GRADE 12 BIOLOGY (SBI4U)
MACROMOLECULES
Macromolecules:
What you need to know!
2
1.
Structure of the basic unit (carbohydrates,
lipids, proteins, nucleic acids)
2.
How they react to form larger molecules
3.
How the larger molecules are broken down into
basic units
4.
Functions of the molecules in living organisms
What is a …
3
Polygons
Polyester
Polygamy
4
Polymers
• long molecules
• have many similar or identical repeating building
blocks (structural units, monomers, small molecules)
• connected by chemical bonds (covalent bonds)
5
Monomers
• The smallest repeating unit of a polymer
• Can exist individually
6
7
Macromolecules
• Organic molecules constructed of smaller units called
polymers – these polymers are subdivided into their
basic units called monomers
+
+
+
8
Macromolecules
• a macromolecule is also called
… biological macromolecule
… biomolecule
… organic molecule
… large carbon-carbon molecule
to name a few…
9
Macromolecules
• fall into 4 major categories – can you name them?
Hint: 3 of the 4 can be found in foods!
10
Macromolecules:
4 major categories
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Macromolecules:
Question: Which one isn’t considered a
polymer and why?
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Macromolecules:
Why do we care?
• Macromolecules are the molecules of life!
• How do you build a cell?
• Start with water, add lots of small carbon-containing
molecules and …….
use these four major classes of macromolecules
14
Macromolecules
• All living things are made of cells
• Cells are:
~72% H2O
~3% salts (Na, Cl, K…)
~25% carbon compounds (macromolecules)
15
Macromolecules
Ions, small molecules (4%)
Lipids (2%)
Nucleic Acids (DNA
and RNA (1% + 6%)
Proteins (15%)
Carbohydrates (2%)
16
Making and Breaking of Polymers
or
“Condensation” or “Dehydration”
Synthesis (aka polymerization)


why synthesis? – a polymer grows in length (a new
bond is made)
why dehydration (or condensation) – formation of a
water molecule
“Addition” polymerization




monomer molecules added to a growing polymer
chain
NO molecules are eliminated in the process
monomer is unsaturated (e.g., had a double bond)
after an addition reaction it becomes saturated
Hydrolysis (Cleavage)

hydrolysis (hydro = water, lysis = break) – reverses the
process of dehydration by breaking down the polymer
with the addition of water molecules
Carbohydrates (sugar/starch)
• Monosaccharide (b/w 3-7 carbon atoms)
- Contain multiple hydroxyl groups and a carbonyl group
– the simplest sugars
glucose
fructose,
galactose
ribose
deoxyribose
21
- Contains C, H, O in ratio
of 1:2:1
Isomers
Isomers – one of two or
more molecules with the
same number and type
of atoms, but different
structural arrangements
e.g. glucose, fructose,
galactose
- Also differ in chemical
and physical properties
22
Carbohydrates
• Disaccharides
– 2 simple sugars (sucrose, lactose = glucose +
galactose, maltose = glucose + glucose)
- Bond linking monosaccarides together = glycosidic
linkage
23
Carbohydrates
• Polysaccharides (‘complex’)
– many sugars (e.g. starch, cellulose, glycogen, chitin)
– energy storage
– structural materials
glycogen
24
cellulose
Carbohydrates (polysaccharides)
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 Note the linking of simple repeating units
Carbohydrates (polysaccharides)
26
Lipids
•
•
•
•
•
fatty acids
hydrocarbons
comprised of fatty acids
hydrophobic
reservoirs of energy
structural materials
– cell membrane
• 4 forms of lipids
– neutral fats, phospholipids, sterols, waxes
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Lipids – Neutral fats
• neutral fats
– three fatty acids and a glycerol
– body’s most abundant lipid
• functions
– energy reservoir
– insulation
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Fats
glycerol + 3 fatty acid  fat (triglyceride)
Ester
linkage
Fats
Animal vs. Plant Fats
Animal Fats
Plant Fats
- Triglycerols containing mostly
saturated fatty acids
-triglycerols are unsaturated and
polyunsaturated FA
- Straight hydrocarbon chains
allowing for van der Waal
attractions
-Hydrocarbon chains have
double bonds and many kinks, ↓
van der Waal attractions
- Solid at room temperature
- Liquid at room temperature
Fatty Acids
saturated fat
unsaturated fat
trans-unsaturated
fat
Lipids – Neutral fats
• Can be used for insulation
adipose tissue
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Lipids - Phospholipids
• form double-layered cell membranes
34
Phospholipids
Glycerol backbone + 2 fatty acids + phosphate 
phospholipid
Phospholipids
Phospholipids have:
1. a hydrophobic head
2. a hydrophobic tail
Due to the dual chemical nature of the molecule,
it is said to be amphipathic.
Phospholipids
Phospholipids
Phospholipid Bilayer
Sterols

