 Water
is a
molecule
, covalent, inorganic
 Due
to unequal sharing of electrons
between oxygen and hydrogen, each atom
has a partial charge
 These
 The
partial charges are called
weak forces that attract and hold
molecules with opposite dipoles together
are called
 Negative
dipoles are those with a partial
negative charge, like oxygen in water
 Positive
dipoles are those with a partial
positive charge, like hydrogen in water
 The
cohesion among water molecules
allows water to travel in tubes such as
roots, up to the leaves of plants and in
blood vessels
 cohesion also accounts for surface
tension


Excellent
High specific heat capacity which is how
some animals maintain a body temperature
that is life sustaining

Great Lubricant

Transparent

Greatest
is at 4oC

Molecules that are ionically bonded
together will
in water and the
water will transport the resulting ions
ex.
NaCl(aq) -> Na+(aq) + Cl-(aq)
 Water
molecules self-ionize to form
hydrogen and hydroxide ions



A strong acid is HCl because it readily
dissociates, producing free hydrogen and
chlorine ions
NaOH is a strong
because it readily
dissociates, producing free hydroxide and
sodium ions
Bases have a neutralizing effect on acids

H2O - > H+ + OH-

HCl - > H+ + Cl-

NaOH - > Na+ + OH-

Na+ + OH- + H+ + Cl- - > NaCl + H2O

pH is a measure of the amount of free hydrogen
ions in a system

pH = -log[H+]

Range from 1 to 14 (in general)

When [H+] = [OH-], the pH = 7, which is neutral

Above 7 is basic and below is acidic

pH in the blood varies from 7.35-7.38 whereas
pH in the stomach is about 2.5
 To
prevent significant changes in pH and to
maintain homeostasis, organisms have buffers
 These
are molecules that can either pick up or
release hydrogen ions
 Bicarbonate
is a common buffer (HCO3- )



When small molecules are combined, water is often a
product, a reaction known as dehydration synthesis
The reverse, involving water as a reactant is called
These are called enzymatic reactions because they
require an enzyme to react
 Macromolecules
are made from unit
molecules, or monomers
 If
the macromolecule is a sequence of
many monomers, it is called a
 Carbohydrates
 Lipids
 Proteins
 Nucleic
 All
acids
but lipids are considered polymers
 Lipids
do not really form a polymer because
the number of unit molecules that can join
together to form a macromolecule is limited
 Which
adjective does NOT apply to
water?
A)
B)
C)
D)
Bent
Polar
Organic
Covalent
 Which
adjective does NOT apply to
water?
A)
B)
C)
D)
Bent
Polar
Organic
Covalent
 The
A)
B)
C)
D)
water in an organism’s body helps
reactions occur
transport molecules
maintain body temperature
all of the above
 The
A)
B)
C)
D)
water in an organism’s body helps
reactions occur
transport molecules
maintain body temperature
all of the above
 Which
of the following is closest to the
pH of blood?
A)
B)
C)
D)
4.8
6.7
7.3
10.8
 Which
of the following is closest to the
pH of blood?
A)
B)
C)
D)
4.8
6.7
7.3
10.8
 Which
of the following BEST describes
an acidic solution?
A)
B)
C)
D)
Lots of H+ present
Lots of OH- present
More H+ than OH- present
More OH- than H+ present
 Which
of the following BEST describes
an acidic solution?
A)
B)
C)
D)
Lots of H+ present
Lots of OH- present
More H+ than OH- present
More OH- than H+ present
 Buffers
that keep the pH from rising
above 8.3 MOST LIKELY
A)
B)
C)
D)
release H+
bond with H+
bond with OHdissociate to release both H+ and OH-
 Buffers
that keep the pH from rising
above 8.3 MOST LIKELY
A)
B)
C)
D)
release H+
bond with H+
bond with OHdissociate to release both H+ and OH-
 An
example of the synthesis of a polymer
could be
A)
B)
C)
D)
amino acids taking up excess hydrogen
ions
joining monosaccharides and removing
water
forming water by combining an acid and a
base
adding water to break a polypeptide into
amino acids
 An
example of the synthesis of a polymer
could be
A)
B)
C)
D)
amino acids taking up excess hydrogen
ions
joining monosaccharides and removing
water
forming water by combining an acid and a
base
adding water to break a polypeptide into
amino acids
are hydrates of carbon


