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Assessment Coversheet
Module Code
Module Title
Student’s name
Student ID Number
Course/ Subject
Assignment
Title/
Number
FZC008
Module Tutor Karen Lupton
Biochemistry
Rosie Bowers
G 2
0
6
2
5
2
9
Foundation applied science
Enzymes Essay
7
‘I confirm that this piece of work which I have submitted is all my own work and that all
references and quotations from both primary and secondary sources have been fully identified
and properly acknowledged in footnotes and bibliography.’
Signature:
Rosie E Bowers
Extension
Agreed date:
Date:
26.3.15
Submission
Deadline
27.3.15
Extension
Agreed by:
Work submitted should be presented in the following format:


Grade*
Double line-spaced, on A4 paper
In Arial or Times New Roman font in black ink
Learning Outcomes To be completed by the
student
Describe and apply key biochemical principles
necessary for study on university level
programmes.
Describe and explain the structure and
function of carbohydrates, lipids and proteins
General comments:
Strengths:
Areas for improvement:
Module Tutor Feedback
Rosie Bowers
ID: 20625297
If there is something you do not understand or some aspect on which you want further information, and
you have not yet had the opportunity, you must make an appointment with your tutor to discuss this
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reflections on this assessment for your future action.
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Word Count: 1031
Rosie Bowers
ID: 20625297
Self-Assessment of Your Assignment
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programme to date.
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1
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questions
What do you think was the Getting to fully
thing you did best in this
explore enzymes
assignment?
and how they work.
2
What was the hardest
thing about this
assignment?
Trying to find
relevant information
from reliable
sources to
reference.
3
If you had the chance to
start this assignment again
from scratch, how (if at all)
might you decide to go
about it differently?
Discuss the
structure a little
more.
4
Jot down 3 short
questions you could like
me to answer about this
example of your work.
1.
Was the information
included completely
relevant?
2.
Is there anything
else I could have
added?
3.
Was the essay
structured properly?
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Tutor’s Response
Your Action Points
Rosie Bowers
ID: 20625297
Describe the chemical structure and discuss the factors that modify enzyme
structure and/or function.
Enzymes are essential intracellular biological catalysts. They help in the
catalysing of the metabolic reactions within the body. They reduce the activation
energy required for the reaction to take place. (1) Enzymes have the potential to
effect a person’s phenotype and therefore there physical appearance. This is
because they aid in the reactions involved with growth and development.
Enzymes have their own nomenclature. They can be categorised by the reactions
they catalyse. These are: Oxidase (Oxidisation/reduction reactions), Hydrolase
(Hydrolysis reactions), Isomerase (Isomerisation) and Ligase/Synthase (catalyse
the joining of two substances).
(2) Enzymes are globular proteins. (3)The structure of enzymes is very specific.
They are made up of primary structures that are a simple sequence of amino
acids that code for the enzyme protein chain. They are joined by peptide bond
during a condensation reactions. These primary structures fold, bend and twist
and are held by hydrogen bonds to produce structures such as α helix but also
as a zig-zag structure called a ß pleated sheet. The tertiary structure is the
precise 3D structure of the enzyme protein with various secondary structures.
These are held together by ionic attraction between the R groups, disulphide
bridges formed between cysteine, hydrogen bonds and hydrophobic attractions.
The shape of active site of the enzyme complimentary to the substrate is
determined by the specific structure of the primary, secondary and tertiary
structure. This very specific structure is altered by temperature and PH amongst
other things.
(4) Chemically almost all enzyme reactions are reversible. The mechanism can
be shown as
(5). A and B are the reactants and C and D are the
products. (4) The reactant will combine with the products until it reaches
equilibrium. The time taken for the reactant to be converted into the product using
the enzyme is dependent on a number of limiting factors. These limiting factors
can also modify the enzymes and change the function
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(4) Temperature is a limiting factor. The temperature of the reaction can cause it
the reaction to speed up. The reactant will move around faster and therefore
collide more frequently. As a result the product is formed quicker. The enzyme
will have an optimum temperature in which the enzyme will work at its best. Just
as the rate of reaction will decrease as the temperature decreases. (6) For
example in metabolic reactions. When a body become hyper/hypothermic it is no
longer at its optimum temperature for enzyme reactions and so the body in the
case of hyperthermia the body’s temperature is increased and the enzymes can
begin denature where as if the body become hypothermic the metabolic reactions
will slow down to a dangerously low rate.
