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LESSON 1
LEARNING INTENTION
-To understand the chemical nature of
biomolecules.
• SUCCESS CRITERIA
•
•
•
- Be able to distinguish:
- between elements and compounds
- between ionic and covalent bonds.
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The chemical basis of life
Living things have certain characteristics in common:
 Movement
 Growth
 Ability to replicate or reproduce
 Detect an respond to changes in their environment
 Take in food or matter, process it and remove waste
products
All parts of living things are made by the activity of their
cells.
All organisms are made up of CELLS
“Almost all aspects of life are
engineered at the molecular level,
and without understanding
molecules we can only have a very
sketchy understanding of life itself.”
‘What Mad Pursuit’ (1988, Ch.5)
Francis Crick (1916 – )
British molecular Biologist
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There are new fields in biological science:
• Genomics – the study of the genome (an organism’s
entire DNA sequence)
• Proteomics – the study of the structure and function
of proteins
• Bioinformatics – the science of managing and
analysing biological data using advanced computing
techniques.
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THE NATURE OF MATTER
Matter has mass and takes up space.
Matter is composed of atoms.
Atoms are made up of a nucleus
which contains protons (+) and
neutrons (0).
Electrons (-) spin around the
nucleus in paths called orbitals.
An atom is neutral if
electrons = protons
The number of protons defines an element.
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The CHEMICAL BASIS OF LIFE
All of the chemicals of life except water are based on the
carbon atom.
99% of the elements that make up living things are:
 C
 H
 O
 N
Organic compounds are chemical compounds
containing carbon and hydrogen produced by or found in
organisms.
Inorganic compounds are all other compounds.
Biologically important inorganic molecules – water,
oxygen, carbon dioxide, nitrogen and minerals. (need
these for chemical reactions in cells)
ISOTOPES
Some atoms of an element can have
more neutrons in their nucleus than
others.
Such atoms are called isotopes of the
element eg. Carbon-14
The nucleus of the isotope is unstable
and breaks apart giving off energy,
which we call radiation.
When this happens we say that the
element ‘decays’.
By giving off radiation, atoms reach a
more stable state.
Radioactive isotopes are useful tools
in the study of many areas of science,
including biochemical reactions and
medical research (Biobox 1.1, pg 6)
because their presence can be
detected by the radiation they
release.
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Chemical Bonds
The number and arrangement of electrons in
an atom’s outer shell determine its chemical
behaviour or reactivity.
Outer shell electrons are called valence
electrons.
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Chemical Bonds
Atoms accept, give away or share their valence electrons
with other atoms, thereby achieving chemical stability.
Compounds are stable combinations of atoms of different
elements that are held together by chemical bonds.
The nature of the bonds differs according to the type of
atoms involved.
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Molecular compounds
Bonds are:
Forces that hold groups of atoms together and
make them function as a unit.
Two types:
IONIC BONDS – transfer of electrons (gained
or lost eg. O2-, Li+
COVALENT BONDS – sharing of electrons.
The resulting particle is called a molecule eg.
H2O
http://www.youtube.com/watch?v=TJZzCPTou-o
Complete worksheet
– The chemical nature of biomolecules
• Discuss questions
• 1, 2, 3, 7, 9, 11, and 12.
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Electrolytes
Salts are ionic compounds that dissolve in water as the
bonds holding the ions together weaken and break,
releasing them.
These particles in solution are called electrolytes.
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LESSON 2
LEARNING INTENTION:
To understand the structure of the water
molecule and why life could not exist without
it.
• SUCCESS CRITERIA:
• Be able to draw a water molecule showing
its polarity.
• Be able to discuss at least 3 different
properties of water.
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Molecular Compounds - water
In the water molecule, oxygen and the two hydrogens
share outer electrons.
Oxygen now has 8 outer electrons (stable)
Each hydrogen now has 2 outer electrons (stable)
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Water – the wonder molecule
Most important compound on the planet.
All known life forms require water.
75 – 85% of a cell is water (by weight).
OH+
OH+
H+
H+
A special bond
holds these
molecules in
place, what is it
called?
Why is water important for Biology?
http://www.youtube.com/watch?v=JRENtSROp3g
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Acids, Bases and Buffers
An acid is a substance that produces hydrogen ions (H+)
in solution.
The acidity of a solution is measured by its pH.
The lower the pH, the more acidic the solution.
A buffer is a substance that can react with an acid or a
base and maintain a steady pH.
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From Jacaranda Biology 3&4
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Water
Opposites
attract
About 75-85% of a cell by weight is water.
Most reactions occur in a watery medium.
Many organisms live in water.
Water molecules are polar and form
hydrogen bonds with each other.
More substances dissolve in water than in
any other substance.
Polar substances dissolve in water and are
Hydrophilic (water loving).
