Transcript Bell Work 3-19-12 - Science is a Blast

Bell Work 3-19-12
1. A chlorine atom that has 17 protons and 18
neutrons is called _____________.
a. Chlorine 17
c. Chlorine 35
b. Chlorine 18
d. Chlorine 1
2. If an atom contains 3 protons, 4 neutrons
and 3 electrons, what is its atomic mass?
a. 11
b. 6
c. 7
d. 3
Atoms
Protons
Neutrons
Great Summaries: http://www.wyzant.com/Help/Science/Chemistry/Bonds/
http://www.biology.arizona.edu/biochemistry/tutorials/chemistry/page1.html
4 Elements found in Living Things
CHON
21 other Trace Elements
Carbon, Hydrogen, Oxygen and Nitrogen
Diagram an Atom
________________________________
• P
• E
• N
P=
N=
Electron
Orbitals
shell1=2e
shell2=8e
shell3=18e
Valence Number
Isotopes
Have the same number of protons, but different
number of neutrons
Important for medical diagnosis and treatment:
• Cancer can be treated with radiation from a
radioactive isotope of cobalt (Co).
• Be using radioactive iodine, the function of
the thyroid gland can be measured
Isomere
Compounds with the same formula but
different three-dimensional arrangement of
the atoms, resulting in the molecules having
different chemical properties.
Same simple structure, but different threedimensional structures.
Carbon is special
Carbon has a valence number of 4, so to become
stable, Carbon atoms form four covalent bonds.
Carbon can bond in 4 places.
Unique because it can for straight chains, branched
chains, or rings
It can bond to itself or other atoms.
It can for single, double or triple covalent bonds.
4 Classes of Macromolecules
•
•
•
•
polysaccharides or carbohydrates
triglycerides or lipids
polypeptides or proteins
nucleic acids such as DNA & RNA
Carbohydrate
(CHO)
Function: used by cells to store and release energy
Composed of carbon, hydrogen, and oxygen
Foods considered carbohydrates:
mostly grains and white potatoes.
Also found in fruits and vegetables.
Types: monosaccharides (isomers: fructose and
glucose), disaccharides (sucrose or table sugar),
polysaccharides (starch, cellulose, glycogen)
Lipids / Triglycerides
(CHO)
Commonly called fats and oils
saturated, unsaturated and transfats
Insoluble in water because molecules are nonpolar
Consist of Carbon, Hydrogen, and Oxygen
(less Oxygen than in Carbohydrates)
Function: Major components of membranes
surrounding all living cells, long term energy
storage, insulation and protective coatings
Most Common Lipid
• 3 fatty acids bonded to a molecule of glycerol
Proteins (CHON)
Large, complex polymers essential to all life because
they build structure and carry out cell
metabolism
Composed of amino acids made of carbon,
hydrogen, oxygen, nitrogen and sometimes sulfur
There are 20 amino acids. The order amino acids
are arranged determines the type of protein
Important for muscle contraction, transporting
oxygen in the bloodstream, and providing
immunity
Types: Complete and Incomplete Proteins
Foods considered Proteins:
Meat and Dairy (complete)
and Beans (Incomplete)
• Proteins are formed by the joining of amino acids.
• Amino acids are linked together by condensation,
the removal of an –H and –OH group to form a
water molecule. The covalent bond formed
between amino acids is called a peptide bond
• Many proteins consist of two or more amino acid
chains that are held together by hydrogen bonds.
Watch an Animation to Learn
How Enzymes Work
Source: McGraw Hill
Enzyme
• An important type of protein that speeds up a
chemical reaction.
• It allows reactions to happen in environments
that would not normally result in a timely
reaction
• Involved in almost all metabolic processes
• Can be used over and over again
• Changes in temperature, pH or pressure may
cause the enzyme to undergo denaturation
Nucleic Acid
(CHON-P)
• Organic compound necessary for life
(DNA and RNA)
• Stores information in cells in the form of a
code.
• Made of small subunits called nucleotides
• Consists of carbon, hydrogen, oxygen, and
phosphorus atoms arranged in three groups
– A base, a simple sugar and a phosphate group
Types of Nucleic Acids
• DNA: deoxyribonucleic acid
– It is a master copy of an organism’s information
code.
– Forms the genetic code.
– Is copied every time a cell divides and is passed to
the next generation.
• RNA: ribonucleic acid
– Forms a copy of DNA for use in protein synthesis.
Nitrogenous Bases
• DNA: A, T, C, G
– adenine, thymine, cytosine, and guanine
• RNA: A, U, C, G
– adenine, uracil, cytosine, and guanine
– Purines (double ring bases): adenine and guanine
– Pyrimidines (single ring bases): thymine, cytosine,
uracil
Ionic Bonds
• A bond in which one atom gives up an electron to
another atom
• Example: NaCl Na+Cl-
• Na had a valence number of 1
• Cl had a valence number of 7
• Now, Na has valence number of 0
• Now Cl has valence number of 8
Ionic Bond
Ion
• A charged atom
Octet Rule
• Atoms seek stability
• Atoms want the valence shell to be complete
with 8 electrons
• HYDROGEN, only has 1 electron, it is stable
with 2 valence electrons.
Ionic Bonds – Atoms from opposite
sides of the periodic table bond.
Covalent Bonds
• Atoms bond by sharing electrons.
• The bond may be represented by a line
• Single, double or triple bonds may exist
Covalent Bond
Water H2O
• 2 atoms of Hydrogen
• 1 atom of Oxygen
• Form a polar covalent bond
Hydrogen bonds
Attractive interaction
of a hydrogen
atom with an
electronegative
Atom.
Hydrogen bonds only form between hydrogen
and oxygen (O), nitrogen (N) or fluorine (F)
The Importance of Water
pH
Coming soon……