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Biology
Chemistry,
Matter, and
Life
Chemistry
 Science that deals with composition
and properties of matter
 Used to understand normal and
abnormal functioning of body
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Matter
 Anything that takes up space, has mass, and is
composted predominantly of atoms consisting
of protons, neutrons, and electrons, that
constitutes the observable universe, and that is
interconvertible with energy.
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Elements
•
Substances from which all
matter is made
•
Everything we see & touch
are made of elements
•
There are 92 naturally
occurring elements (20
additional created in Lab)
•
Periodic Table is a chart used
to organize and describe the
elements
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Elements are
Identified by
Chemical Symbols
Oxygen – O
Nitrogen – N
Potassium – K
Chlorine – Cl
Carbon –
C
Calcium – Ca
Sulfur –
Iron Hydrogen Phosphorus
Sodium -
S
Fe
H
-P
Na
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What is the chemical symbol for
potassium?
a. Po
b. Fe
c. K
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Subunits of elements are
_________
Atoms are the smallest complete units of
matter
They cannot be broken down or changed into
another form by ordinary chemical or physical means
Atoms are so small.....millions can fit on a
sharpened end
of a pencil
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Atomic
Structure
• Nucleus
• Protons (positive charge
[+])
• Neutrons (no charge)
• Electrons (negative
charge [–])
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Nucleus
Center of the atom
Contains particles - protons & neutrons
Neutron
Non-charged particle (neutral)
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Proton
(+) charged particle
Electron
(-) charged particle
In orbit outside the
nucleus
Determines how
the atom will react
chemically
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Protons (+) & Electrons (-) of an atom are
always equal in number in its “normal” state, so
that the atom has a neutral charge.
A proton carries a positive charge (+) and an
electron carries a negative charge (-), so the
atoms of elements are neutral, all the positive
charges canceling out all the negative charges.
Atoms differ from one another in the number of
protons, neutrons and electrons they contain.
Positively charged protons [+] attract
Negatively charged electrons [-]
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Atomic Number
No two elements share the same atomic number
In the Periodic Table (Appendix 3 – Pg 435),
the Atomic Number is located at the top of the box
of each element
Atomic Number
Hydrogen – H =
Carbon – C =
Oxygen – O =
Iron
– Fe =
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Atomic Weight
Together, protons and
neutrons
contribute nearly all of the
atomic weight
14
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Energy Levels
Molecules
- Formed when two (2) or more atoms (elements) unite
on the basis of their electron structure
- Can be made of like atoms
ex: O2
- More often made of two or more different atoms
ex: H20
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Compounds
Substances composed of two or more
different elements
* Molecules are the smallest subunits of a
compound
Ex: carbon monoxide (CO) : 1 atom of carbon
&
1 atom of oxygen
water (H2O):
atoms of hydrogen
2
1 atom of oxygen
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Molecule or Compound ?
O2
Oxygen
H2O
=
=
Water
CO
=
Carbon Monoxide
C6H12O6
=
Glucose
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The Importance of
Water
• Most abundant compound in body
• Critical in all physiologic processes in body
tissues
• Deficiency (dehydration) can threaten health
• Universal solvent
• Stable liquid at ordinary temperatures
• Participates in chemical reactions in body
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Mixtures: Solutions
& Suspensions
- Not all elements or compounds combine
chemically when brought together
- Blends of two or more substances are…
Mixtures
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Mixtures
1.
2.
3.
Combination or blends of different
substances in which each substance remains
intact and retains its separate properties
Chocolate chip cookies (cookie dough & chocolate chips)
Blood Plasma (platelets, RBC, WBC
Air (nitrogen, oxygen, carbon dioxide & other substances)
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Solution
Mixture formed when one substance dissolves in
another
Ex: Salt Water, Koolaid, Coffee
Types of
Mixtures
Suspension
Mixture formed when the substance distributed in
the
background material is not dissolved and will
settle
out unless mixture is constantly shaken
Ex: Oil & Vinegar or Italian Dressing, Finger
Paints
Colloid
Particles do not dissolve but remain suspended
Ex: Fruit in jello
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Atoms interact chemically to alter the
neutrality of atoms and form bonds.
Chemical
Bonds
In chemical reactions, electrons may be
transferred from one atom to another or may
be shared between atoms.
Two types of chemical bonds
Ionic Bonds
Covalent Bonds
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Ionic Bonds
________________________________________
________________________________________
If a sodium atom comes in contact with a chlorine
atom,
the chlorine atom gains an electron from the
sodium atom
and they form an Ionic bond.
The newly formed ions (Na+ and Cl-), have
opposite
charges and are attracted to each other.
They form the compound sodium chloride (table
salt).
