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Lecture Presentation by
Patty Bostwick-Taylor
Florence-Darlington Technical College
Modified by Janice Alvarez, QRMHS
Chapter 2
Basic Chemistry
© 2015 Pearson Education, Inc.
Energy can change the position, physical composition,
or temperature of matter
What again is matter?
Matter and Energy
Matter and Energy
Matter—anything that occupies space and has mass
Matter may exist as one of three states:
Solid: definite shape and volume
Liquid: definite volume; shape of container
Gaseous: neither a definite shape nor volume
Matter and Energy
Matter may be changed
Physically
Changes do not alter
the basic nature of a
substance
Chemically
Changes alter the
chemical composition
of a substance
Forms of Energy
Chemical energy is
stored in chemical bonds
Electrical energy
results from movement
of charged particles
Mechanical energy is
energy directly involved
in moving matter
Radiant energy travels
in waves (light/heat)
Matter and Energy
Energy—the ability to do work.
Has no mass and does not take up space
Kinetic energy: energy is doing work
Potential energy: energy is inactive; stored
Identify examples of
potential and kinetic
energy in these pictures.
Potential and kinetic energy
Potential energy stored in food is converted
to kinetic energy when we exercise.
Work Day Assignment
Read Text p.24-26; take notes. Matter and Energy
Workbook p. 17-18
Done Early? Read ahead: p27-30 WBp18-19
Composition of Matter
Atoms
Building blocks of elements
Atoms of elements differ from one another
Atomic symbol is chemical shorthand for each element
Composition of Matter
96 percent of the body is made from four elements:
Oxygen (O)
Carbon (C)
Hydrogen (H)
Nitrogen (N)
Identifying Elements
Atomic number—equal to the number of protons
that the atom contains
Unique to atoms of a particular element
Indirectly tells the number of electrons in an atom
Atomic mass number—sum of the protons and
neutrons contained in an atom’s nucleus
Chemistry of Life
There are 92 naturally occurring elements.
Of those 92 elements, 25 are essential to life!
An Element Consists of One Kind of Atom
What makes up an atom?
Protons +Neutrons
Electrons -
Nucleus
Subatomic Particles
Electrons determine an atom’s chemical behavior
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(a) Hydrogen (H)
(1p+; 0n0; 1e–)
(b) Helium (He)
(2p+; 2n0; 2e–)
(c) Lithium (Li)
(3p+; 4n0; 3e–)
KEY:
Proton
Neutron
Electron
Electrons determine an atom’s chemical behavior
Electron Shells
An atom is considered stable when their
outer shells are filled to capacity.
Octet Rule
Atoms of the same element that differ in the number of neutrons are called isotopes.
protons + neutrons in nucleus = atomic mass
Isotopes are identified by their mass numbers.
C-14
Isotopes and Atomic Weight
Radioactivity
Radioisotope
Heavy isotope of certain atoms
Tends to be unstable
Decomposes to more stable isotope
Radioactivity—process of spontaneous atomic decay
Molecules and Compounds
Molecule—two or more atoms of the same elements
combined chemically
Compound—two or more atoms of different
elements combined chemically to form a molecule
of a compoundALL COMPOUNDS
ARE MOLECULES
BUT NOT ALL MOLECULES
ARE COMPOUNDS!!!
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Sodium(silvery metal)
Chlorine(poisonous gas)
Sodium chloride (table salt)
Molecules and Compounds
Properties of a compound differ from those of its atoms.
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Chemical Reactions
Chemical reactions occur when atoms combine with
or dissociate from other atoms
Atoms are united by chemical bonds
Atoms dissociate from other atoms when chemical
bonds are broken
Electrons and Bonding
How atoms interact with each other depends on
their valence electrons
Bonding involves only interactions between
electrons in the outer (valence) shell
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Electrons and Bonding
Atoms with full valence shells do not form bonds
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(a) Chemically inert elements
Outermost energy level
(valence shell) complete
2e
He
2e
Ne
8e
Helium (He) Neon (Ne)
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Reactive Elements
Valence shell is incomplete
Atoms will gain, lose, or
share electrons to
complete their outer shell
Atoms reach stable state
Bond formation = stable
valence shell
(b) Chemically reactive elements
Outermost energy level
(valence shell) incomplete
1e
H
Hydrogen (H)
(1p+; 0n0; 1e–)
C
2e4e
Carbon (C)
(6p+; 6n0; 6e–)
O
2e6e
Oxygen (O)
(8p+; 8n0; 8e–)
Na
2e8e
1e
Sodium (Na)
(11p+; 12n0; 11e–)
Chemical Bonds
3 types of chemical bonds Ionic Bonds – when one or more electrons are
transferred from one atom to the other.
