basic chemistry. why study chemistry in biology? biology - study of life! chemistry - part of...
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BASIC CHEMISTRYBASIC CHEMISTRY
Why study Chemistry in Biology?
Biology - study of LIFE! Chemistry - part of chemistry
deals with chemical compounds…. And chemical compounds are important to living things.
Ex: glucose- C6H12O6
water - H2O salt - NaCl
Composition of Matter
Matter - Everything in universe is composed of matter Matter is anything
that occupies space or has massMass – quantity of matter an object has
Weight – pull of gravity on an object
ElementsElements Pure
substances that cannot be broken down chemically into simpler kinds of matter
More than 100 elements (92 naturally occurring)
Each element unique chemical symbol
Consists of 1-2 letters First letter is always capitalized
99% of the mass of an organism is composed of 6 elements (SPONCH)
sulfur (S), phosphorus (P), oxygen (O), nitrogen (N), carbon (C), hydrogen (H) Remaining 1% is composed of trace
elements required by an organism in minute amounts.
Iron (Fe) Iodine (I) Copper (Cu) Zinc (Zn)
AtomsAtoms The simplest
particle of an element that retains all the properties of that element
Our understanding of the structure of atoms based on scientific models, not observation
The ProtonsThe Protons Contain a positive charge Located in the nucleus of an atom # of protons known as the atomic #. Number of protons balanced by an
equal number of negatively charged electrons
The NeutronsThe Neutrons Are neutral Located in the nucleus of an atom
The ElectronsThe Electrons Negatively charged high
energy particles with little or no mass
Travel at very high speeds at various distances (energy levels) from the nucleus
Determine the reactivity of an element.
The NucleusThe Nucleus Central core Consists of
positive charged protons and neutral neutrons
Positively charged
Contains most of the mass of the atom
Atomic Number ALWAYS equal
to the # of protons.
Most of the time is = the # of e- (unless it has become an ion)
Is ALWAYS constant!!! This # identifies the element.
Atomic Mass The atomic mass of an atom is found by
adding the number of protons & neutrons in an atom (p+n)
Ex:
Isotopes
Sometimes the number of NEUTRONS can vary among atoms when they are in the form of an isotope.
Isotope Example: Carbon
**Important in Biology: radioactive tracers for kidney function
Practice: 11 Na Atomic # = _____ 23 p = ___ e- = ___
Atomic mass = _____
Element Identification Au Mercury Pb Mn Ar Neon Si Ag Al Lithium Mg Bromine Be Boron Cl He F Sodium K Ni
CompoundsCompounds
Most elements do not exist by themselves
Readily combine with other elements in a fixed ratio
A compound is a substance made up of atoms of two or more elements The proportion of
atoms are always fixed
Chemical formula shows the kind and proportion of atoms of each element that occurs in a particular compound
Chemical Formulas - Chemical Formulas - ReviewReview
Subscript after a symbol tell the number of atoms of each element
H20 has 2 atoms of hydrogen & 1 atom of oxygen
Coefficients before a formula tell the number of molecules
3O2 represents 3 molecules of oxygen or (3x2) or 6 atoms of oxygen
Atoms in compounds are held together by chemical bonds. The tendency of elements to combine and form compounds depends on the number and arrangement of electrons in their outermost energy level - called valence electrons
Chemical Bonds
The chemical bonds that are important to Biology are covalent, ionic, and hydrogen bonds.
Covalent Bonds Formed by the sharing
one or more pairs of valence electrons of two atoms.
Strongest type of bond Impt to living things Found in Biomolecules Resulting substance is
stable, and is referred to as a molecule.
Ionic Bonds Formed between two atoms when one
atom loses an electron, and the other atom gains an electron.
This giving & receiving results in charged particles known as ions - they have an uneven # of protons and electrons.
Positive Ions - Cations “t” Atoms that lose
electrons are called cations and are “+”
Negative Ions - Anions Atoms that gain electrons are
called anions and are “-”
Hydrogen Bonds
Occurs when H+ (which is already bonded to an electronegative atom) is ATTRACTED to another electronegative atom.
Very weak bond Occurs between molecules, not
elements. Important in DNA. Weak attraction - does NOT involve
sharing or transferring of electrons.
DNA
Water