Flashcards
Lecture 10 Meiosis Part 1
Cards in this deck (24)
- 1Gene-Unit of information about a heritable trait
-Passed from parent to offspring
-Each gene has a specific location on a chromosome called the gene locus - 2Alleles– A unique molecular form of the same gene
– 1 allele comes from the mother, 1 from the father - 3Karyotype-Ordered displays of an individual's chromosomes (during metaphase)
- 4Meiosis-Process in which the nucleus of a cell completes 2 successive divisions that produce 4 nuclei
-Each nuclei with a chromosome number that has been reduced by half - 5Homologous chromosomes have the same-Length
-Shape
-Deal with the same traits - 6Gametes-Haploids cells chromosome number (n)
- 7Somatic cellsNOT gametes, diploid chromosome number (2n)
- 8Sister chromatidsEach piece of your chromosome
- 9ChromosomeThread-like structure located inside the nucleus of animal and plant cells
- 10CentromereHolds the sister chromatids together
- 11Steps of Meiosis-Meiosis I (separate homologous pairs)
-Meiosis II (separate sister chromatids)
(Even though we have 2 rounds of division DNA is only replicated once) - 12Meiosis ISeparates homologous chromosomes
-Prophase
-Crossing Over
-Metaphase I
-Anaphase I
-Telophase I - 13Prophase-Chromosomes condense
-Nuclear envelope breaks down
-Homologous chromosomes pair up and crossing over can occur - 14Crossing Over-In the beginning of meiosis I, while homologous chromosomes are paired next to each other, segments of the chromosomes can exchange segments of DNA.
- 15Metaphase I-Pairs of homologous chromosomes are moved by spindle fibers to the equator of the cell. The homologous, each made of 2 chromatids stay together.
- 16Anaphase I-Homologous pairs separate (similar to mitosis where chromatids separate)
-Chromatids DO NOT separate at their centromeres.
-Each chromosome is still composed of 2 chromatids joined by the centromere - 17Telophase I-Individual chromosomes gather at each of the poles of the cell
-In most cases, cytoplasm then divides (cytokinesis) forming 2 new cells - 18Meiosis IISeparates chromatids and 4 haploid daughter cells result
-Prophase II
- Metaphase II
-Anaphase II
-Telophase II - 19Prophase II-Each chromosome becomes attached to the spindle fibers and starts moving toward its equator
-Condense
-Nucleolus breaks down - 20Metaphase II-All chromosomes are now positioned at the equator
- 21Anaphase II-Centromeres divide and the chromatids NOW called chromosomes move to opposite poles of the cell
- 22Telophase-Four daughter nuclei form. When the cytoplasm divides each new cell is haploid (n). The original chromosome number has been reduced by half.
-One or all of these cells may become gametes. - 23Chiasma-A point at which paired chromosomes remain in contact during the first metaphase of meiosis, and at which crossing over the exchange of genetic material occur between the strands.
- 24Non-Disjunction-An accident in chromosome separation when one daughter cell receives both pairs of chromosomes and the other daughter cell receives none.
-Most common condition that's a result of an extra chromosome is down syndrome
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- Flashcards on Lecture 10 Meiosis Part 1, created by Sydney Franko on 11/04/2016.
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- Sydney Franko
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