Covalent Bonds – when electrons are shared between atoms.
Hydrogen Bonds – weak electrical attraction between molecules .
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Chemical Bonds
Ionic bonds
Electrons are completely
transferred from one atom
to another
Chemical Bonds
Ions: charged atoms
Result from the loss or gain of electrons
Anions - negatively charged ion (gained electron(s))
Cations - positively charged ion (lost electron(s))
Opposite charges attract form ionic bonds
CATION ANION
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Chemical Bonds
Covalent bonds
Atoms become stable through shared electrons
Electrons are shared in pairs
Single covalent bonds share one pair of electrons
Double covalent bonds share two pairs of electrons
Reacting atoms
(b) Formation of a double covalent bond
Resulting molecules
OO
Oxygen atom Oxygen atom
or
Molecule of oxygen gas (O2)
O O
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Covalent Bonds
Covalent bonds are either nonpolar or polar
Nonpolar
Electrons are shared equally between the atoms of
the molecule
Electrically neutral as a molecule
Example: carbon dioxide
Carbon dioxide (CO2)
Covalent Bonds
Covalent bonds are either nonpolar or polar
Polar
Electrons are not shared equally between the atoms
of the molecule
Molecule has a positive and negative side, or pole
Example: water
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Water (H2O)
δ–
δ+δ+
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Hydrogen Bonds
Weak chemical bonds
Hydrogen is attracted to the negative portion of a
polar molecule
Responsible for the surface tension of water
Important for forming intramolecular bonds, as in
protein structure
Anabolic Chemical Reactions
Synthesis reaction (A B AB)
Atoms or molecules combine
Energy is absorbed in bonds
Anabolic activities in the body
Building polymers
Growth
Repair
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(a) Synthesis reactions
Smaller particles are
bonded together to form
larger, more complex
molecules.
Example
Amino acids are joined
together to form a protein
molecule.
Amino acid
molecules
Protein
molecule
Anabolic Chemical Reactions
Dehydration synthesis
Remove water to join two molecules
Take out a hydrogen ion [H+]
Take out a hydroxyl group [OH-]
Monomers unite, and water is released
Repeat to form polymers
Catabolic Chemical Reactions
Decomposition reaction
(AB A B)
Molecule is broken down
Chemical energy is released
Catabolic activities in body
Digestion
Energy release
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Decomposition reactions
Bonds are broken in larger
molecules, resulting in
smaller, less complex
molecules.
Example
Glycogen is broken down to
release glucose units.
Glucose molecules
Glycogen
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Catabolic Chemical Reactions
Hydrolysis
Polymers (large molecules) are broken into monomers
Water molecules are added to break the bonds
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Patterns of Chemical Reactions
Most chemical reactions are reversible
Reversibility is indicated by a double arrow
Biochemistry: Essentials for Life
Inorganic compounds
Lack carbon
Tend to be small, simple molecules
Include water, salts, and some acids and bases
Organic compounds
Contain carbon
All are large, covalently bonded molecules
Include carbohydrates, lipids, proteins, and nucleic
acids
Water is the medium for chemical reactions in your body used to sustain life!
Important Inorganic Compounds
Water
Most abundant inorganic compound in the body
Vital properties
1. High heat capacity
2. Polarity/solvent properties
3. Chemical reactivity
4. Cushioning
Important Inorganic Compounds
Hydrogen Bonds!!
Water’s Vital Properties
1. High heat capacity:
Water absorbs and releases a large amount of heat
before it changes temperature
Prevents sudden changes in body temperature
How Water Moderates Temperature
Water heated = hydrogen bonds break = water absorbs and stores large amounts of heat while warming up only a few degrees.
Water cooled = hydrogen bonds form = release heat = water releases large amount of heat while the water temperature drops only slightly.
Solution – a mixture of two or more substances where the molecules are evenly distributed (homogenous), forming an aqueous solution.
Solute (salt)
Solvent (water)
Water’s Vital Properties:
2. Polarity / Solvent Properties
Water as the Solvent of Life!!
