Download part c – can peroxidase react with other substances?

Unit 2: Biochemistry Review: College Prep
MATTER / WATER
a) element
b) atom
c) ion
d) molecule
e) bond
f) energy
g) hydrogen bonds
h) polarity: polar vs. nonpolar
i) cohesion vs. adhesion
j) surface tension
k) capillary action
THE CONCEPT OF PH
a) pH
b) acid vs. base
c) indicator
d) pH scale
e) acidic and basic substances
f) pH of blood, cells, stomach
g) neutralization reaction
h) buffer
i) alkalosis vs. acidosis
j) 3 causes of acidosis
ENZYMES – ORGANIC CATALYSTS
a) catalyst
b) enzyme
c) reactant vs. product
d) how an enzyme works
e) substrate
f) active site
g) enzyme-substrate complex
h) shape
i) enzyme specificity
j) effect of temperature
k) effect of pH
l) effect of concentration
m) optimum
n) amylase
o) pepsin
p) trypsin
q) digestion: functions of enzymes
r) denaturation
MACROMOLECULES
a) monomer units & polymer units
FROM PREVIOUS UNITS
b) sugar homeostasis!
c) IV, DV, control
Biochemistry - Unit 2
Structure of Matter






Chapter 4.1 & 4.2
Define the term matter.
Distinguish among elements, atoms, ions and molecules.
List the main elements that compose organisms.
Create a model of the structure of an atom with labels.
Contrast covalent and ionic bonds.
Analyze the structure of carbon and its importance to living organisms.
The Characteristics of Water
Chapter 4.4

Construct the structure of a water molecule.

Differentiate between polar and nonpolar molecules.

Summarize hydrogen bonds.

Draw conclusions how the structure of water is related to its various properties.

Compare and contrast adhesion and cohesion as related to surface tension and capillary
action.
The Concept of pH



Chapter 4.4
Use pH indicators to determine the pH of various substances.
Differentiate between acids and bases and their position on the pH scale.
Draw conclusions regarding the role of buffers in maintaining pH homeostasis.
Building Blocks of Life: Macromolecules




Chapters 5.1, 5.2, 5.3, 5.4
Identify the 4 macromolecules of life & their monomer units.
Construct macromolecules.
Compare and contrast properties of the macromolecules.
Analyze the importance of carbon to the structure of biological macromolecules.
Enzymes: Organic Catalysts
Chapter 5.5

Explain the cause & effect relationship between enzymes and activation energy.

Summarize the reaction of peroxidase/hydrogen peroxide & its importance in the body.

Relate how an enzyme’s shape is important to its function.

Compare & contrast the effect of pH, temperature and concentration on enzyme
activity.

Summarize how an enzyme interacts with its substrate.

Illustrate the importance of enzymes.

Investigate and summarize the concept of enzyme specificity.

