Lecture Notes on Physiology and Related Chemistry

Importance of Chemistry and Cytology

• Review Chemistry
  • Atomic structure: protons, neutrons, electrons
  • Molecular bonding: hydrogen, ionic, covalent
  • Concepts: pH, solutions, concentrations
  • Basic organic chemistry: carbohydrates, proteins, lipids, nucleic acids
• Review Cytology
  • Cellular structure: plasma membranes, phospholipids, cholesterol
  • Cellular components: mitochondria, rough ER, smooth ER, ribosomes

Focus on DNA and Cellular Structures

• Nucleus Structure

  • Double membrane with nuclear pores
  • Contains nucleolus for ribosome production
  • Chromatin: dispersed DNA that condenses into chromosomes for cell division

• Genome and Proteome

  • Genome: 25,000 genes coding for proteins
  • Proteome: Over 100,000 proteins due to:
    • RNA splicing
    • Polypeptide linkage
    • Protein modifications (e.g., glycoproteins)

Chromatin and DNA Structure

• Chromatin
  • DNA organized around histone proteins forming nucleosomes
  • Chromatin condenses into chromosomes for division
• DNA
  • Double helix wrapping around histones due to charge attraction

Gene Activation and Transcription

• Euchromatin vs. Heterochromatin
  • Euchromatin: active genes
  • Heterochromatin: inactive genes
• Gene Activation
  • Acetylation: uncoiling DNA for transcription
  • Addition of transcriptional factors and enzyme action

DNA Replication

• Process
  • Semi-conservative: retaining half of the original DNA molecule
  • Enzymes involved:
    • Helicase: unzips DNA
    • Polymerase: adds nucleotides (A-T, G-C)
    • Ligase: links Okazaki fragments
    • Telomerase: prevents DNA shortening
• Directionality
  • 5’ to 3’ growth direction
  • Leading and lagging strands with continuous and discontinuous replication

Telomeres and Aging

• Telomerase Activity
  • Protects against DNA shortening
  • Active in germinal, stem, and cancer cells
• Significance of Telomeres
  • Longer telomeres indicate healthier cells
  • Protects DNA from being considered damaged

Summary

• Understanding of chemistry, cellular structures, and DNA processes is crucial for physiology
• Gene activation and replication mechanisms are key to cellular function and development

Remember, reviewing these fundamental concepts will aid in a deeper understanding of physiological processes. Good luck with your studies!