Organic Compounds
Carbon atoms covalently bonded to each other forming the backbone of the molecule
More than 5 million Hydrocarbons can be produced in a wide
variety of shapes Many organic compounds are large
macromolecules
Properties of Carbon
4 valence electrons Form 4 covalent bonds
Can bond to another Carbon Or another element
Carbon-Carbon bonds are strong Not limited to single bonds (C-C)
Can form double (C=C) or triple (C=C) bonds
Properties of Carbon
Carbon Chains can be: Unbranched Branched Rings
Do not form in a single plane 3-D Symmetrical
Properties of Carbon
Freedom of rotation around each carbon-carbon single bond Organic molecules are flexible Variety of shapes
Can link together in variety of patterns creating even wider variety of shapes
Isomers
Compounds with the same molecular formula but different structures Different properties Different names
Cells can distinguish between isomers
Functional Groups
Change the properties of organic molecules
Participates in chemical reactions Replace a hydrogen P. 46 - 47
Functional Group Name of compounds Functions
Hydroxyl -OH Alcohols hydrophilic and polar
Aldehydes (when the =O
occurs at the end of chain)
Carbonyl -CO Ketones (when the =O hydrophilic and polar
occurs in the middle of chain)
Carboxyl -COOH Carboxylic Acids act as acids, donate protons
Amino -NH2 Amines act as bases, pick up protons
from acids
Polymers
Most macromolecules are polymers, produced by linking small organic compounds called monomers
This diversity comes from various combinations of the 40-50 common monomers. (These monomers can be connected in
various combinations like the 26 letters in the alphabet can be used to create a great diversity of words).
Carbohydrates
Sugars, starches, and cellulose Used for fuel and structural materials Carbon, Hydrogen, and Oxygen in
1:2:1 ratio Ex.
Carbohydrates
1 sugar unit: monosaccharide 2 units: disaccharide many sugar units: polysaccharide Pentoses – 5 carbon sugars
Deoxyribose Ribose
Monosaccharides
Simple sugars 3-7 carbon atoms Glucose and
fructose Glucose important
energy source for cells
Many are ring structures
Polysaccharides
polymers (long chains of repeating units) of monosaccharides
Starch and glycogen Starch – main storage carbohydrate of plants Glycogen – main storage carbohydrate of animals
Starch Plants store starch within plastids, including
chloroplasts. Plants can store surplus glucose in starch and
withdraw it when needed for energy or carbon. Animals that feed on plants, especially parts rich
in starch, can also access this starch to support their own metabolism.
Cellulose Most abundant polysaccharide 50% or more of all the carbon in plants Humans cannot digest cellulose Symbiotic Relationships - Herbivores
Other Polysaccharides with Special Roles
Chitin External skeletons
Insects Crayfish Other arthropods
Cell walls of fungi Tough structures
Multiple hydrogen bonds
Glycoproteins Carbohydrates +
proteins Outer surface of
cells Protection Allow cells to stick
together Ex. mucus
Lipids
Exception: do not have polymers, just large molecules
Fats or fatlike Insoluble in water (hydrophobic)
Nonpolar covalent bonds Mainly hydrogen and carbon, few
oxygen-containing functional groups
Functions of Lipids: Reserve energy storage
2x as much energy/gram than carbohydrates Carbs and proteins can be transformed into fats
and stored in adipose tissue Structural components of cellular
membranes Hormones Insulation Cushioning
Triglycerides (fats) Fatty Acid + Glycerol
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
Saturated Fats
Contain max. possible # of hydrogen atoms
No double bonds Solid at room temperature
Animal fat and solid vegetable shortening
Not a dietary requirement
Unsaturated Fats
Liquid at room temperature Include double bonds Monounsaturated – 1 double
bond Polyunsaturated – more than 1
double bond Some are essential nutrients that
must be obtained from food
Steroids Ring structure with different functional
groups attached Cell membranes Required to make all hormones
Proteins
Complex structures Structure relates to function!
Often, function depends on its ability to recognize and bind to another molecule. Ex. Antibodies, Enzymes
Functions of Proteins (p.59)
Support (keratin for hair and nails & collagen for ligaments, tendons, skin)
Enzymes to catalyze reactions Transport across cell membranes Hemoglobin – oxygen transport Defense from infection Hormones (such as insulin) Cell movement
Proteins
Polymers made of amino acids Amino acids are joined by peptide
bonds Chains are called polypeptides
Amino acids form a wide variety of structures Building blocks for living tissue 20 common amino acids (monomers)
Amino Acids
Plants and bacteria can synthesize all amino acids
Animals can manufacture some of the important amino acids If animals cannot synthesize them, they are
essential amino acids Must be obtained from diet
List of Amino Acids & Functions Amino Acid Structure (Animation)
Protein Structure Different functional groups determine
the amino acid Combination of aa’s determine the protein
One or more polypeptides folded into a complex 3-D structure
Shapes of Proteins
Polypeptide chains are twisted or folded to form a 3-D shape such as: Long fibers Globular – tightly folded into compact,
spherical shape Close relationship between shape and
function
Shapes of Proteins
Primary Structure - sequence of amino acids that form the polypeptide chain
Secondary Structure - Parts of the polypeptide fold into local patterns (alpha helix or pleated sheet) p.63
Tertiary Structure - the overall 3D shape (globular or fibrous) p.64
Quaternary Structure - consists of two or more polypeptide chains or subunits p.65
Changes to Protein Shape
A protein’s conformation can change in response to the physical and chemical conditions.Alterations in pH, salt concentration, temperature, or other factors can unravel or denature a protein.
Nucleic Acids
Informational polymers Contain hereditary information Code that determines what proteins a cell
manufactures DNA (deoxyribonucleic acid)
Makes our genes RNA (ribonucleic acid)
Takes part in process of making proteins
Structure of DNA
5 carbon sugar (deoxyribose) Nitrogen base (adenine, thymine,
guanine, cytosine) Phosphate group
All 3 of these = nucleotide (monomer) Complimentary base pairing: A-T, G-C
Important nucleotides ATP (adenosine triphosphate)
Functions in energy storage Composed of adenine, ribose, 3
phosphates
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