Download Chemical Basis of Life

Chemical Basis of Life
I. How Matter is Organized
A.
Chemistry is the science of the structure and interactions of matter.
1. All living things are made up of ______________ and ___________.
2. Matter is anything that _______________ and _________________.
a.
Mass is the amount of ______________________________.
b.
Weight is the ________________________________________.
i. E.g. in outer space, weight is close to zero, but mass remains
the same as on Earth.
II.
Chemical Elements
A.
B.
__________________ are substances that cannot be __________________
_________________ by ordinary means.
116 elements (92 occur naturally)
1.
26 of naturally occurring elements are in the body
2.
Elements are grouped in the periodic table according to their
characteristics and are represented by chemical symbols.
3.
Four most common elements that form 96 % of the body’s
mass are… _______
_________ _________ and
________
III. Structure of Atoms
A.
Atoms are the smallest units
of matter that retain the
properties of an element
B.
Atoms consist of 3 types of
subatomic particles
1. Protons – have
__________, a _____________ charge and are found in the
_________________.
2. Neutrons – have __________, _____ charge and are found in
the ___________.
3. Electrons – have ______________, ____________ charge and
____________ the nucleus in a ________________ pattern.
IV. Periodic Table
A. Atomic number is the same as the # of _______________ in an element.
If you add or remove protons you get a ___________________________.
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B. Atoms are electronically neutron, so the # of __________________ (e-) is
equal to the # of _____________________ (or the atomic number). If you
add or remove electrons you get ___________.
C. To determine the # of neutrons take the element’s ___________________
and subtract its’ _______________________ or number of ___________.
If you add or remove neutrons you get ___________________.
 Why is the atomic mass for many elements not a whole number?

You don’t need to draw this picture of the periodic table, but you should
know how to use a periodic table to determine the name (any of the
first 20 elements), # of proton, # of neutrons, # of electrons, the # of
rings for any element. You should also be able to tell me the relationship
between the different elements in each respective column.
V. Chemical Bonds
A.
Bonds hold together the atoms in molecules and compounds
B.
C.
An atom with a full outer electron shell is stable and unlikely to form a
bond with another atom
1. The driving force in many chemical reactions is the need to fill in
its ____________ or ____________________ ring.
Ionic Bonds
1. When an Atom _____________ or _____________ one or
more electrons
2. In the body, ionic bonds are found mainly in ______________
and ______________
3.
4.
Ionic compounds generally exist as _______________
______________________ are ionic compounds that have
dissociated in water into + and - ions.
D.
Covalent Bonds1. When two or more atoms __________________________ a
covalent bond is formed and it is represented in structural drawings
as a ________ between two atoms.
2. Electrons spend most of the time between the 2 atomic nuclei
a. single bond = share 1pair (1 line)
b. double bone = share 2 pair (2 lines)
c. triple bond = share 3 pair (3 lines)
3. Polar covalent bonds share electrons unequally between the atoms
involved; e.g. water
E.
Hydrogen Bonds
1. Force of attraction between
________________ and other negatively
charged ions, compounds or molecules.
2. Only about ______% as strong as
covalent bonds
3. Large 3-D molecules are often held
together by a large number of hydrogen
bonds.
VI. Chemical Reactions
A.
Occur when new bonds form or old bonds are broken.
B.
Metabolism is the sum total of all the chemical reactions in the body
C.
Types of Chemical Reactions
1. __________________: Two or more atoms, ions or molecules
combine to form new & larger molecules.
a. All synthesis reactions in the body together are called
_______________________.
2. _______________________: large molecules are split into
smaller atoms, ions or molecules.
a. All decomposition reactions occurring together in the body are
know as ________________________.
3. ___________________: Substances exchange atoms
a. E.g. HCl + NaHCO3 gives rise to H2CO3 + NaCl.
4. __________________: Reactants can become products or
products can revert to the original reactants.
a. H2O <=> H+ + OHVII. Water
A. Most important inorganic compound in living systems
B. ___________________ Solvent
1. Due to ________________ covalent bonds (hydrophilic versus
hydrophobic)
2. Its shape allows each water molecule to interact with 4 or more
neighboring ions/molecules
C. Heat Capacity of Water
1. Heat capacity is ___________, therefore…
a. Can _______________ a large amount of heat with only a
small increase in its own ______________________
b. Due to the large number of hydrogen bonds in water
c. Bonds are broken as ________________________ instead of
increasing temperature of water
d. Large amount of water in body helps ________________ the
impact of environmental changes in _____________________
2. Heat of _________________________ is also high, therefore…
a. Amount of heat needed to change from liquid to gas
b. Evaporation of water from the __________ removes large
amount of ______________
D. Cohesion and adhesion creates high surface tension
1. Difficult to break the ___________________________ if molecules
are more attracted to each other than to surrounding air molecules
2. Some respiratory problems are caused by water’s cohesive
property.
