Biology Exam Review 2 Flashcards
What are the four main classes of macromolecules?
The four main classes are carbohydrates, lipids, proteins, and nucleic acids.
What is the main function of carbohydrates in living organisms?
Carbohydrates serve as a primary source of energy and provide structural support in cells.
Give an example of a monosaccharide and a polysaccharide.
Monosaccharide: Glucose; Polysaccharide: Starch or glycogen.
What is the difference between a saturated and unsaturated triglyceride?
Saturated triglycerides have all carbon atoms bonded to hydrogen atoms (no double bonds), while unsaturated triglycerides have at least one double bond between carbon atoms in the fatty acid chains.
Describe the structure of a phospholipid and explain its amphipathic nature.
A phospholipid has a hydrophilic phosphate head and two hydrophobic fatty acid tails. This structure makes phospholipids amphipathic, meaning they have both hydrophilic and hydrophobic regions.
What are the levels of protein structure and what bonds stabilize each level?
The levels are primary (sequence of amino acids), secondary (alpha helices and beta sheets stabilized by hydrogen bonds), tertiary (overall 3D structure stabilized by various bonds), and quaternary (arrangement of multiple polypeptide chains). Bonds involved include peptide bonds, hydrogen bonds, disulfide bonds, hydrophobic interactions, and ionic bonds.
Explain the difference between hydrolysis and condensation (dehydration synthesis) reactions in relation to macromolecules.
Hydrolysis breaks down macromolecules by adding water molecules, while condensation (dehydration synthesis) builds macromolecules by removing water molecules.
8. What are the main properties of water that make it essential for life?
What are the main properties of water that make it essential for life?
Water exhibits cohesion (molecules stick together), adhesion (molecules stick to other surfaces), high specific heat (resists temperature changes), high heat of vaporization (requires a lot of energy to vaporize), and is a universal solvent (dissolves many substances).
Give an example of a biological process where enzymes catalyze the hydrolysis of a macromolecule.
Example: Amylase catalyzes the hydrolysis of starch into glucose.
How do micelles and bilayers form from amphipathic molecules like phospholipids?
In water, amphipathic molecules arrange themselves to minimize exposure of hydrophobic regions to water. Single-layered spherical structures are micelles, while bilayers are two-layered sheets, both formed by the hydrophobic tails clustering together and hydrophilic heads facing the water.
