Flashcards on Prokaryotic and Eukaryotic Cells

Module Overview

• Lecture 1: Life and cells
• Lecture 2: A tour of eukaryotic cells
• Lecture 3: A tour of prokaryotic cells
• Lecture 4: Water, concentrations, acids and bases
• Lecture 5: Carbon and macromolecules
• Lecture 6: The cell membrane – structure and function

Key Concepts

• Use of Microscopes
  • Biologists utilize microscopes and biochemistry to study cells.
• Eukaryotic Internal Structure
  • Eukaryotic cells possess internal membranes that compartmentalize functions.
• Genetic Instructions
  • Genetic information is contained in the nucleus and executed by ribosomes.
• Endomembrane System
  • Regulates protein traffic and supports various metabolic functions.
• Energy Conversion
  • Mitochondria convert energy for cellular activities; chloroplasts are involved in photosynthesis.
• Cytoskeleton Role
  • A network of fibers organizing cellular structures and activities.
• Cell Coordination
  • Extracellular components as well as cell interconnections aid in coordinating cellular activities.
• Holistic View of Cells
  • A cell functions as an integrated system rather than merely the sum of its parts.

Prokaryotic Cells

• Basic Characteristics
  • Prokaryotes include bacteria and archaea, often thriving in extreme environments.
  • Their structures differ fundamentally from eukaryotic cells, informing antimicrobial development.
• Single Chamber Design
  • Prokaryotic cells are a single compartment where all cellular processes occur simultaneously.
  • While appearing simple, they exhibit organized complexity.

Prokaryotic vs. Eukaryotic Cells

Structural Differences

• Size: Eukaryotic cells are typically larger than prokaryotic cells.
• Nucleus: Eukaryotic cells have a membrane-bound nucleus; prokaryotic cells have a nucleoid region.
• Chromosomes:
  • Prokaryotes have single circular chromosomes; eukaryotes possess multiple linear chromosomes.
  • Prokaryotic DNA is organized without histones, contrasting the DNA supercoiling of eukaryotic cells.

Prokaryotic Cell Components

• Ribosomes: Vital for protein synthesis (translation) in both prokaryotic and eukaryotic cells.
• Cell Wall:
  • Composed of peptidoglycan, defining shape and providing structural integrity.
• Capsule:
  • Acts as a protective layer aiding in moisture retention and immunity against pathogens.
• Flagella and Pili:
  • Structures for movement and attachment.

Evolutionary Relationships

• Origin of Life:
  • Prokaryotic cells are believed to have evolved first around 3.5 billion years ago, leading to the evolution of eukaryotic cells.
• Common Ancestor (LUCA):
  • All cells likely descended from a shared ancestor (Last Universal Common Ancestor).
• Theory of Serial Endosymbiosis:
  • The complex structures of eukaryotic cells may have arisen from prokaryotic cells through endosymbiotic relationships.

Importance of Gut Microbiome

• Health Role:
  • Commensal bacteria contribute to digestion, immunity, and metabolic regulation.
  • They produce essential vitamins (e.g., biotin and K) and influence conditions such as obesity and diabetes.
• Kwashiorkor Disease:
  • Associated with bacterial imbalances, highlighting the significance of gut flora in health.

Key Takeaways

• Prokaryotic cells are essential to our understanding of cellular biology and function within both organisms and environments.
• Their simple structure is well adapted to diverse conditions, showcasing evolution's role in cellular complexity.
• Understanding prokaryotic cells enhances our comprehension of eukaryotic cells' evolution and the role of microbiomes in human health.