Transcript basic chemistry

Topic:
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The Introduction of Biology
Defining of life
Classification of living things
Ecosystem and human interferences
• Basic chemistry, the chemistry of
organic molecules
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Darwin evolutions
History of cells
Cells structures and functions
Photosynthesis and cellular respirations
BASIC
CHEMISTRY
Element – a substance that cannot be broken down to other substances by
any chemicals means
Exp : FE (needed for any forms of life)
I ( required only by certain sp.)
Compound - groups of two or more elements that are bonded together
Types of bonding between compounds:
Covalent compounds happen when the atoms share the electrons
Ionic compounds happen when electrons are donated from one atom to
another.
The elements Hydrogen (H) and oxygen (O) exist as gases –the most
abundant compound on earth (H2O)
Examples of compounds: Only molecule containing two or
more elements, such as water (H2O), carbon dioxide (CO2) and
methane (CH4).
Living organism???
Are composed of matter (occupied space and has mass)
A definition of "matter" that is based upon its physical and
chemical structure is: matter is made up of atoms and molecules.
The Structure of an Atom
Atoms are the basis for everything in the universe.
Three basic parts:
• _________ = "-" negative charge
• _________ = "+" positive charge
• _________ = neutral (a charge of zero)
The thing that makes each element different = # electrons,
protons &neutrons.
Protons and neutrons always in the center of atom (the nucleus).
The electrons are found whizzing around nucleus in areas called
orbitals.
If charge of entire atom is "0", there equal numbers of electrons
and protons.
A neutron walked into a bar and asked how much for a drink. The bartender replied, "for you, no charge." Jaime – Internet Chemistry Jokes
CHEMISTRY OF LIFE
Chemical Bonding and Electron Valences
The electrons in an atom are located at different energy
levels.
The electrons in the highest energy level are called valence
electrons.
Number of valence electrons govern an atom’s bonding
behavior.
The max number of valence electrons is 8…a full valence shell.
There is a 2-8-8 rule for these elements.
Atoms are much more stable, or less reactive, with a full
valence shell.
This can be achieved one of two ways:
- ________ bond
- ________ bond
By moving electrons, the two atoms become linked. This is
known as chemical bonding.
Chemical Bonds
Ionic (donate)
Attractions between
ions of opposite charge
- Exp NaCl
Covalent (share)
Two atoms share
one or more pairs of
outer-shell electrons
- form a molecule
- Exp H2
WATER H2O
Exists in liquid (water), solid (ice cube, snow), and gaseous
(water vapour) states
Essential for all living things.
“Universal solvent” because many substances dissolve in it.
Unique properties result from how H2O molecules interact
with each other.
Bonding electrons are shared unequally by the hydrogen and
oxygen atoms:
- partial negative charge (-) forms at ______ end
- positive charge (+) forms at _______end
When the electrons in a covalent bond are not equally shared,
the molecule is ________.
Physical States
Vapor
Cohesion
• The attraction water
to itself – H bonds
Adhesion
• The attraction of
water to other
surfaces/substances
Surface Tension
• Interaction between hydrogen
bonding and the earth’s
gravitational pull
Capillary Action
• “Wettable” surfaces cause a
film of water to partially pull
away from other water
molecules and cling to the
surface.
• Capillary action is important
in soil and plant/water
relations.
Solutions
Solutions are mixtures in which one substance is dissolved in another.
Solutions have two parts: solute and solvent
The ________ is the substance that is dissolved.
The ________ is the substance that does the dissolving
(remember water, the ‘universal solvent’?)
____________ - A measure of how much of a given substance will dissolve in a
liquid.
A substance that does not dissolve in water is called
insoluble.
Example: Oil is insoluble in water.
A substance that does dissolve in water
is called soluble.
Example: Sugar is soluble in water.
Osmosis
• Osmosis is the net movement of water across a
selectively permeable membrane driven by a
difference in solute concentrations on the two sides
of the membrane
• The water moves from the area of higher solute
concentration to the area of lower solute
concentration until equilibrium is reached
Osmosis
pH: Alkalinity/Acidity
• The measurement of the H+ ions found in that
particular substance
• The scale goes from 0 to 14
• 7 is neutral
• Below 7 is acidic
• Above 7 is alkaline (or basic)
• One pH unit represents a ten-fold change in
H+ concentration
The pH Scale
What are 4 major macromolecules found in living organism?
Macromolecules ?? - large, organic molecules that make up living things.
Carbohydrates, lipids, proteins, nucleic acids:
1. Carbohydrates: Are Molecule composed of carbon, hydrogen, and
oxygen, and they include sugars and starches.
2. Lipids: Are non polar molecule that includes fats, oils, and cholesterol.
3. Proteins: A Proteins is a polymer made of monomers called amino acids.
4. Nucleic Acids: Are polymer that are made up of monomers called
nucleotides.