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Cards In This Set
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The 2n number is called ______and the n number is called______.
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Diploid; haploid
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The two arms of a chromosome are called______and are held together by______.
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Chromatids; centromere
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What word describes pairs of chromosomes and why do they occur this way in cellss?
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Homologous; we get one set from our mother and one from our father.
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What is a histone protien? What is a non-histone protien?
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A protien that DNA wraps around when it semi-coils into the tightly packed chromosomes. A protien that controls the activity of different DNA regions.
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How are synapsis and crossing-over related, when do they occur and why is this beneficial?
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Synapsis is the pairing of homologous chromosomes which allows the exchange of partial chromatids during crossing-over. Both increase genetic variation during prophase I of meiosis.
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Give an example of a cell that stops going through the cell cycle and why is this beneficial?
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Nerve cells or bone marrow cells
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What form is the DNA in during interphase?
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Chromatin
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When does cytokinesis occcur during the cell cycle and why is this step needed.
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After mitosis - so that the cytoplasm and organelles can split and finish dividing the cell
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What does the S phase stand for, what happens here and why is it necessary.
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S = synthesis phase; the DNA is copied because at the end of the last cycle it is unreplicated and you need two copies if a cell is going to divide.
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What is happening in each of these three stages: G0, G1, G2
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G0 = cell stops dividing, G1 = cell doubles in size, makes organelles
and carries out functions, G2 = more growth and replication or
organelles.
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What is mitosis and what type of cells does it occur in?
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The division of the nucleus that occurs in all body cells except sex cells.
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List the phases of mitosis in order.
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Prophase, metapase, anaphase, telophase
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What organelle forms the spindle and how do chromosomes attach to it?
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Centrioles; by the centromere
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State when chromosomes are replicated or unreplicated and haploid or diploid at the beginning and end of mitosis
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Beginning = replicated and diploid; end = unreplicated and diploid
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What are the three steps using chemicals for making an onion root tip slide?
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Soak in HCI to break down cell walls, soak in Carnoy solution to stop cell division in the stages, stain chromosomes with toluidine blue
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