5094856
Description
Flashcards by Sydney Franko, updated more than 1 year ago
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Created by Sydney Franko
over 8 years ago
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| Question | Answer |
| Gene | -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 |
| Alleles | – A unique molecular form of the same gene – 1 allele comes from the mother, 1 from the father |
| Karyotype | -Ordered displays of an individual's chromosomes (during metaphase) |
| Meiosis | -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 |
| Homologous chromosomes have the same | -Length -Shape -Deal with the same traits |
| Gametes | -Haploids cells chromosome number (n) |
| Somatic cells | NOT gametes, diploid chromosome number (2n) |
| Sister chromatids | Each piece of your chromosome |
| Chromosome | Thread-like structure located inside the nucleus of animal and plant cells |
| Centromere | Holds the sister chromatids together |
| Steps 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) |
| Meiosis I | Separates homologous chromosomes -Prophase -Crossing Over -Metaphase I -Anaphase I -Telophase I |
| Prophase | -Chromosomes condense -Nuclear envelope breaks down -Homologous chromosomes pair up and crossing over can occur |
| Crossing 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. |
| Metaphase 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. |
| Anaphase 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 |
| Telophase I | -Individual chromosomes gather at each of the poles of the cell -In most cases, cytoplasm then divides (cytokinesis) forming 2 new cells |
| Meiosis II | Separates chromatids and 4 haploid daughter cells result -Prophase II - Metaphase II -Anaphase II -Telophase II |
| Prophase II | -Each chromosome becomes attached to the spindle fibers and starts moving toward its equator -Condense -Nucleolus breaks down |
| Metaphase II | -All chromosomes are now positioned at the equator |
| Anaphase II | -Centromeres divide and the chromatids NOW called chromosomes move to opposite poles of the cell |
| Telophase | -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. |
| Chiasma | -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. |
| Non-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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