Week 2 - Cytoskeleton and model organisms

• How does one become many functional cell types?

  Specific combination of genes that are expressed (euchromatin) or repressed (heterochromatin) and transcription Factors and master regulators
• What extrinsic and intrinsic factors of the cell influence gene expression and hence cell specialisation?

  Extrinsic: environmental signals like temperature and oxygen levels, proteins like signalling molecules, morphogens, cytokines. Intrinsic: transcription factors, epigenetic modifications.
• 3 cytoskeletal types?

  microtubule, actin filament, intermediate filament.
• Composition of each type of cytoskeleton?

  Microtubules - cylinders formed by long chains of alternating alpha and beta tubulin (heterodimer)

  actin filament (microfilament) - helical conformation based on two intertwined chains of globular actin monomers: G actin

  Intermediate filament - rope like aggregation of homo or heterodimers of various proteins
• Microtubules

  Cell division and intracellular transport
• Intermediate filaments

  • Mechanical stability for cell
  • Take part in nuclear envelope assembly
  • Support plasma membrane when it comes in contact with other cells or ECM
• Function of each type of cytoskeleton

  • Actin filaments/Microfilaments
  • Intermediate filaments
  • Microtubules
• Microtubules


  • Make up centrioles and form spindle in dividing cells
  • Form flagella and cilia of cell
  • Provide pathway for intracellular transport
• Intermediate filaments

  Structural support
• Actin filaments/Microfilaments

  • Cell shape: actin cortex under plasma membrane and actin stress fibres across cytoplasm
  • Cell migration: actin bundles project from cell
• Actin filaments/Microfilaments

  Cell shape and movement
• which type of cytoskeleton helps cytokinesis in mitosis?

  actin filaments / microfilament
• What are the roles of different types of cytoskeleton in shaping and moving cells?

  Microfilaments: Cell shape and movement. Intermediate filaments: Structural support. Microtubules: flagella and cilia, spindles in cell division, and intracellular transport.
• Which type of cytoskeleton plays an important role in axonal migration or determining axonal length?

  microtubules
• Main component of cytoskeleton that allows cell migration in development?

  Actin/microfilament
• myosin microfilaments are highly concentration at the cell periphery, right?

  No.
• Microtubules are involved in maintaining cell shape? Yes or no? why?

  Yes three filament types control mechanical stability, Microtubules resist compression, actin and intermediate filaments maintain cell shape by bearing tension.
• difference between master transcription factor and transcription factor?

  Master transcription factor regulates the activity of other transcription factors. Transcription factor directly binds to DNA to regulate gene expression.
• What does rostral Mean?

  Toward the front of the brain.
• Which cells in body have different genome?

  Gametes, cancer cells, RBCS
• What is the homologous structure to a bird wing in humans, horses whales?

  Arm, forelimb, flipper
• orthologous gene?

  A gene with high homologous present in another species
• 2 key aspects of biology allow us to observe a vast range of organisms to model human development

  Genomic level and developmental processes
• What animals to study germ cells?

  Worms are Mostly germ cells

  frogs large ovaries
• What animals to study haematopoietic cells?

  Zebrafish develop outside the mother
• What animals to study structural cells

  X laevis
• What animals to study neural cells?

  C elegant neural development
• What animals to study myocytes?

  Zebrafish goood at reheating cardiac myocytes
• What animals to study stem cells?

  Allll