Ch 16-1 Flashcards
What are cytoplasmic determinants?
Cytoplasmic determinants are molecules, such as proteins, mRNA, and cellular structures, present in the egg that are unequally distributed and contribute to differential gene expression in the embryo.
Describe the process of Induction.
Induction happens as the embryo grows. It involves interactions between cell-surface molecules and growth factors, influencing gene expression and leading to specific responses based on the cellular environment.
What is Determination?
Determination is the stage where an embryonic cell commits to becoming a particular cell type. Even if its environment changes, the cell will differentiate into that specific type.
How is Cellular Differentiation Regulated?
Differentiation, the process of a cell achieving its determined fate, is often regulated through transcriptional control. This results in the expression of tissue-specific proteins, ultimately changing the cell’s structure.
Explain how muscle cell differentiation works.
Signals from nearby cells induce a cell to become a myoblast. The myoD gene is then expressed, producing the MyoD transcription factor. MyoD activates its own transcription (positive feedback) and triggers the expression of other muscle-specific genes, leading to the production of muscle proteins and inhibitors of cell division.
What is Apoptosis and its role in development?
Apoptosis is programmed cell death that occurs in both embryos and adults. The cell’s contents are broken down, the cell forms blebs, and is then engulfed by phagocytic cells. Apoptosis is crucial for nervous system development and the shaping of limbs.
What is Pattern Formation in development?
Pattern formation is the organized arrangement of tissues and organs in their specific locations. This process relies on positional information provided by molecular cues, which tell a cell its position relative to body axes and neighboring cells.
How is the axis established in an embryo?
The axis is initially set up by cytoplasmic determinants in the egg.
- Maternal effect genes play a crucial role; mutations in these genes in the mother will lead to developmental defects in the offspring, regardless of the offspring’s genotype.
- There are separate sets of maternal effect genes for the anterior-posterior and dorsal-ventral axes.
What is the role of the bicoid gene?
Bicoid is a maternal effect gene involved in anterior-posterior axis formation.
- Mutations in bicoid result in embryos lacking a head and having posterior structures at both ends.
- The study of bicoid helped scientists understand how specific proteins guide pattern formation,
the importance of maternal genes in early development,
What happens to embryonic genes as development progresses?
As the embryo develops, the maternal mRNAs that established the initial axes are no longer needed and are destroyed. Embryonic genes then take over, guiding the formation of body segments and their specific structures.
The molecule used as an energy currency during translation is
GTP
The three processes required for embryonic development are
cell division, cell differentiation, and morphogenesis.
Cell differentiation and morphogenesis require alterations in
Cell behavior
The point at which an embryonic cell is committed to becoming a specific cell type is called
Determination
The process by which a cell attains its determined fate is called
Differentiation
