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40 Cards in this Set
- Front
- Back
sexual reproduction:
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sperm and egg, offspring do not look exactly like parents, but look more like parents than others in species
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asexual reproduction
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no sperm or egg, offspring look exactly like parent cell. inherit DNA from single parent
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how do prokaryotes reproduce
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binary fission (mitosis becase the genetically offspring inherit DNA from single parent)
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chromatid
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one of two identical "sister" parts of a duplicated chromosome
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centromere
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where 2 sister chromosomes are joined together especially tightly
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kinetochore
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anchors that the microtubules attach to
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what happens during the cell cycle, or interphase
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G1, S, G2
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G1
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cell grows
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S
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DNA is synthesized
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G2
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replication of everything else
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interphase
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G1, S, G2
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prophase
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DNA coils and condenses. centosomes move apart and begin to form mitotic spindle
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prometaphase
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nucleur envelope breaks apart so that microtubules can get to the chromosomes. microtubules reach chromosomes
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metaphase
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chromosomes become organized in metaphase plate
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anaphase
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sister chromatids are pulled apart. pull on microtubules lengthens the cell
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telophase/cytokenesis
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cell pinches, microfilament band constricts at the center of the cell, forming a cleavage furrow. cell divides
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cleavage furrow
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shallow groove in the actin ring of the cytoplasm
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why do organisms, both single and multicellular, engage in mitosis?
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single cell: for reproduction. multicellular: to grow.
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somatic cell
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cell that's not a gamete
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homologous (sister) chromosomes
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chromosomes that paire because they both carry genes for the same characteristic at the sam eplace (locus)
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autosome
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non-sex chromosome
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gamete
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cell that has a single set of chromosomes (sperm and eggs)
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zygote
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what happens when 2 gametes are put together (diploid
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stages of Meiosis
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same as mitosis, but times 2
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Prophase I
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nuclear envelop breaks apart. synapsis. crossing over occurs and forms chromosome tetrads. spindle begins forming as the centrisomes move apart
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synapsis
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homologous chromosomes pair up on the metaphase plate
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Metaphase I
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microtubules attach to kinetochores. tetrads move to the metaphase plate. independent variation occurs.
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Anaphase I
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homologous chromosomes separate. pull of microtubules lengthens the cell.
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Telophase I
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microfilament band constricts at the center of the cell, forming a cleavage furrow. chromosomes uncoil. cell splits.
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Prophase II, Metaphase II, Anaphase II, Telophase II
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just like mitosis, except you get 4 haploid cells in the end
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how does meiosis increase variation
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having chromosomes trade DNA
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why mitosis is different from meiosis
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diploid -> diploid, 4 phases. chromosomes duplicate only once.
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why meiosis is different form mitosis
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diploid -> haploid, 8 phases
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genetic recombination
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production of gene combinations different from those carried by original chromosomes
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crossing over
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exchange of corresponding segments between 2 homologous chromosomes
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chiasmata
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place where 2 homologous chromosomes cross over
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karyotype
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ordered display of magnified images of an individual's chromosomes arranged in paris, staring with the longest.
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allele
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unique DNA sequence at a particular locus
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dominant
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allele that determines phenotype
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recessive
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allele that doesn't determine phenotype (masked by dominant)
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