of arthropods. This cicada
strong and flexible surgical
chitin monomer.
is molting, shedding its old
thread that decomposes after
exoskeleton and emerging
the wound or incision heals.
in adult form.