Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

Biological Molecules
1
...
Some examples of
different R groups are: Glycine: H,
Alanine: CH3, Cysteine: CH2SH
...


When you join two amino acids together
a peptide bond is formed through a
condensation reaction this is since a
molecule of water is being removed if the
molecule would have been added this
would have meant it was a hydrolysis
reaction
...

Many more amino acids are joined
together they for a polypeptide
...


The specific sequence of amino acids in a
chain is called the PRIMARY structure of the
protein
...
All proteins contain hydrogen,
carbon, oxygen and nitrogen and some
contain sulphur
...
The others can be
transmitted in the liver
...
The amount
of Hydrogen bonds make this structure stable
...


The overall 3D shape of the molecule is the
tertiary structure
...
If the tertiary structure changes the
protein cannot carry out its function
...
The
bonds formed are determined by the primary
structure – a single change to an amino acid can
change the tertiary structure and function of that
protein
...
Others have an inorganic
component
...


The 3D tertiary and quaternary structure of
proteins determine the role the protein will play
in the body
...

Globular: soluble, made of a non-repeating
sequence of amino acids, usually metabolically
active
...

Collagen: Its insoluble in water and it has high tensile strength and flexibility
...
It’s a structural protein
...
Every 3rd amino acid is glycine ( smallest amino acid)
...
The ends of the
molecules are staggered this prevents weak spots running though the fibrils
...
It contains alose
proline and hydroxyproline
...
In skin collagen form a mesh that is resistant to tearing
...
Its
waterproof which provides an impermeable barrier to infection and prevents
entry of water born pollutants
...
Contains cysteine, a sulphur containing amino acid
...
Flexibility is determined by the
degree of disulphide bonds
...
Allows the following structures to stretch and adapt their shape: walls of
blood vessels, alveoli in lungs, bladder, heart and tendons and ligament and skin
...
Contain alternate hydrophobic and lysine
rich areas
...
It’s an example of a globular protein with a
prosthetic group
...
Each
haemoglobin molecule can bind with up to 4 oxygen molecules
...
Consists of many different amino acids
...

Released into the bloodstream and transported by the blood
...

Conjugated proteins: This contains a non-protein group called prosthetic group
...
When combined with lipids or a carbohydrate they from
lipoproteins or glycoproteins
...

Catalase: A quaternary protein containing 4 haem groups
...
Hydrogen peroxide is a common by-product of metabolism, which can
accumulate will damage cells and cell component s
Ca2+: Need for nerve impulse transmission and muscle contraction
...

NH4+: Needed for production of nitrate ions
K+: Needed for nerve impulse transmission
H+: Needed for catalysis of reactions and Ph determination

NO3- : Needed for nitrogen supply to plants for amino acid and protein
fromation
HCO3- : Needed for maintainance of blood Ph
OH-: Needed for catalysis of reactions , acids and protein formation
Cl- : Needed to balance charge of sodium and potassium formation
PO43- : Needed for cell memebrane formation , nucleic acid and ATP
formation and bone formation
...
Carbohydrates , Lipids and Water

Carbohydrates contain carbon, hydrogen, oxygen
...

All carbohydrates have the general formula of Cn (H2O) n
...

Polysaccharides: cellulose, starch, glycaton structure and
energy storage, long chains made of monosaccharides
...
They can be
categorised by how many carbons they have
...


Disaccharides are formed when two monosaccharides join
together chemically by a condensation reaction
...
Both of these reactions are
catalysed by enzymes
Alpha glucose + Alpha glucose= maltose
...
Alpha glucose + Beta galactose = lactose
Beta glucose + Beta glucose= cellobiose

There are 3 polysaccharides :
Starch (amylose): Is an energy store in plants, insoluble and a metabolically inactive molecule
...
They coil around to make a long spiral
this makes it compact, as its insoluble it doesn’t affect the water potential of the cell on the plant
and it doesn’t interfere with any chemical reactions that take place
...
This branches the
chain so glucose molecules can be
hydrolysed and used in respiration
...
Polymerised from alpha
glucose molecules
...
Insoluble in water so it
does not interfere with the water
potential on the cells and it’s also
metabolically inactive
...

Cellulose: Forms cells walls in plants that are very strong and they resist the pressure that occurs
when water enters the cell
...
Every second monomer is rotated 180* by a condensation
reaction so it needs two hydroxide groups so it results in very long chains ( 10000 monomers) and
straight
...
These are held together by hydrogen bonds to form microfibrils
...
Can be reinforced with other molecules to provide extra support if needed
...


Contain carbon, hydrogen and oxygen its
non-polar as it has no charge
...

They are not polymers like polysaccharides
instead they are macromolecules
...
Because
of their structure and hydrogen atoms they
yield a large amount of energy
...
The glycerol has
3 carbon atoms, 3 alcohols (OH group)
...
hydrocarbon tail
...


If only a C-C bond is present, this means its saturated
...

When they join through a condensation reaction an ester
bond is formed which makes it more fluid at room
temperature
...
Insects and leaves are covered in wax
to keep them waterproof
...


For each ester bond that forms there is one bond of
water eliminated so there are 3 molecules of water
eliminated for each triglyceride formed
...
Triglyceride are used as energy
store because they are insoluble in water so do not
affect the water potential as release twice as much
energy than glucose as it doesn’t have any effect on
osmosis
...