Interpret how denaturation affects enzyme activity.
2
College Prep Biology – Unit 2
ATOMS = BUILDING BLOCKS
Atoms are the basis of chemistry. They are the basis for everything in the Universe. You should start by
remembering that matter is composed of atoms. Atoms and the study of atoms are a world unto
themselves. We're going to cover basics like atomic structure and bonding between atoms. As you learn
more, you can move to the biochemistry tutorials and see how atoms form compounds that help the
biological world survive.
SMALLER THAN ATOMS?
Are there pieces of matter that are smaller than atoms? Sure there are. You'll soon be
learning that atoms are composed of pieces like neutrons, electrons, and protons. But
guess what? There are even smaller pieces moving around in those atoms. Scientists
have many names for those pieces, but you may have heard of nucleons and quarks.
Nuclear chemists and physicists work together with
particle accelerators to discover the presence of these
tiny, tiny, tiny pieces of matter.
Even though those super tiny atomic particles exist,
there are three basic parts of an atom. The parts are
the electrons, protons, and neutrons. What are
electrons, protons, and neutrons? A picture works best.
You have a basic atom. There are three pieces to an
atom. There are electrons, protons, and neutrons.
That's all you have to remember. Three things! As you
know, there are over 100 elements in the periodic
table. The thing that makes each of those elements
different is the number of electrons, protons, and
neutrons. The protons and neutrons are always in the center of the atom. Scientists call
the center of the atom the nucleus. The electrons are always found whizzing around
the center in areas called orbitals.
You can also see that each piece has either a "+", "-", or a "0." That symbol refers to
the charge of the particle. You know when you get a shock from a socket, static
electricity, or lightning? Those are all different types of electric charges. There are even
charges in tiny particles of matter like atoms. The electron always has a "-" or negative
charge. The proton always has a "+" or positive charge. If the charge of an entire atom
is "0", that means there are equal numbers of positive and negative pieces, equal
numbers of electrons and protons. The third particle is the neutron. It has a neutral
charge (a charge of zero).
Biochemistry
3
Structure of Matter
All substances on earth are made of different combinations of the 109 known elements. Oxygen (O),
gold (Au) and Iron (Fe) are examples of elements. Notice that each element is identified by an
abbreviation (H = hydrogen, Na = sodium, K = potassium)
1. Element____________________________________________________________________
___________________________________________________________________
Approximately 25 elements occur in living things. Four of these elements make up 96% of the living
matter in your body.
2. Main elements of life:____________________________________________________
Reread the following passage after completing the next page as a refresher of vocab words.
In the human body, oxygen & hydrogen exist mainly in the form of water. Carbon’s importance to life starts with its versatile
bonding behavior. Each carbon atom can share pairs of electrons with as many as 4 other atoms. This provides a stable
covalent bond since the electrons are shared equally. The carbons can either form a line that we call a ‘backbone’ or a ring
structure. Other atoms such as hydrogen, oxygen, and other elements can bond to the carbons and form many of the
various compounds found in our body! The covalent bonds allows 3-D shapes of organic compounds to form. Organic
compounds are any compound that has one or more carbon molecules in addition to other elements. Some examples are
carbohydrates, proteins, fats, nucleic acids, hormones, & vitamins.
4
College Prep Unit 2:
The word atom comes from the Greek word atomos meaning “indivisible.”
3. Atom= ________________________________________________________________________
Please write the charge below:
Protons:
_____
Neutrons:
_____
Electrons:
_____
Sometimes atoms can lose their electrons or gain extra electrons. This changes the electrical charge of the
atom…it is now called an ion.
4. Ion =
________________________________________________________________________
The atoms of most elements interact with one another forming molecules. Molecules can be made up of atoms of the
same element (O2) or of different elements (CO2). When atoms form molecules, they either share or donate electrons
creating a bond. Bonds contain ENERGY and holds two or more atoms together.
5. Bond = ________________________________________________________________________
6. Covalent bond= __________________________________________________________________
7. Ionic bond= __________________________________________________________________
8. Molecule = __________________________________________________________________
__________________________________________________________________
* Important biological molecules:
____________________________________
A subscript shows the number of atoms present in the molecule. If there is a single capital letter or a capital
and lowercase without a subscript, it means that there is only one atom of that element in the molecule. The
number of molecules is represented with a number infront of the formula.
Name
Sodium chloride
Calcium carbonate
Methane
Hydrochloric acid
Caffeine
Carbon dioxide
Use
Table salt
Limestone
Gas
Fertilizers & dyes
Sitmulant
Soft drinks, atmosphere
Formula
NaCl
CaCO3
CH4
4HCl
