Biochemistry Exam 1 Study Guide - Spring 2025

Biochemistry Exam 1 Study Guide - Spring 2025

• Chapter 1: Introduction to Biochemistry

  • Organic life forms are distinguished by high carbon content.
  • Four classes of biomolecules: Proteins, Nucleic Acids, Lipids, and Carbohydrates.
  • Proteins are polymers of amino acids.
  • Nucleic acids are polymers of nucleotides.
  • Lipids are amphipathic molecules that self-assemble into bilayers, creating cellular compartments.
  • Carbohydrates are polymers of monosaccharides.
  • Prokaryotic cells lack organelles and possess a cell wall.
  • Eukaryotic cells contain organelles including: Nucleus, Rough ER, Smooth ER, and Mitochondria.

• Chapter 2: Water and Weak Interactions in Biological Systems

  • Water molecules are polar, forming ordered clusters.
  • Water can solubilize charged/polar but not nonpolar molecules.
  • Four types of weak interactions: Hydrogen bonding, Electrostatic interactions, Van der Waals interactions, and Hydrophobic effect.
  • Hydrogen bonds form between hydrogen-bearing and electronegative atoms.
  • Electrostatic interactions are between charged molecules.
  • Van der Waals forces occur at close distances between nonpolar molecules.
  • Hydrophobic effect maximizes the number of disordered water molecules.

• Chapter 3: Amino Acids

  • Amino acids share a basic template with an alpha-carbon atom, amino group, carboxyl group, and a variable side chain (R group).
  • L-amino acids are the dominant form in proteins.
  • At pH 7.4, amino acids exist primarily as zwitterions (carrying both negative and positive charges).
  • Twenty standard amino acids are categorized by their side chain properties: Hydrophobic, polar, positively charged (basic), and negatively charged (acidic).
  • Aromatic amino acids include phenylalanine, tyrosine, and tryptophan.
  • Specific amino acids are important based on physical characteristics.

• Chapter 4: Peptides and Proteins

  • Peptide bonds form between amino acids via dehydration.
  • Peptides have polarity (N-terminus and C-terminus).
  • Properties of protein chains include backbones, disulfide bridges, peptide planes, torsion angles.
  • Primary structure is the amino acid sequence; secondary consists of structures such as alpha-helices and beta-sheets.
  • Tertiary structure is the three-dimensional arrangement of secondary structural elements, mainly stabilized by hydrophobic effect.
  • Quaternary structure involves interactions of multiple polypeptide chains.

• Chapter 6: Introduction to Enzymes

  • Enzymes are biological catalysts that accelerate reactions without being consumed.
  • Enzymes lower activation energy.
  • Important enzyme features include their active sites, specificity, and factors influencing catalysis.
  • Different models, like lock-and-key and induced fit, explain enzyme-substrate interactions.
  • Cofactors, like vitamins and metals, are necessary for enzyme activity,
  • Enzyme kinetics, described by Michaelis-Menten equation.

• Chapter 7: Enzyme Kinetics -The Michaelis-Menten equation describes the rate of enzyme-catalyzed reactions, showing the parameters v_max (maximal velocity) and K_m (Michaelis constant).

  • The Michaelis-Menten equation provides useful information about enzyme kinetics.