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36 Cards in this Set
- Front
- Back
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What is a zygote?
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fertilized egg cell, the first cell of a new individual
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How many chromosomes are there in human somatic cells?
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46
2 sets of 23 |
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Define what happens in Anaphase?
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-centromeres divide
-two chromatids (somes) move toward opposite poles -spindle fibers shorten |
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Define Mitosis.
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the process during cell division in which the nucleus of the cell is divided into two nuclei
-each nucleus ends up with the same number and kinds for chromosomes as the origional cell |
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what are sex chromosomes?
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one of the 23 pairs of human chromosomes, that determine the sex of the individual
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What occurs in plant cells, with rigid cell walls?
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the form a cell plate by vesicles the fuse in the golgi apparatus instead
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What is chromosome?
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as a eukaryotic cell prepares to divide, the DNA and the protiens associated with the DNA coil into this structure.
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What occurs during cytokinesis?
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-cytoplasm of cell is divided in half
-cellmembrane grows to enclose each cell, forming two seperate cells |
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What happens during Telophase?
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-nuclear envelope forms around the chromosomes at each pole
-chromosomes at each pole uncoil -spindle dissolves -mitosis complete |
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Define disjunction.
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when the chromosome and the homologue seperate.
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Define interphase.
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-first three phases of the cycle, where a cell spends 90% of its time
-preparation for the nucleus to divide |
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What happens during the Second Growth Phase (G2)?
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-mirotobules are assembled (used to move chromosomes during mitosis)
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What happens during the Synthesis Phase (S)?
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-DNA is copied
-at the end, each chromosome is 2 cromotids attached at the centromere |
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What happens at the DNA synthesis checkpoint (G2)?
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-DNA replication is checked at this point by repair protiens
-prepares for mitosis |
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What happens in the first growth phase (G1)?
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-cell carries out its routine functions
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What happens in Prophase?
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-chromosomes coil up and become visible
-nuclear envelop dissolves -spindle forms |
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Describe what happens in Metaphase.
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-chromosomes move to center of cell; line up across the equator
-spindle fibers link the chromotids of each chromosome to opposite poles. |
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What is the mitosis checkpoint?
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-triggers the exit from mitosis
-signalsthe beginning of G1 |
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What is the G1 checkpoint?
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-will the cell divide?
If healthy conditions, synthesis begins. If not, it is stopped. |
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What is Binary Fission: Stage 1 and 2
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1.DNA is copied, cell divides
2. Squeeze toward the center by a new cell membrane, and pinches off like a balloon. |
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Define A haploid.
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A cell, such as a gamete, that has only one set of chromosomes.
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Define a diploid.
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A cell, such as a somatic cell, that contains two sets of chromosomes.
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Describe what happens in Metaphase.
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-chromosomes move to center of cell; line up across the equator
-spindle fibers link the chromotids of each chromosome to opposite poles. |
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What is the mitosis checkpoint?
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-triggers the exit from mitosis
-signalsthe beginning of G1 |
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What is the G1 checkpoint?
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-will the cell divide?
If healthy conditions, synthesis begins. If not, it is stopped. |
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What is Binary Fission: Stage 1 and 2
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1.DNA is copied, cell divides
2. Squeeze toward the center by a new cell membrane, and pinches off like a balloon. |
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Define A haploid.
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A cell, such as a gamete, that has only one set of chromosomes.
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Define a diploid.
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A cell, such as a somatic cell, that contains two sets of chromosomes.
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Define Meiosis.
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a form of cell division that halves the number of chromosomes when forming specialized reproductive ells, such as gametes or spores.
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Define Spermatogenesis.
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the process by which sperm are produced in male animals.
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Define Oogenesis.
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the process by which gametes are produced in female animals.
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Defin Asexual Reproduction.
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a single parent passes copies of all of its genes to each of its offspring; there is no fussion of haploid cells such as gametes.
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Define Clone.
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an individual produced by asexual reproduction.
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Define Sexual Reproduction.
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two parents each form haploid reproductive cells,which join to form offspring.
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Define Life Cycle.
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the entire span in the life of an organism from one generation to the next.
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Define Spore.
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a haploid reproductive cell produced by meiosis that is capable of developing into an adult without fusing with another cell.
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