Transcript CHAPTER 3 ORGANIC CHEMISTRY

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Water as a solvent
 Acids, bases and pH
Organic compounds
 Hydrocarbons
 Functional groups
 Dehydration synthesis/
hydrolysis
Water and life
4. The universal solvent
• Water can form hydrogen bonds with any polar or
ionic compound.
• Therefore, many things can be dissolved in water
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The dissolving agent is called the solvent
The dissolved substance is called the solute
A liquid of two or more evenly mixed substances is a
solution
Acids & Bases
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Acids:
 Donate H+ ions to a
solution.
Bases
 Accept H+ ions &
remove them from
solution.
So what is pH??
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pH= A measure of hydrogen ion concentration, but
on a logarithmic scale (potential of Hydrogen)
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Solutions with high hydrogen ion concentrations
 have low pH
 are acidic
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Solutions with low hydrogen ion concentrations
 have a high pH
 are basic
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There is a 10-fold difference in hydrogen ion
concentration between solutions that differ by one
pH unit.
Acids & Bases

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Acids:
 Donate H+ ions to a
solution.
Bases
 Accept H+ ions &
remove them from
solution.
Acids & Bases
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Acids:
 Donate H+ ions to a
solution.
Bases
 Accept H+ ions &
remove them from
solution.
Implications of extreme pH in the
environment…
Acid deposition affects land and
aquatic environments
What US regions are affected by acid
deposition?
EPA Air Quality Website
Some common acids, bases and salts
Salts
Neither acids or bases
 Can form when acids and bases react
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The dissociated hydrogen ions and hydroxide ions join
to form water.
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The remaining ions form ionic bonds creating a salt.
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This is an example of neutralization.
H+Cl- + Na+OH- →
Na+Cl- + H+OH-
Hydrocloric + Sodium
acid
hydroxide
Sodium + Water
chloride
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Molecules containing carbon and hydrogen
Long chains or rings of carbon form backbone of
diverse biological compounds.
C9H8O4
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All organic molecules have a carbon skeleton.
◦ This determines the overall shape of the
molecule.
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Organic molecules differ in these ways:
1. The length and arrangement of the carbon
skeleton.
2. Which atoms are attached to the skeleton
Length: How long is the carbon based
skeleton?
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Dehydration synthesis:
Single units/ monomers are
linked to form large units/
polymers; water removed
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Hydrolysis:
Polymers are broken into
monomers during
metabolism; water is added.
Arrangement of the skeleton: Isomers
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Organic molecules can
have the same number
and composition of atoms,
but can have different
arrangements.
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These are called isomers.
Isomers
Atoms attached to C-H skeleton
Polar functional groups=
hydrophilic
Non-polar functional groups=
hydrophobic
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Macromolecules are very large organic molecules.
The most important organic compounds found in living
things are:
1.
2.
3.
4.
Carbohydrates
Proteins
Lipids
Nucleic acids
Carbohydrates
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Compounds with a 1:2:1 ratio of C:H:O
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Monomers= monosaccharides
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Polymers= polysaccharides
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Hydrophobic or hydrophilic?
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Function?
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Simple sugars are described by the number of
carbons in the molecule.
◦ Triose-3 carbons
◦ Pentose-5 carbons
◦ Hexose-6 carbons
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When two simple sugars are combined they
form disaccharides
◦ Formed via dehydration synthesis
◦ Examples: Maltose, lactose and sucrose
So how is high fructose corn syrup
different from sugar?
HFCS
“Sugar”
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Contain many simple sugars connected by
_________________
Examples of polysaccharides:
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Primarily C, H and O but not a fixed ratio
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Monomer = amino acid
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Polymers= proteins or polypeptides
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Hydophobic or hydrophilic?
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Function?
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An amino acid contains:
1. Amino group
2. Carboxyl group
3. Side chain/ “R
group”
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There are 20 different
amino acids
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Amino acids are joined via dehydration synthesis.
◦ The bond formed between amino acids is called a
peptide bond.
Several amino acids joined together form polypeptide
chains or proteins.
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The sequence of amino acids in a polypeptide
constitutes the primary structure of the protein
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Polypeptides twist and fold into their secondary structure
◦ Form a-helix or b-pleated sheet
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The 2° structure folds in a random manner to form a
globular 3° structure.
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Multiple polypeptides interact to form a functional
protein
Denaturation:
When heat or other environmental conditions break
the bonds that stabilize tertiary structure.
