Download Enzymes & pH - SchoolWorld an Edline Solution

Do Now
What are the functions of these macromolecules:
1. Carbohydrates (polysaccharides)
2. Lipids
3. Proteins
4. Nucleic Acids
Do Now
1. How is a cell receptor similar to an enzyme?
2. How is a cell receptor different from an enzyme?
3. Are enzymes organic? Why?
DO NOW
1. Enzymes, hormones and cell receptors are examples of
which type of macromolecule?
2. How are enzymes, hormones and cell receptors different
from one another?
Enzymes - Do Now
1. How can we break down a piece of pepperoni pizza?
2. What is the pizza broken down into?
3. Can those nutrients be synthesized into new molecules? How?
Enzymes & pH
http://phet.colorado.edu/sims/html/ph-scale/latest/ph-scale_en.html
Chemical reactions with enzymes are used to
break molecules down and…
Carbohydrate

Monosaccharide + Monosaccharide
Lipid

Fatty acid + Fatty acid
Protein

Amino acid + Amino acid
Nucleic Acid

Nucleotide + Nucleotide
Chemical reactions with enzymes are used to
break molecules down and Synthesize large molecules
Monosaccharide + Monosaccharide 
Carbohydrate
Fatty acid + Fatty acid

Lipid
Amino acid + Amino acid

Protein
Nucleotide + Nucleotide
 Nucleic Acid
Wait, what’s a chemical reaction?
When one or more substances react to form
new substances.
Na + Cl
Silver solid
Green gas
NaCl
Table Salt
The substances
that react.
Reactants
Na +
Cl
The substances that
are produced.
Products
NaCl
Why do we need enzymes??
Isn’t water all you need to break down & synthesize molecules?
Lets take a look: (Think about these 2 questions while observing)
http://lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html
1. Will molecules breakdown or synthesize without enzymes?
Yes, but much slower (slower rate)
2. Why are enzymes important for chemical reactions?
 Enzymes speed up chemical reactions.
 Allow reactions to happen more often.
Hmmmm…
1. Does a Jolly rancher or Starburst dissolve faster in
your mouth or a glass of water?
It will dissolve faster in your mouth
2. Why might this happen?
Because enzymes speed up the breakdown process!
How could you speed up this chemical reaction?
Adding enzymes!
Enzyme doing Hydrolysis
Do Now “Complex”
1. Why are enzymes necessary for living organisms?
Allow chemical reactions to happen fast enough to
maintain homeostasis
2. How are enzymes different from one another?
Enzymes all have specific shapes for specific reactions
3. Can chemical reactions occur without enzymes? Explain.
Allow chemical reactions to happen fast enough to
maintain homeostasis
Enzymes
Enzymes:
 Are organic catalysts that speed up chemical reactions
 Catalyst – something that speeds up a reaction
Example: Carbon Dioxide and Water come together to make
Carbonic Acid
– Happens in red blood cells, but only about 200 molecules of
carbonic acid form an hour
– Add the enzyme carbonic anhydrase,
and an estimated 600,000 molecules
of carbonic acid are now formed
every second!
Enzymes
Enzymes are very specific.
 Each enzyme only has one reaction it will help
Example:
 Lactose (a disaccharide), will only be broken down by the
enzyme lactase
 Maltose will only be broken down by maltase
 Starch (amylose) will only be broken down by amylase
 Proteins will only be broken down by protease (peptidase)
Wait a minute… what do you notice about
many enzyme names?
Protease, amylase, maltase, lactase, lipase…
Using words alone, how can you tell which word is a
sugar and which is an enzyme? (label the sugar and enzyme)
Amylase vs.
Amylose
Why do enzymes only help catalyze (speed up)
only one type of reaction?
Enzyme shape allows only certain reactants (substrates)
to bind to the enzyme
– Substrate: the specific reactants that an enzyme acts on
– Active site: the part of the enzyme where the substrate
connects. Specific to only one substrate!
• Substrate + active site = like a lock and key!
Specific, Picky Enzymes
(Plays hard to get!)
Lets take a look at how enzymes are specific:
http://lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html
When watching, keep in mind these questions:
