Mastering Biology Chapter 12
DNA replication produces two identical DNA molecules, called _________, which separate during mitosis.
sister chromatid(s)
Cohesins break down
Anaphase
Kinetochores move toward poles of cell
Anaphase
Consider a question concerning an animal cell that has been treated with an inhibitor: Will the chromosomes move to the poles of the cell?
No
Comparing chromosome separation in Eukaryotes and Bacteria: *Chromosome separation begins at the origin of replication on DNA *Before separation, duplicated chromosomes condense *Nuclear envelope fragments, permitting chromosome separation *Two copies of duplicated chromosome are attached at their centrosomeres before separation *Chromosomes replicated before cell division *Replicated chromosomes separate by attaching to some other structural feature of the cell
BACTERIA ONLY: *Chromosome sweparation begins at the origin of replication on DNA EUKARYOTES ONLY: *Before separation, duplicated chromosomes condense *Nuclear envelope fragments, permitting chromosome separation *Two copies of the duplicated chromosome are attached at their centromeres before separation BOTH BACTERIA AND EUKARYOTES: *Chromosomes replicate before cell division *Replicated chromosomes separate by attaching to some other structural feature of the cell
The presence of a cell wall prevents the cell from dividing by constriction
Bacteria: FALSE Animals: FALSE Plants: TRUE
Tubulin or tubulin-like molecules function in binary fission (in bacteria) or cytokinesis (In animals and plants)
Bacteria: TRUE Animals: FALSE Plants: TRUE
Cells divide by constriction of a ring of protein
Bacteria: TRUE Animals: TRUE Plants: FALSE
After chromosomes condense, the _________ is the region where the identical DNA molecules are most tightly attached to each other.
Centromeres
The _______________are the organizing centers for microtubules involved in separating chromosomes during mitosis.
Centrosome(s)
During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called ____________.
Chromatin
Cytochalasin B is a chemical that disrupts microfilament formation. How would this interfere with cell division? formation of the mitotic spindle formation of the cell plate DNA replication cleavage binary fission
Cleavage
In most eukaryotes, division of the nucleus is followed by ____________, when the rest of the cell divides.
Cytokinesis
During telophase, the nonkinetochore microtubules ___________
Disassemble
During mitosis, microtubules attach to chromosomes at the ____________.
Kinetochore(s)
Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle? M G1 cytokinesis S G2
G1
During prophase, the microtubules of the mitotic spindle _________
Lengthen
During anaphase, the nonkinetochore microtubules _________ and move past each other, and the kinetochore microtubules _________
Lengthen..........shorten
Kinetochores are motionless in relation to poles of cell
Metaphase
The ____________ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.
Mitotic spindle(s)
Microtubules attach to kinetochores
Prometaphase
Cohesins join sister chromatids of duplicated chromosome
Prophase
Tubulins assemble into spindle microtubules
Prophase
Cytokinesis in animal cells is accomplished by constriction of the cell along the plane of cell division (formation of a cleavage furrow). In plant cells, which have cell walls, a completely different mechanism of cytokinesis has evolved. Which of the following statements are true of cytokinesis in plant cells? Select the two that apply. After chromosome separation is complete, a network of microfilaments forms near the plane of cell division that will separate the two new cells. The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells. The plasma membrane of the parent cell grows inward, eventually joining with the cell plate. Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate.
THe cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate
Spindle microtubules disassemble
Telophase
Why do some species employ both mitosis and meiosis, whereas other species use only mitosis? They need only mitosis to make large numbers of cells such as sperm. They need only meiosis if they produce egg cells. They need both if they are producing animal gametes. A single-celled organism only needs mitosis. They need meiosis if the cells are producing organs such as ovaries.
They need both if they are producing animal gametes
Consider a question concerning an animal cell that has been treated with an inhibitor: Will the cell elongate during mitosis?
Yes
Consider a question concerning an animal cell that has been treated with an inhibitor: Will the sister chromatids separate from each other?
Yes