Non-polar substances (eg. Oil, petrol) do
not dissolve in water and are Hydrophobic.
Most gases dissolve in water.
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Properties of Water
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Adhesion occurs between
water molecules and
other molecules.
Cohesion occurs
between water molecules
and other water
molecules.
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Complete worksheets:
- polarity
- Physical properties of water
Discuss questions
14, 15, 16 and 18.
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LESSON 3
LEARNING INTENTION
To understand the synthesis of carbohydrates and
their function.
SUCCESS CRITERIA
- Know the general formula of a carbohydrate.
- Be able to list at least 3 different functions of
carbohydrates.
- Understand the difference between a
condensation and a hydrolysis reaction.
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macromolecules
Four main classes
 Proteins
 Nucleic acids
 Carbohydrates
 Lipids (fats and oils)
Autotrophs - are able to make their own
macromolecules needed
Heterotrophs – make their own macromolecules from
the organic compounds they take in from their food.
These are broken down into simpler substances and
used to make organic compounds required.
macromolecules
Large bio-macromolecules are made inside the
cell. They are built up linking small repeating
molecules (monomer) to form long chains called
polymers.
monomer
single units
polymerisation
polymer
macromolecules
• Protein, nucleic acids and carbohydrates are
polymers. Lipids are not. Lipids are composed of
distinct chemical groups of atoms.
MAIN
MACROSUBUNITS
MOLECULE ELEMENTS
EXAMPLE
CARBOHYDRATE
C, H, O
Saccharides
Glucose, starch,
cellulose, sucrose
LIPID
C, H, O
Fatty acids
Vegetable oil
PROTEIN
C, H, O, N
Amino acids
enzymes
NUCLEIC ACID
C, H, O, N, P
Nucleotides
DNA, RNA
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Carbohydrates
Each molecule consists of carbon, hydrogen and oxygen
atoms in the ratio of 1:2:1, giving the general formula for
carbohydrates of nCH2O.
Carbohydrates are classified as:
monosaccharides (eg. glucose)
disaccharides (eg. sucrose)
and
polysaccharides (eg. cellulose)
Run Molworks
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Carbohydrates
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Carbohydrates
Organisms use carbohydrates as an energy source
(eg. starch and glycogen) and for structural components
(eg. cellulose and chitin).
Most animals do not have the enzymes to break down
cellulose in their diet, but have to rely on bacteria in their
gut to do it for them.
Carbohydrate molecules can combine with other atoms
or groups to form important compounds, eg.
glycoproteins, which are a combination of carbohydrate
and protein molecules.
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• Monosaccharides (eg. Glucose) are single
monomer molecules. They are easily absorbed
and broken down.
• Disaccharides (eg. Sucrose) are made up of two
monomers joined together. They are a good store
of energy and are easily broken down.
• Polysaccharides (eg. Starch, Cellulose,
Glycogen, Chitin) are composed of long chains of
monomers. They have different bonding and
branching which gives them different properties
including energy storage and structural strength.
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carbohydrates
Making polysaccharides from monosaccharides
In order to convert monosaccharides to starch
or glycogen, a process of condensation occurs.
In this process H2O molecules are removed so
that the chain of monosaccharides which make
up the starch or glycogen molecules take up less
space.
The Condensation Reaction
I provide a hydrogen
(H) from my OH group
I give up my OH
group
O-H
When
the
functional
groups react together a
new chemical bond forms
linking the monomers
together.
O-H
O-H
Monomer
It’s raining
water
molecules
Monomer
O-H
A water molecule has been
eliminated.
That is why the reaction is
called a condensation
reaction
Making polysaccharides from
monosaccharides
Glucose (monosaccharide)
C
C
Glucose (monosaccharide)
H
H
C
C
C
C
C
C
C
C
OH
C
OH
C
Condensation reaction
Maltose (disaccharide)
C
C
HH
C
C
C
C
C
C
C
C
O
C
C
Making monosaccharides from
polysaccharides
When a plant or animal needs to make the energy rich
polysaccharide available for cellular respiration again (ie.
change them from storage polysaccharides back to
monosaccharides) the H2O molecules must be added in
again.
This process of adding water to split the macromolecules
is called hydrolysis (water split).
H2O
H2O
S
S
S
H2O
H2O
S
S
H2O
S
S
H2O
Hydrolysis and condensation
• Hydrolysis and condensation are the
opposite of each other.
Hydrolysis adds water and condensation
removes water.
http://www.youtube.com/watch?v=f4Gicf7ONGA
(watch 1st part on carbohydrates)
cellulose
Cellulose is the most abundant organic
compound found in nature.
Used for timber construction, making paper and
clothes.
Important in the human diet – helps clear out the
digestive system.
Cellulose does not supply us with any nutrients.