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Electrolytes
•
•
•
•
Ionically bonded substances
Separate in solution into charged particles (ions)
Cation [+] positive ion / Anion [-] negative ion
Conduct electric current
Influence homeostasis (stable condition of normal organism)
(body fluids – proper function)
Electrolytes are…
salts – sodium chloride and potassium chloride
acids & bases
calcium, potassium, magnesium, sodium
* Electrolytes must be present in exactly the right quantities in
intracellular and extracellular fluids or damaging effects will
result, preventing cells from functioning properly
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Covalent Bonds
Formed by
_________ of
electrons
between
atoms
Non-polar
covalent bond
Polar covalent
bond
Equal sharing
of electrons
(ex: Hydrogen
gas H2)
Unequal
sharing of
electrons (ex:
Water H20)
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Nonpolar
Covalent
Bond
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Acids,
Bases
and Salt
Acids are molecules
that dissociate in
water, producing
hydrogen ions
(H+).
Acids are
______________
________
Chemical substance
capable of
donating a
hydrogen ion (H+) to
another
substance
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Acids, Bases and
Salt
Bases are molecules that are willing to
_________ a hydrogen ion.
A base is a chemical substance, usually
containing a hydroxide ion (OH-), that can
accept a hydrogen ion
A base is also called an Alkali
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3
0
Acids, Bases
and Salt
Salt is
formed by a
reaction
between an
acid and a
base
pH Scale (power of
hydrogen)
Used to measure relative acidity & alkalinity (base) of a
solution
Indicates the concentration of hydrogen ions (H+) in solution
Acidic = greater concentration of H+ in a solution
Basic (Alkaline) = greater concentration of OH- (hydroxide ion) in
a
solution
As the concentration of H+ ↑,
As the concentration of OH- ↑,
the concentration of OH- ↓
the concentration of H+ ↓
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pH Scale
Units are from 0
– 14
Each whole
number on the
pH scale, (014), represents
a
tenfold
difference in
hydrogen ion
concentration
0 = most acidic
14 =
most basic
A pH of ___ is neutral
Body fluids
usually 7.357.45 pH
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pH Scale
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The only
substance
that has an
absolute pH
of 7 is…
water
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Buffers
• Chemicals that prevent sharp
changes in
hydrogen ion concentration
• Maintain relatively constant pH
in body
fluids
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Isotopes and
Radioactivity
Elements can exist in several
forms (isotopes)
• Same number of protons and
electrons
• Different number of neutrons
• Different atomic weights
• May be stable or
unstable (radioactive)
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Use of Radioactive
Isotopes
Radioisotopes are
the rays given off by
some radioactive
elements.
Can penetrate and
destroy cancer cells
- Cancer therapy
Can aid in diagnosis
• X-rays
• Tracers
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Chemistry of
Living Matter
Of the 92 elements that exist in nature,
only
26 have been found in living organisms
96% of cells are made up of 4 elements
1. Carbon
2. Hydrogen
3. Oxygen
4. Nitrogen
(C)
(H)
(O)
(N)
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Chemistry of
Living Matter
4% of cells are made up of 9 elements
1. Calcium (Ca)
2. Sodium (Na)
3. Potassium (K)
4. Phosphorus (P)
5. Sulfur (S)
6. Chlorine (Cl)
7. Magnesium(Mg)
8. Iron (Fe)
9. Iodine (I)
The remaining 13 elements are found in
“trace” amounts and
include:
Zinc, Selenium, Copper, Cobalt, Chromium,
Boron, Fluorine,
Aluminum, Silicon, Vanadium, Manganese,
Molybdenum, Tin
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Organic
Compounds
Chemical compounds that characterize living
things
• Contain carbon, hydrogen, and oxygen
(carbon most identifying characteristic)
Main Types of Organic Compounds
– Carbohydrates
– Lipids
– Proteins
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Organic
Compounds
Carbohydrates:
Simple
Sugars (monosaccharides)
Lipids:
Fats
Proteins:
Amino Acids
(building blocks)
Contain C, H,
O and N (nitrogen)
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Carbohydrates
• Sugars and Starches
• Made up of simple sugars
Monosaccharides (simple sugars)
– Glucose
Disaccharides
Polysaccharides
– Starch
– Glycogen
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Lipids
Fats and Steroids
Fats made of glycerol
and fatty acids
• Triglycerides
• Glycerol (glycerin)
• Phospholipids
• Steroids
• Cholesterol
• Steroid hormones
• Sex hormones
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4
4
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Proteins
•
•
Structural materials and Enzymes
Made of amino acids (building
blocks)
Enzymes
• Proteins essential for metabolic
function.
• Compound that speeds up the rate of
a chemical reaction but is not
changed in the reaction
• Substance on which an enzyme
works