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
Apoptosis is triggered by specific
Signal transduction pathways
Which of the following is NOT a characteristic of apoptosis?
○
a) Blebbing of the cell membrane
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b) Uncontrolled cell division
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c) Engulfment by phagocytic cells
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d) Destruction of internal cellular components
B
What is the function of maternal effect genes?
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a) They determine the sex of the offspring.
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b) They establish the body axes in the early embryo.
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c) They control the development of specific organs.
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d) They regulate cell division during embryonic development.
B
What is a morphogen?
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a) A type of cell that gives rise to all other cell types.
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b) A protein that inhibits cell differentiation.
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c) A signaling molecule that forms a concentration gradient and influences cell fate.
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d) A gene that is only expressed during embryonic development.
C
Which of the following statements about bicoid is FALSE?
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a) It is a maternal effect gene.
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b) It is involved in anterior-posterior axis formation.
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c) A mutation in bicoid results in an embryo with two heads.
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d) It supports the morphogen gradient hypothesis..
C
A mutation in bicoid results in an embryo with posterior structures at both ends, lacking an anterior end (head).
What happens to maternal mRNAs as embryogenesis proceeds?
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a) They are replicated and passed on to daughter cells.
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b) They are targeted for destruction.
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c) They are translated into proteins that regulate embryonic gene expression.
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d) They are modified and used to establish new body axes.
B
Which of the following is an example of induction during embryonic development?
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a) A cell dividing to produce two daughter cells
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b) A cell changing its gene expression in response to signals from neighboring cells.
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c) A cell undergoing apoptosis.
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d) A cell migrating to a new location in the embryo.
B
What is the role of the MyoD protein in muscle cell differentiation?
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a) It is a structural protein found in muscle fibers.
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b) It is a transcription factor that activates muscle-specific genes.
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c) It is a signaling molecule that promotes cell division in myoblasts.
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d) It is an enzyme that breaks down proteins during muscle development.
B
Which of the following is a key characteristic of determination in embryonic development?
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a) The cell becomes visibly different from other cell types.
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b) The cell’s fate is irreversibly committed.
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c) The cell begins to express all the genes required for its final function.
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d) The cell stops dividing.
B
What is the main function of cytoplasmic determinants?
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a) To provide nutrients for the developing embryo
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b) To protect the embryo from environmental stress
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c) To establish initial differences in gene expression within the embryo
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d) To trigger cell division.
C
What is the difference between determination and differentiation?
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a) Determination refers to the process of cell division, while differentiation refers to the process of cell specialization.
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b) Determination and differentiation are the same process.
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c) Determination is the commitment of a cell to a specific fate, while differentiation is the process by which the cell achieves that fate.
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d) Determination occurs in the early embryo, while differentiation occurs later in development.
C
T/f
The “P” site of a ribosome brings in the next amino acid.
F
The “A” site brings in the next amino acid, while the “P” site holds the growing polypeptide chain.
T/f
Different cell types in multicellular organisms result from differential gene expression programming.
T
T/f
Morphogenesis is the development of the form of an organism
T
T/f
Cytoplasmic determinants are uniformly distributed within the egg.
F
Cytoplasmic determinants are not uniformly distributed, leading to differential gene expression
T/f
Induction involves the interaction of cell-surface molecules and growth factors.
T
T/f
Differentiation is the process by which a cell attains its determined fate.
T
T/f
Differentiation primarily relies on the translation of specific genes.
F
Transcription is the most common way to regulate differentiation.
T/f
Apoptosis is important for the normal development of the nervous system
T
T/f
Positional information refers to molecular cues that control pattern formation.
T
T/f
Bicoid is involved in dorsal-ventral axis formation.
f
Bicoid is involved in anterior-posterior axis formation.
