enzyme – biological catalyst (part ii). objectives for today mode of actions of enzymes naming of...
Post on 18-Dec-2015
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Overview Biological Molecules
Water and Living Organisms
Carbohydrates, Fats and Proteins
Enzymes
Lock & Key hypothesis
Mode of Action
Factors affecting enzyme
reactions
Speed up chemical
RxnNot chemically altered at the endOf Rxn
Lowering Activation Energy
Specificity
Temperature pH
Cut the wire
ScissorsSpeed up the cutting
process!
After cutting, still remain as a
scissors! Not altered!
Enzyme as biological catalyst
ENZYMESpeed up the
chemical reaction! Like condensation and hydrolysis
Not chemically altered at the end of
the reaction!
3. Lower Activation energy
Reactants = “ You in bed in
home clothes”
6:20am
Products = “ You in school with uniform”
7:29am
Normal Day
Exam!
3. Lower Activation energy
Reactants = “ Starch + Water”
Products = “Glucose
molecules”
Without Enzyme
s
With Enzyme
s!
Demonstration on the breakdown of starch by enzyme (amylase)
Saliva contain amylase, an enzyme that breaks complex carbohydrates (starches) into simple sugar (glucose)
“Now that we know enzymes are catalysts, and roughly know its shape, but we still do not know how the enzymes interact with the reactants!”
Mode of action1. Enzymes reaction depends on the
availability of active sites2. Active sites are depression or “pockets” on
the surface of an enzyme molecule into which substrate molecule can fit.
3. The substrates binds to the enzyme, forming an enzyme-substrate complex
4. Reactions takes place at the active sites to convert the substrate molecules into product molecules
5. The products separates, leaving the enzyme unaltered and free to combine again with more substrate molecules.
Activity time!Using plasticine to model
enzymes mode of actions!Split into 4 groupsEach group take a set of
plasticineMake your
own enzyme!
ObjectivesMake your own enzymes that fits
the substrates given to youTime limit is 5minsAfter making, each group is
supposed to describe the mode of actions of enzymes.
Specificity of enzymes explained by the Lock and Key hypothesisOne key only fits one lock! Inside the lock, it has a specific
shape that only takes in the correct key with the correct complimentary shape.
Enzymes are specific◦Each chemical reaction is catalysed
by a unique enzyme◦A substrates fits into an enzyme’s
activity site in a way similar to how a key fits into a lock.
◦Lock and Key hypothesis
How do Canberra name their classes?3E1All the sec 3 classes start with the
number 3Follow by E, N or TThis allows people to quickly
recognize the classes. So, how can we name enzymes so
that people can recognize that the names given actually belongs to the enzymes and not something else?
Enzyme Nomenclature and Classification:
Enzymes are commonly named by adding a suffix "-ase" to the root name of the substrate molecule it is acting upon. For example,
Lipase catalyzes the hydrolysis of a lipid triglyceride into fatty acids and glycerol.
Sucrase catalyzes the hydrolysis of sucrose into glucose and fructose.
A few enzymes discovered before this naming system was devised are known by common names.
Examples are pepsin, trypsin, and chymotrypsin which catalyzes the hydrolysis of proteins.
Summary
Enzymes
Characteristics
Specific
Speed up Chemical
Rxn
Lower activation
energy
Remains unaltered
Requires in minute amount
Mode of action
Lock and key hypothesis
Induced fit hypothesis
HW- Due Next Tue 31st MarchGo to the biology blog
canberra3E1.wordpress.com and do a short online quiz. Participation marks will be given.
Watch a video posted on the web and State some common uses of enzymes in
our societyScientist can create ‘super enzymes’ that
can break down bio molecules very fast and efficient. Do you think it is safe to mass produce this and use it in our society?
Review questions1) Are Enzymes:
A - Carbohydrates B - Protiens C - Nucleic Acids D - Lipids E - Other
Going a bit furtherG6PD, a functional enzyme gone
missing in in the body!Cannot break down Glucoe-6-
Phosphate, which will be accumulated in the cells.
And it disrupts many other chemical reaction in the body
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