 E.g. ______________________ allows water to collect in the air
sacs of lungs, which makes it more difficult to inflate the lungs.
E. Water is a good _________________
1. Major component of lubricating fluids within the body
a. _______________ in respiratory and digestive systems
b. _____________________ fluid in joints
c. _____________________ fluids in chest and abdominal cavities
d. organs slide past one another
VIII.
Inorganic Acids, Bases & Salts
A.
Acids, bases and salts always dissociate into ions if they are dissolved
in water
1. ________________ increase the concentration of H+ in solution
2. _______________ increase OH- concentration or decrease H+
concentration.
3. ________________ dissociate into anions and cations, none of
which are either H+ or OHB.
Acid & bases react in the body to form salts
1. _______________________ are important salts in the body that
carry electric current (in nerve or muscle)
IX.
Concept of pH
A.
pH scale runs from ___ to ______ (concentration of H+ in moles/liter)
1. pH of _____ is neutral (distilled water -- concentration of OH- and
H+ are equal)
2. pH below 7 is _____________ and above 7 is ______________
B.
Buffer Systems of the Body
1. Body fluids vary in pH but the range of each is limited and is
maintained by a variety of buffering systems.
a. gastric juice 1.2 to 3.0; saliva 6.35 to 6.85; bile 7.6 to 8.6 and
blood 7.35 to 7.45
2. Buffers convert _______________ acids to ____________ ones
which contribute fewer H+ ions & have less effect on pH
3. Carbonic acid - bicarbonate buffer system
a. together they contribute H+ or OH- ions as needed to keep the
pH of the blood stable
HCl + ______________ —> ______________ + NaCl
b. Why not neutralize the strong acid with a strong base?
4. What would your body do if it were exposed to a strong base
like Draino (NaOH)? Write out equation!
Organic Chemistry
I.
Organic Compounds
A. Always contain _____________ and _________________
B. Usually contain ____________________ bonds
C. Usually large, unique molecules with complex functions
D. Make up __________% of body mass
E. Draw and explain the HONC rule?
II. Functional Groups
A. Hydrocarbons
1. Composed of hydrogen and carbon and form the backbone of most
organic molecules.
2. Have a lot of stored ________________.
3. Insoluble in water. Why?
4. Examples: methane, propane, butane, octane etc.
B. Alcohols (R-OH)
1. A __________________ group.
 What does the “R” stand for?
2. Soluble in water.
3. Also good fuels.
4. Examples: CH3CH2OH (Ethanol)
C. Carboxylic Acid (R-COOH)
1. Many are aromatic
 What does this mean?
2. Water soluble
3. Taste __________
D. Amines (R- NH2)
1. ___________________ in water
2. Alkaline or basic (a proton acceptor)
3. Strong odors: Example: putresine and cadaverine and
methylamine
III. Carbohydrates
A. Diverse group of substances formed from C, H, and O
1. Ratio of one ______________ atom for each ___________ molecule
(carbohydrates means “watered carbon”)
2. Glucose is 6 carbon atoms and 6 water molecules (H20) = C6H1206
B. Main function is source of ________________ for ATP formation
C. Forms only 2-3 % of total body weight
1. _________________ is storage in liver and muscle tissue
2. Sugar building blocks of _________ & ________ (deoxyribose &
ribose sugars)
D. Only plants produce ________________ or cellulose for _______________
IV. Diversity of Carbohydrates
A. Monosaccharides
1. Called simple sugars
2. Contain 3 to 7 carbon atoms
3. We can absorb only 3 simple sugars without further digestion in our small
intestine:
a. Glucose found syrup or honey
b. Fructose found in fruit
c. Galactose found in dairy products
B. Disaccharides (page 39)
1. Composed of two sugar units
2. How does a disaccharide form?
3. This process is called dehydration synthesis or a condensation reaction.
4. The opposite of dehydration synthesis is hydrolysis, when water is added
to separate a bond.
C. Polysaccharides
1. Contain 10 or 100’s of monosaccharides joined by dehydration synthesis
2. In animals glycogen is a chain of hundreds of glucose molecules found in
liver & skeletal muscle.