also known as steroids
Proteins
Proteins are used for:
structure
 metabolism (enzymes)
 immunological protection
 molecular transport

Proteins are made of subunits of amino acids.
Proteins are the most diverse class of
macromolecules due to 20 available amino acids.
Amino Acids
Amino Acids in Aqueous Solutions
•
Amino acids contain a basic amine group, which can
act as a proton acceptor, and an acidic carboxylic
acid group, which can act as a proton donor
Amino Acids
Essential vs. Non-essential Amino Acids
Essential Amino Acids:
 Cannot be produced by the body, therefore must be
consumed in ones diet
 8 essential Amino Acids
Non-essential Amino Acids:
 Can be produced by the body
 13 Non-essential Amino Acids
Peptides
amide bond
Protein Organization
Four layers of protein organization:
1.
2.
3.
4.
primary (1°) structure
secondary (2°) structure
tertiary (3°) structure
quaternary (4°) structure
Primary (1°) Structure


sequence of amino acids
polypeptide chain
Second (2°) Structure

H-bond between
peptide bonds
1.
a-helix
2.
b-pleated sheets

not necessarily in
all proteins
Second (2°) Structure
Tertiary (3°) Structure


provides protein a final 3-D structure
four major bond types between R groups of
amino acids
1.
2.
3.
4.
H-bonding
ionic bonding
hydrophobic interactions
covalent bond (disulfide bridge)
Tertiary (3°) Structure
General Protein Shapes

Globular Proteins
(Hemoglobin)

Fibrous Proteins
(Tropomyosin & Keratin)
Quaternary (4°) Structure

fully functional
protein requires all
subunits present

not all proteins have
quaternary structure
Protein Properties
Proteins have optimal conditions at which they
function.
When exposed to extreme conditions, proteins
begin to unfold – denature.
If denaturation occurs moderately over time,
returning to the original conditions may result
in renaturation.
Protein Folding
Proper folding in the cell is
completed by chaperonin
molecules.
Utilizes ATP to help proteins
fold properly.
Nucleic Acids
Nucleic acids are used for:
 maintaining
genetic continuity
 delivering information for protein synthesis
 energy molecule (ATP – adenosine triphosphate)
Two major nucleic acid polymers:
1.
2.
DNA – deoxyribonucleic acid
RNA – ribonucleic acid
Nucleic Acids
DNA
RNA

located in the
nucleus

mainly found in
cytoplasm

double-stranded,
double helix
structure

single-stranded
structure

stable molecule
Nucleotides
The basic subunit of nucleic acids is a
nucleotide.
Three components:
1.
2.
3.
phosphate
pentose sugar
nitrogenous base
Pentose Sugar
Nitrogenous Bases
purines
pyrimidines
Nucleic Acid

reaction between
1.
2.

pentose sugar OH
group of one
nucleotide
phosphate group of
another nucleotide
forms
phosphodiester
bond
In Conclusion

