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3.00_Chemistry of Biology
Biology I
Biochemistry, Atoms,
Subatomic Particles, Elements
Slides 1-28
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CHEMISTRY FOR BIOLOGY
The Chemical Context of Life
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Why Are We Studying Chemistry
• Biology has chemistry at its foundation
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What is Biochemistry?
• Biochemistry = chemistry of life.
• Biochemists use physical and chemical
principles to explain biology at the
molecular level.
• Basic principles of biochemistry are
common to all living organism
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How Does Biochemistry Impact You?
• Medicine
• Agriculture
• Industrial applications
• Environmental applications
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Principle Areas of Biochemistry
• Structure and function of biological
macromolecules
• Metabolism – anabolic and catabolic
processes.
• Molecular Genetics – How life is
replicated. Regulation of protein
synthesis
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Chemistry of Life
• Atoms, Elements, & Compounds
• Chemical Reactions
• Water and Solutions
• The Building Blocks of Life
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Chemistry of Life
• Elements: simplest form of a substance cannot be broken down any further without
changing what it is
• Atom: the actual basic unit - composed of
protons, neutrons, and electrons of atoms =
elements
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Atom
• Chemistry is the study of matter.
• Atoms are the building blocks of matter.
• Neutrons and protons are located at the
center of the atom called the nucleus.
• Protons are positively charged particles (p+).
• Neutrons are particles that have no charge
(n0).
• Electrons are negatively charged particles
that are located outside the nucleus (e-).
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The Basics
• Everything is made of matter
• Matter is made of atoms
• Atoms are made of:
– protons
+
mass of 1
nucleus
– neutrons
0
mass of 1
nucleus
– electrons
mass <<1
orbits
• Just like cells are the basic unit of life, the ATOM
is the basic unit of matter.
• They are very small. If placed side by side one
million would stretch a distance of 1cm.
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• Different kinds of atoms = elements
Atoms
• Atoms have 3 components: protons, neutrons, and electrons
– The type of element (carbon, iron, etc. ) is entirely determined by how
many protons are in the nucleus.
• protons and neutrons are in the nucleus
– Protons have a +1 charge
– Neutrons have no charge
• Electrons circle around the nucleus, in a series of shells.
– Electrons have a -1 charge
– Chemical bonds are created by movements of the electrons between
atoms
• The number of protons determines which element the atom is.
– Hydrogen: 1 proton, carbon = 6 protons, oxygen = 8 protons.
– Biological and chemical processes never change the number of
protons in any atom.
• Normally, the number of electrons is equal to the number of protons, so 11
the atom has no electrical charge: it is neutral.
Atomic structure determines behavior
• The number of protons in an atom
determines the element
– # of protons = atomic number
– this also tells you # of electrons
• All atoms of an element have same
chemical properties
– all behave the same
– properties don’t change
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Subatomic Particles
• Quarks
– component of
protons &
neutrons
– 6 types
3 quarks =
1 proton or
1 neutron
He
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Atoms
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Models of Atom
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Electrons
• Electrons are not present within the nucleus,
instead THEY REVOLVE AROUND THE
NUCELUS OF THE ATOM & FORM THE
ELECTRON CLOUD
NEUTRONS
ELECTRONS
PROTONS
ATOMIC # = 2
(PROTONS)
+ +
-
ATOMIC MASS = 4
(PROTONS &
NEUTRONS)
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Atoms
The weight of one
proton or neutron.
Amu-stands
for atomic
mass unit. It's
a very small
unit of mass
used to express
the mass of
atoms and
molecules,
conceptually
equal to 1
gram divided
by Avogadro’s
constant.
An atomic
mass unit is
approximately
1/12 the mass
of an atom of
carbon-12.
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https://www.delsearegional.us/Academic/Classes/highschool/science/chemistry/firstyear/Notes/academic/Unit02/slideshow
s/atomicstructure.html
Electron Cloud
In the 1920’s scientists determined that electrons do
not orbit the nucleus like planets. Instead, they can
be found anywhere in a cloudlike region around the
nucleus. (the cloud is a visual model)
An electron’s movement is related to its energy
level. or specific amount of energy it has.
Electrons of different energy levels are likely to be
found in different places of the ‘cloud’.
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Modern Model
The modern model describes an atom as consisting of
a nucleus that contains protons and neutrons,
surrounded by a cloud-like region of moving
electrons.
The number of protons always equals the number of
electrons. This ensures that the overall atom is
neutral.
The number of neutrons does not have to equal the
number of protons. Neutrons don’t affect the charge
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of an atom because they have no charge.
Particle Masses Compared
It takes almost 2000 electrons to equal the mass of just
one proton.
A proton and a neutron are about equal in mass.
Atoms are too small to describe with everyday units of
mass (grams, kilograms). Scientists use units known as
Atomic Mass Units (AMU) to describe the mass of
atoms and its particles.
A proton or neutron has a mass equal to about one amu
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(atomic mass unit).
Scale & Size of Atoms
Most of the volume of an atom is the space in
which the electrons move (electron cloud).
The nucleus is extremely small compared to
the size of the overall atom.
In a speck of dust there may be 10 million
billion atoms.
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Atomic Number
Every atom of an element has the same
number of protons. Ex/ Every atom of
carbon (C) has 6 protons.
The number of protons in the nucleus is
called the Atomic Number.
Atomic number identifies an element.
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Elements
• An element is a pure substance that cannot be
broken down into other substances by physical
or chemical means.
• There are 118 known elements, 92 of which
occur naturally.
• Each element has a unique name and symbol.
• All of this data, and more, are collected in an
organized table called the periodic table of
elements.
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Elements
An element is a pure substance that cannot be
broken down into other substances by physical or
chemical means.
There are 118 known elements, 90 of which occur
naturally.
25 were synthesized (made) by scientists
Each element has a unique name and symbol.
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Life requires – 25 chemical elements
• About 25 elements are essential for life
– Four elements make up 96% of living matter:
• carbon (C)
• oxygen (O)
• hydrogen (H)
• nitrogen (N)
– Four elements make up most of
remaining 4%:
• phosphorus (P) • calcium (Ca)
• sulfur (S)
• potassium (K)
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Naturally Occurring Elements in Human Body
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Elements Song
http://www.privatehand.com/flash/elements.html
https://www.youtube.com/watch?v=zGM-wSKFBpo
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Elements Song
The NEW Periodic Table Song (Updated)
https://www.youtube.com/watch?v=VgVQKCcfwnU
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