Cell Differentiation Quiz

Cell Differentiation

• Cell differentiation is the process where cells become specialized.
• Multicellular organisms have different cell types with specific roles for maintaining homeostasis (internal balance).
• Humans have over 200 different cell types, despite all cells having the same DNA.
• Differentiation is controlled by gene expression (turning genes on or off).

Why Cells Differentiate

• Cell differentiation creates specialized cells necessary for multicellular organism function.
• Complex systems like the cardiovascular and respiratory systems require various cell types for their functions.
• Differentiation allows for the development of different organs from a single fertilized cell.

Cell Differentiation Process

• Differentiation involves expressing/repressing specific genes.
• Extracellular signals (e.g., molecules from other cells, temperature changes) trigger signal transduction pathways.
• These pathways activate/repress proteins within cells.
• The process influences transcription factors (proteins that bind to DNA for gene activation).
• RNA polymerase copies DNA into mRNA.
• Ribosomes translate mRNA into proteins, changing cell function.
• Tissue-specific proteins (specific to a tissue/cell type) are crucial in the differentiation process.

Factors Causing Cell Differentiation

• Changes in gene expression are the main cause.
• Signaling molecules in the environment activate or repress transcription factors.
• Chromosome structure affects gene expression. Heterochromatin (tightly condensed) inhibits gene expression while euchromatin (less condensed) facilitates it.

When Does Differentiation Occur?

• Differentiation happens when stem cells divide and create specialized cells.
• Stem cells are undifferentiated and can become various cell types.
• Embryonic stem cells arise during development, and adult stem cells replace tissues in the body.

How Cells Become Specialized

• Embryonic stem cells are undifferentiated and must specialize through the process of differentiation.

• Cytoplasmic localization: Uneven distribution of molecules in the egg affects gene expression in daughter cells.

• Cytoplasmic induction: Neighboring cells signal to influence a cell's development and differentiation based on the cell's location.

• Cell commitment has two stages:

  • Specialization: Commitment to a cell fate is reversible.
  • Determination: Permanent commitment to a cell fate.

Examples of Cell Differentiation

• Cardiomyocytes: Heart cells for contraction and electrical signals.
• Neurons: Brain cells for electrochemical signals.
• Osteocytes: Bone cells, encased in calcium matrix.
• Rods and Cones: Eye cells for light detection.
  • Rods are for low-light and black/white vision, expressing rhodopsin.
  • Cones are for color vision, expressing opsin proteins.
  • Both express neural proteins for signal transmission to the brain.

Test your understanding of cell differentiation and its significance in multicellular organisms. Explore the processes behind how cells specialize and the role of gene expression in maintaining homeostasis. Challenge yourself with questions on the different cell types and their functions.