Transcript The Nature of Matter

Unit Sections:
1- Atoms, Molecules, and Bonds
2- Water: The Universal Solvent
3- Acids, Bases, and Solutions
4- Organic Macromolecules
5- Polymers and Monomers:
Assembly and Disassembly
6- Enzymes
What is Matter?
-Matter is the “stuff” that makes
up everything in the universe.
-Matter can be any shape, texture,
or color.
-Matter has the ability to change
states…
Types of
Matter…
Pure Substances
•Made of only one
kind of matter, has
definite properties
Elements
•Cannot be broken down into
simpler substances
•All the “stuff”
in the Universe
Mixtures
•Two or more substances
mixed together, but not
chemically combined
Compounds
•A chemical combination of
two or more elements
Particles of matter



The smallest possible particle of
matter that retains its unique
properties is called an atom.
Groups of atoms that combine
together and act as single units
are called molecules.
The forces that hold atoms
together are called chemical
bonds.
How small is an atom?…….

There are
2,000,000,000,000,000,000,000
atoms of oxygen
in one drop of
water! (two
thousand billion
billion)….
Inside an atom

An atom is the smallest unit of matter
that still retains the properties of a
particular element.
Atoms and electrons…

The nucleus is surrounded by negatively
charged electrons which move extremely
fast. It is impossible to know where any
electron is at any given time…
Atoms and Electrons (cont…)

Atoms are 99.99% empty space…
nucleus
Electrons (cont…)

Electrons are about 1/2000th the size of
protons and neutrons.
Proton (+)
Electron (-)
Ionic Bonds

When an atom has
fewer than 4
valence electrons,
they will often
transfer them to
another atom that
has more than four
valence electrons.
Ionic Bonds (cont…)
An “ion” is an atom
that is electrically
charged. It has either
lost or gained
electrons.
Ionic Bonds (cont…)


If an atom loses
an electron (-), it
becomes a
positive ion.
If an atom gains
an electron (-), it
becomes a
negative ion.
Ionic Bond
Ionic Bonds (cont…)

An ionic bond is the
attraction between
two oppositely
charged ions. This
results in a neutral
compound,
commonly known as
a “salt.”
Ions (cont…)



What charge does a
chloride ion have?
What charge does a
magnesium ion have?
How many chloride ions
would be needed to
balance out the charge of
a magnesium atom?
-
1- (Cl )
2+
2+ (Mg )
2
(MgCl2)
Covalent Bonds


A chemical bond
formed when two
atoms share
electrons is called a
covalent bond.
In a covalent bond,
both atoms have an
equal attraction to
the shared electrons.
Covalent Bonds

The number of
bonds an atom will
form is dependent
on the number of
electrons it needs to
make a total of 8….
The “octet rule”
Polar molecules

Polar molecules have a slightly
negative charge at one end, and a
slightly positive charge at the other end.
Attractions between molecules


Because of the unequal
pull of electrons
exhibited by polar
molecules. They have a
tendency to attract one
another.
Non-Polar molecules do
not attract one another
as much, and therefore
exhibit different
properties.
Water: A Unique Compound!



The cohesive and adhesive
properties water exhibits are products
of its polar nature.
Water’s high boiling point and
relatively low freezing point allow it to
remain a liquid in most conditions.
Water heats slowly and retains heat
effectively, allowing organisms to
control temperature and maintain
homeostasis.
Water: the “Universal”
Solvent

Because water dissolves so many
substances, and is so plentiful on
Earth, it is referred to as “the
Universal Solvent”
Particles in Solution
When a solution
forms, particles of the
solute leave one
another, and become
surrounded by particles
of the solvent.
Particles in a solution
+
Na
NaCl
Cl
Ionic solids (salts) in Solution
Particles in a solution

When molecular
solids (such as
sugar) are dissolved
in water, the
molecules
disassociate from
one another, but
stay in tact.
Acids and Base in Solution
How to recognize an acid…

Acid:

In Solution
HNO3 - nitric acid
H+ + NO3-
HCl - hydrochloric acid
H+ + Cl-
H2SO4 - sulfuric acid
2H+ + SO42-
HClO4 - perchloric acid
H+ + ClO4-
HI - hydroiodic acid
H+ + I-
How to recognize a base

Base:
LiOH - lithium hydroxide

In Solution…
Li+ + OH-
NaOH - sodium hydroxide
Na+ + OH-
KOH - potassium hydroxide
K+ + OH-
Ca(OH)2 – calcium hydroxide
Ca2+ + OH-
Ba(OH)2 - barium hydroxide
Ba2+ + OH-
Properties of Acids


Although tasting a compound as a means
of identifying it is never smart, you taste
acidic compounds every day…
SOUR!!!
Properties of acids (cont.)


Acids are corrosive, meaning they wear away
other materials.
Some metals react with acids to create hydrogen
gas.
Properties of Acids (cont.)

Litmus paper changes color in the
presence of an acid or a base. In the
presence of an acid, litmus paper turns
red…
Everyday acids…

Vitamin C is an acid present in fruits.

Acid in our stomach helps digest food.

Hydrochloric and sulfuric acid are used
extensively in industry, as cleaning agents,
and in fertilizers.
Properties of Bases

Bases taste bitter…

Bases feel slippery…
Properties of Bases cont.