The
of a carbohydrate is CH2O
(i.e. C + H2O = CH2O)
Either sugars or polymers of sugars
(a
is a very common
that has a molecular formula of C6H12O6)

Glucose undergoes dehydration synthesis to become the
double sugar
(or a
)

Continued DS will result in larger molecules called
and finally
 An
empirical formula is the simplest form of
it’s molecular formula
 Think
of the empirical formula as the
smallest ratio of all of the elements present
in the molecular formula
 For
example,
take C6H12O6
 The
empirical
formula is CH2O
,
, and
same chemical formula, i.e.
all have the
, (C6H12O6)
 They
differ only in the arrangement of their
atoms
is another simple sugar (C5H10O5)
 Table
sugar, or sucrose
(glucose + fructose)
 Lactose, the
sugar in milk
(glucose + galactose)


Differ by the way the monosaccharides are bonded
together
Starch is a linear polymer that spirals to form a helix
that sometimes branches
 Glycogen
is highly branched, in
comparison to starch
 Cellulose
is a linear sequence of glucose
molecules




The product of photosynthesis
Plants make it, metabolize it for energy, store it as
a starch and convert it into cellulose to build new
cell walls for growth
Our food contains carbohydrates
Starches and disaccharides are digested into
glucose molecules, which are transported by our
circulatory system to body cells where they are
oxidized in the mitochondria during the process
of cellular respiration
 Excess
glucose is stored in the liver in
the form of glycogen
 Cellulose
is sometimes referred to as
dietary fiber, as people are unable to
digest it in food, and serves a useful
purpose in the production of feces

A second group of biochemicals is lipids

Lipids will not mix freely with polar solvents like water



We eat them as food, our bodies produce them and they
are the second most important energy molecule for us
They unfortunately tend to be stored as adipose (fat) cells
Include fatty acids, neutral fats, oils, steroids like
cholesterol and some hormones, waxes and other
specialized molecules
 Fatty
acids are non-polar chains of carbon
and hydrogen with a carboxylic acid end
 Some
fatty acids are saturated (without double
bonds) while others are
(with
double bonds and therefore less hydrogen)
 In
general, the fatty acids produced by animal
tissues are more saturated and tend to be solid
at room temperature
 Those
produced by plant tissues are
unsaturated and tend to be liquid, like
vegetable oil (good for body)
 Produced
by the DS of one or more fatty
acids with glycerol, an alcohol
 Many
types are possible due to the number
and variety of fatty acids and the three
different bonding locations on glycerol
A
monoglyceride has one fatty acid
combined with a glycerol
A
diglyceride has two fatty acids and a
glycerol
A
triglyceride has three and a glycerol
 Lipids
that are biologically important including
phospholipids, steroids and waxes
 Phospholipids
are a variation of a tryglyceride
where one of the fatty acids is replaced with a
phosphate and nitrogen containing group
 The
replacement of a phosphate and
nitrogen containing group creates a polar
region on an otherwise nonpolar
molecule
 Consequently
phospholipids can mix
with both polar and nonpolar material
 They
are an integral component of all cell
membranes
 Nonpolar
ring structures
 Sex
hormones
(estrogen and testosterone)
 Cholesterol, which
helps maintain the
integrity of cell membranes
 Waxes
are combinations of fatty acids and
an alcohol larger than glycerol
 Which
of the following is NOT a
polysacchraide?
A)
B)
C)
D)
Starch
Glycerol
Cellulose
Glycogen
 Which
of the following is NOT a
polysacchraide?
A)
B)
C)
D)
Starch
Glycerol
Cellulose
Glycogen
 Which
biochemical is a component of
cell membranes?
A)
B)
C)
D)
Hormones
Triglycerides
Disaccharides
Phospholipids
 Which
biochemical is a component of
cell membranes?
A)
B)
C)
D)
Hormones
Triglycerides
Disaccharides
Phospholipids
 Which
of the following molecules is the
most highly branched?
A)
B)
C)
D)
Starch
Maltose
Glucose
Glycogen
 Which
of the following molecules is the
most highly branched?
A)
B)
C)
D)
Starch
Maltose
Glucose
Glycogen
 What
A)
B)
C)
D)
is a phospholipid composed of?
Cholesterol, glycerol, fatty acids
Phosphate group, cholesterol protein
Fatty acids, phosphate group, glycerol
Glycerol, amino acids, phosphate group
 What
A)
B)
C)
D)
is a phospholipid composed of?
Cholesterol, glycerol, fatty acids
Phosphate group, cholesterol, protein
Fatty acids, phosphate group, glycerol
Glycerol, amino acids, phosphate group
 To
convert a saturated fatty acid into an
unsaturated fatty acid,
A)
B)
C)
D)
Add hydrogen and double bonds
Remove hydrogen and add double
bonds
Add hydrogen and remove double
bonds
Remove hydrogen and double bonds
 To
convert a saturated fatty acid into an
unsaturated fatty acid,
A)
B)
C)
D)
Add hydrogen and double bonds
Remove hydrogen and add double
bonds
Add hydrogen and remove double
bonds
Remove hydrogen and double bonds
are polymers of unit molecules
called amino acids
 Range
from 9 to hundreds of amino
in their structure
 There
 At
are twenty different amino acids
one end there is an amino group and
at the other there is a carboxyl
 Include
enzymes, antibodies, and transport
proteins (like hemoglobin), each having a
metabolic function
 Example, enzymes
reactions
 Maltase
catalyze chemical
is the enzyme that cleaves maltose
into glucose molecules, carbonic anhydrase
is an enzyme in blood which plays a role in
preparing carbon dioxide for transport from
tissue to the lungs
 Form
parts of structures
 Keratin, a
component of fingernails and
hair, and collagen, found in connective
tissue, are two examples
Amino Acids

