Chemistry of Life
MCAS Review
Inorganic Chemistry
Types of Bonds
Type
Formed When…
Characteristics
Ionic
Electron is
Transferred
Covalent
Electron is Shared
Between atoms
with different
electronegativity
Very strong bond
Van der Waals
Forces or
Hydrogen
Bonds
Attraction between
oppositely charged
regions of
molecules
Hydrogen bonds
individual = weak
many = strong
Ionic – Electron Transferred
Covalent – Electron Shared
Van der Waals Forces (oppositely
charged regions )
Properties of Water
#1Polarity
• Water molecules have
a slightly negative
charge near the
oxygen atom and a
slightly positive
charge around the
hydrogen atom.
Properties of Water
#2 Universal Solvent
• Water dissolves more
substances than
sulfuric acid because
of its polar
characteristic. It can
surround molecules of
a substance and pull
it apart.
Properties of Water
#3 Cohesion
• Water is attracted to
other water. This is
called cohesion.
Properties of Water
#4 Adhesion
• Water can also be
attracted to other
materials. This is
called adhesion.
Properties of Water
#5 Density
• Ice is less dense
than water which is
why it floats.
It expands as it
freezes
Fish can live in
water during
winter
Properties of Water
• Surface Tension
• Cohesion of water
molecules at the surface
of a body of water causes
the water to pull itself into
a shape with the smallest
amount of surface area
(sphere).
• Surface tension allows
water striders to 'skate'
across the top of a pond.
(Cohesion)
Properties of Water
• Capillary Action
• Adhesive properties of
water. Placing a straw into a
glass of water, it 'climbs' up
the straw. Molecules are
attracted to the straw
molecules (adhesion).
When one water molecule
moves, the other water
molecules follow (cohesion)
• Capillary action is limited by
gravity and the size of the
straw. Plants take
advantage of capillary
action to pull water into the
roots.
Cohesion or Adhesion?
Define Organic!
• Compounds that
contain carbon
atoms that are
covalently bonded
to other elements;
typically:
hydrogen, oxygen,
and other carbon
atoms.
Carbon
Importance of Carbon (C)
# C is in all living Things
# C is necessary for ALL life
# C can bond with other C; giving it the ability to form
long chains or rings
Macromolecules
AKA= “Giant Molecules”
# Made from 100’s to 1000’s of smaller molecules
# Smaller molecules are called “monomers”
# Monomer + Monomer = Polymer
# Polymers are formed by a process called
polymerization
CHNOPS
• The six most common elements that make up
biological organisms are:
Carbon
Oxygen
Hydrogen
Phosphorus
Nitrogen
Sulfur
Categories of Organic Molecles
Molecule
Building Blocks
Examples
Uses
Carbohydrates Monosaccharides Sugars and
CHO
Starches
Quick Energy
Lipids
CHO
Glycerol and
Fatty Acids
Fats, Oils,
Waxes
and
Steroids
Stored Energy
Cell Membranes
Proteins
CHNO
Amino Acids
Muscle
Enzymes
Collagen
Antibodies
Help Carry Out
Cellular Activities
Nucleic Acids
CHNOP
Nucleotides
DNA, RNA
Instructions for all cell
activities
Help make proteins
Carbohydrate (Hydrated Carbon)
Lipids (Glycerol and 3 Fatty Acids)
Saturated / Unsaturated
Protein (Polymers of Amino Acids)
Nucleic Acid (Phosphate, Sugar,
Base aka Pool, House and Barn)
4 Groups of Organic Compounds
Where do we get these molecules?
• From
our
Food!!!
Enzymes
Enzymes
• Enzymes =
Catalysts that speed
up reactions in our
body
• Enzymes have a
specific job – each
fits like a lock and
key with its specific
substrate
How Enzymes Work
Four steps in the process of an enzyme working.
1. An enzyme and a substrate (the biological molecule
that the enzyme will attack) are in the same area.
2. The enzyme grabs onto the substrate with a special
area called the active site which is a specially shaped
area of the enzyme that fits around the substrate. The
active site is the keyhole of the lock.