Bases turn litmus
paper blue

Bases do not react
with carbonates
Everyday Bases



Drain cleaners, and various
household cleaning products are
made with ammonia (NH3) a
powerful base…
Cement is made using the base
Calcium Hydroxide (CaOH2).
Bases neutralize excess stomach
acid…
Measuring pH
The Chemistry of Carbon



Organic chemistry is the study
of all compounds that contain
bonds between carbon atoms.
Carbon atoms have four
valence electrons that can join
with the electrons from other
atoms to form strong covalent
bonds.
A carbon atom can bond to
other carbon atoms, giving it
the ability to form chains that
are almost unlimited in length.
The Chemistry of Carbon



Living organisms are made of molecules
that consist of carbon and other elements.
Chains of carbon can even close upon
themselves to form rings.
Carbon has the ability to form millions of
different large and complex structures.
Copyright Pearson Prentice Hall
Life with Carbon


Nutrients are substances that
provide the energy and raw
materials the body needs to grow,
repair itself, and function properly.
The 4 classes of polymers found in
all living things are carbohydrates,
proteins, fats, and nucleic acids.
Macromolecules

Macromolecules


Macromolecules are
formed by a process
known as
polymerization.
The smaller units, or
monomers, join
together to form
polymers.
Carbohydrates

Living things use carbohydrates as their
main source of energy. Plants and some
animals also use carbohydrates for
structural purposes.
Carbohydrates

Carbohydrates are energy rich organic molecules
composed of carbon, hydrogen, and oxygen.
Complex Carbohydrates
Simple Carbohydrates
glucose
Cellulose, starch
Carbohydrates

Starches and sugars are examples of
carbohydrates that are used by living
things as a source of energy.
Glucose
Monosaccharide
Monosaccharide
Disaccharide
Proteins

Most of the body’s structures are composed of
proteins. Proteins are complex polymers
composed of a specific arrangement of
monomers called amino acids.
Proteins



Some proteins control the rate
of reactions and regulate cell
processes.
Some proteins are used to
form bones and muscles.
Other proteins transport
substances into or out of cells
or help to fight disease.
Proteins

Proteins can have up to four
levels of organization:




Amino acids have a specific
protein chain.
The amino acids within a chain
can be twisted or folded.
The chain itself is folded.
If a protein has more than one
chain, each chain has a specific
arrangement in space.
Proteins

Amino
Acids
The instructions for arranging
Proteins (cont.)

The body uses the
proteins we eat to build
and repair body parts.
Proteins are broken down
in the digestive process
and the monomers are
re-assembled into
thousands of proteins.
Lipids


Like carbs, lipids are energy rich polymers made of
carbon, hydrogen, and oxygen.
Lipids include fats, oils, waxes, and cholesterol.
Fatty acid
(saturated)
Glycerol
Fatty acid
(unsaturated)
Unsaturated fat
Nucleic Acids

Nucleic acids (also called
nucleotides) are the molecules
which make up our DNA (also
our RNA).

There are only four different
kinds of nuclotides that make
up our DNA, which include
carbon, oxygen, hydrogen,
nitrogen, and phosphorus
atoms.
Nucleic Acids
The
differences
among living things
are determined by the
order of nucleotides in
the DNA.
Assembling
Monomers

Monomers are almost
always assembled into
polymers (complex
carbohydrates, proteins, or
lipids) inside they body by
enzymes carrying out
condensation reactions.
What is this
condensation
reaction
resulting in?
Disassembling polymers

The process of digestion (as well as thousands of other
cellular functions) requires that macromolecules be broken
down at the molecular level. This process, called depolymerization, requires specialized enzymes to carry out
hydrolysis.
Enzymes




Enzymes are special proteins that can break large molecules
into small molecules. Different types of enzymes can break down
different nutrients:
carbohydrase or amylase enzymes break down starch into
sugar.
protease enzymes break down proteins into amino acids
lipase enzymes break down fats into fatty acids and
glycerol.
Getting Reactions Started

There is always a
minimum amount of
energy needed to start a
chemical reaction…this
is referred to as the
“activation energy.”
Enzymes



A catalyst is a substance
that speeds up the rate of
a chemical reaction.
Catalysts work by
lowering a reaction's
activation energy.
Biological catalysts are
called enzymes.
Enzymes

Enzymes play
essential roles in:




regulating chemical
pathways.
making material that
cells need.
releasing energy.
transferring
information.
Enzymes

Lowering the
activation energy
has a dramatic
effect on how
quickly the
reaction is
completed.
Enzyme Action

The Enzyme-Substrate Complex

1

Enzymes provide a site where reactants can be
brought together to react, reducing the energy
needed for reaction.
The reactants of enzyme-catalyzed reactions
are known as substrates.
Enzyme Action

2

The substrates bind to the active site on
the enzyme forming an enzyme-substrate
complex.
The fit is so precise that the active site and
substrates are often compared to a lock
and key.
Enzyme Action

3

The enzyme and substrates remain bound
together until the reaction is done and the
substrates are converted to products.
The products of the reaction are released
and the enzyme is free to start the process
again.

An Enzyme-Catalyzed Reaction

Regulation of Enzyme Activity



Enzymes can be affected by any variable that
influences a chemical reaction.
Enzymes work best at certain pH values.
Many enzymes are affected by changes in
temperature.
Specialized enzymes
target specific
macromolecules…
Look closely. What
is going on in this
picture? What is
“Sucrase?”
That’s All Folks!
Extra Credit
(1 point each)
1. How would you
characterize
this reaction?
2. What is being
assembled as a
result of this
reaction?
(be specific)