C8H10N4O2
3CO2
# Atoms
# Molecules
Biochemistry
5
Structure of Matter Reinforcement
Complete the following WITHOUT using your notes…
There are 109 known ____________________________ which are the smallest parts of matter. The
four elements that make up 96% of the human body are
_____________________________________. The smallest part of an element is an
____________________. A ______________________ holds two or more atoms together forming
a _____________________________. Bonds contain ______________________. The subatomic
particle that is responsible for bond formation is the ______________________________. If an
atom gains an electron, it will have a ___________________________ charge. If an atom loses an
electron, it will have a ___________________________ charge. Charged atoms are called
_________________.
6
College Prep Unit 2:
Anticipation Guide:Try to place the following words where they belong in the paragraph.
HYDROGEN MOLECULES
UNEVENLY
WEAK
POLAR molecules are __________________________ charged and form
________________________ bonds with other polar molecules. The bond formed between two
polar molecules is called a hydrogen bond. Hydrogen bonds are ________________________
bonds because the attraction does not involve sharing or donating electrons. These bonds exist
between two __________________ rather than between two atoms. Hydrogen bonds play a role in
making the shapes of things such as enzymes, protein and DNA. This is a twisted ladder strand of
DNA – held in that shape by hydrogen bonds. These bonds are broken fairly easily, which is what
allows DNA molecules to replicate, and water to flow.
WATER IS A POLAR MOLECULE!
Water forms when 2 hydrogen atoms form covalent
bonds with 1 oxygen atom. When this happens, it forms
a molecule that looks like Mickey Mouse, with the
hydrogens as the ears and the oxygen as the head.
Since the negative electons in the hydrogen are being
pulled towards the oxygen, the parts away from the
oxygen become slightly positve. The oxygen, however,
keeps it’s electrons away from the hydrogen, making that
part slightly negative. Therefore, the water molecule has
two “poles”, a negative and a positive. This causes a
water molecule to act like a small magnet, attracting
other polar substances such as wood, paper products,
and glass.
NONPOLAR molecules are ___________________ charged and do NOT form bonds with
polar molecules.
Biochemistry
7
The Unique Properties of Water
Chapter 4.4
1.
What percentage of your cells consist of water?
________________________
2.
What two qualities of water allow it to do “special things?”
_____________________________________________________________________
TEMPERATURE MODERATION
3.
When a substance is heated, how are its molecules affected?
_____________________________________________________________________
4.
When water is heated, some of the heat energy is used to
__________________________________________________________________. As are
result, the water undergoes ________________ temperature change than other
substances.
5.
How does this property affect land areas near oceans and lakes?
_____________________________________________________________________
6.
When you sweat, water moderates temperature through ________________________.
7.
Heat from the ______________ is used to break ________________ bonds of water,
releasing water molecules into the air. Since the heat is being taken away from the skin, the
result is cooling.
8
College Prep Unit 2:
LOW DENSITY OF ICE
8.
In most substances, solids are ____________________ dense than liquids.
9.
In water, the solid form (ice) is __________________________ dense than liquid water
because in ice the hydrogen bonds keep the molecules
_________________________________. This causes ice to _____________________.
10. How is this property of water important to living things?
_____________________________________________________________________
WATER’S ABILITY TO DISSOLVE OTHER SUBSTANCES
11. Water is a good solvent because it can
_____________________________________________________________________
12. Water is the main solvent inside all ___________________, in ____________________
and in ____________________________.
This property of water allows chemical reactions to take place in living things!
Biochemistry
9
The Behavior of Water
1. ______________________________________ = The tendency of water molecules to form
hydrogen bonds with other water molecules.
+
2. ______________________________________ = The tendency of water molecules to form
hydrogen bonds with other polar molecules.
+
3. Water also exhibits __________________________________________ which results from
both cohesion and adhesion working together creating hydrogen bonds on the surface of any
body of water.
4. Cohesion and adhesion also work together to direct water up
the stem of plants against gravity. This phenomenon is called
_______________________________________.
10
College Prep Unit 2:
Water is a very important molecule to living things. Answer each set of questions based on your observations.
Water in a beaker and graduated cylinder
1. Observe the water in the beaker and the graduated cylinder. Draw the shape of the water at the top of the beaker
and in the graduated cylinder.
Explain your observations using the terms cohesion, adhesion, polar and hydrogen bonds
Drop Shape on Glass and Wax Paper
1. Observe the water on the wax paper and glass slide. Move each and notice how the water moves. Which
substance, wax or glass, is polar? Which is non-polar? How can you tell?
Capillary Action
