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29 Cards in this Set
- Front
- Back
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Chromatin
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DNA in its uncoiled form
Not easily seen in this form |
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Chromosome
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DNA in its coiled form
more easily seen only seen during cell division |
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supercoiling
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the process of DNA coiling up on itself, using histone proteins to tightly wrap the DNA strand
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histone proteins
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Proteins used to aid in DNA coiling, and to give shape to the chromosomes
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Chromatid
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one of two identical halves of a chromosome
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Centromere
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the part of a chromosome that holds the two identical chromatids together
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Sex Chromosome
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- chromosomes that determine the gender of the organism
- in humans XY= male XX= female |
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Autosomes
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any chromosome that is NOT a sex chromosome
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Diploid
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- A cell that contains the full number of chromosomes for that organism (all chromosomes are in pairs)
- In humans the diploid number is 46 |
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Haploid
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- A cell containing only half of the number of chromosomes for that organism (only one chromosome per pair is present)
- in humans the haploid number is 23 - only found in sperm and egg cells |
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What do the number of chromosomes show between two organisms?
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- They show how closely related two organisms are to each other
- horses have 64 chromosomes, donkeys have 62 |
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Binary Fission
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Cell division in prokaryotes (unicellular organisms)
- the circular DNA is copied - the cell splits into two cells |
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Interphase
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the longest part of the cell cycle, when the cell is NOT dividing
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G1 Phase
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Cell growth
part of interphase |
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S phase
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DNA is copied
part of interphase |
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G2 phase
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cell prepares for cell division
- part of interphase |
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Prophase
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- nucleus disappears
- chromosomes form - spindle fibers form |
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Metaphase
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Chromosomes line up in the middle of the cell
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Anaphase
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Chromosomes split apart and move towards the poles
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Telophase
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- chromosomes uncoil into chromatin
- nucleus reforms - cell splits into two cells |
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cytokinesis
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The process of a cell splitting into two cells
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Sex Cells
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-Type of cell that undergoes meiosis
- has half the normal number of chromosomes |
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Differences between mitosis and meiosis
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- cells divide twice in meiosis
- crossing over occurs in meiosis - chromosomes are pulled apart randomly in anaphase I |
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Crossing Over
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Process where one part of a chromosome switches with the same area on its homologue (identical chromosome)
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Number of sperm and egg cells to survive at the end of meiosis
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4 sperm
1 egg increases the chance of fertilization |
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Prophase (picture)
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Metaphase (picture)
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Anaphase (picture)
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Telophase (picture)
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