Biology projectwork.please download to view more efficiently because there are A LOT of transitions and animations to consider before viewing ( it looks like pictures rest on the text because the text flies onto the screen, moves away and the pictures fall in )

1. BIOLOGICAL
MOLECULES
Carbohydrates, fats , proteins and water
1

2. CARBOHYDRATES
 Carbohydrates
are a large group of organic compounds
occurring in foods and living tissues and including sugars,
starch, and cellulose.
 They
contain carbon, hydrogen and oxygen.
 hydrogen
and oxygen are in the same ratio as water (2:1) and
typically can be broken down to release energy in the animal
body.
 They
 It
have a general formula Cx(H2O)y.
is divided into 3 main groups: Monosaccharides,
Disaccharides and Polysaccharides.
2

3.  Monosaccharaides
are sugars which dissolve easily in water
to form a sweet solution.
 They
are single sugars (mono)
 They
have the formula (CH2O)n where n is an integer.
 The
are classified according to the number of carbon atoms
in each molecule. Example Triose has 3 carbon atoms.
 All
sugars end in -ose
MONOSACCHARIDE
3

4. Monosaccharides
can be
represented in straight form or
ring form.
Its role in living organisms is to:
provide
a source of energy in
respiration
Serve
as building blocks for larger
molecules (starch)
STRUCTURES AND FUNCTIONS
4

5. DISACCHARIDES
 These
are any of a class of
sugars whose molecules contain
two monosaccharide.
 When
two monosaccharides
bond they form a glycosidic
bond through a condensation
reaction.
 Hydrolysis
is the reverse of the
condensation reaction and
forms two monosaccharides
from one disaccharide.
5

6. POLYSACCHARIDES
It
is a carbohydrate whose
molecules consist of a number of
sugar molecules bonded together by
a glycosidic bond.
They
are not sugars because they
are insoluble.
In
animals polysaccharides are
glucose and in plants starch.
The
most common polysaccharide is
cellulose.
6

7.  Starch
 They
and glycogen are very similar.
are both made up of amylose and amylopectins.
 Amylose
is made of many alpha-glucose molecules bonded
together forming 1,4 linked glucose molecules, the chains
are curved and coil into a helical structure.
 Amylopectin
is also made up of 1,4 linked glucose
molecules but also has branches formed by1,6 linkages.
 The
difference between starch and glycogen is that
glycogen have more branches than that of starch.
STARCH AND GLYCOGEN
7

8. Cellulose
It
makes up the cell wall of a plant cell.
is a polymer of beta-glucose
In
order for a glycosidic bond to be formed in
beta-glucose must be rotated.
This
makes cellulose a strong molecule because of
its hydrogen bonds.
CELLULOSE
8

9. TESTING FOR THE PRESENCE OF
REDUCING SUGARS
 Benedict's
reagent (copper(II) sulphate) is used to test for the
presence of sugars. It has a blue colour and only reacts in alkaline
conditions.
 The
benedict's solution must be added in excess to the sample
being tested and heated in a water bath. A positive test will cause
the solution to turn from blue to green to yellow to orange and
finally brick-red.
 All
monosaccharides and disaccharides have this effect on
benedict's because they are reducing sugars.
9

10. TESTING FOR THE PRESENCE OF
NON-REDUCING SUGARS
 Some
disaccharides are non-reducing hence Benedict's will
have no effect on it.
 The
sample sugar must be heated with hydrochloric acid
(HCl) in order to break the glycosidic bonds.
 The
solution must then be neutralised with sodium
hydroxide before the benedict’s solution can be added and
heated.
 If
there is a sugar present the solution will change colour if
not there will be no colour change hence no sugar is
10
present.

11. TESTING FOR THE PRESENCE
OF STARCH
The
spiralled shape of starch molecules allows just
enough space for iodine molecules.
Therefore
iodine solution (potassium iodide
solution) can be used to test for the presence of
starch.
Iodine
solution is orange-brown in colour and when
added to a solution containing starch turns blue- 11
black.

12. Lipids
are a group of chemicals. The most common type
are the triglycerides, which are commonly known as fats
and oils.
Fats
are solids at room temperature whereas oils are
liquid. Also fats are found in animals whiles oils are
found in plants. Their solid and liquid states arise from
the saturated nature of fats and the unsaturated nature
of oils.
The
unit structures of fats are fatty acids and glycerol
LIPIDS

13.  Triglycerides
are made by the combinationof 3 fatty acid
molecules with one glycerol molecule. The longer the chain
of fatty acids, the more energy can be released during
oxidation. Double bonds in the fatty acids caus ea kink in
the chain which determines if it is is saturated on
unsaturated.
TRIGLYCERIDES

