Lecture 20 Review
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What is the significance of Hox genes in Drosophila development?

  • Hox genes consist of proteins that initiate cellular respiration.
  • Hox genes determine the segmentation along the A-P axis. (correct)
  • Hox genes only play a role in embryonic fertilization.
  • Hox genes are unique to Drosophila and not found in other organisms.

    • What is the approximate time from fertilization to sexual maturity in Drosophila?

  • 3 days
  • 14 days
  • 1 day
  • 9 days (correct)

    • Who were the laureates that won the Nobel Prize in Physiology in 1995 for their work on Drosophila?

  • Barbara McClintock and Sydney Brenner
  • Craig Venter and J. Craig Venter
  • James Watson and Francis Crick
  • Ed Lewis, Christine Nusslein-Volhard, and Eric Wieschaus (correct)

    • Which process is responsible for the initial segmentation of the Drosophila embryo?

    <p>Gastrulation</p> Signup and view all the answers

    Which of the following best describes an aspect of segmentation in Drosophila?

    <p>Segment identity is influenced by genetic control mechanisms.</p> Signup and view all the answers

    What is the primary role of egg-polarity genes during early embryonic development?

    <p>They organize the A-P axis of the early embryo.</p> Signup and view all the answers

    Which types of genes are expressed in the syncytial blastoderm stage?

    <p>Gap genes and pair-rule genes</p> Signup and view all the answers

    What do segment-polarity genes encode for in developing organisms?

    <p>Signaling molecules and transcription regulators</p> Signup and view all the answers

    What is the main function of gap genes in the early embryo?

    <p>To determine the number, spacing, size, and polarity of segments.</p> Signup and view all the answers

    How do segments maintain their identity throughout development?

    <p>By a combination of gap, pair-rule, and segment-polarity genes.</p> Signup and view all the answers

    What is the primary function of egg-polarity genes in Drosophila embryos?

    <p>Organize the anterior-posterior axis in the early embryo</p> Signup and view all the answers

    Which gene is crucial for the formation of anterior segments in a Drosophila embryo?

    <p>Bicoid</p> Signup and view all the answers

    What occurs during the syncytial blastoderm stage in Drosophila embryogenesis?

    <p>Nuclear division occurs without cell division</p> Signup and view all the answers

    Which type of genes is responsible for organizing the segments in Drosophila embryos?

    <p>Egg-polarity genes</p> Signup and view all the answers

    What results from defects in maternal Bicoid mRNA localization?

    <p>Lack of anterior segments</p> Signup and view all the answers

    Which of the following gene classes is regulated by Bicoid in Drosophila?

    <p>Gap genes</p> Signup and view all the answers

    What is a key feature of Drosophila early embryonic development?

    <p>There are 13 synchronous nuclear divisions prior to cellularization</p> Signup and view all the answers

    What role do Hox genes play in Drosophila development?

    <p>Assign identity to each segment</p> Signup and view all the answers

    Which statement is true regarding the gradients formed by egg-polarity gene products?

    <p>Both Bicoid and Nanos create opposing gradients in the cytoplasm</p> Signup and view all the answers

    What is observed in Drosophila mutants with polarity defects?

    <p>Missing anterior or posterior segments</p> Signup and view all the answers

    What characterizes the early Drosophila embryo?

    <p>It is a syncytium without individual cell boundaries.</p> Signup and view all the answers

    Which class of genes is primarily responsible for regulating anterior-posterior patterning in Drosophila?

    <p>Gap Genes</p> Signup and view all the answers

    How do segment polarity genes maintain their expression?

    <p>By using feedback loops and interacting with other gene classes.</p> Signup and view all the answers

    What is a major difference in embryo patterning between Drosophila and vertebrates?

    <p>Drosophila has a highly polarized egg structure.</p> Signup and view all the answers

    Which gene class acts after gap genes during Drosophila segmentation?

    <p>Pair-rule Genes</p> Signup and view all the answers

    Which of the following is NOT a mechanism involved in early Drosophila development?

    <p>Phenotype determination</p> Signup and view all the answers

    Why is Drosophila regarded as an important model organism in developmental biology?

    <p>The genetic pathways and development processes are well understood.</p> Signup and view all the answers

    What defines egg-polarity genes in Drosophila?

    <p>They set up the coordinates for the embryo's axes.</p> Signup and view all the answers

    What is the primary role of gap genes in the expression of gene A?

    <p>They regulate the expression of gene A in specific stripes.</p> Signup and view all the answers

    Which statement is true about pair-rule genes?

    <p>They encode transcription factors and are expressed in 7 segments.</p> Signup and view all the answers

    What type of mutation might display a polarity defect in segments?

    <p>Segment polarity gene mutations.</p> Signup and view all the answers

    Which of the following genes is expressed at the posterior portion of each segment?