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The protein’s overall shape determines function
◦ Example: Sickle cell anemia
◦ A mutation in one gene causes the protein to have a
different shape- changes RBC shape.
◦ Different shape altered function
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Composed of C, H and a little O, but no fixed ratio
There
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are three types of lipids:
True fats (e.g. pork chop fat and oils)
Phospholipids (membrane components)
Steroids (most hormones)
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Hydrophobic/ hydrophilic?
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Function?
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True fat= triglyceride
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Used to provide energy
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The building blocks of
fats= fatty acid
◦ A glycerol molecule
◦ Three fatty acid tails
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If the carbon skeleton of a fatty acid has as
much hydrogen as possible, the fat is called a
saturated fat.
If the carbons of a fatty acid have double
bonded carbon molecules in them, the fat is
called unsaturated fat.
Trans (Elaidic acid)
Elaidic acid is the principal trans
unsaturated fatty acid often found
in partially hydrogenated
vegetable oils.[22]
Cis (Oleic acid)
Saturated (Stearic acid)
Stearic acid is a saturated fatty
Oleic acid is a cis unsaturated fatty acid found in animal fats and is the
acid that comprises 55–80% of
intended product in full
olive oil.[23]
hydrogenation. Stearic acid is
neither cis nor trans because it
has no double bonds.
These fatty acids are geometric isomers (structurally identical except
for the arrangement of the double bond).
This fatty acid contains no double
bond and is not isomeric with the
previous
^ Alonso L, Fontecha J, Lozada L, Fraga MJ, Juárez M (1999). "Fatty acid composition of
caprine milk: major, branched-chain, and trans fatty acids". Journal of Dairy Science 82 (5): 878–
84. doi:10.3168/jds.S0022-0302(99)75306-3. PMID 10342226.
^ Alfred Thomas (2002). "Fats and Fatty Oils". Ullmann's Encyclopedia of Industrial Chemistry.
Weinheim: Wiley-VCH. doi:10.1002/14356007.a10_173.
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Phospholipids:
◦ Are complex organic
molecules that resemble
fats but contain phosphate
groups.
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Phospholipids are the
major components of cell
membranes.
◦ Some are known as
lecithins.
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Nonpolar molecules that are arranged in rings of carbon
Steroids are important components of cell membranes.
◦ Cholesterol
Steroids often serve as hormones and serve in
regulation of body processes.
◦ Testosterone, estrogen
Cholesterol: LDL vs HDL
Cholesterol does not travel freely in the bloodstream. Carried by lipoproteins (L)
LDL
HDL
LOW Density Lipoproteins
HIGH Density Lipoproteins
Deposit excess cholesterol
on arterial walls.
Remove cholesterol from
the blood.
“bad” cholesterol
“good” cholesterol
Nucleic acids
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Contains C, H as well as lots of N, P and O
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Monomer = nucleotide
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Polymer= nucleic acids
DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)
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Hydophobic or hydrophilic?
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Function?
The functions of DNA
1. Replicate itself
2. Store information and pass to
offspring
3. Make proteins
The nucleotide
monomer
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Each nucleotide contains
1. A 5-carbon sugar
DNA: deoxyribose
RNA: ribose
2. A phosphate group
3. A nitrogenous group
The 4 nucleotides of DNA
The DNA polymer
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Nucleotides are linked
by ______________
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Each DNA molecule is
made of two strands.
◦ Strands are held
together by
hydrogen bonds
between the
nitrogenous bases.
◦ The bases pair
according to base
pair rules
 Adenine - Thymine
 Cytosine – Guanine
a-helix structure of DNA
DNA, genes, and chromosomes
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Each DNA strand is divided into segments called genes
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◦ Genes are the recipes for proteins
 The sequence of nucleotides in a gene dictate the
order of amino acids in a polypeptide.
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Each DNA strand is called a chromosome
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Human cells have 46 chromosomes in each cell.
The RNA polymer
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RNA is a single stranded molecule
Nucleotides:
◦ 4 nucleotides BUT contains uracil instead of thymine
Base pairs with itself and DNA
◦ A-U
◦ G-C
RNA
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is found in three different forms:
mRNA (messenger RNA)
rRNA (ribosomal RNA)
tRNA (transfer RNA)
A special nucleotide- ATP
- Adenosine triphosphate (ATP) contains
1. Ribose sugar
2. Adenine sugar
3. 3 phosphate groups
- Bonds between phosphates are used for energy storage
Overview