The building blocks (monomers) of macromolecules are
amino acids, nucleotides, simple sugars, and fatty acids
In Conclusion
• Name the two main chemical reactions shown
making and breaking organic molecules
In Conclusion




Carbohydrates are use for energy storage and as
structural materials
Lipids are used as energy storage and structural
components
Proteins are made of amino acids which form
structures, enzymes, transport, movement, and are
part of the immune system
Nucleic acids are the basis of inheritance and
reproduction
In Conclusion


The versatility of carbon makes possible the great
diversity of organic molecules
Variation at the molecular level lies at the foundation of
all biological diversity
Answers to post-presentation activity #1 – the activity could be use alone
as a pre-assessment (what should be known from Grade 11 SBI3U)
Macromolecule
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Example(s) of
subunits
Main functions
Examples of
macromolecules
carbohydrates
sugars (such as
glucose) and polymers
of glucose
energy storage
sugars, starches, and
glycogen
lipids
glycerol and three fatty
acids or glycerol and
two fatty acids
energy storage and cell
membranes
fats, oils, and
phospholipids
proteins
polymers of amino acids
transport, blood clotting,
support, immunity,
catalysis, and muscle
action
hemoglobin, fibrin,
collagen, antibodies,
enzymes, actin, and
myosin
nucleic acids
polymers of nucleotides
transfer and expression of
genetic information
DNA and RNA
Day 2
68
• In building large macromolecules carbon
usually combines with other carbons
… AND with one or more functional groups
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Why study Functional Groups?
• These are the building blocks for organic molecules
(or macromolecules – large organic molecules)
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Why study Functional Groups?


the components of organic molecules most commonly
involved in chemical reactions
the number and arrangement of functional groups give
each organic molecule unique properties
Types of functional groups
• 6 functional groups most important to
chemistry of life:
 hydroxyl
 carbonyl
 carboxyl
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 amino
 sulfhydryl
 phosphate
Functional groups
• they affect reactivity (e.g., hydrophilic,
increase solubility in water)
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Hydroxyl
 organic compounds with OH = alcohols
 alcohols, carbohydrates, nucleic acids, some acids,
and steroids
 highly polar (makes molecules more soluble)
 e.g., ethanol
Carbonyl
 if C=O at end molecule = aldelhyde
 if C=O in middle of molecule = ketone
 react with molecules (H-R2) to form H-R2-C-OH
 a ketone and an aldehyde may be structural
 isomers with different properties, e.g.,
acetone
and
propanal
75
Carboxyl
 compounds with COOH = acids
 fatty acids, amino acids
 acidic – tends to lose a proton (COO-)
 involved in peptide bonds
 e.g., acetic acid - gives vinegar its sour taste
76
Amino
 compounds with NH2 = amines
 amino acids, nucleic acids
 NH2 acts as base - can pick up a proton (H+) from
the surrounding solution (ionized)
 under cellular conditions
 glycine (has amine and carboxyl groups) – replace
an H with an R group
to get an amino acid
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Sulfhydryl
 compounds with SH = thiols
 2 sulfhydryl groups can interact to help stabilize
protein structure (S-S, disulfide bonds)
78
Phosphate
• compounds called organic phosphates
• Acidic – up to 2 negative charges when H+ dissociates
• Links nucleotides in nucleic acids
• Energy-carrier group in ATP
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Review
Review
Review
Do the functional groups make that
much difference?
 identical basic structure of male & female hormones
 attachment of different functional groups
 interact with different targets in the body
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2003-2004
A Bit of Honey:
 Bee keeping was used in Crete
over 4000 years ago to allow for
the collection of honey, a highly
prized food having great value in
ancient civilizations
 Field bees gather the nectar,
a sweet secretion in plant
blossoms that contains fructose,
glucose and sucrose
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 Some worker bees secrete beeswax - Hexacosanoic
acid, C26H52O2, and triacontanol, C30H62O