Biochemistry Basics Quiz

Chemical Level of Organization Part 1

• Water properties in aqueous solutions are described
• Concentration and osmolarity concepts are discussed
• Enzymatic activity and activation energy are reviewed
• Inorganic and organic compounds are differentiated
• The role of pH in physiology is explained
• Macromolecules and their functions are detailed, and various types are classified
• Cellular respiration steps are outlined

Four Properties of Water

• Solubility: Water dissolves solutes to form solutions. (e.g., sugar in water)
• Reactivity: Most body chemistry occurs in water. DNA structure is maintained in water.
• High Heat Capacity: Water absorbs and retains heat, maintaining homeostasis.
• Lubrication: Water moistens and reduces friction, (e.g., in joints)

Molecules and Water

• Hydrophilic: Molecules that react with water (water-loving)
• Hydrophobic: Molecules that do not react with water (water-fearing)

Electrolytes

• Substances that can dissolve in water and dissociate into ions.
• Electrolyte imbalances disrupt vital body functions (e.g., potassium imbalance causing muscle cramps, sodium imbalance affecting nerve conduction).
• Specific electrolytes (NaCl, KCl, CaPO4, NaHCO₃) and their released ions (Na+, K+, Cl−, Ca²+, PO₄²⁻, HCO₃⁻) are listed.

Importance of Electrolytes

• Potassium (K+) is crucial for normal body function, and imbalances can cause significant health issues (e.g., muscle paralysis when low, weak and irregular heartbeats when high.)
• Electrolyte homeostasis means maintaining the correct balance of electrolytes.
• Kidneys play a significant role in electrolyte excretion and retention.

pH and Buffers

• pH is the relative concentration of hydrogen ions (H+) and hydroxide ions (OH−) in a solution
• Neutral pH is 7.0 (pure water)
• Acidic pH is below 7.0 (high H+ concentration, low OH− )
• Basic pH is above 7.0 (low H+ concentration, high OH−)
• Buffers are chemicals that resist pH changes by neutralizing either strong acids or bases.

Acids and Bases

• Acid: Electrolyte that dissociates to release hydrogen ions (H+).
• Base: Substance that releases ions that combine with hydrogen ions.

pH Scale

• pH has an inverse relationship with hydrogen ion (H+) concentration; higher H+ ions mean lower pH, and less H+ ions mean higher pH.
• More hydroxide ions (OH−) ions mean higher pH, and less OH− ions mean lower pH
• Blood pH is maintained between 7.35-7.45

Acidosis and Alkalosis

• Acidosis: Excess H+ ions in body fluid, lowering body pH
• Alkalosis: Excess OH− ions in body fluid, raising body pH

pH Homeostasis

• Buffers resist pH changes, neutralizing strong acids or bases. Weak acids and salts are common buffers

Organic and Inorganic Molecules

• Organic Molecules: Contain carbon (C) bonded to hydrogen (H). Often forms hydrocarbon chains.

• Inorganic Molecules: Usually do not contain C and H as primary structure.

• Examples of inorganic molecules: Water (H₂O), Oxygen (O₂), Carbon Dioxide (CO₂)

Macromolecules

• Carbohydrates: Hydrophilic organic molecules, broken down for energy.
• Proteins: Abundant and essential organic molecules, made of amino acids
• Lipids (Fats): Major component of cell membranes and energy stores
• Nucleic Acids: Carry genetic information (DNA, RNA).

Carbohydrates: Starches & Sugars

• Hydrophilic organic molecules
• Broken down to provide energy

Monosaccharides and Disaccharides

• Monosaccharides: Simple sugars with 3-7 carbon atoms. Examples: glucose, galactose
• Disaccharides: Two monosaccharides condensed by dehydration synthesis, forming a bond, releasing water molecule. Examples: sucrose (glucose + fructose)

Polysaccharides

• Chains of many simple sugars (e.g., glycogen). "Poly" means many.

Protein Structure

• Proteins: Most abundant and important organic molecules.
• Basic elements: Carbon (C), hydrogen (H), oxygen (O), and nitrogen (N)
• Basic building blocks: 20 amino acids

Protein Functions

• 7 major protein functions: Support, movement, transport, buffering (metabolic regulation), coordination (hormones), defense (antibodies)

Amino Acids

• Structure: Central carbon atom, hydrogen atom, amino group (-NH₂), carboxyl group (-COOH), and a variable side chain (R group).

Peptides

• Form peptide bonds by dehydration synthesis. The bond forms between the amino group of one amino acid and the carboxyl group of another amino acid, removing a water molecule

Shape and Function of Proteins

• Protein function depends on structure
• Protein shape is due to the sequence of amino acids.
• Denaturation: Loss of shape and function due to heat or pH changes.

Protein Structure Levels

• Primary structure: Linear sequence of amino acids in a polypeptide.
• Secondary structure: Hydrogen bonds create spirals (alpha-helices) or pleats (beta-sheets).
• Tertiary structure: Folding of the secondary structure into a unique 3D shape.
• Quaternary structure: Combining of multiple polypeptide chains.