When Salt Dissolves in Water
Water Molecule
Water is considered the “UNIVERSAL SOLVENT”,
dissolving other polar and ionic
compounds
3. Chemical reactivity
Water is an important reactant in chemical reactions
Hydrolysis reactions require water
helps digest food
breaks down biological molecules
Water’s Vital Properties
Important Inorganic Compounds
4. Cushioning
Water serves a protective function
cerebrospinal fluid protects the brain from trauma
amniotic fluid protects a developing fetus
Important Inorganic Compounds
Salts (electrolytes – ions that conduct electrical charge)
Contain cations and anions other than H+ and OH–
Easily dissociates into ions when in water
Vital to many body functions
sodium and potassium ions aide nerve impulses
Important Inorganic Compounds
Acids (Acidic)
Release hydrogen ions (H+) when dissolved in water
Example: HCl H+ Cl–
Are proton donors
hydrogen ions are essentially just protons
Strong acids ionize completely; liberate all protons
Weak acids ionize incompletely
Important Inorganic Compounds
Bases (Alkaline)
Release hydroxyl ions (OH–) when dissolved in water
Are proton acceptors
Example: NaOH Na+ + OH–
Strong bases seek hydrogen ions
Important Inorganic Compounds
Neutralization reaction
Acids and bases react to form water and a salt
Example: NaOH HCl H2O NaCl
Acids, Bases and pH
H2O (H+) + (OH-)
Water (hydrogen ion) + (hydroxide ion)
more (H+) ions
more (OH-) ions
pH – “The Rules”
Measures relative concentration of hydrogen ions
Based on the number of protons in a solution,
expressed in terms of moles per liter
Each successive change on the pH scale
represents a tenfold change in H concentration
pH
pH 7 neutral [H+] = [OH-]
pH below 7 acidic [H+] > [OH-]
pH above 7 basic/alkaline [H+] < [OH-]
Buffers—chemicals that can regulate pH change
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pH
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Acidic
solution
Neutral
solution
Basic
solution
OH–
OH–
OH–
OH–OH–
OH–
H+
H+
H+
H+H+
H+
OH–
OH–
OH–
OH–
H+
H+
H+H+
H+
H+OH–
OH–
In
cre
asin
gly b
asic
In
cre
asin
gly a
cid
ic
Ne
utra
l
[H
+]=[O
H–]
Examples
1M Sodium hydroxide (pH 14)
Oven cleaner, lye
(pH 13.5)
Household ammonia
(pH 10.5–11.5)
Household bleach
(pH 9.5)
Egg white (pH 8)
Blood (pH 7.4)
Milk (pH 6.3–6.6)
Black coffee (pH 5)
Wine (pH 2.5–3.5)
Lemon juice, gastric juice
(pH 2)
1M Hydrochloric acid (pH 0)
Assignment
Due Friday: Read Text pg. 26-41; take notes. Chemistry – Atoms, Molecules, Bonds, Reactivity Biochemistry – Water, Salts, pH
Workbook pg. 19-22
Done Early? Read ahead: Ch 2 (all) and Workbook up to p.27
Chemical Reactions
Many biological
molecules are
polymers, such as
carbohydrates and
proteins
Polymer: chainlike
molecule made of
many similar or
repeating units
(monomers)
Carbon Compounds:Biological MoleculesChemistry of Carbon - Organic chemistry is the study of all compounds that contain bonds between carbon atoms.
The most versatile element!
Carbon Compounds
Carbon can form single, double or triple bonds with other elements. Each line represents 1 covalent bond (2 electrons).
methane
acetylene benzene
“Giant Molecules”
Macromolecules, or “giant molecules” are formed from monomers, small units that are joined together to form polymers, by a process called polymerization.