1. Observe the chromatography paper with ink on it. Is paper polar or nonpolar? Explain. Is the ink polar or
nonpolar? Explain.
2. Observe the chromatography paper with the crayon on it. Is the crayon polar or nonpolar? Explain.
Water and Oil
1. Observe the beaker of water and oil that has already been set up for you. Which is less dense?
2. Explain the mechanism that causes water molecules and oil molecules to separate from one another including the
following terms: polar, nonpolar, hydrogen bond
Density of Ice
1. What property of water is being shown in this beaker? Why is this important to living things?
Biochemistry
11
Anticipation Guide: pH
Part A
Directions: Read each statement and decide whether it is true or false. Write out the word TRUE
or FALSE on the line in front of the statement.
1. __________
pH is a measure of how much acid or base is in a liquid.
2. __________
The pH scale measures from 0-14.
3. __________
Distilled (pure) water has a pH of 1.
4. __________
Bases are between 0 and 7 on the pH scale.
5. __________
Acids contain a high amount of H+ ions.
6. __________
Bases contain a high amount of H+ ions.
7. __________
A buffer controls the pH of a liquid by accepting and donating OH- ions.
8. __________
The pH of your stomach acid is between 2-3.
9. __________
An indicator is a special chemical that changes color with different pH values.
10. __________
Litmus paper will change color when the pH goes past 7.
11. __________
Every step on the pH scale increases or decreases the ions by +10.
Part B
Now, read page 12 of your packet and pages 85-86 in your text and correct the eleven statements
above. Then correct the answers on page 13 by rewriting the statements. IF
they are false, change them, if they are true, rewrite them the same way.
12
College Prep Unit 2:
ACIDS AND BASES ARE EVERYWHERE
Every liquid you see will probably be either an acid or a base. The only exception would be distilled
water. Distilled water is just water. That's it. Most water you drink has ions in it. Those ions in solution
make something acidic or basic. In your body there are small compounds called amino acids. Those
are acids. In fruits there is something called citric acid. That's an acid, too. But what about baking
soda? When you put that in water, it makes a base. Vinegar? Acid.
pH is how much acid or base is in a liquid. Scientists use something called the pH scale to measure
how acidic or basic a liquid is. The scale goes from 0 to 14. Distilled water is 7 (right in the middle).
Acids are liquids that contain H+ ions. They are found
between 0 and 7 on the pH scale. Bases liquids that contain
OH- ions. They are found from 7 to 14 on the pH scale. Each
step on the scale increases or decreases the ion concentration
by ten times. Most of the liquids you find every day have a pH
near 7. They are either a little below or a little above that mark.
When you start looking at the pH of chemicals, the numbers
go to the extremes. If you ever go into a chemistry lab, you
could find solutions with a pH of 1 and others with a pH of 14.
Those chemicals are very dangerous. There are pH values higher than 14 and lower than 0, but let's
just start with 0-14.
There are many important acids and bases in biology. Your stomach has hydrochloric acid (HCl) in it
to help break down your food. Hydrocloric acid can be any pH, depending on how it is made. The
HCl in your stomach has a pH of 2-3. That is why it burns so much when you vomit. It is also where
“acid reflux” gets its name; the acid in your stomach backs up into your esophagus. You also have
many buffers in your body; they are chemicals that control the pH level to maintain homeostasis.
pH Indicators are very special chemicals; they will change color if you change the pH (by adding acid
or base). Indicators change color at different pH values. Litmus changes at pH 7 but Phenolphthalein
changes from pink to colorless at pH 9.
Indicator
pH
Color in Acid
Color in Base
Litmus
7.0
Red
Blue
Phenolphthalein
9.7
Colorless
Red // Pink
Methyl Orange
3.7
Red
Yellow
Bromophenol Blue
4.0
Yellow
Blue
Biochemistry
13
Acid alkaline balance in the human body
Name: _____________________
http://www.essortment.com/all/acidalkalineba_rkci.htm retrieved 19February2009
Approximately 50 to 60 percent of a human’s body weight is from water. The percentage varies based on several factors. For
instance, fat holds very little water while muscle is about 75 to 77 percent water. The obese couch potato may contain 50
percent or less in water weight. On the other hand, a fit muscular person may have 60 to 65 percent of water in body weight.
The water in the body can be compared to swimming pool water. Swimming pools are strictly monitored to keep the water at a
certain pH balance. The water should not be too acidic nor too alkalitic. The fluid in the human body must stay within normal
ranges also. Th normal pH balance in the human body is 7.35 to 7.45, (which is basically neutral). If the pH gets low (acidosis) or
high (alkalosis) there will be specific problems that could be life threatening. The water in the human body is further broken
down into specific categories. Intracellular fluid (ICF) is water actually contained inside cells. Extracellular fluid (ECF) is water
outside the cells. Combined, ICF and ECF equal 60 percent on average of the total body weight. Extracellular fluid is further
broken down into interstitial fluid, plasma, bone, connective tissue, and transcellular fluid. Interstitial fluid, primarily located in
the lymphatic system, equals about 12 percent of body weight. Plasma, basically the liquid portion of the blood, equals about 4.5
