What are three reasons that a cell might divide?
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Tumor suppressor gene
A gene that normally functions to inhibit cell division; mutated forms can lead to the unrestrained cell division of cancer, but only when both copies of the gene are mutant
Proto-oncogene
A normal cellular gene that can act as an oncogene when mutated
Cyclin
Any of a number of proteins that are produced in synchrony with the cell cycle and combine with certain protein kinases, the cyclin-dependent kinases, at certain points during cell division
Cyclin-dependent kinase (Cdk)
Any of a group of protein kinase enzymes that control progress through the cell cycle. These enzymes are only active when complexed with cyclin. the cdc2 protein, produced by the cdc2 gene, was the first Cdk enzyme discovered.
Maturation promoting factor (MPF)
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Motor protein
Motor proteins are a class of molecular motors that are able to move along the surface of a suitable substrate. They are powered by the hydrolysis of ATP and convert chemical energy into mechanical work.
Diploid
(of a cell or nucleus) containing two complete sets of chromosomes, one from each parent.
Haploid
(of a cell or nucleus) having a single set of unpaired chromosomes.
Gamete
A haploid reproductive cell
Homologous chromosome
Refers to a pair of the same kind of chromosome in a diploid cell
Synapsis
The point-by-point alignment (pairing) of homologous chromosomes that occurs before the first meiotic division; crossing over takes place during synapsis
Crossing over
In meiosis, the exchange of corresponding chromatid segments between homologous chromosomes; responsible for genetic recombination between homologous chromosomes.
Sister chromatid
One of two identical copies of each chromosome, still linked at the centromere, produced as the chromosomes duplicate for mitotic division; similarly, one of two identical copies of each homologous chromosome present in a tetrad at meiosis.
Non-sister chromatid
Two chromosomes on different, non homologous chromosomes
Sex cell
reproductive cell: a spermatozoon or an ovum; a cell responsible for transmitting DNA to the next generation
Somatic cell
Any of the cells of a multicellular organism except those that are destined to form gametes (germ-line cells)
zygote
The diploid (2n) cell resulting from the fusion of male and female gametes (fertilization)
What processes contribute to the movement of chromosomes during mitosis and meiosis? Hint: see Raven et al. page 196.
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How is prokaryotic cell division similar to eukaryotic cell division? What is prokaryotic cell division called?
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Describe experimental evidence that supports the idea that mitosis is regulated by intracellular signaling molecules.
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With your knowledge of cell cycle regulation, design a drug that could target a component of the cell cycle to inhibit mitosis
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What are 4 differences between mitosis and meiosis? Refer to Figure 11.7 and 11.8.
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In which meiotic division does the cell go from being diploid to haploid (aka the reduction division)? Why is the cell considered haploid at this point?
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What are two ways that meiosis generates genetic diversity in the gametes? What phases of meiosis do these occur in? Draw diagrams of each of these phases, and label: homologous chromosomes, centromere, sister chromatids.
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What is another factor (besides meiotic events) that explains the genetic difference between siblings?
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In broad terms, what conditions must be met before a cell can divide? Specifically, what is “checked” at the G1/S checkpoint? The G2/M checkpoint? The Spindle Checkpoint?
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What is a protein kinase? How are these enzymes involved in cell cycle regulation? What is the role of the cyclins?
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Describe how cyclin and Cdk work together to regulate cell division at the G2/M checkpoint.
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