(4) After that temperature the enzyme will denature. If the temperature of the
enzyme is too high it can modify the shape of the active site rendering the enzyme
ineffective. Where most enzyme reactions are reversible, the denaturing of the
enzyme is irreversible.
This can also be the case for the PH. The PH also has an optimum PH in which
the enzymes work the best. For example digestive enzymes in the stomach work
best at around 2 on the PH scale. An extreme PH increase or decrease will cause
the enzymes active site alteration. (4) The H+ and OH- ions in acid and alkali
solutions alter the ionic and hydrogen bonding holding the whole structure
together. The active site will no longer be complimentary to its substrate and as
a result the enzyme will be denatured.
There are also other non-chemical and thermal components that can modify the
enzymes structure and therefore their active site. Inhibitors can be competitive
and non-competitive which can be further broken down into reversible and
irreversible inhibition. (6) Inhibitors are a molecule than effects a single amino
acid or even a side chain which ultimately alters the final structure of the enzyme.
(4) Competitive inhibition happens when a compound with a similar to shape to
that of the substrate bind to the active site instead of the complimentary substrate.
This makes that substrate unable to bid and the reactants cannot convert into the
product. Competitive inhibition is classed a reversible. The inhibitor will remove
from the active site of the enzyme and the enzyme can be used again. By
increasing the substrate concentration in the experiment, the enzyme is more
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Rosie Bowers
ID: 20625297
likely to collide with the substrate to produce the enzyme-substrate complex
rather that producing an enzyme-inhibitor complex.
Non-competitive inhibition, on the other hand, modifies the structure and active
site of the enzyme rather that blocking the active site and has no similarity to the
substrate at all. (4) Non- competitive inhibitors bind covalently away from the
active site. Ultimately they interfere with the tertiary structure of the enzyme which
leads to the alteration of the active site. Enzymes with attached non- competitive
inhibitor are classed as ‘switched off’. This is a reversible reaction, when the
inhibitors are removed the enzyme will become functional again.
Irreversible inhibition is a category on its own. Unlike reversible inhibitors they
destroy the overall tertiary structure of the enzyme rendering them completely
ineffective. (6) Some irreversible have no similar structure related relationships
to a substrate. They bind covalently like non-competitive inhibitors but in some
cases they can also bind by other means to an active site. As a result they break
down essential functional groups needed for the active site to be functional.
Examples of irreversible enzymes include cyanide. Cyanine will bind to
respiratory enzymes and therefore respiratory reactions cannot take place. In the
case of the human body irreversible inhibitors can be fatal.
All in all, enzymes are an essential factor in the function of the living organism.
They have specific structure that allows them to catalyse individual biochemical
reactions that have substrates complimentary to that of its active site. Other
molecules can alter and modify that active site making it impossible for a
substrate to bind. Due to the specific and quite fragile tertiary structure even the
slightest change in PH or Temperature can alter the effectiveness of the enzymes.
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ID: 20625297
Bibliography.
(1) Mike Boyle, Katherine Senior. Collins Advanced Science: Biology, 3rd ed.
London: Collins; 2008. Pg73-93
(2) University Of Arazonia. Energy, Enzymes and catalyst problems.
http://www.biology.arizona.edu/biochemistry/problem_sets/energy_enzymes_ca
talysis/01q.html(accessed23.3.15)
(3) Dr. Edward Meyertholen Enzymes.
http://www.austincc.edu/emeyerth/enzymes (accessed 23.3.15).
(4) Jim Clark. Enzyme Inhibitors.
http://www.chemguide.co.uk/organicprops/aminoacids/enzymes3.html
(accessed 23.3.15)
(5) Image can be found at: https://encryptedtbn0.gstatic.com/images?q=tbn:ANd9GcS6HfSAIXCOsQEG8GYwU9ClNx9axTOxHXb--41FgKplfRM23kWlg
(6) Rakesh Sharma (2012). Enzyme Inhibition: Mechanisms and Scope,
Enzyme Inhibition and Bioapplications, Prof. Rakesh Sharma (Ed.), InTech,
Available from: http://www.intechopen.com/books/enzyme-inhibition-andbioapplications/enzyme-inhibition-mechanisms-andscope
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