Transcript Bio Chap 2 Biomolecules

Chemistry of Biomolecules
• Most biological compounds are ORGANIC
– compounds of CARBON
• The study of these compounds is
ORGANIC CHEMISTRY.
Carbon!
Why it’s cool, and
what it can do
6 electrons
2-4
ORGANIC = CONTAINING CARBON
• The fact that Carbon has 4 electrons in its
outer valence level, means it can make
four covalent bonds with other atoms.
• It can also do neat things like:
• form long chains, branches, rings,
and double bonds
Monomers & Polymers:
when carbons get together
• Individual units called MONOMERS
are linked together to form big
molecules called POLYMERS.
monomer + monomer + monomer =
Polymer
A polymer of glucose (sugar) units
Very large polymers made from Carbonbased chains are called
MACROMOLECULES
“Macro” = giant
(so, “giant molecule”)
How do monomers come together
to form a polymer?
Dehydration
Synthesis:
Chemical reaction
where two
monomers join
together and
release water.
How do polymers break down into
monomers?
Hydrolysis:
Chemical reaction in which water
is added and splits a polymer
back into monomers
Hydrolysis of a disaccharide
MACROMOLECULES come in
different varieties
4 important groups:
–Carbohydrates
–Proteins
–Lipids
–Nucleic Acids
What type of macromolecule
is shown here?
Carbohydrates
• Monomer = monosaccharide
–Ex: glucose, fructose, galactose
• Function: energy, structure
• Example: Sugar, cellulose
(crunchy part of plants), starch,
glycogen (glucose storage in the
liver)
Facts about carbs
• Carbohydrates include C. H, and O in a
1:2:1 ratio, such as in glucose C6H12O6.
• They exist as rings with an integral
Oxygen and many H and OH groups.
• The simplest are monosaccharides,
such as glucose, fructose, or
galactose.
Glucose C6H12O6 – a monosaccharide
Disaccharides
• Disaccharides have two rings, such
as sucrose which is table sugar.
Lactose – milk sugar
Polysaccharides – many
monosaccharides linked
together, such as in glycogen,
starch, and cellulose
Types of polysaccharides
• a. Glycogen: Animal glucose storage in
the liver and muscles
• b. Starch: Plant energy storage.
• c. Cellulose: wood, plant material
Most abundant carbohydrate
Glycogen in liver cells
Plant starch in potato cells
Cellulose fibers in plant cells
Models of carbohydrates
Test for Sugars
the Benedict’s Test
Test for starch - iodine
What type is
shown here?
(Okay, there
are a few
“hints”.)
Proteins
• Monomer = amino acid (20 of them)
• Functions
1.
2.
3.
4.
Structure – muscle proteins
Fight disease - antibodies
Control rates of reaction - enzymes
Transport substances in & out of the cell
- hormones, channel proteins
An Amino Acid
The structure of an amino acid
AMINO
GROUP
ACID
GROUP
The R groups is any atom or group of atoms.
It makes each amino acid unique.
Structure of an Amino Acid
There are 20 different amino acids
with different R groups.
Amino acids are held together by peptide bonds
Peptide Bond Formation
Notice the loss of a water molecule.
A Polypeptide is many amino
acids linked together….
beginning of a protein
Proteins have complex shapes that
determine their function.
The levels of protein structure
• Primary – chains of
amino acids
• Secondary – folds
• Tertiary –
compacting
• Quaternary – two or
more chains
What level is shown here in the
protein insulin?
Quaternary –
Two chains
If the primary structure is disrupted,then
the protein may not be shaped correctly
and will not be able to function as in
hemoglobin in the disease sickle cell
anemia.
Test for protein
the Biuret test
What type of
macromolecule
is shown here?
Lipids
• Function:
– Chemical messengers (steroids)
– Insulation and cushioning
– Long lasting energy source
• Examples:
– Fats and oils
– Phospholipids (cell membrane fats)
– Steroids (cholesterol)
– composed of: fatty acids on a
“glycerol backbone”
Are NOT SOLUBLE in water!
composed of: fatty acids and a “glycerol
backbone”
ACID group
Joined to three fatty acid tails
Fatty acids have many C-H bonds - good energy source.
When three fatty acids join to the glycerol
molecule, three water molecules are lost.
Glycerol
Lipids
Fatty
Acids
To separate parts of the fat
molecules, you have to add 3 water
molecules in a hydrolysis reaction
Hydrolysis of a triglyceride
Saturated fats have only C TO C single bonds in their
fatty acid “tail”.
Unsaturated fats have one or more C = C double bonds
in their fatty acid tail.
Fats and Oils
• Saturated fatty acids
(butter, fats) are solid
at room temperature
• Unsaturated fatty
acids (oils) are liquid
at room temperature
and better for you and
your arteries.
Polyunsaturated
more than one C-C double bond
Is there a shorter way to
represent these BIG molecules?
Omega
end
Short-hand way to write a
fatty acid. The end away
from the acid end is the
Omega end.
An Omega – 3 – fatty acid
OMEGA END
• Omega 3 fatty acids are better for you
than Omega 6 ones.
Trans Fats are not good for you.
Food labels help you decide if the
food you are eating is healthy.
• Due to their chemical structure, lipids
are not soluble in water.
Phospholipids – used in cell membranes
They have a phosphorus atom in their
structure.
The Polar Part is
attracted to water so
HYDROPHILIC
Tails are
HYDROPHOBIC.
The Polar Part
is
attracted to
water so
HYDROPHILIC
Tails are
HYDROPHOBIC.
Another type of lipid that makes up
cell membranes is cholesterol. It is a
steroid and exists as fused rings.
Cell membranes and lipids
A test for fats is a “greasy”
transparent spot on paper.
Nucleic Acids
• Monomer = nucleotide
• Function:
– In heredity – DNA makes up genes
– Direct production of proteins
Examples: DNA and RNA
Can you identify this type of macromolecule?
A nucleotide is made of a sugar,
phosphate group, and a Nitrogen
base.
The Nitrogen
Bases have
Four different
Ones.
DNA’s main job
• To code for the
amino acids that
make a PROTEIN
• RNA helps.
So, hope you have it!
Because this is a QUIZ!
1, How many bonds go to each
Carbon?
2. Is this a monosaccharide,
disaccharide, or polysaccharide?
3. Is this fat saturated or unsaturated?
4. This is a phospholipid found
in cell membranes. Which part
(color) is hydrophobic?
5. What is this a model of?