Transcript biochem notes

Chapter 3
Biochemistry
I. Carbon Compounds
• Inorganic vs. Organic
• Inorganic compounds
do not contain carbon
atoms
• Organic compounds
contain carbon atoms
Carbon Bonding
• Carbon has 4 electrons in its outer
shell
– It wants to gain 4 more to become
stable with 8
– Carbon readily forms four covalent
bonds with atoms of other elements
– Carbon is unique from other
elements because it can bond with
other carbon atoms
– Because of all the preceding, carbon
is able to form an enormous variety
of organic bonds
• Single Bond-sharing
one pair of electrons
• Double Bondsharing two pair of
electrons
• Triple Bond-sharing
three pair of
electrons
Functional Groups
• Clusters of atoms
that influence the
properties or
characteristics of
the molecule
Large Carbon Molecules
• Monomers- a simple molecule, smallest
subunit
• Polymers- made of repeating monomers
• Macromolecules- made up of large
polymers
• Condensation
Reactionsrelease a
molecule of
water to form
a bond
• Hydrolysis- water
• is added to break
• a polymer
You Down with ATP?
• Cells run on energy in
the form of ATP
– Adenosine triphosphate
– Phosphate groups
attached by covalent
bonds, which store high
amounts of energy
II. Molecules of Life
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Carbohydrates
Lipids
Proteins
Nucleic Acids
Carbohydrates
• Composed of carbon, hydrogen, and oxygen in a
ratio of 1C:2H:1O, Serve as a source of energy or
used for structural materials
• Monosaccharides- a monomer of a carbohydrate
(glucose, fructose and galactose)
• Disaccharides- two monosaccharides or a double
sugar (glucose + fructose = sucrose)
• Polysaccharides- three or more monosaccharides
• Animals store glucose in the form of the
polysaccharide glycogen
• Plants store glucose as the polysaccharide
starch
• Strength and rigidity in plants is caused by
the structure of the polysaccharide cellulose
Proteins
• Composed mainly of carbon, hydrogen, oxygen,
and nitrogen, provide structure for cells
• Amino acids-monomers of protein (building
blocks)
• Dipeptides-two amino acids held together by a
peptide bond
• Polypeptides- three or more amino acids, held
together by peptide bonds
Amino Acids
• 20 different amino acids
• All contain
–
–
–
–
–
Central carbon
Amino group
A carboxyl group (COOH)
A single hydrogen
R group (the only thing different between the 20 amino
acids) influences the properties of the amino acid
Peptide Bond
• Covalent bond linking two amino acids
• A condensation reaction (water is formed
and released)
• Long chains of amino acids has positive and
negative regions which fold to give protein
molecules unique shapes
• The shapes can be denatured when heated
Enzymes
• RNA or protein
molecules that act
as biological
catalysts
• Depend on the fit
between
– Substrate
– Enzymes active
site
Lipids
• Long chains of carbon with many
hydrogens
• Function is to store energy
• Include: fatty acids, triglycerides,
phospholipids, waxes, steroids
Fatty Acids
• Unbranched carbon chains that make up most
lipids
• Long chain of carbon with a carboxyl group at one
end
• Carboxyl end is polar and therefore hydrophilic
• Hydrocarbon end is nonpolar and therefore
hydrophobic
• Fatty acids include triglycerides, phospholipids,
and waxes
• Saturated Fatty Acids
– Carbon atoms fully saturated with hydrogens
• Unsaturated Fatty Acids
– Carbon atoms with double bonds
Triglycerides
• 3 molecules of a fatty acid
joined to one molecule of
the alcohol glycerol
• Saturated triglycerides
have high melting points
and are hard at room temp
(butter and fats in red
meat)
• Unsaturated are usually
soft or liquid at room temp
and found in plant seeds
(olive oil)
Phospholipids
• Two fatty acids attached to a
molecule of glycerol and a
phosphate group attached to the
third carbon of the glycerol
• Help make up the cell
membrane
• Lipid bilayer
– Hydrophobic head
– Hydrophilic tail
Waxes
• A long fatty acid chain
connected to a long
alcohol chain
• Waterproof
• Help form protective
coating in plants and
animals (earwax)
Steroids
• Four fused carbon
rings with various
functional groups
• Hormones
• Cholesterol
Nucleic Acids
• DNA
– Contains information that determines the characteristics
of an organism and directs cell activities
• RNA
– Stores and transfer information of DNA to make
proteins
• Composed of nucleotides
– Sugar
– Phosphate
– Base
Review
• What do all organic compounds contain?
– Carbon
How many electrons are shared
in a double bond?
• 4 electrons (aka 2 pair)
How many electrons does
carbon want to gain?
• 4 electrons
What is the smallest subunit
• Monomer
• What is the monomer
of carbohydrates?
– monosaccharides
• What is the monomer
of proteins?
– Amino acid
• How do animals store
glucose?
– Glycogen
• How do plants store
glucose?
– Starch
• What are the polymers
of carbohydrates
– polysaccharides
• What are the polymers
of protein?
– Polypeptides
• What are the only two
macromolecules that
contain nitrogen?
– Proteins
– Nucleic Acids
• Which macromolecule
is nonpolar?
– Lipids