3. A process called catalysis happens which is when
the substrate is changed ( broken down or combined to
make something new)
4. When the enzyme lets go, it returns to normal, ready
to do another reaction. The substrate is no longer the
same and is now called the product.
Can you stop them????
• Good question!
• There are many
factors that can
regulate enzyme
activity, including
temperature,
activators, pH
levels, and
inhibitors.
pH Scale
MCAS Review Questions
1. Which of the following best explains why enzymes are
necessary for many cellular reactions?
A. Enzymes supply the oxygen necessary for the reactions.
B.
Enzymes change reactants from solid to liquid during the
reactions.
C.
The reactions take up too much space in the cell if
enzymes are missing.
D.
The reactions are too slow to meet the needs of the cell if
enzymes are missing.
1. Which of the following best explains why
enzymes are necessary for many cellular
reactions?
D. The reactions are too slow to meet
the needs of the cell if enzymes are
missing.
2.
Lemurs’ bodies are adapted to efficiently store
energy for times when food is scarce. This
adaptation may help to explain how lemur
ancestors survived the trip across the
Mozambique Channel from mainland Africa to
Madagascar.
Which of the following types of molecules are
primarily used for long-term energy storage in
the lemur?
•
•
•
•
A.lipids
B.monosaccharides
C.nucleic acids
D.proteins
2.
Lemurs’ bodies are adapted to efficiently store
energy for times when food is scarce. This
adaptation may help to explain how lemur
ancestors survived the trip across the
Mozambique Channel from mainland Africa to
Madagascar.
Which of the following types of molecules are
primarily used for long-term energy storage in
the lemur?
• A.lipids
3. In the human body, fibrinogen is necessary for
sealing cuts and stopping the loss of blood. Since
fibrinogen is made of chains of amino acids, it is
an example of which type
•
•
•
•
A.carbohydrate
B.protein
C.fatty acid
D.nucleic acid
3. In the human body, fibrinogen is necessary for sealing
cuts and stopping the loss of blood. Since fibrinogen is
made of chains of amino acids, it is an example of which
type
• B.protein
4. A scientist is analyzing a sample of
tissue from a plant. Which of the following
elements will be most abundant in the
sample?
•
•
•
•
A.zinc and copper
B.sodium and chlorine
C.carbon and hydrogen
D.magnesium and calcium
4. A scientist is analyzing a sample of
tissue from a plant. Which of the following
elements will be most abundant in the
sample?
• C.carbon and hydrogen
5.
Baby food manufacturers sometimes use proteases
in their products. Proteases catalyze the breakdown
of the proteins in these foods, making digestion
easier for infants.
Proteases are which of the following types of
molecules?
•
•
•
•
A.enzymes
B.fatty acids
C.hormones
D.monosaccharides
5.
Baby food manufacturers sometimes use proteases
in their products. Proteases catalyze the breakdown
of the proteins in these foods, making digestion
easier for infants.
Proteases are which of the following types of
molecules?
• A.enzymes
6. Ovalbumin is a protein found in eggs. Which
of the following best describes
the molecular structure of ovalbumin?
• A.a group of six carbon atoms joined in a ring
• B.a chain of amino acids folded and twisted into
a molecule
• C.a set of three fatty acids attached to a
molecule of glycerol
• D.a sequence of nitrogenous bases attached to
a sugar-phosphate backbone
6. Ovalbumin is a protein found in eggs. Which
of the following best describes
the molecular structure of ovalbumin?
• B.a chain of amino acids folded and
twisted into a molecule
7. When lactose is digested by the human body,
each lactose molecule is broken
down into smaller molecules. To which of the
following categories of molecules
do these smaller molecules belong?
•
•
•
•
A.amino acids
B.monosaccharides
C.nucleic acids
D.polypeptides
7. When lactose is digested by the human body,
each lactose molecule is broken
down into smaller molecules. To which of the
following categories of molecules
do these smaller molecules belong?
