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The Chemistry of Biology
Transcript of The Chemistry of Biology
What is matter?
What is it made of?
In what forms can we find matter?
Why is matter of importance to us?
Elements in Living Organisms
Anything that has mass and takes up space
3 States of Matter
Building blocks of matter
There are different atoms for different pure substances.
These pure substances are called...
Label the Atom
Structure of atom due to
between protons and electrons
Elements cannot be broken down into other substances
Rows = periods
itrogen make up 96.3% of humans.
(Based on # of protons)
An atom of a certain element always has the
HOWEVER, some atoms of elements can have different numbers of
, which changes...
Atoms of the
element that have
Same # of...
Different # of...
Does adding neutrons increase atomic mass? Charge?
Sometimes, if the nucleus has
too many neutrons
(it gets too heavy), the nucleus becomes
The nucleus starts to
(decay) to get to a more
As the nucleus breaks apart, it emits
Why is this important?
What happens when you combine 2 or more different elements to form a pure substance?
Specific combination of elements in a
E.g. Sodium Chloride Salt is always formed from 1 sodium (Na+) atom and 1 chlorine (Cl-) atom
Physically different from elements that comprise them.
E.g. Sodium Chloride Salt is
chemically and physically different
from pure sodium atom and pure chlorine
Cannot be broken down by physical means
E.g. You cannot break water apart by tearing it. You will never pull the Hydrogen atoms and the Oxygen atom apart.
Compounds can only be chemically separated.
Lets go back to the
are the components of the atom that have
The mass of each is approximately
No matter what state
The atoms and molecules are
substances are made of many of the same
Water is made of many
Forces that hold substances together
the atoms are held together by
In an atom, what can change?
Electrons in the outermost shell
Partially filled shells are
CHEMICAL BOND FORMATION
Two Types of Chemical Bonds
2 atoms share their valence electrons
In other words
is a compound whose atoms are held together by covalent bonds.
Most of the compounds that comprise living organisms are
1 pair of electrons is shared
2 pairs of electrons are shared
3 pairs of electrons are shared
What kinds of bonds does a water molecule have?
One way atoms can become stable is by
When an atom accepts or donates an electron, it becomes
, making it an
Which atoms are more likely to donate electrons?
Which atoms are more likely to accept electrons?
electrons _____________ their outer electron shell.
electrons ___________ their outer electron shell.
Ions with a (+) charge
Ions with a
To get a
, an atom must have _______________ electrons.
To get an
, an atom must have _______________ electrons.
Ions are held together by an
between opposite charges.
Now we have looked at what holds two atoms together, but
what holds molecules together
Which atoms/elements are the most stable? Why?
van der Waals forces
Remember electrons are
moving around the nucleus of an atom
______________ than another,
at this moment
, the side with more electrons will have a
than the other side.
This side will be considered temporarily _______________ and the other side will be temporarily __________________.
Then, the temporarily ______________ side of one molecule will be attracted to the temporarily _______________ side of another molecule
These attractions are called __________________________________________, and these forces hold ______________________ together.
of rocks or fossils by radioactive
Studying activity within an organism via
van der Waals forces are very weak intermolecular attractions
Covalent bonds are formed when 2 atoms _______________________________.
When electrons are evenly shared, the molecule formed is ___________________.
When electrons are unevenly shared, the molecule formed is ____________________.
In a polar molecule, electrons are ______________ shared.
This means one side of the molecule is ______________________ and the other side is _________________________.
How are polar molecules different from other molecules that experience van der Walls forces?
The partially _______ end of a molecule attracts to the partially _______ end of a different molecule
This forms a...
Weak electrostatic attraction
Partially negative charge
Partially positive charge
When a polar molecule involves a Hydrogen atom and either a Fluorine, Oxygen, or a Nitrogen atom, the _____________________ attractions are called ___________________________.
Hydrogen bonds are
for the existence of life
They are hold
Why are hydrogen bonds weaker than ionic bonds?
valence electrons from another atom
The mass of electrons is considered to be
's life-sustaining properties are due to its
and ability to form
Ice is less dense thank liquid water because…
hold water molecules further apart in ice
This is why ice floats in water
Unique Properties of Water
Hydrogen bonds are stable
Columns = groups
Atoms with few (1-2) valence electrons
Atoms with more (6-7) valence electrons