Download UNIT 2 : BIOCHEMISTRY

UNIT 2 : BIOCHEMISTRY
Importance of Biochemistry
• Everything that happens in a living organism involves ___________________________________
• __________________________ occurs when these chemical reactions can no longer occur
Elements and Atoms
Subatomic Particle
Charge
Location in an atom
Size
1 amu
Proton
1 amu
Neutron
1/1,800 of an amu – very small!
Electron
Atomic # - The # of protons in the nucleus of an atom. The atomic # determines the identity of the atom/element.
Atomic # 6: ____ # of protons = element _____________,
_____________
Atomic # 1: ____ # of protons = element
Atomic # 7: ____ # of protons = element _____________,
_____________
Atomic # 8: ____ # of protons = element
B. Mass # - The total number of protons and neutrons in the nucleus.
Mass # 12 = the element _________________, which has ______ protons and ______ neutrons.
Mass # 16 = the element _________________, which has ______ protons and ______ neutrons.
Element - A pure substance that consists entirely of one type of atom.
• Six elements (_______________________________________) are commonly found in living things.
Elements and Atoms, continued
• Isotopes
– Atoms of the same element that have a different number of neutrons are called ______________
– A neutron has no _____________________, so there is no change in charge
– A neutron has mass, so the mass of an isotope is ______________________
• Since Isotopes have the same number of electrons all isotopes of an element will have
_______________________________________________________________________________
C-12 = _____ p+ and _____ n0
C-13 = _____ p+ and _____ n0
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C-14 = _____ p+ and _____ n0
Radioisotopes – Radioactive or unstable isotopes due to an imbalance in the # of ____________ & ___________.
Q: What are some biological uses of radioisotopes?
a) Cellular tracers – Tract the movement of molecules
d) Medical treatments- treating cancer
b) Medical testing – Brain scan, blocked arteries and intestines.
c) Biochemical analysis of blood or urine (hormones, drugs, antigens).
D. Electrons (e-) – Particles found traveling at specific distances (orbitals/energy levels/shells) from the nucleus; has
a negative charge and a mass so small that it is not factored into the mass of the atom.
The first and closest energy level/orbital/shell can hold a maximum of 2 e-. The rest of the shells hold a maximum
of 8 e- (for atoms we discuss in this biology class). The electrons farthest from the nucleus, located in the outer energy
level are called valence electrons.
Complete the diagrams below by: (a) writing in the correct number of electrons in the correct shells, (b) write in
the correct number of protons in the nucleus (the shaded area in the middle of the atom), (c) then write the number of
valence electrons in the parenthesis after the atoms name.
Carbon (# of valence e- = 4)
Sodium (
)
Nitrogen (
)
Example
4e-
6p+
2e-
Oxygen (
)
Hydrogen (
)
→ Atoms want a full outer shell and will share, donate, or accept electrons. As a result of sharing, giving, or getting
electrons chemical bonds are formed between atoms. Because a full shell is usually 8 e-, it is called the octet rule.
→ In an electrically neutral atom, the # of protons (+) equals the # of electrons (-). An atom that has an imbalance in
the
# of protons and electrons is called an ion. Atoms with more protons than electrons, and thus a positive charge, are
known as cations. Atoms with more electrons than protons, and thus a negative charge, are known as anions.
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
Protons +17
Electrons -17
Charge
0
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Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
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ATOMS  MOLECULES  ORGANELLES  CELLS  TISSUES  ORGANS
Covalent Bonds
 A ___________________________________ is formed when two atoms share electrons.
Q: How many electrons are shared in: a single covalent bond? _______ Double bond? ______Triple bond? _____
Hydrogen bonds - Weak electrical attractions between hydrogen atoms and larger atoms of polar
molecules. Polar molecules are the result of unequal sharing of valence electrons. THESE DO NOT
RESULT IN THE FORMATION OF MOLECULES, but do aid in maintaining the shape of larger
molecules (Nucleic Acids & Proteins) & water.
Ionic Bonds
 An ionic bond is formed when one atom _________________________ an electron to another. The positive ion is
then attracted to a negative ion to form the ionic bond.
Chemical formulas
• a chemical formula indicates the __________________________________ in each substance; H2O contains
3 atoms (2 hydrogen and 1 oxygen)
– ___________________________ indicates the number of atoms
Law of Conservation of Mass
• Matter is never __________________________________, only changed from one form to another
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•
•
In a chemical reaction, the mass of the ______________________ is always equal to the mass of the
_______________________________
So
• A chemical equation is always balanced; the _____________________________________
____________________________________________________________________________
Chemical Equation
• All chemical equations have __________________________________
• __________________________ on the left side of the arrow
• Arrow that is read as ________________________________
• ________________________________- are on the right side of the arrow
• ___________________________ indicates the number of molecules; 6H 2O is six molecules of water
Balance These!
• Na + Cl2  NaCl
O2 
•
H2 +
•
Zn + HCl 
•
HgO

H2O
Hg
Zn2Cl
+
+
H2
O2
C6H12O6 +
O2 
H2O +
CO2
– And Name this equation!
Energy in living things
• Energy is stored in _____________________________, and released when compounds are broken down and
new ones are made from the existing atoms.
