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Biological molecules

Carbohydrates:



Monosaccharides
-

glucose, CHO



Have six carbons so are
called
hexose sugars. This is an

glucose.

OH= Hydroxyl group




This is a glucose.



It has the same structure
as the
alpha glucose but the H
and OH
are reversed on carbon-
1




Disaccharides- Before:




After:

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Maltose (2 alpha glucose

bonded together)




Water is released from

bond formation =>

condensation

It forms a 1-4 glycosidic

bond.



Bond making=> water
appears- condensation
Bond breaking=> water is
used to break bonds-
hydrolysis


Polysaccharides-
starch, glycogen,
cellulose:

Starch (amylose) ­
a polymer of alpha
glucose with 1-4
glycosidic bonds…

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Glycogen=> a
polymer of
alpha
glucose with
1-4 and 1-6
glycosidic
bonds,
formed

by condensation
reactions- the
molecule is
branched.
Function= energy
storage in muscle
and liver cells in
animals. It's compact
as it is branched and
it's
insoluble and all the
glucose molecules
are used in
respiration to
provide…

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produce cellulose
fibres.
Function: to provide
tensile strength in
plant cell walls-
strong because of
all the molecules
hydrogen
bonded together.



Biochemical tests:

Testing for: Description Result

Starch Add a few drops Brown to black
of iodine
solution
Reducing Like glucose. Blue to orange to red
sugar Add Benedict's
solution…

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There are many
different
triglycerides
because they have
different
combinations of
fatty acids. Fatty
acids are different
because they have
different numbers
of carbons in the
chain and they have
different levels of
saturation (double
bonds).

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Phospholipids (hydrophobic tails Glycerol molecule


2 fatty acids


Inorganic phosphate
group

ester bonds
and hydrophilic head).

Formed by condensation and forms a
main part of the plasma membrane.
It also controls the movement of
molecules across the membrane by
preventing cell leakage.


Cholesterol ­ made up of 4
carbon- based…

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Amino acids- 20 different ones
found in proteins

R= variable group · NH=amine group ·
COOH= carboxylic group
If R= H => glycine

If R=CHSH => cysteine




Dipeptide
Peptide bond formation > condensation


Poly peptides are a chain of amino acids
joined by peptide bonds

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Protein structure:
Primary level (1°) => order of amino acids in the poly peptide chain. This is controlled by DNA.
Secondary level (2°) => the chain spirals to form an helix. Hydrogen bonds form between

the spirals. Or it can form a pleat.
Tertiary level (3°) => enzymes. Hydrogen bonds…

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Nucleic acids (DNA & RNA) ­ these are
polymers of nucleotides.
5 organic bases:
Adenine
Thymine (DNA)
Uracil (RNA)
Cytosine
Guanine


DNA:

polynucleotide

Double helix

Two strands are antiparallel

Complementary base pairing occurs

A always bonds to T

G always bonds to C

AT are joined by 2 hydrogen bonds…

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