Course review
Review each learning objective in this topic, then open its concept explanation or question set.
Learning objective
• A zygote divides to produce unspecialized cells that later differentiate • Differentiation occurs when different genes are activated in different cells • Morphogen gradients control gene expression and body pattern formation
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Learning objective
• Stem cells self-renew by repeated division while remaining undifferentiated • Stem cells have potency: the capacity to differentiate into mature cell types • Embryonic stem cells have broader potential than most adult stem cells
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Learning objective
• Stem cell niches provide signals that maintain, activate, or differentiate stem cells • Bone marrow niches regulate haematopoietic stem cells that form blood cells • Hair follicle bulge niches contain multipotent stem cells for hair regeneration
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Learning objective
• Totipotent cells can form all body cells plus placental cells • Pluripotent cells form all body cell types but not placenta or totipotent cells • Multipotent adult stem cells repair and maintain limited tissues or organs
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Learning objective
• Specialized cells vary widely in size according to function • Egg cells are large for nutrient storage; sperm are small with a long flagellum • Neurons can be very long, and striated muscle fibres are extended multinucleate cells
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Learning objective
• Surface area controls exchange, while volume controls metabolic demand • As cells grow, volume increases faster than surface area • Low surface area-to-volume ratio limits diffusion and therefore cell size
Start with the concept explanation, then practise to create mastery evidence.