Lecture 3 Flashcards
Large Biological Molecules
– Carbohydrates
– Lipids
– Proteins
– Nucleic acids
Macromolecules
- Large molecules composed of thousands of covalently connected atoms.
- Each cell has thousands of different kinds of macromolecules
– Vary among cells of an organism
– Vary more within a species
– Vary even more between species
Examples
- DNA
- RNA
- Proteins
- Polysaccharides
Molecular structure and function
are inseparable
Shape dictates function
Carbohydrates & Lipids
– Fuel molecules for energy
– Structural roles
Nucleic Acids
- Store, Transmit, and Decode Hereditary Information
– Also some structural roles
Proteins
Consist of one or more polypeptides
Account for more than 50% of the dry mass of most cells
– Perform an incredible number of functions! • Structural proteins • Transport proteins • Enzymes • Hormones & signaling molecules • Storage proteins • Receptor proteins • Contractile & motor protein • Defense proteins (against microbes)
Common features of macromolecules
Protein, carbohydrate and nucleic acid polymer
molecules
– can fold into complex 3-dimensional shapes
– specific shape depends on sequence of monomers
Ionic bonds, Hydrogen bonds and Van der Waal’s
interactions are important in specifying and maintaining shape
Three of the four classes of life’s organic molecules are polymers:
– Carbohydrates
– Proteins
– Nucleic acids
Condensation (Dehydration) Reaction
• Occurs when two monomers bond together
through the loss of a water molecule
Enzymes
– Macromolecules that speed up the dehydration process
Polymers Disassembled to monomers by hydrolysis
• Reaction that is essentially the reverse of the dehydration reaction. Hydrolysis adds a water H2O
molecule, by breaking a bond.
Hormonal Proteins
Function: Coordination of an organism’s activities
Example: Insulin, a hormone secreted by the pancreas, causes other tissues to take up glucose,
thus regulating blood sugar concentration
Enzymatic proteins
Function: Selective acceleration of chemical reactions
Example: Digestive enzymes catalyze the hydrolysis of bonds in food molecules.
Defensive proteins
Function: Protection against disease
Example: Antibodies inactivate and help destroy
viruses and bacteria.
Organic compounds can contain atoms other than C and H
– Form “Functional Groups”
– Characterized by the types of atoms present and the way they are bonded
• Giving these groups special properties
– Bonds between C and O or N - polar covalent bonds
• Can form Hydrogen Bonds.