    <p>Engrailed.</p> Signup and view all the answers

    What maintains the expression of segment-polarity genes throughout development?

    <p>Mutually reinforcing signals between neighboring cells.</p> Signup and view all the answers

    How do pair-rule genes regulate segment-polarity genes?

    <p>Via indirect regulatory mechanisms.</p> Signup and view all the answers

    Which gene product normally represses gene A in stripe Y?

    <p>Gap gene Z.</p> Signup and view all the answers

    What is the primary characteristic of mutations in pair-rule genes?

    <p>They disrupt expression in every segment.</p> Signup and view all the answers

    Which of the following describes the expression patterns of segment polarity genes?

    <p>Expressed in 14 stripes.</p> Signup and view all the answers

    What is the function of the Wingless and Hedgehog proteins?

    <p>They serve as paracrine signaling molecules.</p> Signup and view all the answers

    What primary role do Hox genes play in development?

    <p>Providing identity to each body segment</p> Signup and view all the answers

    Which of the following genes assists in organizing the anterior-posterior (A-P) axis in the early embryo?

    <p>Gap genes</p> Signup and view all the answers

    How do Hox proteins function at the molecular level?

    <p>As transcription regulators that bind DNA</p> Signup and view all the answers

    What mechanism is involved in maintaining Hox gene expression during development?

    <p>Epigenetic inheritance of histone modifications</p> Signup and view all the answers

    Which of the following best exemplifies the conservation of Hox genes across species?

    <p>Similar expression patterns in both flies and mammals</p> Signup and view all the answers

    What occurs if Hox 10 is ectopically expressed in the thoracic region?

    <p>It represses thoracic character</p> Signup and view all the answers

    Who was awarded the Nobel Prize for the discovery of Hox genes?

    <p>Ed Lewis</p> Signup and view all the answers

    Which type of genetic alteration is indicated by the term 'paralogs' in relation to Hox genes?

    <p>Gene duplication</p> Signup and view all the answers

    What is the effect of Hox10 expression in the lumbar region of mice?

    <p>It confers and maintains segment identity</p> Signup and view all the answers

    Which genes control segmentation along the A-P axis?

    <p>Gap genes</p> Signup and view all the answers

    What type of inheritance allows Hox gene expression to be maintained?

    <p>Epigenetic inheritance</p> Signup and view all the answers

    What is the primary function of segmentation genes in embryonic development?

    <p>To regulate body segment placement</p> Signup and view all the answers

    Which Hox gene is specifically mentioned as being involved in limb development?

    <p>Hox 10</p> Signup and view all the answers

    What type of genes are responsible for controlling segmentation along the anterior-posterior axis?

    <p>Pair-rule genes</p> Signup and view all the answers

    Which of the following is TRUE about segment-polarity genes?

    <p>They encode signaling molecules and transcription regulators.</p> Signup and view all the answers

    What is the main role of the gap genes during early embryonic development?

    <p>To define the identity of each segment.</p> Signup and view all the answers

    What do egg-polarity genes primarily function to organize in the Drosophila embryo?

    <p>The anterior-posterior axis</p> Signup and view all the answers

    Which of the following best describes gap genes?

    <p>They regulate segmentation by defining the size and spacing of segments.</p> Signup and view all the answers

    What is the significance of the segmentation patterns in Drosophila development?

    <p>They establish the basic body plan by organizing the embryo along the A-P axis.</p> Signup and view all the answers

    Which of the following statements accurately describes a feature of Hox genes?

    <p>Hox genes have conserved functions across different species, including humans.</p> Signup and view all the answers

    Which statement accurately reflects the organization of an early Drosophila embryo?

    <p>The early Drosophila embryo is structured as a syncytium.</p> Signup and view all the answers

    How does the segmented pattern in Drosophila embryos initially form?

    <p>By the interaction of egg-polarity genes and maternal factors.</p> Signup and view all the answers

    What is the key role of genetic and molecular biology tools in Drosophila research?

    <p>They enable the investigation of genetic control mechanisms governing development.</p> Signup and view all the answers

    What is the primary function of Hox genes in Drosophila development?

    <p>They define the anterior-posterior axis and segment identity.</p> Signup and view all the answers

    Which class of genes plays a role in establishing the boundaries of segments in Drosophila?

    <p>Segment polarity genes</p> Signup and view all the answers

    What concept explains why each segment in Drosophila embryos knows its identity?

    <p>The establishment of precise molecular gradients and genetic regulation.</p> Signup and view all the answers

    How do segment polarity genes maintain their expression throughout development?

    <p>They rely on feedback mechanisms from surrounding cells.</p> Signup and view all the answers

    What is the role of gap genes in the development of Drosophila?

    <p>They define broad areas along the A-P axis.</p> Signup and view all the answers

    Why is Drosophila considered an effective model organism for studying developmental processes?

