1. Explain the role of plant cell division in plant cell patterning
Plants have evolved with specialized regulatory mechanisms to achieve proper tissue growth and morphogenesis. During development, an organism acquires a characteristic shape and size and establishes vigorous organ morphologies. in order to achieve this, growing tissues undergo multiple rounds of growth, division, and differentiation until a highly organized structure is formed
The most-studied roles of patterned cell divisions in the development of flowering plants are those of shoot development (including formation of leaves and flowers) and primary root development, embryo development. The basic body organization of a plant is laid out after the fertilization, when the plant embryo forms in the developing seed, as the seed matures development stops . On germination, the mature embryo produces a seedling consisting of the embryonic leaves (cotyledons), a root, with a root meristem, and a stem (hypocotyl) with a shoot apical meristem from which the leaves, the stem and the flowers arise.
example. in the model plant Arabidopsis, the axial pattern of the embryoduring embryogenesis is established during the first asymmetrical cell divisionof the zygote, giving rise to an apical cell(small , cytoplasmically dense) and a basal cell( large and vacuolated) . it establishes the axial polarity. nearly the entire embryo is derived from the small apical cell. the apical cell undergoes two longitudinal divisions followed by a transverse division to from an eight celled , octant stage globular embryo. additional cell division increases the number of cells in the globular embryo . the larger vacuolated basal cell also divides, but all of its division are horizontal, at right angle to the long axis, it gives a filament of six to nine cells known as the suspensor that attches the embryo to the vascular system of the plant. the basal cell derivative nearest the embryo is known as the hypophysis and it gets divited to form the quiescent center of the root apical meristem and the root cap.
by the globular stage , the embryo divides into three domains. the top and bottom halves of the embryo correspond to the apical and central domains. whereas the uppermost cell of basal cell derivatives,the hypophysis constitutes the basal domain. the shoot apical meristem and most of the cotyledons derive from the apical domain, part of the cotyledons, the hypocotyl, radicle, and part of the root apical meristemcomes from the central domain, and the quiescent center of the root apical meristem and root cap are from the basal domain.
Describe segmentation during drosophila embryogenesis. Include how patterning is initially established and how continuous sub-division of regions results in patterning the A-P body axis.
Summarize the role of Hox genes, neural crest cells, and epidermal: mesenchymal signaling in the patterning of vertebrates. Give an example from each class of vertebrates. How do hox genes, neural crest cells, and epidermal: mesenchymal interactions of the integument give each type of vertebrate their unique and special traits?
1. a.) Describe two functional examples of bacterial cell polarity or spatial patterning (from the video). One example has to be symmetric and the other asymmetric. (2 points) b.) According to Dr. Jacobs-Wagner, what are the 3 main elements of the bacterial spatial organization? (3 points) Video: https://www.ibiology.org/microbiology/bacterial-tubulin-ftsz-actin-mreb-homologues-spatial-organization-bacterial-cells/#part-1
Explain the relevance of patterning, positional information, and signalling pathways in the process of regeneration.
Explain the structural role of the different biomolecules within a cell.
Explain how the abnormal cell division of cancerous cells escapes normal cell cycle controls.
1. Explain both the ways in which signal transduction can happen inside a plant cell 2. Explain any 2 ways in which a plant will avoid self-fertilization
1) The Shh (sonic hedgehog) signaling molecule is important for patterning the dorsal-ventral axis of the spinal cord. Briefly describe where Shh is expressed and how its expression patterns the spinal cord. 2)What is the role of the proliferating chondrocytes and hypertophic chondrocytes in bone development and bone growth? a) Proliferating chondrocytes: b) Hypertrophic chondrocytes:
Describe how an HIV particle enters a host cell: Explain the role of the reverse transcriptase in the life cycle of a retrovirus: Explain the significance of the formation of a provirus:
A) Assuming the life of a cell starts as soon as cell division is completed and ends when the cell starts a new process of cellular division, how many times in a cell’s life does it replicate its DNA? Explain. B) How is DNA replication related to mitosis? C) When does a multicellular organism undergo mitosis (when it wants to reproduce, all the time, only when injured, when it’s growing, or when)?