This type of lipid is similar to triglyceride
but they contain a phosphate group in
place of one of the fatty acid molecules

...
They
are made of 1 glycerol , 2 fatty acids and 1
phosphate group it has a hydrophilic head
( phosphate group) and a hydrophobic tail
(fatty acid)
...
Phospholipids are amphipathic they from
20-80% of the membrane in plant and animal cells
...
They are part of the fluid
mosaic structure so nothing that’s polar or large can go though
...
They are complex
alcohols made from 4 carbon rings, hydroxyl
group (OH) at one end hydrophilic and the rest
of the molecule is hydrophobic
...

As it is small and hydrophobic, it can be found
in-between the hydrogen carbon tails of a
phospholipid bi layer
...
Planta have
cholesterol derivative the only difference is the C=C
...
The lipid nature (small hydrophobic) means it can pass through the
bi-layer to get to its receptors
...


For a lipid test you must mix the sample with ethanol, mix the
solution with water and shake if the lipid is present a white
emulsion will be form if it’s not the test will remain clear hence
it will be negative

Water is a very small molecule it has two hydrogen atoms that are
covalently bonded to one oxygen atom
...

In pure liquid form: The molecules form hydrogen bonds between the
molecules which can continually form and break as the molecules
move around each other
...

Cooling water down: Water is a dense liquid (1
...
Then below this temperature the density
decreases so if it’s less dense then it floats that is why ice floats on the surface of the water
...

Cohesion and tension: Hydrogen bonds pull water molecules in at the surface so they stick together
this is called cohesion because of cohesion, tension can be observed at the surface of a body of
water known as surface tension this is strong in small animals so they can walk on water
...
Water
molecules cluster around the slightly charged part of the solute
...
They are dissolved
...

As a transport medium: Water can act as a convent for many chemicals
...

3
...

There are 5 bases which are divided into 2 groups
Purines (they have 2 carbon rings): Adenine, Guanine
Pyrimidines (they have 1 carbon ring): Thymine, Uracil and
Cytosine

Nucleotides monomers are joined together to make nucleic acids
...
Ribonucleic
acids contain ribose sugar, Deoxyribonucleic acids contain
deoxyribose sugar as they have an extra hydroxyl group
...

The two strands are antiparallel
...

5” end means that the carbon atom is attached to the 5th carbon
atom of the sugar
...
They run from 5-3 and 3-5

DNA is a double helix it has two
polynucleotides strands wind round each other
to form a double helix
...
The
DNA molecule is unwanted by gyrase enzyme
and is unzipped by breaking the hydrogen
bonds between the complementary base pairs
using DNA helicase
...
And a
phosphodiester bond is formed to join the
nucleotides together
...
This produces 2 identical strands of
DNA each containing a strand of the original
DNA and one new strand
...
There are 3
forms of RNA
MiRNA: Copy of DNA structure required in protein synthesis
Trna: Transfers amino acids in protein synthesis
Rrna: Forms ribosomes from proteins

Adenosine triphosphate can supple a usable form
of energy
...

The structure is a ribose sugar, adenine, 3
phosphates – ATP 2 phosphate – ADP
Energy is releases approx
...
6kjmol-1
...
ATP is unstable so is not good
in long term energy store
...
ADP is rapidly converted to ATP which
means large stores are not needed as it is an immediate store of energy
...

There are 2 processes during protein synthesis
the first one is transcription
...
The enzyme DNA helicase catalyses
this
...
RNA
polymerase catalyses the formation of temporary
hydrogen bonds between free nucleotides of
RNA found in the nucleolus and the unpaired
DNA bases
...
As the RNA
nucleotides join together they form bonds via
condensation reactions and complimentary
length of MiRNA is formed
...
When the end of the gene is reaches the
MRNA then passes out of the nucleus , though the nuclear envelope and attaches to a ribosome
...
Two codons are attached
to the subunit and exposed to the larger
subunit
...
Using ATP and an enzyme , Trna with
anticodon UAC and the amino acid
methionine forms hydrogen bonds with the
codon
...
A peptide
bond forms between the two adjacent
amino acids
...


4
...
The globular protein contains an active
site which is the area where the catalytic activity
takes place
...
They are extremophiles which
means that they work at low temperatures The
whole molecule may consist of 100s of amino acids
...
Most the
whole enzyme is involved in supporting the arrangement of the specific active site
...
This is due to their unique
tertiary structure
...
But organisms can live in a range of
environments that are not conducive to their conditions
...
Enzymes reduce the amount of
activation energy required for the reaction to
take place
...
The
lock and key model describes this mechanism
the substrate key fits the active site lock this is
held in place so the reaction can go ahead
...
The substrate is held in place
because oppositely charged groups on the substrate
and the active site are near to each other, We have the
enzyme substrate complex, the reaction occurs and
the product is formed
...


An intracellular enzyme is an enzyme that catalyses
biological reaction within the cell
...
It’s found in nearly all
living things that are exposed to oxygen
...
It consists of 4
polypeptide chains and contains a haem group with iron

...
Found in small vesicles called peroxisomes in
eukaryotes , used to help kill microbes when white
blood cells ingest pathogens
...

Amylase: secreted by our salivary gland or digest starch
...

Trypsin: made in the pancreas and acts in the lumen of the small intestine to digest proteins into
smaller peptides via hydrolysis

Competitive inhibition: The inhibitor fits into the
active site so a substrate molecule won’t be able to
enter it
...
More inhibitor molecules mean more will
collide with the active side
...
Increasing substrate concentration,
effectively dilutes the effect of the inhibitor
...

Non – competitive inhibition: Inhibitor binds or the allosteric site of the enzyme
...
The active site is no longer complementary to the
substrate so the reaction won’t be catalysed
...
The rate of reaction cannot be changed even if you add more substrate
...




---