• B.monosaccharides
8. A diagram of an organic molecule is below
Which element is found at the positions marked by the
dots (•) in the molecule?
•
•
•
•
A.carbon
B.nitrogen
C.phosphorus
D.sulfur
8. A diagram of an organic molecule is below
Which element is found at the positions marked by the
dots (•) in the molecule?
• A.carbon
9. Students in a biology laboratory are monitoring the rate at which hydrogen
peroxide breaks down to produce water and oxygen gas. They begin monitoring a
sample of hydrogen peroxide and then add catalase, an enzyme that speeds up its
breakdown. Their data are shown in the table below.
• Time Rate of
Hydrogen Peroxide
Breakdown(molecules
per
min)0.00.000
0.50.0
30
1.00.032
1.5
4,970,000.000
2.05,
001,000.000
2.54,98
5,300.000
3.05,021,
700.000
9.
Students in a biology laboratory are monitoring the rate at which
hydrogen peroxide breaks down to produce water and oxygen gas.
They begin monitoring a sample of hydrogen peroxide and then add
catalase, an enzyme that speeds up its breakdown. Their data are
shown in the table below.
Based on the data in this table, during which of the following time
periods did the students add the catalase to the hydrogen
peroxide?
A.between 0.0 and 0.5 min
B.between 1.0 and 1.5 min
C.between 2.0 and 2.5 min
D.between 2.5 and 3.0 min
•
Time (min)
•
•
•
•
•
•
0.0
0.5
1.0
1.5
2.0
2.5
Rate of Hydrogen
Peroxide Breakdown(mol/min)
0.000
0.030
0.032
4,970,000.000
5,001,000.000
4,985,300.000
•
3.0
5,021,700.000
9.
Students in a biology laboratory are monitoring the rate at which
hydrogen peroxide breaks down to produce water and oxygen gas.
They begin monitoring a sample of hydrogen peroxide and then add
catalase, an enzyme that speeds up its breakdown. Their data are
shown in the table below.
Based on the data in this table, during which of the following time
periods did the students add the catalase to the hydrogen
peroxide?
B.between 1.0 and 1.5 min
•
Time (min)
•
•
•
•
•
•
0.0
0.5
1.0
1.5
2.0
2.5
Rate of Hydrogen
Peroxide Breakdown(mol/min)
0.000
0.030
0.032
4,970,000.000
5,001,000.000
4,985,300.000
•
3.0
5,021,700.000
10. Some bacteria live in hot springs. Their cells contain
enzymes that function best at temperatures of 70°C or
higher. At a temperature of 50°C, how will the enzymes in
these bacterial cells most likely be affected?
• A.The enzymes will be destroyed
by lysosomes.
• B.The enzymes will lose their
bond structure and fall apart.
• C.The enzymes will require
less energy to function than
at 70°C.
• D.The enzymes will not increase the
rate of reactions as much as they
would at 70°C.
10. Some bacteria live in hot springs. Their cells contain
enzymes that function best at temperatures of 70°C or
higher. At a temperature of 50°C, how will the enzymes in
these bacterial cells most likely be affected?
• D.The enzymes will not increase the
rate of reactions as much as they
would at 70°C.
Define chemical reaction.
• The process during which chemical bonds
between atoms are broken and new ones
are formed, producing one or more
different substances.
Write an example of a chemical reaction and label
the reactants and products.
• Na
• Reactants
→
Na+ + ClProducts
Define activation energy.
• The energy needed to start a chemical
reaction
Define enzyme.
• Proteins that increase the speed of a
chemical reaction
How does an enzyme affect the activation energy
for a chemical reaction?
• Enzymes are catalysts;
they reduce the activation energy needed
for a chemical reaction to take place
Any factors that affect the shape of an enzyme
affect the enzyme’s activity. What effect
does pH and temperature have on an enzymes
ability to catalyze (speed up) a reaction?
• Enzymes work well within very specific
ranges of pH and temperature. If the pH or
temperature changes to outside of the
range, the enzyme shape changes and
thus no longer works to speed up the
reaction.