percent of body weight. Connective tissue accounts for about 4.5 percent, with the smallest amount of 1.5 percent being
composed of transcellular fluid. The body has several different ways to ensure that the pH balance stays in the normal range of
7.35 to 7.45. These are referred to as buffer systems. Through normal day to day activity in the body, acids are formed as
waste products that need to be neutralized or eliminated. Some of the acids are released with CO2 from exhaling; others are
excreted via the kidneys. These systems work together in the healthy human body to keep the pH level within normal ranges. If
for some reason the buffering systems fail or are hindered, the pH balance will be upset. Either too much or too little of the
acids will be neutralized. The causes of this can be as simple as the flu or as complications from trauma, disease or serious
illness. Once the body senses the pH is out of kilter, it will attempt to compensate to correct the problem. The conditions for
when this happens are known as acidosis or alkalosis. These are further broken down into either metabolic or respiratory in
nature. This includes metabolic acidosis, respiratory acidosis, metabolic alkalosis, and respiratory alkalosis.
One of the chief buffers in the blood is bicarbonate, which helps neutralize acids. This is like taking an antacid for heartburn.
Metabolic acidosis is caused by the loss of bicarbonates or an increased production of acids. Some causes for bicarbonate loss
can be severe diarrhea, drug intoxication or abuse, or severe illness. Some causes for increased acid production include serious
illness or injuries, and decreased blood flow. An example of this is when you leg "falls asleep". Blood flow is decreased allowing
acid to build up. Upon standing, blood flow is restored. The tingly pin and needle sensation is caused from the excess acid in the
tissues. The acid is then neutralized resulting in the pin and needle sensation subsiding.
Respiratory acidosis is usually caused by insufficient respirations or air exchange. This can be caused by head or chest trauma
and respiratory diseases such as emphysema. In cases of emphysema, the lungs cannot perform normally due to an increase of
dead air space. Acidosis develops slowly over a period of time. These are usually treated with bronchodilators and small amounts
of oxygen to increase air exchange in the lungs. With a severe decrease in breathing caused by trauma or respiratory arrest,
the amount of acid quickly increases. Adequate measures need to be taken to treat the cause. Metabolic alkalosis occurs when
too much acid is excreted from the body. This can be caused by eliminating too much fluid by frequent urination, by excessive
vomiting, or various diseases. If the body becomes too alkalitic, the nervous system and the heart can be affected. The heart
may speed up and become irritable while breathing slows in order to compensate. By slowing respirations, less acid is "blown off"
from the lungs. This is in contrast to hyperventilation often seen in metabolic acidosis. Metabolic alkalosis is treated based on
findings from laboratory tests.
Respiratory alkalosis is caused when the body is stressed. Some of the causes include shock, sepsis, trauma and asthma. Too
much acid is "blown off" from increased respirations or hyperventilation. In cases of hyperventilation of psychogenic origin, the
increase in alkalosis causes the tingly sensation around the mouth and in the fingertips. Because of hyperventilation, blood is
slowed to the brain so the respiratory center tells the body to increase respirations. In psychogenic hyperventilation, the
symptoms of tingling and feeling of smothering continue to worsen. Treatment of respiratory alkalosis is basically to treat the
cause. This can include the simple paper bag method for psychogenic hyperventilation, to using sedation to slow respiration. By
slowing the breathing, the blood flow is returned to the brain. This allows the respiratory center to regulate itself and get the
levels back to normal. Interesting, in psychogenic hyperventilation, if the person continues to hyperventilate, they often pass
out. Respirations slow and return to normal, in turn the body gets back to normal.
14
College Prep Unit 2:
Please answer the following questions below and underline the answers in the above reading.
1.
How can water in our body be compared to swimming pools?
2.
What is acidosis?
3.
What is alkalosis?
4.
How does the body ensure that our pH stays between 7.35 & 7.45?
5.
What are 2 ways the body releases the acids that build up from day to day activities?
6.
What is the primary buffer in the blood system?
7.
What are 3 causes for acidosis to occur in our bodies?
8.
Explain what occurs when our legs ‘fall asleep,’ using the word acidosis, acid, and blood flow.
9.
What are 3 causes for alkalosis to occur in our bodies?
10. How can our bodies be affected by alkalosis?
Biochemistry
15
The Concept of pH: RECAP
Acid = _______________________________________________________________________________________
Base = _______________________________________________________________________________________
Indicator =________________________________________________________________________________
Sketch a pH scale
pH scale
_______________________________________________________________________________________
pH in the Body
Blood: ________________
Cells:
___________________
Stomach:
______________
Buffer = _______________________________________________________________________________________
Alkalosis = _________________________________________________________________________________