1. How are the enzymes shown different?
**Remember: SUBSTRATE - ENZYME
Label your diagram
Word Bank… don’t get
used to this
Enzyme (2x)
Substrate
Products
Reactants
Active Site
Enzyme-Substrate Complex
1. Look at the active site. Did it change after the reaction?
2. Exit Question – Write a sentence or two stating the conclusion
or relationship between the active site and the specific substrate.
3. Bonus question – can this enzyme be used again for the same
reaction? For a different reaction?
Do Now
(4)
1. Write sentences describing the relationship between:
 Active Site / Specific Substrate
 Enzyme / Breaks down, Synthesis
 Enzymes / “ASE”
 Enzyme / Catalyst
Bonus Question
Example: Amylase only breaks down starch (amylose)
– Which molecule is the enzyme and which is the substrate?
Enzymes are Reused
Over and Over and Over again
1. What type of reaction is this (break down or synthesis)?
2. What changed in this reaction?
3. What stayed the same?
Enzymes are Reused
Over and Over and Over again
Your conclusion?
http://lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html
Enzymes = Specific, Picky and High Maintenance
The rate at which enzymes catalyze their reactions changes as
the conditions inside the cell change!
Conditions that effect enzyme reaction rate are:
1. Temperature
2. Relative concentrations of enzyme and substrate
3. pH (acidic, basic, neutral)
Temperature affects Enzyme Function
To cold = enzyme works to slow
To hot = enzyme begins to denature!
– Denature = proteins begin to break apart at high
temperatures changing the active site!!
Why is this bad?
If the active site is
changed, that specific
reaction can’t
happen!
Every enzyme has an
optimal temperature
it works best at!
Why is a very high fever considered dangerous
where you have to go to the hospital?
http://lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html
pH affects Enzyme Function
What is pH?
– Measures how acidic or basic a solution is
Acids – compounds that release H+ ions in solution (corrosive)
Bases – compounds that remove H+ from solution
pH scale - measures how acidic a solution is
– pH = usually between 0 -14
– pH 0 = very acidic (high H+ concentration)
– pH 14 = very basic (low H+ concentration)
– pH 7 = neutral (not basic or acidic)
pH
What is basic and what is neutral?
What is the pH of human blood?
What is the pH of water?
Acids vs. Bases
How do we test the pH of a solution?
Using litmus paper!
Litmus paper turns this color when:
1. Acidic 2. Basic What color did the litmus paper turn with:
• Lemon juice –
• Bleach –
pH affects Enzyme Function
Just like temperature, enzymes (proteins) will start to breakdown
permanently if the pH is not what the enzyme needs!
1. Do all enzymes work best at the same pH?
2. What is the optimum rate for Gastric Protease in graph B?
Most enzymes work best in
neutral solutions
B
pH affects Enzyme Function
• Humans need to keep their pH within a very
narrow range around neutral (pH 7.0).
– Some organisms need different pH ranges
• The azalea plant thrives in acidic (4.5) soil
• The microorganism Picrophilus survives best at an
extremely acidic pH of 0.7 (lowest among all organisms)
Enzyme-Substrate Concentration
Enzymes can only catalyze so fast.
– If you keep adding substrates, the enzymes reaction rate
will go up
– At a certain point, enzymes can not work any faster and
the rate will not increase! It will level off!
Why does the reaction
rate line level-off or
flatten out?
Summary of Diagrams you will see
Questions
1. Do all enzymes react best at the same temperatures?
2. Do all enzymes react best at the same pH?
3. What is pH a measure of?
4. What happens to an enzyme when it is to hot or acidic?
Do Now(1)
On a separate sheet of paper
Put in size order:
– Enzymes
– Amino acid
– Cell organelle
– Cell
– Atom
– Tissue
– Organ
Do Now
lab1
1. Describe enzymes:
2. What is a reaction?
3. When referring to rate of reaction, what do we mean by rate?
4. If you constantly add more substrate, increasing concentration,
will the rate of reaction always increase?
Do Now
1. How would you create this graph?
lab2