The carboxylic group donates a carboxylic acid –
hence the term amino acid

Each amino acid has a unique “R” group bonded to
the central carbon

When two amino acids bond together through DS,
they form a dipeptide

The new bond called a peptide bond, which links the
amino acids together, is a strong covalent bond

A tripeptide has two peptide bonds and holds three
amino acids together
 Primary
Structure
 Secondary
 Tertiary
Structure
Structure
 Quaternary
Structure
 The
sequence of amino acids
 Millions
of sequences of amino acids as
there are twenty different amino acids
 Consequently, millions
proteins are possible
of different

As a cell builds a protein, the molecule begins to twist due
to the angle of the peptide bonds

Due to the attraction between H-bonds, the linear
arrangement can take on other conformations



A spring-like shape forms called an alpha helix (α-helix),
which is held together by H-bonds between every forth
amino acid
The alternate structure forms when the H-bonds form
between linear segments of amino acids forming what is
called a beta (β)–pleated sheet
All proteins have secondary structures

Some proteins, like enzymes, reach this stage

It is the bending and folding of the α-helix


As a growing helix gets longer, some amino acids
cannot fit in the configuration and cause kinks or
bends in the otherwise regular spiral pattern
When this happens, segments of the
helix are brought close to each other
and new bonds are formed between
these adjacent sections to hold it into
a 3D shape

The weak H-bonds of the tertiary structure are fairly
sensitive to things like pH changes, temperature
changes, and the presence of heavy metal ions

Proteins may lose their tertiary shape due to
breaking of H-bonds

Reconfigured proteins like these are called
denatured

When the shape is changed, so does its functions (i.e.
The protein in milk, casein, denatures and forms
insoluble floating lumps)
 Occurs
in some proteins where different
tertiary configurations associate together
and function as a unit
 Hemoglobin
is a well-known
protein that is actually made
up of four tertiary polypeptides
associated with a central
iron-containing component,
called a “heme” group
 How
many peptide bonds link 108 amino
acids together?
A)
B)
C)
D)
106
107
108
109
 How
many peptide bonds link 108 amino
acids together?
A)
B)
C)
D)
106
107
108
109
 When
two amino acids join together they
form a
A)
B)
C)
D)
dipeptide
diglyceride
disaccharide
dinucleotide
 When
two amino acids join together they
form a
A)
B)
C)
D)
dipeptide
diglyceride
disaccharide
dinucleotide
 An
alpha helix bent and folded into a 3D
shape represents a
A)
B)
C)
D)
primary structure
secondary structure
tertiary structure
quaternary structure
 An
alpha helix bent and folded into a 3D
shape represents a
A)
B)
C)
D)
primary structure
secondary structure
tertiary structure
quaternary structure
 What
A)
B)
C)
D)
type of bond is the bond marked X?
Ionic
Peptide
Hydrogen
Electrostatic
 What
A)
B)
C)
D)
type of bond is the bond marked X?
Ionic
Peptide
Hydrogen
Electrostatic