Acidosis =
_______________________________________________________________________________
Acidosis can be caused by …
1) Breakdown of sugar produces ___________________________ as a waste product which reacts with water to
form _____________________________________________. Older people with poor circulation cannot get rid of
this substance fast enough and therefore experience acidosis.
2) When working out, if oxygen can’t get to cell fast enough, the cells start breaking down sugar without using
oxygen. This can occur in _______________________ tissue and results in
_______________________________ being produced.
3) Breakdown of fats releases acidic __________________________________. When fats are broken down
quickly, these molecules cannot decompose fast enough and therefore build up in the body.
16
College Prep Unit 2:
Section 5.1: Carbon Compounds
1. Distinguish between organic and inorganic molecules. Give some examples.
2. How many electrons does carbon have? How does this affect its bonding ability?
3.
What shapes can carbon molecules make?
4. Why are functional groups important in organic compounds? Name four common functional groups and their
structural formulas. What does Hydrophilic mean and how does it pertain to functional groups?
5. How are monomers, polymers and macromolecules related to one another?
6. What are the four major categories of macromolecules (large molecules)?
7. Explain a dehydration (condensation) reaction and hydrolysis reaction.
Section 5.2: Carbon
1. What are carbohydrates (include element ratios) and list 3 different types.
2. What are the 3 most common monosaccharides? Where are they found? What are they used for?
Biochemistry
17
3. Define disaccharide and give an example. What type of reaction (from question 7) is responsible for making
them?
4. Define polysaccharide and give 3 specific examples along with their functions. Describe them in terms of
monomers and polymers.
5.
Are carbohydrates hydrophilic or hydrophobic? Explain
Section 5.3: Lipids
1. What is a lipid? How are they different than carbohydrates? What are they used for?
2. Describe a fat. Distinguish between hydrophobic, hydrophilic, saturated and unsaturated as they
pertain to fatty acids.
3. How are steroids different than other lipids? Give some examples.
Section 5.4: Proteins
1. What makes up a protein? Is it a monomer or a polymer? Describe some of their functions in the body.
2. What are amino acids? How are they similar? How are they different? (Draw this)
18
College Prep Unit 2:
3. Define polypeptide and how they are created.
4. How does the theme of Form and Function relate to proteins? Give examples.
Biochemistry
19
Complete the following chart:
Name of
Macromolecule
Monomers
Proteins
Lipids
Phospholipid
Triglyceride
Carbohydrates
Polysaccharide
Starch
Glycogen
Cellulose
Nucleic Acids
DNA
RNA
20
College Prep Unit 2:
Examples
Elements
Functions/Uses
Enzymes – Organic Catalysts
Chemical reactions make life possible. Hundreds of chemical reactions are involved in a
process as simple as digesting a chocolate bar. If these chemical reactions proceeded too slowly,
not only would the chocolate bar remain in the stomach for a long time, but the ordinary activities of
life would come to a halt as well. Since this is not the case, some substances in the body must be
responsible for speeding up the process.
A substance that speeds up the rate of a chemical reaction is called a catalyst. Catalysts are
NOT changed by the reactions they promote, and therefore they are not used up during the reaction
– they can be used again and again. Catalysts work by lowering the amount of energy, called
activation energy, needed to start a chemical reaction. They do this by either bringing substances
together so less energy is needed to join them or weakening the bonds between atoms or molecules
so less energy is needed to break them apart. Chemists often seek catalysts that will speed up
reactions important to industry. Living organisms have done the industrial chemist one better - they
contain their own special catalysts, which are known as enzymes. Nonliving substances that speed
up chemical reactions are called inorganic catalysts. Catalysts of, relating to or derived from living
organisms are called organic catalysts.
1. Define catalyst:
___________________________________________________________________________
________________________________________________________
2. How do catalysts work?
___________________________________________________________________________
___________________________________________________
3. What is the difference between inorganic and organic substances?
_________________________________________________________________________
_________________________________________________________________________
Most enzymes are proteins that speed up the rate of a chemical reaction. Simple cells may
have as many as 2000 different enzymes, each one catalyzing a different reaction. A single enzyme
molecule can catalyze thousands of substrate reactions each second. Thus, only small amounts of
any enzyme need to be present in a cell at any given time. An enzyme may accelerate a reaction by
10,000,000,000 times!!!! Thus a reaction that might take as long as 1500 years without an enzyme
can be completed in just 5 seconds!
4. What is an enzyme?________________________________________________________
_________________________________________________________________________
Biochemistry
21
Enzymes speed up a reaction by binding to the reactants, which are the substances that enter