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Important Organic Compounds
Carbohydrates
Contain carbon, hydrogen, and oxygen
Include sugars and starches
Classified according to size
Monosaccharides—simple sugars
Disaccharides—two simple sugars joined by
dehydration synthesis
Polysaccharides—long-branching chains of linked
simple sugars
Carbohydrates
Monosaccharides—simple sugars
Single chain or single-ring structures
Contain 3 to 7 carbon atoms
Examples: glucose (blood sugar), fructose,
galactose, ribose, deoxyribose
Carbohydrates
Disaccharides—two simple sugars joined by
dehydration synthesis
Examples include sucrose, lactose, and maltose
Important Organic Compounds
Lipids
Most abundant are
Triglycerides
Phospholipids
Steroids
Contain C, H, O
C and H outnumber O
Insoluble in water, but soluble in other lipids
Lipids
Made mostly from carbon and hydrogen – C, H
Used to…
store energy
form biological membranes
as waterproof covering
as chemical messengers
Lipids
Common lipids in the human body
Neutral fats (triglycerides)
Found in fat deposits
Source of stored energy
Has three fatty acids and one glycerol molecule
Saturated fatty acids
Unsaturated fatty acids
Lipids – Good and Bad Fats in Your Diet
Trans fats
Oils solidified by the addition of hydrogen atoms at
double bond sites
Increase risk of heart disease
Lipids – Good and Bad Fats in Your Diet
Omega-3 fatty acids
Found in cold-water fish and plant sources,
flax, pumpkin, and chia seeds; walnuts and soy foods
Appears to decrease risk of heart disease
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Lipids
Common lipids in the human body (continued)
Phospholipids
Contain two fatty acids rather than three
Phosphorus-containing “head” carries an electrical
charge and is polar
Charged region interacts with water and ions while the
fatty acid chains (“tails”) do not
Form cell membranes
Lipids
Common lipids in the human body (continued)
Steroids
Formed of four interlocking rings
cholesterol, bile salts, vitamin D, and some hormones
Some cholesterol is ingested from animal products.
The liver also makes cholesterol
Cholesterol is the basis for all steroids made in the body
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Nucleic Acids
Nucleic acids store and transmit hereditary, or genetic, information.
ribonucleic acid (RNA)
deoxyribonucleic acid (DNA)
Nucleic Acids
Nucleotides are made out of H, O, N, C and P and they contain three parts:
a 5-carbon sugar
a phosphate group
a nitrogenous base
Monomer of nucleic acid
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Important Organic Compounds
Nucleic acids
Make up genes
Composed of carbon, oxygen, hydrogen, nitrogen,
and phosphorus atoms
Largest biological molecules in the body
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Nucleic Acids
Built from nucleotides containing three parts:
1. A nitrogenous base
A Adenine
G Guanine
C Cytosine
T Thymine
U Uracil
2. Pentose (five-carbon) sugar
3. A phosphate group
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Nucleic Acids
Deoxyribonucleic acid (DNA)
The genetic material found within the cell’s nucleus
Provides instructions for every protein in the body
Organized by complimentary bases to form a double-
stranded helix
Contains the sugar deoxyribose and the bases
adenine, thymine, cytosine, and guanine
Replicates before cell division
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Nucleic Acids
Ribonucleic acid (RNA)
Carries out DNA’s instructions for protein synthesis
Created from a template of DNA
Organized by complementary bases to form a single-
stranded helix
Contains the sugar ribose and the bases adenine,
uracil, cytosine, and guanine
Three varieties are messenger, transfer, and
ribosomal RNA
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Nucleic Acids
Adenosine triphosphate (ATP)
Composed of a nucleotide built from ribose sugar,
adenine base, and three phosphate groups
Chemical energy used by all cells
Energy is released by breaking high-energy
phosphate bond
ATP is replenished by oxidation of food fuels
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Figure 2.22 ATP—structure and hydrolysis.
(a) Adenosine triphosphate (ATP)
Adenine
(b) Hydrolysis of ATP
Highenergybonds
Phosphates
Ribose
ATP
P P P
P P P
H2O
P P
Adenosine diphosphate
(ADP)
Pi Energy
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Nucleic Acids
ADP (adenosine
diphosphate)
accumulates as ATP
is used for energy
Three examples of
how ATP drives
cellular work are
shown next
(a) Chemical work. ATP provides the energy
needed to drive energy-absorbing chemical
reactions.
ATP
Pi
Solute
Pi
PiP
A B
ADP
ADPATP
ATP
Pi
ADP
P PiMembrane
protein
Relaxed smooth
muscle cell
Contracted smooth
muscle cell
(b) Transport work. ATP drives the transport
of certain solutes (amino acids, for example)
across cell membranes.
(c) Mechanical work. ATP activates contractile
proteins in muscle cells so that the cells can
shorten and perform mechanical work.
Proteins
Function
Build bones and muscles
Control the rate of reactions – enzymes
Transport substances into or out of cells
Help fight disease - antibodies
Proteins
Contain N, C, H, O and S
Monomers of amino acids form proteins
There are 20 different amino acids that occur
in nature!!
Protein Shape
Up to 4 Levels of Organization
1. Sequence2. Amino acids in the chain are
twisted or folded3. Chain is twisted or folded4. Complex proteins with multiple
chains – each chain has a specific arrangement.
