organic molecules - st. johns county school...
TRANSCRIPT
Organic Molecules
• Contain C
– Can form 4 strong covalent bonds
– Ergo can form many complex, stable molecules
– Chemistry of life is complex, and requires complex
molecules
– However, several kinds of molecules contain carbon
but are not organic. CO2, for example
– All organics are naturally produced by processes in
living cells.
The greater % of any organism consists of 4 elements:
carbon, oxygen, hydrogen and nitrogen.
The Four Main Types of
Organic Molecules • Carbohydrates
– Structure
• Consist of C, H, O
• General formula = (CH20)n
• Often end in -ose
sugars
• 1.) Monosaccharides- simple sugars one ring; most are
C6H12O6
– Isomers: same number and type of atoms, different structure
» Glucose- store and release energy, mainly from C-H bonds;
main transport sugar in vertebrates
» Fructose
» Galactose
The straight chains form rings in
solution.
Monosaccharide isomers
• The difference between glucose and galactose is
simply in the way two things (H and OH) are
attached to one of the carbons in the ring.
Double sugars
• 2.)Disaccharides :eg – sucrose, lactose, maltose
– 2 mono’s bonded by dehydration synthesis
– Hydrolysis breaks them back into mono’s
– Sucrose = glucose bonded to fructose
» It is the main transport sugar in plants
Complex Carbohydrates
• Complex Carbs
– Polysaccharides-most are glucose polymers which form chains and branches
• Animal starch - glycogen
– Store energy in liver and muscles
• Plant starch- amylose
• Cellulose- structural function
– Cell walls
• Chitin-arthropod exoskeleton, fungus cell walls
Making and Breaking Organics
• All large organic polymers are made by joining smaller molecules called monomers in a chemical process called dehydration synthesis.
• They are broken back down by hydrolysis.
Lipids • Lipids-functions include energy storage, forming structural
parts, insulation, cushioning body organs, and being hormones
– Store 2 X as much energy/gram as carbs
– Insoluble in H2O
Structure of most common lipids: Glycerol and fatty acids- Triglyceride (main type of lipid): 3 fatty acids and gycerol
• Fats and oils-
– Fats:Saturated- no double bonds between carbons, most H possible, animal products, solid at room temp.
– Oils: Unsaturated- double bonds, liquid (oils), plant products
– Lipid with a structural function example: Phospholipids in ALL cell membranes (NOT cell walls)
– Omega 3 oils are unsaturated and very healthy
– Hydrogenated trans fatty acids are bad
• Waxes
• Lipids are an exception among macromolecules
because they do not have polymers.
• The unifying feature of lipids is that they all
have little or no affinity for water.
– This is because their structures are dominated by
nonpolar covalent bonds.
• Lipids are highly diverse in form and function.
Introduction
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Although fats are not strictly polymers, they are
large molecules assembled from smaller
molecules by dehydration reactions.
• A fat is constructed from two kinds of smaller
molecules, glycerol and fatty acids. You should
be able to recognize a sketch of a fatty acid and a
glycerol.
1. Fats store large amounts of energy
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Glycerol consists of a three carbon skeleton with
a hydroxyl group attached to each.
• A fatty acid consists of a carboxyl group attached
to a long carbon skeleton, often 16 to 18 carbons
long.
Fig. 5.10a
• The many nonpolar C-H bonds in the long
hydrocarbon skeleton make fats hydrophobic.
• In a fat, three fatty acids are joined to glycerol
creating a triglyceride.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 5.10b
Saturated vs. Unsaturated Fats
Lipid hormones made from
cholesterol
Cholesterol is a sterol. Not a
glyceride type, but a lipid still.
Cholesterol is needed for:
• Your cells use it to make the sterol
hormones testosterone and estrogen as well
as vitamin D (with sunshine’s help in your
skin cells).
• Cholesterol is in all animal cell membranes,
but not plant or any other cell membranes,
which is why plants have no
cholesterol.Watch
Proteins - Amino Acid Polymers
Peptide bond formation
• Amino acids are joined by a type of covalent bond called a peptide bond during dehydration synthesis. Bonding is always between the carboxyl group of one and the amine group of the other.
Proteins show great variety
• There are 20 different kinds of amino acids
• An infinite number of different proteins is
possible by combining different amino acids
in different sequences.
• In actuality, we find several thousand kinds
of proteins in living things.
Protein Functions
• Structural proteins- eg. Keratin, collagen, silk
• Hormones: Insulin, Human Growth Hormone
• Enzymes- catalysts; ususally have an -ase ending. Sucrase.
• Transport proteins: in cell membrane and in circulatory systems. Hemoglobin, for example.
• Defense function: Antibodies - made by white blood cells in the immune system
Denaturation - when bonds break, often by heat, the protein loses its natural shape, and therefore its function
Primary Structure
• The order of amino
acids determines what
the shape of every
protein will ultimately
be.
• Identical chains will
always fold up the
same way.
Even small changes in primary
structure can be deadly
Secondary structure
• Linus Pauling won a
Nobel Prize for
discovering the alpha
helical shape of many
proteins. 20 structure is
caused by hydrogen
bonding between amino
acids in the chain,
producing regular,
repeated patterns.
Tertiary Structure
• These irregular
foldings are due to
many different types
of bonds between R
groups. The H bonds
which determine
secondary structure
are not between R
groups.
Quaternary structure: multiple
chains combine to make 1 protein
Two overall shapes of proteins
• When a protein has taken its final shape, it
will be classified as one of two possible:
• Fibrous (string-like): Collagen, silk
• Globular (roundish): Hemoglobin, insulin,
all enzymes
• Let’s look at some animations…
• Secondary tertiary quaternary
Which of the following is not
normally a function of proteins in
healthy cells?
A. functioning as catalysts
B. long-term energy storage
C. a component of cell membranes
D. Transport of particles
Athletes are often concerned with the question of
how much protein they need in their diets
because of the requirement of growing muscles
for protein. Just as muscles need the basic
building block of protein, protein itself has basic
building blocks. Which of the following are
the basic building blocks of protein?
a. Nitrates
b. Amino acids
c. Monosaccharides
d. Nucleotides
Based on the students’ results, at what pH does
catalase work best: 1,4,7, or 10?