Transcript 02 B organic chemistry - macromolecules

Organic Chemistry
What is it?
What does it include?
Why do we care?
chapter 2.3, 2.4 and 2.5 in text
Carbon:
the defining atom of organic chemistry.
← -Four electrons available for
covalent bonding
(valence electrons).
-Forms chains, branches, rings. →
- Can carry a wide variety of “add-ons”.
(What are the 4 kinds of organic molecules?)
Macromolecules
… BIG molecules
Polymer:
Macromolecule formed
by stringing together
smaller monomers.
Dehydration synthesis:
→
a water molecule is
removed to form a bond
between monomers.
Hydrolysis:
→
a water molecule is
inserted,
breaking (lysing) a bond.
Types of organic molecules; 1 of 4
Carbohydrates
One to many sugars: mono-, di-, polysaccharides.
Uses: energy, structure, components of other molecules.
Examples of monosaccharides:
Note especially:
-general formula (CnH2nOn)
-the ending “-ose”
denotes a sugar
-used for energy,
as subunits of other molecules,
or as monomers of diand polysaccharides.
glucose: the currency of
cellular energy exchange.
ribose: part of nucleic acids.
Carbohydrates (cont.)
Disaccharides
Note:
- dehydration
reactions
- sucrose is table
sugar
- used for short-term
energy storage
Carbohydrates (cont.)
Polysaccharides
Note:
- these two are for
longer-term energy storage;
starch (less branched) in plants
glycogen (more branched)
in animals
Carbohydrates (cont.)
Polysaccharides (cont.)
Note:
-cellulose is a structural
carbohydrate (in plants)
- The difference between
digestible (to us) starch and
indigestible cellulose is…
(can you see it?)
[Only certain bacteria make
the enzymes to digest
cellulose. Generally,
any animal living
off grass or wood has these
specific bacteria in their
guts to break the cellulose
into digestible disaccharides.]
Types of organic molecules; 3 of 4
Lipids
3-carbon Glycerol backbone with fatty acid add-ons, hence “triglycerides”
Uses: long-term energy storage, structural, hormonal
Note:
- another dehydration!
- C, H, very little O.
- non-polar, hydrophobic
- This is NOT a polymer
Lipids (cont.)
Saturated fatty acids are solid at lower temperatures,
and may contribute more to blocked blood vessels than
Unsaturated fats, which have double bonds.
Lipids (cont.)
Phospholipids
- Instead of the third
fatty acid, these have
a phosphate group,
which is hydrophilic
As the “heads” stay in contact with water,
and the “tails” stay away,
small droplets
and bilayers
spontaneously form.
Cells and organelles
are surrounded by these
phospholipid bilayers.
Lipids (cont.)
Cholesterol is a
steroid, which is a lipid
that doesn’t fit
the structural model.
-It is hydrophobic.
-It is required for
membrane flexibility
(though too much in the
diet precipitates out).
-It can be converted
into any of many
steroid hormones →
student.britannica.com/eb/art-62250
Types of organic molecules; 4 of 4
Nucleic Acids
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)
Polymers of 4 nucleotides
guanine, cytosine, adenine, thymine, and uracil. Hey, that’s 5!...
Uses: Information transformation
We will have more detail later, when we study
DNA replication
(making sure that all cells get the same information),
Transcription
(DNA sequence directing RNA sequence), and
Translation
(RNA directing amino acid sequence
in proteins construction).
(Have you already learned about nucleic acid structure?)
Nucleic Acids (cont.)
Note:
- nucleotides have three parts
- letters correspond to nitrogenous base
- differences between DNA and RNA
Nucleic Acids (cont.)
