Untitled Quiz

Macromolecules Overview

• Carbohydrates: Serve as fuel and building material.
• Lipids: Function in energy storage, insulation, and cushioning vital organs.
• Proteins: Perform numerous roles such as storage, support, transport, communication, movement, defense, and serving as enzymes.
• Nucleic Acids: DNA holds instructions for proteins synthesis; RNA acts as the messenger in this process.

Macromolecule Structures

• Carbohydrates: Composed of multiple ring structures linked by alpha (1,4 and 1,6) and beta (1,6) glycosidic linkages.
• Lipids: Consist of one glycerol molecule bonded to three fatty acids via ester linkages.
• Proteins:
  • Primary Structure: A chain of amino acids bonded by peptide bonds.
  • Secondary Structure: Forms alpha helices or beta-pleated sheets stabilized by hydrogen bonds.
  • Tertiary Structure: Three-dimensional folding of a protein chain, involving disulfide bonds.
  • Quaternary Structure: Multiple polypeptide chains clustered together without covalent bonds.

Monomers of Macromolecules

• Nucleic Acids: Composed of nucleotides.
• Carbohydrates: Made up of monosaccharides like glucose, fructose, and galactose.
• Lipids: Built from glycerol linked to three fatty acids.
• Proteins: Formed from amino acids.

Carbohydrate Forms

• Disaccharides: Two monosaccharides linked together, examples include sucrose, maltose, and lactose.
• Polysaccharides: Three or more monosaccharides bonded, such as amylose, amylopectin, cellulose, and glycogen.

Lipid Types

• Fats: Serve as long-term energy storage and protect organs, stored in adipose cells.
• Phospholipids: Comprise a phosphate group linked to glycerol, with two fatty acids; they possess a hydrophilic head and hydrophobic tails.
• Steroids: Characterized by a structure of four fused rings.

Proteins and Their Functions

• Collagen: Composed of three helical polypeptides, it strengthens connective tissues like skin and tendons.
• Enzymes: Act as catalysts, speeding up reactions by lowering activation energy.

Reaction Dynamics

• Activation Energy: Energy required to break reactant bonds, often in the form of heat.
• Exergonic Reactions: Release energy, starting with higher reactant energy.
• Endergonic Reactions: Require energy input, starting with lower reactant energy.

Enzyme Mechanism

• Enzymes: Increase reaction rates by lowering activation energy and providing active sites for substrate binding.
• Active Site: Region on an enzyme where substrates bind.
• Enzyme-Substrate Complex: When an enzyme and substrate bind together.
• Factors Affecting Enzyme Activity: Include pH, temperature, concentration of enzyme and substrate, and salinity.

Regulation of Enzyme Activity

• Inhibition: Slows down reactions by preventing enzyme function.
• Types of Inhibition:
  • Competitive Inhibitors: Compete with substrates for active site binding.
  • Non-competitive Inhibitors: Bind to regulatory sites, altering the active site.
• Allosteric Regulation: Involves effector molecules binding to an enzyme, changing its active form.

Membrane Structure and Function

• Fluid Mosaic Model: Describes the dynamic structure of the cell membrane, composed of phospholipid bilayers.
• Components: Include cholesterol, proteins (peripheral and integral), and carbohydrates (glycoproteins and glycolipids).
• Cholesterol: Stabilizes membrane fluidity across temperature variations.
• Transport Mechanisms:
  • Passive Transport: Moves materials without energy (e.g., diffusion, facilitated diffusion, osmosis).
  • Active Transport: Requires energy to move substances against concentration gradients.

Types of Transport

• Facilitated Diffusion: Uses integral proteins to assist large molecules across the membrane.
• Osmosis: Water movement across membranes to balance solute concentrations.
• Endocytosis Types:
  • Phagocytosis: Engulfing large molecules.
  • Pinocytosis: Engulfing liquids or dissolved solutes.

Active Transport Methods

• Protein Pumps: Integral proteins that actively transport specific molecules.
• Sodium-Potassium Pump: Moves 2 potassium ions in for every 3 sodium ions out, essential for cellular function.
• Bulk Transport: Forms vesicles to move large molecules into/out of the cell.