3. When blood sugar level drops, liver hydrolyzes glycogen to create and
release glucose into the blood
V. Lipids (fats)
A. Formed from mainly C, and H, with little O
1. Includes fats, phospholipids, steroids, eicosanoids, lipoproteins and
some vitamins
B. 18-25% of body weight
C. Hydrophobic: What does this mean? What about solubility
D. Combines with proteins for transport in blood
1. Lipoproteins (LDL and HDL)
E. Triglycerides
1. Neutral fats composed of a single glycerol molecule and 3 fatty acid
molecules
a. Three-carbon glycerol molecule is the backbone
b. Fatty acids attached by dehydration synthesis
2. Very concentrated form of energy
a. 9 calories/gram compared to 4 for proteins & carbohydrates
b. Our bodies store triglycerides in fat cells if we eat extra food
3. Saturation of Triglycerides
a. Determined by the number of single or double covalent bonds
b. Saturated fats contain single covalent bonds and are covered with
hydrogen atoms----lard
c. Monounsaturated are not completely covered with hydrogen---safflower oil, corn oil
d. Polyunsaturated fats contain even less hydrogen atoms----olive
and peanut oil
F. Phospholipids
1. Composition of phospholipid molecule
a. a polar head
i. A phosphate group (PO4-3) & glycerol molecule
ii. Can form hydrogen bonds with water
b. 2 non-polar fatty acid tails
i. Interact only with lipids
2. Major component of cell membranes
a. Double layer of phospholipids with tails in center
3. Chemical Nature of Phospholipids
G. Steroids
1. Formed from 4 rings of carbon
atoms joined together
2. Common steroids
a. Sex hormones, bile salts,
vitamins & cholesterol
b. Cholesterol found in animal cell
membranes
c. Starting material for synthesis
of other steroids
3. Four Ring Structure of Steroids
VI. Proteins
A. 12-18% of body weight
B. Contain carbon, hydrogen, oxygen, and nitrogen
C. Constructed from combinations of 20 amino
acids.
D. Dietary sources are meats, dairy and a few
plants (legumes)
E. Amino Acid Structure
1. Central carbon atom
2. Amino group (NH2)
3. Carboxyl group (COOH)
4. Side chains (R groups) vary between
amino acids
5. Be able to identify “R” group for any
given amino acid.
F. Formation of a Dipeptide Bond
1. Dipeptides formed from 2 amino acids joined (dehydration synthesis)
by a covalent bond called a peptide bond
2. Polypeptides chains formed from 10 to 2000 amino acids.
G. Levels of Structural Organization
1. Primary is unique sequence of amino acids
2. Secondary is alpha helix or pleated sheet folding
3. Tertiary is 3-dimensional shape of polypeptide chain
4. Quaternary is relationship of multiple polypeptide chains
H. Protein Denaturation
1. Function of a protein depends
on its ability to recognize and
bind to some other molecule
2. Hostile environments such as
heat, acid or salts will change a
proteins 3-D shape and destroy
its ability to function
a. raw egg white when cooked
is vastly different
VII. Enzymes
A. Enzymes are protein molecules that
act as catalysts
B. Enzymes usually end in suffix -ase and
are named for the types of chemical
reactions they catalyze
C. Activation Energy
1. Atoms, ions & molecules are
continuously moving & colliding
2. Activation energy is the collision
energy needed to break bonds &
begin a reaction
3. Increases in concentration &
temperature, increase the
probability of 2 particles colliding
D. Catalysts or Enzymes
1. Normal body temperatures
and concentrations are too
low to cause chemical
reactions to occur
2. Catalysts speed up chemical
reactions by lowering the
activation energy needed to
get it started
3. Catalysts orient the colliding
particles properly so that they
touch at the spots that make
the reaction happen
4. Catalyst molecules are unchanged and can be used repeatedly to
speed up similar reactions.
5. Effectiveness of Catalysts
a. 1000 known enzymes speed up metabolic reactions to 10 billion
times that in beaker
E. Galactosemia
1. Inherited disorder in which baby lacks a digestive enzyme
2. Galactose accumulates in the blood causing anorexia
3. Treatment is elimination of milk from the diet
VIII. DNA Structure
A. Huge molecules containing C, H, O, N and phosphorus
B. Each gene of our genetic material is a piece of DNA that controls the synthesis
of a specific protein
C. A molecule of DNA is a chain of nucleotides
D. Nucleotide = nitrogenous base (A-G-T-C) + pentose sugar + phosphate group