Title: Structure and Function of Macromolecules
1Structure and Function of Macromolecules
2Monomers, Polymers, and Macromolecules
- Monomers repeating units that serve as
building blocks for polymers - Polymers long molecule consisting of many
similar or identical building blocks linked by
covalent bonds - Macromolecules groups of polymers covalently
bonded 4 classes of organic macromolecules to
be studied - 1. Carbohydrates 3. Proteins
- 2. LiPIDs 4. Nucleic Acids
3How to the monomers link up/break back into
monomers?
- Condensation reaction (specifically, dehydration
synthesis) - two molecules covalently bond and lose a water
molecule in the process - (THIS TAKES ENERGY TO DO!!!)
- Hydrolysis
- polymers are disassembled to monomers by
adding a water molecule back - (ex. Digestion of food)
4Figure 5.2 The synthesis and breakdown of
polymers
5Key to diversity of polymers from limited
monomers available
- ARRANGEMENT variation in the linear sequence
the units follow - (think of the number of words possible from
our 26 letter alphabet) - Molecular logic of life is simple but elegant
and ORDERLY!!!
6Organic Compounds and Building Blocks
- Carbohydrates made up of linked
monosaccharides - Lipids -- CATEGORY DOES NOT INCLUDE POLYMERS
(grouping based on insolubility) - Triglycerides (glycerol and 3 fatty
acids) - Phospholipids
- Steroids
7- Proteins made up of amino acids
- Nucleic Acids made up nucleotides
8Carbohydrates fuel and building material
- Exist as three types
- 1. monosaccharides
- 2. disaccharides
- 3. polysaccharides (macromolecule stage)
- Made up of C, H, and O
- Has carbonyl group and multiple hydroxyl groups
(location of carbonyl determines if is an aldose
or a ketose - Names end in ose
- Size of carbon skeleton determines category
9Figure 5.3 The structure and classification of
some monosaccharides
10In aqueous solns, most sugars form rings
11Monosaccharides
- Are major sources of energy for cells
- Ex. Glucose cellular respiration
- Are simple enough to serve as raw materials for
synthesis of other small organic molecules such
as amino and fatty acids - Most common glucose, fructose, galactose
12Glucose, Fructose, Galactose
- Glucose made during photosynthesis
- main source of energy for plants and
animals - Fructose found naturally in fruits
- is the sweetest of monosacc
- Galactose found in milk
- is usually in association with glucose
or fructose - All three have same molecular formula but
differstructurally so are ISOMERS
13Disaccharides
- Consists of two monosaccharides joined by a
GLYCOSIDIC LINKAGE a covalent bond resulting
from dehydration synthesis -
- Ex. Maltose 2 glucoses joined
- Sucrose glucose and fructose
- Lactose glucose and galactose
14Figure 5.5 Examples of disaccharide synthesis
15Figure 5.5x Glucose monomer and disaccharides
Glucose monomer
Sucrose
Maltose
16Polysaccharides
- These are the polymers of sugars the true
macromolecules of the carbs - Serve as storage material that is hydrolyzed as
needed in body or as structural units that
support bodies of orgs
17Storage Polysaccharides Starch and Glycogen
- Starch found in plants
- made up of glucose monomers in alpha
configuration - has a helical shape
- can be unbranched (amylose) or branched
(amylopectin) - stored as granules in plants in the
PLASTIDS - (these granules are stockpiles of glucose for
later use carb BANK) - You can find starch in potatoes and grains
18- Glycogen found in animals
- extensively branched group of glucose
units - stored in liver and muscle cells
- glycogen bank is depleted within 24
hours needs replentishing
19Figure 5.6 Storage polysaccharides
20Structural Polysaccharides
- Cellulose major component of plant cell
walls - most abundant organic compound on Earth
- polymer of glucose, but all glucose
molecules are in the beta configuration - thus, cellulose is always straight, and
this provides for strength (Ex. Lumber)
21Figure 5.7a Starch and cellulose structuresÂ
22Figure 5.7b,c Starch and cellulose structuresÂ
23Figure 5.7x Starch and cellulose molecular
models
? Glucose
? Glucose
Cellulose
Starch
24Figure 5.8 The arrangement of cellulose in plant
cell walls
25Cellulose and the diet
- Few orgs possess the enzymes to digest cellulose
- Cellulose passes through the digestive tract and
is eliminated in feces - BUT, the fibrils of cellulose abrade the wall of
the digestive tract and stimulate secretion of
mucus which is necessary for smooth food passage
so though cellulose is not nutritious, it is
necessary - Orgs that can digest cows (with help of
bacteria), termites (with help of microbes), some
fungi
26Figure 5.x2 Cellulose digestion cow
27Figure 5.x1 Cellulose digestion termite and
Trichonympha
28Chitin
- Another structural polysaccharide
- Used by arthropods to build their exoskeletons
- Pure chitin in leathery, but when encrusted with
calcium carbonate it hardens into shell form - Also used by fungi in their cell walls (instead
of cellulose) - Similar to cellulose, but the glucose monomer has
a nitrogen containing appendage
29Figure 5.9 Chitin, a structural polysaccharide
exoskeleton and surgical thread
30Chemical Identification of Carbohydrates
- Benedicts Test Identifies the presence of a
MONOSACCHARIDE by changing from blue to orange in
the presence of heat - Iodine Test Identifies the presence of a
POLYSACCHARIDE by changing from yellow to
purple/black - Process of Elimination If there is no reaction
with either the Benedicts or Iodine Tests, then
a DISACCHARIDE is present.