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47 Cards in this Set
- Front
- Back
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Cell cycle stages |
Interphase: 1) gap 1 2)synthesis 3)gap 2 4)Mitosis 5)cytokinesis
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What stages take up the most amount of time in the cell cycle? |
Interphases (G1, synthesis, G2)stages |
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Stages of mitosis |
Prophase Metaphase Anaphase Telophase |
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Single celled |
Zygote |
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Body cells |
Somatic |
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Sex cells |
Gametes |
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Mitosis vs meiosis |
Mitosis body cells, 1 cell division, no crossing over/recombination, produces TWO DIPLOID cells, daughter cells are identical Meiosis sex cells, 2 cell divisions, crossing over/ recombination, produces FOUR HAPLOID cells, daughter cells are different |
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Interphase MITOSIS |
Uncondensed chromatin DNA in defined nucleus Centrosomes and other organelles have been duplicated Cell is larger to prepare for division |
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Metaphase MITOSIS |
Chromosomes along equatorial plate Micro tubule spindle fibres attach to the centromere of each chromosome |
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Prophase Mitosis |
DNA supercoils and chromosomes condense Chromosomes are made of genetically similar sister chromatids Centrioles move to poles of membrane Nuclear membrane starts to break down |
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Anaphase MITOSIS |
Spindle fibers contract and pull chromosomes apart Genetically identical chromosomes move to opposite sides of the cell |
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Telophase mitosis |
Chromosomes decondenses into chromomatin Nuclear membrane begins reforming
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Telomeres |
Caps at ends of chromosomes that determine the lifespan of a cell The more a cell divides the shorter it’s life |
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Haploid vs diploid numbers |
N and 2n |
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Homologous chromosomes |
Each chromosome in an egg will have a “matching” partner in sperm. Partners are called homologous. |
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Sister chromotids vs homologous chromosomes |
Homologous are different and are “matching” partners (male and female) Sister chromotids are identical pairs attached by the centromere. They are made in the S phase of Interphase. |
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Stages of meiosis |
Interphase ( g1, S, g2) Pro phase 1 Metaphase 1 Anaphase 1 Telophase 1 Interphase 2 (GROWTH ONLY) Rest is repeated again.
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Interphase 1 |
2n = 2 G1 growth S Synthesis and DNA replication G2. Growth and enzymes |
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Prophase in MEIOSIS |
Prophase 1 and 2 are similar. Spindle fibres attach Nuclear membrane begins dissolving Centrioles to poles ⭐️crossing over of homologous pairs |
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Metaphase 1 MEIOSIS |
Homologous pairs line up beside (not along) equatorial plate. NOT single file Spindle fibres are attached |
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Anaphase 1 MEIOSIS |
Homologous pairs are separated as spindle fibres shorten. Each Homologous pair is composed of two chromatids (because of replication) |
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Telophase 1 |
Nuclear membranes start reforming Chromosomes UNCONDENSE into CHROMATIN |
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Cytokinesis 1 |
N=1 Division of cells into TWO HAPLOID cells (the parent cell began as diploid) |
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Interphase 2 |
NO REPLICATION (S PHASE) Growth period |
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Prophase 2 |
Similar to prophase 1 Nuclear membrane starts dissolving Chromatin condenses into chromosome(s) Spindle fibres attach Centrioles to poles |
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Metaphase 2 |
Chromosomes line SINGLE FILE along the equitorial plate (instead of beside the EQ in metaphase 1) Spindle fibres are attached |
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Anaphase 2 |
Spindle fibres pull chromatids apart. There is now one chromatid per pole. (Rather than a set of sister chromotids per side.) |
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Telophase 2 |
Nuclear membranes start to reform Chromotids uncondense into chromatin There are now FOUR nucleus’s |
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Cytokinesis 2 |
Nuclear membranes completely reform. There are now FOUR HAPLOID cells. ( meaning each cell is n=1) Each cell is different from eachother. |
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Act of homologous pairs meeting |
Synapse Takes place during prophase 1 |
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Tetrad |
Two replicated homologous chromosomes |
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Crossing over process |
In prophase 1 1) sister chromosomes, each with a pair of sister chromatids, line up. This is called homologous chromosomes or a TETRAD 2) a chiasma forms between the chromotids. Information is spread. 3) breakage results in recombinant chromotids which contain parts of each other’s genetic material |
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Purpose of synapsis and crossing over |
Increases biodiversity and variations to increase the possibility of survival. |
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Purpose of synapsis and crossing over |
Increases biodiversity and variations to increase the possibility of survival. |
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Effects of crossing over |
Can cause chromosomal mutations Creates millions of combinations (permutations) Genetic variation |
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Spermatogenesis |
The process where sperm cells are made |
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Spermatogenesis |
The process where sperm cells are made |
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Spermatogenesis steps |
Spermatagonium 2n Primary spermatocyte 2n Secondary spermatocyte n Spermatids n Sperm n |
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Oogenesis steps |
Oogonium 2n Primary oocyte 2n Secondary oocyte n Ovum n + 3 polar bodies n |
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Karyotyping |
A method of viewing chromosomes and determining some genetic disorders |
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Karyotyping |
A method of viewing chromosomes and determining some genetic disorders |
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Male vs female karyotype |
Male XY female XX |
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Non disjunction |
Chromosomal mutations and mishaps which can occur in both mitosis and meiosis |
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How do non disjunctions happen? |
In meiosis: Failure of homologous chromosomes to separate in anaphase 1 Failure of sister chromatids to separate properly in anaphase 2 |
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Can plants have more than one set of chromosomes? How? |
Yes they can. These are called polyploids. A 2n cell is fertilized by a gamete (n), creating a 3n |
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What does non disjunction create in humans ? |
Produces GAMETES that are either trisomy (2n+1) or monosomy (2n-1) |
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Down’s syndrome |
Trisomy 21 Smaller chromosome results in less severe effects than other non disjunction disorders |