Note:
-complementary base pairing
-held together by hydrogen bonds,
-to form the double helix
-chains run in opposite directions…
-Phosphodiester linkage is another
dehydration reaction!↓
original.britannica.com/eb/art-106485/The-hum...
www.web-books.com/MoBio/Free/Ch3A5.htm
Types of organic molecules; 2 of 4
Proteins
Polymer of amino acids (20)
Uses: many …
structural
amino acid storage
transport
hormones (some)
receptors
movement
defense
enzymes
web silk, collagen in cartilage, keratin in nails….
ovalbumin in eggs, casein in milk…
hemoglobin in blood, membrane proteins…
insulin to control blood glucose…
on cell membranes, so they can sense chemicals..
actin and myosin in muscles…
antibodies of the immune system…
facilitate chemical reactions, like peptidase…
(We will encounter many of these throughout the year…)
the Amino Acids
Note
-common core structure:
carbon atom
“amine” (nitrogen) group
“acid” (here a carboxyl
group)
variable “R” group
Peptide bond
This is another
dehydration reaction.
(Can you identify the
amino acids illustrated?)
Proteins:
Their complex structure
contributes
to their specificity-
←secondary:
H bonds form
helices
and sheets.
←primary:
sequence of amino acids.
tertiary: ↓ R group interactions.
quaternary: multiple molecules interacting ↑
Enzymes:
Why are they needed?
Any reaction that isn’t
spontaneous has an
activation energy:
The energy to get it going
could be thermal,
mechanical (pressure)…
Extreme pH can break
some molecules.
Is a body a good place
for fluctuations like these?
Enzymes lower the
activation energy,
and ensure specificity.
ghs.gresham.k12.or.us/.../notes/chpt8/chpt8.htm
Enzymes (cont.):
The ‘lock and key’ model of enzyme function
Note: - Only certain things fit the active site.
- The enzyme is not consumed in the reaction.
- Enzymes mediate anabolic
as well as catabolic reactions.
(Contrast with induced fit model)
ghs.gresham.k12.or.us/.../notes/chpt8/chpt8.htm
Enzymes (cont.):
To some extent increased temperature
speeds reactions up
(more collisions between
enzyme and ligand),
but too much thermal energy will
denature the protein
(causing it to lose its specific
2o, 3o and 4o structure,
and therefore its active site
and enzymatic properties).
pH extremes will also denature proteins
by interfering with the hydrogen bonds.
Each enzyme has its optimal
temperature and pH.
How do we obtain these materials?
Assignment:
Make a layered (flip) book addressing the followingFor each of the 4 major groups of organic molecules include
-name of group
-name and drawing of macromolecule
-name and drawings of monomers or subunits
-at least two specific examples
(i.e., a monomer, and a polymer)
-uses performed in the body
-a brief reflection of how the structure enables the function
-dietary sources
Include bibliography at back.
Be creative. Your grade will reflect how original/colorful/engaging,
as well as how accurate and precise it is.
Which organic macromolecules are polymers?
What are the monomers for each?
List all the uses
for each category.
Which are hydrophobic? Hydrophilic?
Ramifications for each?
Form determines function:
Describe how this applies to each group.
What atoms are included in each macromolecule?
What foods would be a good source for each group?
Can your body absorb macromolecules?
Benchmark SC.912.L.18.1
Describe the basic molecular structures
and primary functions
of the four major categories
of biological macromolecules.
Enduring Understandings
Differentiation of macromolecules
allows organisms to most effectively
meet their biological needs.
Essential Questions
Why can we all be considered
carbon-based life forms?
Why do different types (?) of carbon
chains meet our needs?
organic chemistry
amino acid
steroid
valence electron
amine
nucleic acid
macromolecule
carboxyl
nucleotide
polymer
R group
DNA
monomer
carboxyl
RNA
dehydration synthesis
enzyme
guanine
hydrolysis
lipid
cytosine
carbohydrate
glycerol
adenine
monosaccharide
fatty acid
thymine
disaccharide
triglyceride
uracil
polysaccharide
saturated
ribose
starch
unsaturated
phosphate group
glycogen
phospholipid
nitrogenous base
cellulose
phosphate group
complementary base pairing
protein
phospholipid bilayer
double helix
lock and key
cholesterol
denature
monomer
polymer
sugar
starch
carbohydrate
lipid
fatty acid
glycerol
nucleic acid
nucleotide
protein
amino acid
chemical reaction
reactants
products
activation energy
active site
catalyst
enzyme
rate of reaction
substrate
temperature