14. Each
molecule has the unusual property of one end
hydrophilic and one end hydrophobic ; this is
because the glycerol head has a phosphate group
embedded in to and the three fatty acids are
replaced by two instead
PHOSPHOLIPIDS

15. Amino
acids are the unit structures of proteins.
Linking these structures are peptide bonds .
During this linkage, water is lost by condensation
to form dipeptides and finally polypeptides.
THE AMINO ACID

16. Primary structure: it shows the sequence in which amino acids are joined.
Secondary structure: due to the effect polypeptide chains have each
other, the polypeptide chain usually coils into an alpha helix or beta
pleated sheet ( hydrogen bonds occur when –CO group of one amino acid
is attracted to the –NH group of the other amino acid 4 places ahead of
it)
Tertiary structure: the precise way in which the secondary structure is
coiled into a 3d figure is the tertiary structure
Quaternary Structure: the quaternary structure is made up of two or
more tertiary structures, it is the association of polypeptide chains
POLYPEPTIDE STRUCTURE

17. Denaturation occurs when the
WHAT HOLDS A PROTEIN bonds holding the shape of a protein
are broken. If the protein is soluble,
MOLECULE TOGETHER? the protein renders it insoluble.
Extreme pHs break ionic bonds by
altering the charges on the R groups
 Hydrogen Bonds :broken by high
Reducing agents break disulfide
temperatures or pH changes
bonds which can be seen in perming
 Disulphide Bonds : formed by two
hair.
cysteine molecules , bonds can be
Globular proteins are more
broken by reducing agents
susceptible to denaturation the
fibrous proteins, this could be
 Ionic Bonds: formed between amine
and carboxylic acid groups, bonds can because fibrous proteins have more
disulphide bonds holding them
be broken by pH changes.
together, it could also be because
 Hydrophobic interactions also occur
fibrous proteins are mostly found
between hydrophobic side chains
outside the cell where temperature
is not as easily controlled.

18. ADDITIONAL
INFORMATION
Gel
electrophoresis using size and using pH
Collagen
and Haemoglobin: haemoglobin is
made up of four polypeptide chains, two
identical alpha chains and 2 identical beta
chains; therefore in each haemoglobinn
molecule, four haem groups carry four oxygen
molecules.

19.  Water
is a dipole. Because hydrogen and
oxygen atoms are different in size and
electronegativity, the water molecule is
non-linear and polar.
polarity means that individual water
molecules can form hydrogen bonds with
other water molecules Although these
individual hydrogen bonds are weak,
collectively they make water a very
Hydroge
n atom
stable substance.
Hydroge
n atom
 This
WATER: THE LIFE MOLECULE
Oxygen
atom
Hydroge
n atom
Oxygen
atom
Hydroge
n atom

20.  Solvent
properties: the polarity of water makes it an excellent solvent. The
electrostatic attractions between polar water molecules and ions of a
solute are stronger than those between the cations and anions of the
solute.
 High
specific heat capacity: lots of energy needed to break hydrogen bonds.
 High
latent heat of vaporization: hydrogen bonds attract molecules of
liquid water to one another and make it difficult for the molecules to
escape as vapor.
 Molecular
mobility: the weakness of individual hydrogen bonds means the
individual water molecules mobile.
 Cohesion
and surface tension: hydrogen bonding causes water molecules to
stick together, and also stick onto other molecules causing cohesion. This
results in surface tension.
PHYSICAL PROPERTIES

21. IMPORTANCE OF WATER
 Solvent
properties allow water to act as a transport medium
for polar solutes: movements of minerals to lakes and seas,
transport via blood and lymph in multicellular animals, etc.
 Cohesion
between water molecules create the continuous
column of water in transpiration streams.
 Molecular
mobility allows water molecules to move easily
relative to one another-this allows osmosis to take place.
 Expansion
on freezing allows ice to float and insulates
organisms in the water below it.
 Water
can be used directly as a reagent in photosynthesis, to
hydrolyze macromolecules to their subunits in digestion and is
also the medium in which all biochemical reactions take
place.

22. IMPORTANCE CONTINUED
 Volatility
is balanced at the Earth’s temperatures so that a water
cycle of evaporation, transpiration and precipitation is
maintained.
 Water’s
cohesive and adhesive properties mean that it is viscous,
making it a useful lubricant in biological processes:

Synovial fluid: lubricates vertebrate joints

Pleural fluid: minimizes friction between lungs and thoracic cage during
breathing

Mucus: permits easy passage of feces down the colon and lubricates the
penis and vagina during sexual intercourse.
 The
high specific heat capacity of water means that bodies
composed largely of water are very thermostable and thus less
prone to heat damage by changes in environmental temperatures.
 The
high latent heat of vaporization of water means that body
can be considerably cooled with a minimal loss of water. This can
be seen in sweating, gaping in mammals and transpiring leaves.