Two types: deoxyribonucleic acid (DNA) and ribonucleic acid
(RNA)
Polymers of unit molecules called nucleotides (composed of a
sugar, a phosphate group, and a nitrogen-containing, or
nitrogenous, base)
In DNA, the sugar is deoxyribose; in RNA, it is ribose
The phosphate group is always the same, but the bases differ
slightly between DNA and RNA

A double helix has a double backbone of alternating deoxyribose and
phosphate molecules

The bases are bonded onto each sugar and H-bonded to each other so
that the two strands are held together

The four different bases of DNA are:

adenine (a double ring structure called a purine)

Thymine (a smaller, single ringed structure called pyrimidine that is
always paired with adenine

Guanine (purine)

Cytosine (Which is always H-bonded with gaunine, pyrimidine)
Other combinations of purines and pyrimidines do not exist because unable
to H-bond to each other
 Shorter, single
stranded molecule
produced by a segment of DNA
 Uracil
takes the place of thymine in RNA
Basis of
Contrast
DNA
RNA
Sugar
Deoxyribose
Ribose
Location
Nucleus
Nucleus and
cytoplasm
# strands
Two
One
Bases present
A, T, G, C
A, U, G, C

DNA, along with particular proteins, histones, forms
chromosomes

Three functions:

Replicate, or make copies of itself for cell division

Controls cellular activity by containing the codes for
the synthesis of all proteins, including enzymes

Is be able to change, or mutate, to provide raw
material


Adenosine triphosphate (ATP) is a particularly
important nucleic acid
It is an RNA nucleotide with an adenine base
(adenine + ribose = adenosine) and three
phosphate groups attached to it

The phosphate bonds
are very energy-rich bonds

Cells store energy in this way
(as chemical energy)
 In
order to release the energy an enzyme,
ATPase, breaks one of the bonds, thus
producing ADP
 Often
 ATP
illustrated as the ATP cycle
is sometimes
referred to as the
energy currency of a
cell
 Which
bond type exists between the
bases in DNA?
A)
B)
C)
D)
Ionic
Peptide
Covalent
Hydrogen
 Which
bond type exists between the
bases in DNA?
A)
B)
C)
D)
Ionic
Peptide
Covalent
Hydrogen
 The
helical portion of a peptide consists
of
A)
B)
C)
D)
a sequence of “R” groups only
…RCC…RCC…RCC…etc
…NCC…NCC…NCC…etc
…P-sugar…P-sugar…P-sugar…etc
 The
helical portion of a peptide consists
of
A)
B)
C)
D)
a sequence of “R” groups only
…RCC…RCC…RCC…etc
…NCC…NCC…NCC…etc
…P-sugar…P-sugar…P-sugar…etc
 RNA
A)
B)
C)
D)
is composed of a series of
purines
nucleotides
pyrimidines
amino acids
 RNA
A)
B)
C)
D)
is composed of a series of
purines
nucleotides
pyrimidines
amino acids
 Which
combination makes up a
nucleotide?
A)
B)
C)
D)
base – acid – salt
DNA – RNA – water
base – sugar – phosphate
adenine – thymine - uracil
 Which
combination makes up a
nucleotide?
A)
B)
C)
D)
base – acid – salt
DNA – RNA – water
base – sugar – phosphate
adenine – thymine - uracil
 “Available
energy” for cells is
represented by
A)
B)
C)
D)
W
X
Y
Z
 “Available
energy” for cells is
represented by
A)
B)
C)
D)
W
X
Y
Z
 ATP
A)
B)
C)
D)
is significant in cells because it
contains adenine
stores ribose for RNA
has high energy bonds
is a unit molecule for chromosomes
 ATP
A)
B)
C)
D)
is significant in cells because it
contains adenine
stores ribose for RNA
has high energy bonds
is a unit molecule for chromosomes