    <p>It shares key developmental mechanisms with vertebrates.</p> Signup and view all the answers

    What are the primary signals that define egg polarity in a Drosophila embryo?

    <p>Localized maternal mRNAs and their protein products.</p> Signup and view all the answers

    What is the role of gap gene 'Z' in relation to gene A's expression in Drosophila?

    <p>It activates gene A in stripe X and represses it in stripe Y.</p> Signup and view all the answers

    Which statement describes the expression patterns of pair-rule genes?

    <p>They are expressed in seven segments, alternating between odd and even.</p> Signup and view all the answers

    What is the characteristic defect associated with segment polarity genes?

    <p>Polarity defects observed in every segment.</p> Signup and view all the answers

    Which genes negatively regulate the expression of gene A?

    <p>Gap gene 'Z' in stripe Y.</p> Signup and view all the answers

    What is the primary function of segment polarity genes?

    <p>To establish segment boundaries and polarity.</p> Signup and view all the answers

    Which is a known characteristic feature of pair-rule genes?

    <p>Their mutations cause loss of entire segments.</p> Signup and view all the answers

    What components are encoded by segment polarity genes?

    <p>Transcription factors and paracrine signaling molecules.</p> Signup and view all the answers

    What is the effect of mutations in gap genes on Drosophila development?

    <p>Loss of specific segments depending on the gap gene affected.</p> Signup and view all the answers

    Which pair of genes work through a signaling loop to maintain segment polarity?

    <p>Wingless and Hedgehog.</p> Signup and view all the answers

    What is the general function of egg-polarity genes in Drosophila embryonic development?

    <p>To organize the anterior-posterior axis of the early embryo</p> Signup and view all the answers

    Which type of genes are primarily responsible for establishing anterior-posterior patterning in Drosophila?

    <p>Egg-polarity genes</p> Signup and view all the answers

    What is the outcome of a bicoid mutation in Drosophila?

    <p>Lack of anterior segments</p> Signup and view all the answers

    What is the role of Hox genes during Drosophila segmentation?

    <p>To determine the identity of individual segments</p> Signup and view all the answers

    What type of gradients do egg-polarity gene products create in the Drosophila embryo?

    <p>Opposing gradients</p> Signup and view all the answers

    Which maternal molecule is critical for anterior patterning in Drosophila embryos?

    <p>Bicoid</p> Signup and view all the answers

    During which stage do Drosophila embryos exhibit rapid nuclear divisions without cellular division?

    <p>Syncytial blastoderm stage</p> Signup and view all the answers

    Which class of genes is responsible for creating the segments in Drosophila and their distinct features?

    <p>Hox genes</p> Signup and view all the answers

    What is the primary function of pair-rule genes during Drosophila development?

    <p>To create alternating segments in the embryo</p> Signup and view all the answers

    What does the presence of a gradient of Bicoid protein in the Drosophila embryo indicate?

    <p>Regulation of gap gene expression</p> Signup and view all the answers

    What is the role of Hox genes in segment identity?

    <p>Hox genes provide identity to each segment.</p> Signup and view all the answers

    Which process is essential for maintaining Hox gene expression throughout development?

    <p>Epigenetic inheritance of histone modifications.</p> Signup and view all the answers

    Which type of proteins do Hox proteins primarily act as?

    <p>Transcription regulators that bind to DNA.</p> Signup and view all the answers

    What outcome occurs from ectopic expression of Hox10 in the thoracic region of mice?

    <p>Repression of thoracic character.</p> Signup and view all the answers

    Which genes are responsible for organizing the anterior-posterior axis of the early embryo?

    <p>Egg-polarity genes.</p> Signup and view all the answers

    What significance do paralogs have in the context of Hox genes?

    <p>They are duplicated genes with potential functional redundancy.</p> Signup and view all the answers

    What was a key finding regarding Hox gene expression in vertebrates and invertebrates?

    <p>Hox gene expression patterns are conserved across species.</p> Signup and view all the answers

    Who is credited with the discovery of Hox genes and received a Nobel Prize for it?

    <p>Ed Lewis.</p> Signup and view all the answers

    What do segment-polarity genes control in developing organisms?

    <p>Segmentation along the anterior-posterior axis.</p> Signup and view all the answers

    What is a function of Hox genes in vertebrates aside from segment identity?

    <p>Influence limb development.</p> Signup and view all the answers

    Which mechanism enables Hox gene expression to be maintained throughout organismal development?

    <p>Chromatin remodeling complex recruitment.</p> Signup and view all the answers

    Which gene class acts as master regulators by controlling the expression of multiple downstream genes?

    <p>Hox genes.</p> Signup and view all the answers

    What aspect of genetic diversity in Hox genes is indicated by the term 'gene duplication'?

    <p>Generation of paralogs with potentially redundant functions.</p> Signup and view all the answers

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