We lack the enzyme to break the bonds.
Herbivores – host large bacterial populations that
break down the cellulose for their hosts. This is a
symbiotic relationship.
Complete worksheet
– Organic compounds
• Discuss questions 18, 24 and 25.
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LESSON 4
LEARNING INTENTION
To understand the synthesis of lipids and their
function.
SUCCESS CRITERIA
- Know the general formula of a triglyceride (fats
and oils)
- Know the difference between a saturated and an
unsaturated fat and where they are found.
- Complete a worksheet about lipids.
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lipids
Lipids (fats and oils) are hydrophobic
Important functions of lipids:

Energy storage (2x more energy than carbohydrates)

Structural component of membranes

Help in transmission of chemical signals within and
between cells
Terpenes – lipids in plants that give flavour and odour eg. lavender,
citrus.
Waxes are lipids that form protective waterproof coatings.
Amphipathic – some lipids have one end being hydrophilic and the
other end hydrophobic. (amphi – both)
The phospholipid bilayer found in cell membranes is a good example.
lipids
Triglycerides
A lipid molecule that contains a glycerol (alcohol) unit
and three fatty acid chains.
H
H
C
fatty acid chain
H
C
fatty acid chain
H
C
fatty acid chain
H
Saturated fats have a single bond between carbon
atoms. Come from animals eg. lard, butter
Unsaturated fats have a double bond between carbon
atoms. Come from plants eg. olive oil, canola, sunflower
oil
Lipids
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lipids
Phospholipids – form when a phosphate group is
added to the glycerol backbone rather than a third fatty
acid chain.
Glycolipids – form when a carbohydrate group attaches
to the glycerol backbone rather than a third fatty acid
chain.
Cholesterol – a common component of cell membranes
and of myelin sheaths around nerve cells.
Steroids are also lipids such as oestrogen and
testosterone
Watch 2nd half of
http://www.youtube.com/watch?v=f4Gicf7ONGA
About lipids
Complete worksheet on lipids.
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LESSON 5
LEARNING INTENTION
To understand the structure and functional
diversity of proteins.
SUCCESS CRITERIA
- Be able to give examples of proteins and their
functions.
- Be able to state the difference between proteins.
- Know the different structure of proteins and how
each is formed.
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Proteins
Virtually everything a cell is or does depends on
the proteins it contains.
Keratin is a protein found in your hair, feathers
of birds, the rattle of a rattlesnake and the
spines of an echidna.
The whole set of proteins produced by a cell is
called its proteome and the study of proteomes
is proteomics.
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Proteins
Proteins are large complex molecules and are the most
important molecules in living organisms.
As enzymes they control the thousands of chemical
reactions that maintain life processes.
This diversity of proteins can be explained by the way
their subunits, the 20 amino acids, are sequenced in
various combinations (like arranging 20 kinds of beads
in different ways to make different necklaces of different
lengths and the necklace chains can then be arranged
differently in loops and folds to give each its
characteristic features).
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Proteins
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Proteins - amino acids
Amino acids are small molecules that have
the same basic structure:
 a central carbon atom
 a hydrogen atom
 a carboxyl acid group (COO )
+
 an amine group (NH3 ) and
 an R group.
It is the difference in the R group that distinguishes one
amino acid from another and gives them their particular
chemical properties.
There are only 20 different amino acids found in the
proteins of living organisms
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Amino Acids
An amino acid is a relatively small molecule with characteristic
groups of atoms that determine its chemical behaviour.
The structural formula of an amino acid:
Phenylalanine
Cysteine
Glycine
Alanine
Valine
Amino
H3H
C
H
H N
H
S
H H
CH
3
C
H
R
H
C H
C C O H
H O
Acid
The R group is the
only part that
differs between the
20 amino acids.
proteins
Proteins can be divided into two types
according to their shape, fibrous or globular.
Fibrous proteins have a long and narrow shape,
such as collagen in skin and hair.
Globular proteins have a rounded shape, such
as enzymes or haemoglobin. This rounded
shape allows things to move readily through
narrow blood vessels.
Proteins - structure
Primary structure
DNA determines the sequence of amino acids in the
polypeptide.
Secondary structure
various parts of the polypeptide undergo coiling and
folding due to interactions between the various amino
acids that are present.
Hydrogen bonding
Ionic bonding
Disulfide bridges
Hydrophobic Interactions (van der Waals’ interactions)
Tight coils are known as α-helices and the folding forms
β-sheets.
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Proteins – structure: α-helix
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Proteins – structure: β-sheet
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Proteins - structure
Tertiary structure
R groups attract similar R groups.
This causes the polypeptide chains to become folded,
coiled or twisted into the protein’s functional shape or
conformation.
Protein molecules with the same sequence of amino
acids will fold into the same shape.