•
Kinetic and Potential Energy
• Energy in the ____________ of chemical compounds represents __________________________
• Plants store energy in a compound with many bonds, called ___________________
• Animals store energy in a similar compound, called _________________________
• Energy is transferred throughout all living things in a molecule called __________________
___________________________________
•
________________________________ in living organisms occurs as chemical reactions take place, allowing
for all the processes of living things to occur
Energy Currency
• Adenosine triphosphate (ATP) ________________________________ energy during cell processes, enabling
organisms to function.
Energy and Chemical Reactions
• Activation Energy
– Enzymes ____________________________________________________ necessary for a reaction
to begin in living systems
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Energy and Chemical Reactions
‘
Polarity
• Water is considered to be a polar molecule due to an ____________________________________.
• The ________________________ in a water molecule are ____________________________ between
hydrogen and oxygen.
• Solubility of Water
• The polarity of water makes it effective at _______________________________________ such as
sugars, ionic compounds, and some proteins.
Hydrogen Bonding
• A hydrogen bond is the force of _________________________ between a hydrogen molecule with a
____________________ charge and another atom or molecule with a partial or full negative charge.
Temperature Moderation (high specific heat)
• Water has the ability to ___________________ a relatively large amount of energy as __________
• This property is called _________________________, the amount of heat needed to raise the
temperature of _________________________________________________________
• and the ability to cool surfaces through ___________________________
Acids and Bases
Acids
– Acidic solutions contain more hydronium ions than hydroxide
ions. _____________
– Examples:
___________________________________________________
____________
• Bases
– Basic solutions contain more hydroxide ions than hydronium
ions. _____________
– Examples
___________________________________________________
____________
• pH
– Scientists have developed a scale for comparing the relative
concentrations of hydronium ions and hydroxide ions in a
solution. This scale is called the ________________________,
and it ranges from 0 to 14.
– pH of ______________________________
• Buffers
– Buffers are chemicals that ____________________ the effects
of adding small amounts of either
________________________________ to a solution.
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Carbon Bonding
• ______________________________________ contain carbon atoms and are found in living things.
• Most ______________________________ do not contain carbon atoms.
• Carbon atoms can readily form ________________________________________ with other atoms including other
carbon atoms. The carbon bonds allow the carbon atoms to form a _________________ of simple and complex
organic compounds.
Macromolecules
• Large molecules formed by ___________________________, the process of small monomers or subunits
joining together to form large macromolecules
– Be sure you know the _________________ that makes up each group of macromolecule!
• Four major groups of macromolecules found in living things
– ____________________________
– ____________________________
– ____________________________
– ____________________________
• Condensation reactions join monomers (small simple molecules) to form polymers. A condensation reaction
____________________________ as a by-product.
• A condensation reaction is a type of _________________________________; it is also called
dehydration synthesis
A+BC
(in this case a small amount of water is also produced)
• In a ____________________________________, water is used to split polymers into monomers.
• A hydrolysis reaction is a form of _____________________________________
CA+B
Reaction
Water
Energy
Purpose
(lost or gained?)
(lost or gained?)
(end result)
Dehydration
Synthesis
Hydration Synthesis
(Hydrolysis)
Carbohydrates
• Carbohydrates are organic compounds composed of ____________________________________ in a ratio
of about ________________________________________________________________
• Carbohydrates are a _____________________ are used as ____________________________ in organisms.
• Monosaccharides
• _______________________ are made up of monomers called monosaccharides.
• Disaccharides and Polysaccharides
• Two monosaccharides join to form a double sugar called a _______________________.
• A complex sugar, or _____________________, is made of three or more monosaccharides.
Proteins
• Proteins are organic compounds composed mainly of ____________________________________.
• Proteins have many functions including __________________________, and ____________ roles.
• Amino Acids
– Proteins are made up of monomers called ________________________________.
– The ___________________________________ determines a protein’s shape and function.
• Dipeptides and Polypeptides
– Two amino acids are _____________________________________ to form a dipeptide.
– A long chain of amino acids is called a ___________________________
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Structure of Proteins
•
Enzymes
– Enzymes _________________ and bind to specific substrates.
– The binding of a substrate with an enzyme causes a _________________________
_________________________________________ and reduces the activation energy of the reaction.
Induced Fit model
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Lipids
•
•
•
•
Lipids are __________________________ molecules that store energy
and are an important part of ___________________________________
Because lipids are nonpolar, they are all _______________________ in
water.
Fatty Acids
– Most lipids contain fatty acids, unbranched carbon molecules
that have a hydrophilic end and a hydrophobic end.
Triglycerides
– Triglycerides consist of (Monomers)
______________________________ and one molecule of
_______________________________
Phospholipids
– Phospholipids, which make up cell membranes, consist of
____________________ and ___________________________
molecule.
•
Waxes
– A wax is made of one ___________________________________________ joined to one long
_____________________.
•
Steroids
– A steroid is composed of _________________________________________________.
–
Cholesterol is required in the _________________________________________________, and is
used to make ___________________________________________, shown below
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Nucleic Acids
• A nucleic acid is a large and complex organic molecule that ___________________________
_________________________________________________________________________
Structure of Nucleic Acids
•
The nucleic acid _______________________________________________________________ contains
genetic information for cell activities.
•
__________________________________________________ molecules play many key roles in building of
proteins and can act as enzymes as well as interfere with normal gene actions
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