into a chemical reaction. The reactants affected by an enzyme are known as substrates. Substrates
bind to enzymes at a region known as the active site. When an enzyme is interacting with its
substrate, they form a temporary union called the enzyme-substrate complex. Enzymes not only
break substrates apart, they also can join two substrates together! The substance(s) that result from
a chemical reaction are called the products.
5. CIRCLE the word reactant and underline its definition.
6. CIRCLE the word substrate and underline its definition.
7. LABEL the substrate (reactant) in the graphic below.
8. LABEL the enzyme-substrate complex below.
9. CIRCLE the word product and underline its definition. LABEL the products.
10. LABEL the enzyme.
Enzymes are very specific. A particular enzyme can catalyze only one particular chemical
reaction involving specific substrates. Scientists theorize that this has something to do with the
shape of an enzyme’s active site. In fact, the fit between an enzyme’s active site and its substrate is
often compared to that of a lock and a key. This phenomenon is called enzyme specificity.
11. How is shape important to an enzyme’s function?
_______________________________________________________________________
_______________________________________________________________________
12. Describe enzyme specificity in your own words:
_______________________________________________________________________
_______________________________________________________________________
It will help you to remember that the names of enzymes usually end with the suffix -ase. The
rest of the name is often derived from the name of the substrate. For example, enzymes that break
down proteins are called proteases. Enzymes that break down lipids are called lipases.
13. Circle the substances that is NOT an enzyme from the list below.
protease, peroxidase, ethanol, catalase, amylase
22
College Prep Unit 2:
Investigating The Action of Peroxidase
Name:
Observation:
Questions:
_________________________
______ / 50 points
Enzymes speed up chemical reactions.
a) What is the basic action of the enzyme peroxidase in living organisms?
b) Do enzymes change during a normal chemical reaction or are they
reusable?
c) Does a particular enzyme react with all substances?
Research:
Refer to the Enzyme NOTES during this lab!
In this lab, you will study an enzyme that is found in the cells of many living tissues (including
chicken liver!). The name of the enzyme is peroxidase; it speeds up a reaction that breaks
down hydrogen peroxide, a toxic chemical into water and oxygen. This reaction is important to
cells because hydrogen peroxide (H2O2) is toxic but is produced as a byproduct of many normal
cellular reactions. If cells did not break down the hydrogen peroxide, they would be poisoned
and die.
a) What is the overall function of an enzyme? (1 pt)
_________________________________________________________________________
_________________________________________________________________________
Hypotheses:
Propose a hypothesis for each of the questions asked in the beginning of the lab. Each
hypothesis should include reference to both the independent and dependent variables. It
should state what will happen. Be certain to use "if" and "then". (2 pts each = 6 pts)
a. _________________________________________________________________________
_________________________________________________________________________
b. _________________________________________________________________________
_________________________________________________________________________
c. _________________________________________________________________________
_________________________________________________________________________
Materials:
3% hydrogen peroxide
fresh liver
test tubes
test-tube holder
Biochemistry
23
Methods:
PART A – THE BASIC ACTION OF PEROXIDASE
1. Pour about 1 cm of hydrogen peroxide into a clean test tube.
2. Using forceps and scissors, cut off a SMALL (pea-sized) piece of liver and add it to the test
tube.
3. Record ALL observations in results section a. Observe for at least 5 minutes. Describe
what is happening in your test tube.
4. When the reaction is COMPLETELY finished, move onto part B.
5. While you are waiting, do part C.
PART B – ARE ENZYMES REUSABLE?
6. Pour off the liquid into another test tube marked B. Leave the liver in test tube A.
7. Add another SMALL (pea-sized) piece of liver to tube B. Record results section B.
8. Add about 1 cm of hydrogen peroxide to the liver remaining in test tube A. Describe what
you observe in results section B.
9. Clean both test tubes well.
PART C – CAN PEROXIDASE REACT WITH OTHER SUBSTANCES?
10. Carbon dioxide is also produced as a result of cellular reactions. Obtain a test tube and fill it
with 1 cm of water.
11. Blow through a straw into the water for 30 seconds to accumulate carbon dioxide.
12. Add a small piece of liver to see if the liver will react to the carbon dioxide and record your
results in results section C.
13. Then, in a clean test tube, combine alcohol and liver. Does peroxidase react with alcohol?
Record your results.
14. Before leaving the lab, clean up all your materials, clean test tubes, wipe area and wash
hands thoroughly!!! Failure to complete this part will result in lost points!!
Results:
A
B
TUBE A
C
24
College Prep Unit 2:
TUBE B
INDIVIDUAL Analysis Questions: (33 pts)
 For this lab we will be answering analysis questions INSTEAD of writing a discussion.
 Answer using COMPLETE sentences when applicable. EXPLAIN your results
CONCISELY!
 Please do not use personal pronouns (I, you, we, our group) in your answers.
