Lecture 02

• What is the concept of cell differentiation?

  Process by which cells become specialised
• What occurs during embryonic development?

  The zygote divides and cells differentiate
• How is differentiation controlled in cells?

  Through genetic instructions and environmental signals
• What is an example of a specialised cell?

  Red blood cells
• What are differentiated cells?

  Cells that have specialised functions
• What are stem cells?

  Undifferentiated cells with potential to specialise
• How does embryonic development begin?

  The zygote divides into 2, 4, then 8 cells
• What happens after three divisions of the zygote?

  Cells begin to differentiate towards functions
• What is the consequence of removing cells from an early blastocyst?

  It allows for genetic testing and analysis
• What happens if cells are removed after the 8-cell stage?

  It can be fatal to the embryo
• What do pools of stem cells give rise to?

  Several adult tissues
• How does the developmental potential of cells change as the embryo grows?

  Most cells become increasingly restricted
• What are the three types of stem cells?

  Totipotent, pluripotent, multipotent
• What is totipotent stem cell potential?

  Up to the third division of the zygote
• What are pluripotent stem cells?

  Embryonic stem cells in the blastocyst
• What are multipotent stem cells?

  Adult stem cells with limited versatility
• What does the ectoderm give rise to?

  Epidermis and nervous system
• What does the mesoderm give rise to?

  Connective tissues and muscle
• What does the endoderm give rise to?

  Lining of airways and digestive system
• When does asymmetric cell division occur?

  More during embryonic development
• What drives symmetrical division during maturation?

  External factors
• What happens to cells as they grow and proliferate?

  They organise into complex structures
• What does each cell follow during division?

  A set of genetic instructions
• What does the DNA in mature specialised cells represent?

  It is identical to the zygote's DNA
• What is embryonic cell differentiation?

  Process of generic cells becoming specialised
• What do Hox genes control?

  Layout of the embryo's anterior-posterior axis
• Who discovered the Antennapedia gene mutation?

  Edward Lewis
• What is the effect of mutations in PAX Hox genes?

  Causes anatomical disorders of the eye
• What do IGF growth factors stimulate?

  Mitosis, growth, and metabolism regulation
• What is the role of epidermal growth factor?

  Promotes cell proliferation
• What do transforming growth factors promote?

  Cell differentiation and proliferation
• What happens to embryonic cholinesterase during development?

  It disappears after organ structures form
• What do red blood cells synthesize?

  Haemoglobin for oxygen transport
• What do differentiated muscle cells synthesise?

  Actin and myosin proteins
• What do nerve cells develop for connection?

  Long axons
• What do pancreatic beta cells produce?

  Insulin for secretion into the gut
• How do fat cells appear and function?

  They are round and store fat
• What do melanocytes develop for their function?

  Dendritic tentacles to deliver melanin
• What do epithelial cells of the small intestine develop?

  Microvilli to increase absorptive surface area
• What is required after embryonic differentiation?

  Growth, regeneration, and repair