Download Biology 1 B – Chapter 2

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Biology CPA – Chapter 2
The Chemistry of Life Study Guide
The Nature of Matter
An atom is: the simplest particles of an element that retains all the properties of that element.
Subatomic particles
Electrical charge
Found in
Protons
+
Nucleus
Neutrons
Neutral
Nucleus
Electrons
orbital
Diagram and label an Oxygen Atom:
Oxygen has how many:
Protons
8
Neutrons
8
Electrons
8
Elements and Isotopes
An element is a substance that cannot be broken down chemically
into simpler kinds of matter.
Atomic Number & Atomic Mass
The Atomic number of an atom is equal to:
# protons
The Atomic mass of an atom is equal to:
# protons and # of neutrons
An isotope are atoms of the same element that have a different # of neutrons
Chemical Compounds
A compound is made up of atoms of two or more elements in fixed proportions
Examples of compounds:
Compound:
H20
Made of elements:
Hydrogen, oxygen
Chemical Bonds
Ionic Bonds
Formed by
Explain how ions are formed
Draw an example of a
substance that is formed by
ionic bonding
NaCl
Sodium, chloride
the attractive force between oppositely charged ions
When an atom gains or loses an electron
Covalent Bonds
Formed by
Sharing of electrons
Draw an example of a
substance that is
formed by covalent
bonding
Properties of Water
A water molecule is polar because of uneven distribution of electrical charges on a molecule
Draw one water molecule here showing polarity:
Explain why we were able to float a paper clip on the surface of water. What type of bonds
were present that allowed this to happen?
Hydrogen bonds formed between water molecules are strong which produces a tension on
the surface of the water.
What does cohesion mean? What does adhesion mean? How are they important for life?
Cohesion is the attractive force that holds molecules of a single substance together
Adhesion is the attractive force between two particles of different substances
They are important for life because they allow capillary action to occur which is the attraction
between molecules that results in the rise of the surface of a liquid when in contact with a
solid
Water is the universal solvent. What does this mean and why is it important?
Water is able to dissolve or break down compounds into their components. Important
because we need ions to carry out important life processes. (Na+ and electrical impulses)
Explain how the density of ice is important for life?
Water expands when frozen which causes ice to be less dense than liquid water. This is
important for life because ice floats and organisms wouldn’t survive if bodies of water froze
from the bottom up.
Acids, Bases and pH
The pH scale
The pH scale measures the concentration of H+ and OH- ions in solution.
The pH scale ranges from 1 to 14.
A pH of 7 is considered to be neutral.
An acid is any substance that forms Hydrogen ions (H+) in solution.
A base is any substance that forms Hydroxide ions (OH-) in solution.
Chemical Reactions
A chemical reaction occurs when one or more substance change to produce one or more
different substances
The elements or compounds that enter into a chemical reaction are called the reactants.
The elements or compounds that are produced by a chemical reaction are called the products.
Chemical reactions always involve breaking bonds in the reactants and creating new bonds in
the products.
Energy in Reactions
Define energy: The ability to do work
Solid
Liquid
Gas
compact
More freely
Free moving
Fixed Volume
Fixed volume
Fills container
Phase of Matter
Movement of atoms
Volume
ENERGY must be added or removed for a substance to change states of matter.
Label the following equation:
Reactant + Reactant
Product
An example of a Reduction/Oxidation or REDOX reaction is:
What is “activation energy?”
Activation Energy is the amount of energy needed to start a chemical reaction
Catalysts
Some chemical reactions that are necessary for life occur too slowly or have a high activation
energy.
A catalyst speeds up the rate of the reaction by lowering the amount of activation energy
needed to start the reaction
Catalysts work by lowering the activation energy needed to get a reaction going.
Enzyme Action
Substrates are substances with which an enzyme binds to chemically change it.
Use the following terms to identify the components of the following enzyme reaction.
Explain why we can describe the enzyme-substrate complex as a “lock & key.”
Enzymes are very specific and will only work on one specific type of substrate, much like only
one key will fit into a lock.
The site where the substrate binds to the enzyme is called the active site.
Name two ways that enzyme activity is important in humans.
Digestion, immune system