 Complete these by yourself!!!!
1. (1 pt) What was the OVERALL GENERAL purpose of this lab – parts A, B and C?
______________________________________________________________________
2. (2 pts) What is an enzyme and generally how does it work?
______________________________________________________________________
______________________________________________________________________
3. (1 pt) What was the ENZYME used in this lab? _________________________________
4. (1 pt) What was the SOURCE of the enzyme? _________________________________
5. (1 pt) What was the SUBSTRATE?
_________________________________
6. (2 pts) What does this particular enzyme do specifically? Why does this benefit us? (See
background section).
_________________________________________________
_________________________________________________________________________
_________________________________________________________________________
7. (1 pt) What was the purpose for part A? ______________________________________
_________________________________________________________________________
8. (2 pts) Analyze your hypothesis for part A. Was it correct or not and explain.
_________________________________________________________________________
_________________________________________________________________________
9. (1 pt) What gas is released in part A?
______________________________________
10. (1 pt) What was the liquid left after the reaction in part A?
______________________
11. (1 pt) What was the purpose for part B? ______________________________________
_________________________________________________________________________
_________________________________________________________________________
12. (2 pts) Analyze your hypothesis for part B. Was it correct? Why or why not?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Biochemistry
25
(4 pts) Are enzymes reusable OR do they change during a chemical reaction? Incorporate
your observations as you answer the question.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
13. (2 pts) Explain why there was no reaction in the tube with the new liver and the old
hydrogen peroxide. _____________________________________________________
________________________________________________________________________
________________________________________________________________________
14. (1 pt) What was the purpose for part C? _____________________________________
_____________________________________________________________________
_____________________________________________________________________
15. (2 pts) Analyze your hypothesis for part C.
Was it correct or incorrect and why.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
16. (4 pts) Based on your observations in part C, does peroxidase react with other
substances or just hydrogen peroxide? Explain in detail using information from your
notes. Incorporate results.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
17. (2 pts) Name and define the term that is used to describe the phenomenon you just
explained in #16. Hint: It's in your Enzyme notes!
_____________________
________________________________________________________________________
________________________________________________________________________
26
College Prep Unit 2:
ENZYME LAB EXTENSION
Objective:
Investigate how environmental changes affect the enzyme functions.
Procedure:
1. Choose one slip per group from the front desk. That slip will give one factor that you
must change for the enzyme.
2. Design an experiment to test how the environmental change (IV) you selected will affect
the action of the enzyme.
3. Write a separate report including your hypothesis, procedure, and a one paragraph
conclusion describing the lab using the following terms:
Form and function, shape, denaturation, pH or heat, enzyme activity.
Use the space below and on the back to create a rough draft of your experiment and report.
Independent Variable:
_____________________________________________
Dependant Variable:
_____________________________________________
Hypothesis: _________________________________________________________
_________________________________________________________
What materials will you need?
Use the back of this paper to write your rough procedure.
Biochemistry
27
Biochemistry Review- CP Bio
Directions: These concepts are important for your test. Use a separate sheet of paper to complete
this review.
I. Matter
7
N
Nitrogen
14.012
a.
b.
c.
d.
What is the Atomic number of N?
Give the number of protons, neutrons, and electrons.
Give the number of electrons in outer shell.
Differentiate Ionic vs. Covalent bonding using a Venn diagram.
II. Water
a. Define polarity. Draw a water molecule and show its polarity.
b. Compare and contrast cohesion vs adhesion.
c. Compare and contrast capillary action and transpiration
d. List 3 unique properties of water and describe how they allow for life.
III. pH
a. Differentiate between acids and bases.
a. What type of ions are in each?
b. pH scale- What does it go from and how much is each step?
c. Define buffers.
IV. Macromolecules- name the building blocks (monomers) as well as any special properties
a. Carbohydrates
b. Lipids
c. Proteins
d. Nucleic acids
e. Vocab: glucose, amino acids, saturated, nonsaturated, fatty acid chains, glycerol,
nucleotides.
V. Enzymes
a. What is the difference between “catalyst” and “enzyme”?
b. Describe enzyme specificity.
c. What are enzymes made of?
d. Why does form and function matter in enzymes?
i. What happens to enzymes if they are heated or if the pH is changed?
28
College Prep Unit 2: