CHAPTER 3 THE MOLECULES OF LIFE. POLYMERS ARE BUILT OF MONOMERS Organic molecules are formed by...
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CHAPTER 3 THE MOLECULES OF LIFE
CHAPTER 3 THE MOLECULES OF LIFE. POLYMERS ARE BUILT OF MONOMERS Organic molecules are formed by living organisms. Carbon-based core The core has attached
POLYMERS ARE BUILT OF MONOMERS Organic molecules are formed by
living organisms. Carbon-based core The core has attached groups of
atoms called functional groups. The functional groups confer
specific chemical properties on the organic molecules.
Slide 3
FIVE PRINCIPAL FUNCTIONAL GROUPS Found InGroupStructural
Formula Ball-and- Stick Model OO P OO O O OH O C H H N CO OH OO O P
O OO O O HO H H N C C Lipids Proteins DNA, ATP Carbohydrates
Carboxyl Carbonyl Hydroxyl Amino Phosphate
Slide 4
MACROMOLECULES The building materials of the body are known as
macromolecules because they can be very large. There are four types
of macromolecules: 1. Proteins 2. Nucleic acids 3. Carbohydrates 4.
Lipids
Slide 5
MACROMOLECULES Large macromolecules are actually assembled from
many similar small components, called monomers. The assembled chain
of monomers is known as a polymer.
Slide 6
DEHYDRATION SYNTHESIS All polymers are assembled the same way.
A covalent bond is formed by removing a hydroxyl group (OH) from
one subunit and a hydrogen (H) from another subunit.
Slide 7
H H H Energy HO H2OH2O DEHYDRATION SYNTHESIS Because this
amounts to the removal of a molecule of water (H 2 O), this process
of linking together two subunits to form a polymer is called
dehydration synthesis.
Slide 8
HYDROLYSIS The process of disassembling polymers into component
monomers is essentially the reverse of dehydration synthesis. A
molecule of water is added to break the covalent bond between the
monomers. This process is known as hydrolysis. H H H HO Energy HO
H2OH2O
Slide 9
PROTEINS Proteins are complex macromolecules that are polymers
of many subunits called amino acids.
Slide 10
O CN H O CN H H HNC H H H2OH2O HC O C H HNC H H C O C RR RR
Amino acid OH Polypeptide chain PROTEINS The covalent bond linking
two amino acids together is called a peptide bond. The assembled
polymer is called a polypeptide.
Slide 11
PROTEINS Amino acids are small molecules with a simple basic
structure, a carbon atom to which three groups are added: an amino
group (NH 2 ) a carboxyl group (COOH) a functional group (R) The
functional group gives amino acids their chemical identity. There
are 20 different types of amino acids.
Slide 12
PROTEINS Protein structure is complex. The order of the amino
acids that form the polypeptide is important. The sequence of the
amino acids affects how the protein folds together.
Slide 13
PROTEINS The way that a polypeptide folds to form the protein
determines the protein s function. Some proteins are comprised of
more than one polypeptide.
Slide 14
PROTEINS There are four general levels of protein structure:
1.Primary 2.Secondary 3.Tertiary 4.Quaternary N N N N N H H H C C O
O O C C C C C C O C N N H H C O C C O C N N H O C C C H O C C
Secondary structure -pleated sheet -helix Tertiary structure
Quaternary structure Amino acids Primary structure O
Slide 15
PROTEINS Primary structure the sequence of amino acids in the
polypeptide chain. Determines all other levels of protein
structure. Amino acids Primary structure
Slide 16
PROTEINS Secondary structure forms because regions of the
polypeptide that are nonpolar are forced together; hydrogen bonds
can form between different parts of the chain. The folded structure
may resemble coils, helices, or sheets. N N N N N H H H C C O O O C
C C C C C O C N N H H C O C C O C N N H O C C C H O C C Secondary
structure -pleated sheet -helix O
Slide 17
PROTEINS Tertiary structure the final 3-D shape of the protein.
The final twists and folds that lead to this shape are the result
of polarity differences in regions of the polypeptide. Tertiary
structure
Slide 18
PROTEINS Quaternary structure the spatial arrangement of
proteins comprised of more than one polypeptide chain. Quaternary
structure
Slide 19
PROTEINS The shape of a protein affects its function. Changes
to the environment of the protein may cause it to unfold or
denature. Increased temperature or lower pH affects hydrogen
bonding, which is involved in the folding process. A denatured
protein is inactive. Denaturation Folded protein Denatured
protein
Slide 20
PROTEINS Enzymes are globular proteins that have a special 3-D
shape that fits precisely with another chemical. They cause the
chemical that they fit with to undergo a reaction. This process of
enhancing a chemical reaction is called catalysis. Active-site
cleft
Slide 21
NUCLEIC ACIDS Nucleic acids are very long polymers that store
information. Comprised of monomers called nucleotides. Each
nucleotide has 3 parts: 1.a five-carbon sugar 2.a phosphate group
3.an organic nitrogen-containing base
Slide 22
NUCLEIC ACIDS There are five different types of nucleotides.
Information is encoded in the nucleic acid by different sequences
of these nucleotides.
Slide 23
NUCLEIC ACIDS There are two types of nucleic acids:
Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA) RNA is similar
to DNA except that it uses uracil instead of thymine it is
comprised of just one strand it has a ribose sugar O O O O O O O O
O O O O P P P G C P P P P P P C C G G A A T T P P Phosphodiester
bond Hydrogen bonds between nitrogenous bases Sugar-phosphate
backbone OH
Slide 24
NUCLEIC ACIDS The structure of DNA is a double helix because:
There are only two base pairs possible Adenine (A) pairs with
thymine (T) Cytosine (C) pairs with Guanine (G) Properly aligned
hydrogen bonds hold each base pair together. A sugar-phosphate
backbone comprised of phosphodiester bonds gives support.
Slide 25
A A G G C C T T G and C can align to form three hydrogen bonds.
A and T can align to form two hydrogen bonds. G and T cannot
properly align to form hydrogen bonds. A and C cannot properly
align to form hydrogen bonds.
Slide 26
NUCLEIC ACIDS The structure of DNA helps it to function. The
hydrogen bonds of the base pairs can be broken to unzip the DNA so
that information can be copied. Each strand of DNA is a mirror
image so that the DNA contains two copies of the information.
Having two copies means that the information can be accurately
copied and passed to the next generation.
Slide 27
CARBOHYDRATES Carbohydrates are monomers that make up the
structural framework of cells and play a critical role in energy
storage. A carbohydrate is any molecule that contains the elements
C, H, and O in a 1:2:1 ratio.
Slide 28
CARBOHYDRATES The sizes of carbohydrates varies: Simple
carbohydrates consist of one or two monomers. Complex carbohydrates
are long polymers.
Slide 29
CARBOHYDRATES Simple carbohydrates are small. Monosaccharides
consist of only one monomer subunit. An example is the sugar
glucose (C 6 H 12 O 6 ). Disaccharides consist of two
monosaccharides. An example is the sugar sucrose, which is formed
by joining together glucose and fructose.
Slide 30
CARBOHYDRATES Complex carbohydrates are long polymer chains.
Because they contain many C-H bonds, these carbohydrates are good
for storing energy. These bond types are the ones most often broken
by organisms to obtain energy. The long chains are called
polysaccharides.
Slide 31
CARBOHYDRATES Plants and animals store energy in polysaccharide
chains formed from glucose. Plants form starch. Animals form
glycogen. Some polysaccharides are structural and resistant to
digestion by enzymes. Plants form cellulose cell walls. Some
animals form chitin for exoskeletons.
Slide 32
LIPIDS Lipids fats and other molecules that are not soluble in
water. Lipids are nonpolar molecules. There are many different
types of lipids. fats oils steroids rubber waxes pigments
Slide 33
LIPIDS Fats are converted from glucose for long- term energy
storage. Fats have two subunits 1. fatty acids 2. glycerol Fatty
acids are chains of C and H atoms, known as hydrocarbons. The chain
ends in a carboxyl (COOH) group.
Slide 34
SATURATED AND UNSATURATED FATS
Slide 35
LIPIDS Fatty acids have different chemical properties due to
the number of hydrogens that are attached to the non-carboxyl
carbons If the maximum number of hydrogens are attached, then the
fat is said to be saturated. If there are fewer than the maximum
attached, then the fat is said to be unsaturated.
Slide 36
SATURATED AND UNSATURATED FATS C H H C H H C H C H (c) Oil
(unsaturated): Fatty acids that contain double bonds between one or
more pairs of carbon atoms (b) Hard fat (saturated): Fatty acids
with single bonds between all carbon pairs
Slide 37
PHOSPHOLIPIDS Biological membranes involve lipids.
Phospholipids make up the two layers of the membrane. Cholesterol
is embedded within the membrane. Cell membrane
CholesterolPhospholipid Inside of cell Membrane proteins Outside of
cell Carbohydrate chains