A change to just one amino acid will alter the shape of
the protein molecule and it may not function properly.
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Proteins - structure
Quaternary structure
Many large, complex protein molecules consist of two or
more polypeptide chains.
Haemoglobin, for example, which carries oxygen in the
blood, consists of four polypeptide chains. A variety of
bonds holds the polypeptide chains together and gives
the overall shape to the molecule.
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Proteins - structure
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Proteins - structure
The function of protein molecules may change as a
result of a number of factors:
 misreading the DNA code for proteins
 high temperatures
 strong salty solutions or
 very acidic or alkaline conditions (pH).
These conditions can denature or change the shape of
the protein molecules.
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Complete worksheet on Proteins
Watch
http://www.youtube.com/watch?v=lDUk7_dfNSQ
(start at 6.20 for proteins)
Discuss questions 28, 30, 31, 33 and 34.
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LESSON 6
LEARNING INTENTION
To understand the structure of nucleic acids.
SUCCESS CRITERIA
- Be able to state the three chemical parts of a
nucleotide.
- Know the difference between DNA and RNA.
- Know the base pairing rule.
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Nucleic Acids
Nucleic acids store information in a chemical code that
directs the machinery of the cell to produce proteins.
Nucleic acids DNA (deoxyribonucleic acid) and RNA
(ribonucleic acid), are large, linear polymers.
A molecule of DNA is composed of two long strands of
subunits called nucleotides, wound around each other to
form the familiar double helix.
RNA is usually composed of a single chain of
nucleotides and forms a single strand.
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Nucleic Acids - Nucleotides
A nucleotide has three chemical parts:
 a five carbon sugar (ribose in RNA and deoxyribose
in DNA)
 a negatively charged phosphate group
 an organic nitrogen-containing compound called a
base
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Nucleic Acids - Bases
There are four kinds of nitrogenous bases in DNA:
 adenine (A)
 thymine (T)
 guanine (G)
 cytosine (C).
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Nucleic Acids - Nucleotides
In each nucleotide strand, the
sugar molecule of one nucleotide
binds to the phosphate group of
the next nucleotide, leaving the
nitrogenous base sticking out
from each sugar and opposite
the nitrogenous base of the
second strand.
Hydrogen bonds between the
opposing pairs of nitrogenous
bases hold the double helix
together, much like the rungs of
a twisted ladder or a spiral
staircase.
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Nucleic Acids - Nucleotides
The bonding of the
nitrogen bases does not
happen by chance:
 A bonds with T and
 C bonds with G,
giving rise to the
base-pairing rule.
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Nucleic Acids – DNA vs RNA
The difference between the deoxyribose
sugar of the DNA and the ribose sugar of
RNA is that ribose has one more oxygen
atom.
The nitrogenous base thymine is replaced
by the base uracil (U) in RNA.
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Nucleic Acids – DNA code
The code carried by the DNA is organised in triplets
(three nucleotides) that determine the order in which
the amino acids are sequenced and this determines
which protein is formed.
Each cell of our body has over a metre in length of
DNA, twisted and coiled into 46 chromosomes that
have more than three billion base pairs (bp).
The parts of the DNA that code for proteins are called
genes.
The total set of genes that each cell of an organism
has is called its genome.
The study of these sets of genes and the way they
interact with each other is called genomics.
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LEARNING INTENTION
To understand how proteins are formed.
SUCCESS CRITERIA
Know the function of a gene.
Able to explain the steps involved in producing a
protein.
Completing textbook questions 39 – 44
Completing worksheets on Nucleic acids.
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Nucleic Acids – function of RNA
RNA has many functions in producing proteins.
The information on genes in the DNA that codes for making proteins
is transferred to messenger RNA (mRNA).
The mRNA molecule carries the code out of the nucleus and into the
cytoplasm.
This is where the protein-making factories (ribosomes) are located.
The ribosomes read the mRNA code three nucleotides at a time (in
codons).
The ribosomes are composed of ribosomal RNA (rRNA) and protein.
The incoming amino acids are attached to transfer RNA (tRNA)
molecules.
Each tRNA molecule has an anticodon that will bind with a
complementary codon on mRNA.
This is how the ribosomes know the correct amino acid to add to a
growing protein chain.
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Watch :
http://www.youtube.com/watch?v=lDUk7_dfNSQ
Watch:
http://www.youtube.com/watch?v=D3fOXt4MrOM
Answer and then discuss questions
39 – 44 on page 35.
Complete worksheet on Nucleic acids.
Complete page 18 of Biozone workbook.
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GTAC Summary Slides
covering all biomolecules.
Have a look at Weebly and GTAC.
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Visual
Summary
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At the end of the chapter do the following
activities:
Matchup (on text CD)
Self-test (on text CD)
Biotech Game
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