Protein shape is very important!!!!
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Important Organic Compounds
Proteins
Account for over half of the body’s organic matter
Provide for construction materials for body tissues
Play a vital role in cell function
Act as enzymes, hormones, and antibodies
Contain carbon, oxygen, hydrogen, nitrogen, and
sometimes sulfur
Built from amino acids
Proteins
Amino acid structure
Contain an amine group (NH2)
Contain an acid group (COOH)
Vary only by R groups
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Figure 2.17 Amino acid structures.
(b) Glycine is
the simplest
amino acid.
(a) Generalized
structure of
all amino
acids.
(c) Aspartic acid
(an acidic
amino acid)
has an acid
group (—COOH)
in the R group.
(d) Lysine (a
basic amino
acid) has an
amine group
(—NH2) in the
R group.
(e) Cysteine (a
basic amino
acid) has a
sulfhydryl
(—SH) group in
the R group,
which suggests
that this amino
acid is likely to
participate in
intramolecular
bonding.
Amine
group
Acid
group
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Proteins
Protein structure
Polypeptides contain fewer than 50 amino acids
Large proteins may have 50 to thousands of amino
acids
Sequence of amino acids produces a variety of
proteins
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Proteins
Structural levels of proteins
Primary structure
Secondary structure
Alpha helix
Beta-pleated sheet
Tertiary structure
Quaternary structure
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Figure 2.18a The four levels of protein structure.
(a) Primary structure. A protein’s
primary structure is the unique
sequence of amino acids in the
polypeptide chain.
Amino
acids
CysGlu Leu Ala Ala
AlaAla
Met Lys Arg His Gly Leu Aps
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Figure 2.18b The four levels of protein structure.
(b) Secondary structure. Two types of secondary structure are the
alpha-helix and beta-pleated sheet. Secondary structure is reinforced
by hydrogen bonds, represented by dashed lines in the figure.
Hydrogen bonds
Alpha-
helix
𝛃-pleated sheet
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Figure 2.18c The four levels of protein structure.
(c) Tertiary structure. The overall three-
dimensional shape of the polypeptide
or protein is called tertiary structure. It is
reinforced by chemical bonds between
the R-groups of amino acids in different
regions of the polypeptide chain.
Polypeptide
(single subunit)
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Figure 2.18d The four levels of protein structure.
(d) Quaternary structure. Some proteins
consist of two or more polypeptide chains.
For example, four polypeptides construct
hemoglobin, the blood protein. Such
proteins have quaternary structure.
Complete protein,
with four polypeptide
subunits
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Proteins
Fibrous (structural) proteins
Appear in body structures
Exhibit secondary, tertiary, or even quaternary
structure
Bind structures together and exist in body tissues
Stable proteins
Examples include collagen and keratin
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Figure 2.19a General structure of (a) a fibrous protein and (b) a globular protein.
(a) Triple helix of collagen
(a fibrous or structural
protein).
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Proteins
Globular (functional) proteins
Function as antibodies, hormones, or enzymes
Exhibit at least tertiary structure
Can be denatured and no longer perform
physiological roles
Active sites “fit” and interact chemically with other
molecules
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Figure 2.19b General structure of (a) a fibrous protein and (b) a globular protein.
Heme group
(b) Hemoglobin molecule composed of
the protein globin and attached heme
groups. (Globin is a globular or
functional protein.)
Globin
protein
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Enzymes
Act as biological catalysts
Increase the rate of chemical reactions
Bind to substrates at an active site to catalyze
reactions
Recognize enzymes by their –ase suffix
Hydrolase
Oxidase
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The enzyme
releases the product
of the reaction.
Figure 2.20 A simplified view of enzyme action.
Substrates (S)
e.g., amino acids
3
The E-S complex
undergoes internal
rearrangements that
form the product.
2Substrates bind at active
site, temporarily forming an
enzyme-substrate complex.
1
Product (P)
e.g., dipeptide
Peptide
bond
Water is
released.
H2O
Energy is
absorbed;
bond is
formed.
Active site
Enzyme (E) Enzyme (E)
Enzyme-substrate
complex (E-S)
Assignment
Due Wed: Read Text p. 42-55; take notes.Organic Compounds
Carbs, Lipids, Nucleic Acids, Proteins, ATP
Workbook p. 23-27
Complete Biological Molecules packet, with partner(s)
Done Early? Read ahead: Ch 3