Download 4 Classes of Large Biological Molecules Carbohydrates Lipids

4 Classes of Large Biological Molecules
Carbohydrates
Lipids
Proteins
Nucleic Acids
Monomer vs. Polymer
Most biological molecules are made from smaller subunits called monomers
Polymers are formed by covalently bonded monomers
Building and Breaking of Polymers
Condensation Reaction
Hydrolysis
Diversity of Macromolecules
Polymer arrangement can be compared to the alphabet
Most living things use 40-50 most common monomers
Arrangement is the most important aspect
Carbohydrates
Include sugar and the polymers of sugars
Monosaccharides
Disaccharides
Polysaccharides
Monosaccharides
Molecular Formula: CH2O
Glucose: most common monosaccharide
Ketose vs. Aldoses
Number of carbons dictates naming of simple sugars
Most sugars form rings in the presence of water
Disaccharides
Two monosaccharides joined together by glycosidic linkage
Glucose and Fructose = Sucrose (table sugar)
Lactose = Glucose and Galactose
Polysaccharides
Polymers of a few hundred to a few thousand monosaccharides
Can be used in storage of E and structural
Storage
Starch: consists entirely of glucose
Joined together by 1-4 glycosidic linkages
Allows plants to stockpile E
Most animals have enzymes that hydrolyze starch
Glycogen
Branched version of starch that is used by animals as glucose storage
Located in the liver and muscle cells
In human, glycogen supply can last about 1 day
Structural Polysaccharides: Cellulose
Most abundant organic compound on Earth
Polymer of glucose, but differs from cellulose
Starch vs. Cellulose
Starch : 1-4 linkage of alpha glucose
Cellulose: 1-4 linkage of beta glucose
Interesting fact: humans do not have the enzyme to hydrolyze beta glucose linkages
Chitin: the “unused” structural polysac
Composes the exoskeleton of arthropods
Chitin is soft but hardened with calcium carbonate
Fungi also contains chitin
Lipids
One class of biological molecules that does not contain polymers
Common trait: hydrophobic
Composed mostly of hydrocarbons
Fats
Composed of glycerol and fatty acids
Glycerol: alcohol with 3 C’s, each possessing a –OH group
Fatty acid: hydrocarbon of 16-18 C’s in length, one end has carboxyl group
Ester linkage: bond between hydroxyl and carboxyl group
Saturated vs. Unsaturated Fat
Fat vs. Polysaccharides
1g of fat contain 2X the amount of E as 1g of starch
Fat from plants comes from seeds
Phospholipids
Has two fatty acids attached to a glycerol molecule
The 3rd –OH group is attached to a phosphate group (- charge)
Show ambivalent properties toward water
Steroids
Have C skeletons consisting of 4 rings, only variation come in functional groups
Cholesterol: precursor from which many other steroids are made
Proteins
Compose 50% of the dry mass of most cells
Some are enzymes; others play roles in structural support, storage, transport, cellular
communications, movement, and defense
Enzyme
Acts as cellular catalyst: selectively speed up reaction w/o being consumed
Substance enzyme attaches to is called a substrate
Most important Aspect of Proteins
A proteins structure defines its function. Change its structure and the protein’s function
will change completely.
Amino Acid Monomers
All proteins are made from 20 different Amino Acids
Polymers of amino acids are called polypeptides
Protein consists of one or more polypeptides folded into specific configurations
General Amino Acid Structure
Amino Acid Polymerization
Carboxyl group and amino group covalently bond to form a peptide bond
N terminus and C terminus
Proteins
One or more polypeptides precisely folded, twisted, and coiled into a unique shape
Amino acid sequence determined 3-D conformation
Proteins structure determines its function
4 Levels of Protein Structure
1. Primary
2. Secondary
3. Tertiary
4. Quaternary
Denaturation
pH, salt concentration, and temperature can alter a protein’s shape
Sometimes proteins can renature
Central Dogma of Biology
DNA à RNA à Protein
Nucleic Acids
Determines the primary structure of a polypeptide
Gene: codes for an amino acid sequence in a polypeptide
DNA
Arranged in chromosomes that contain one long DNA molecule consisting of several
hundred or thousand genes
Bound to the nucleus
RNA: smaller pieces of nucleic acids that directly make the proteins for the DNA codes
1. Transfer
2. Messenger
3. Ribosomal
Nucleic Acid Structure
Ring Structure of Nitrogenous Bases
Pyrimidine: 1 ring structure; includes cytosine, uracil, thymine
Purine: 2 ring structure; includes guanine and adenine