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15bio5785
CU intro to bio: lecture 15
| Question | Answer |
|---|---|
| In asexual reproduction, | the parent passes an exact copy of all if his/her genes (e.g. both pairs of the homologous pair) to the offspring |
| In Asexual reproduction what will the offspring look like? | .Therefore the offspring will be a genetically identical clone of that parent.nes |
| In sexual reproduction, | each parent passes on only 1 chromosome of each homologous pairs of chromosomes on to the offspring. |
| How many genes does will will the offspring aquire from one parent in sexual reproduction? | Therefore the offspring will acquire only 1 rather than 2 genes for each trait from a particular parent. (The other parent supplies the other gene.) |
| alleles | Genes for each trait come in slightly different forms. |
| Meiosis shuffles the alleles during gamete formations resulting in what? | and fertilization produces offspring with unique combinations of alleles |
| Meiosis begins with | diploid (2n) germ cells and produces haploid (n) gametes. |
| Homologous chromosomes | In 2n cells, there are two chromosomes of each type, |
| What happens to homologous chromosomes during meiosis? | Homologous chromosomes partner up during meiosis. |
| What type of cell doe Meiosis produce? | Each of the gametes produced by meiosis receives only one chromosome from the homologous pair; gametes are therefore haploid cells |
| How does meiosis resemble mitosis? | The chromosomes are duplicated during the S phase of interphase to form sister chromotids held together at the centromere. Chromosomes are moved by the microtubules of the spindle apparatus |
| What is the major difference between mitosis and meiosis? | Unlike mitosis, meiosis has two series of divisions - meiosis I and II. |
| Meiosis I: | Homologous chromomsomes partner together adn then separate. This is followed by cytoplasmic division and results in two daughter cells. |
| What is the result of Meiosis 1: Are they Haploid or diploid? | Two daughter cells. Each of the two daughter cells receives one set of chromosomes in the duplicated state. Therefore, each daughter cell is haploid (n) |
| ToF: During Meiosis 1 the homologous pairs stay together and the sister chromatids separate. | FALSE: during meiosis I, homologous pairs separate, but the sister chromatids are still together (ie, each chromosome is still in its duplicated form.).... |
| What is Synapse | homologous chromosomes partner together. |
| Meiosis II: | the sister chromatids separate, the cytoplasm divides again, and the result is four haploid cells from the original germ cell. |
| What is the bottom line of Meiosis? | Bottom Line: Meiosis I -separates homologues; Meiosis II - separates sisters |
| Prophase I: | synapses happens: crossing over happens |
| Chiasmata: | thought to be the point where two homologous non-sister chromatids exchange genetic material during chromosomal crossover during meiosis |
| Metaphase I: | The homologous chromosomes line up at the spindle equator in a random order. |
| Anaphase I: | Homologous chromosomes (still duplicated) separate into two haploid cells each of which has a random mix of maternal and paternal chromosomes. |
| Telophase I: | The phase during which the chromosomes have arrived at opposite poles, and two haploid cells have formed. Total # of chromosomes per human cell is 23, each still joined to its sister chromatid. |
| Cytokinesis (happens between meiosis 1 and meiosis 2). | the cytoplasm divides at this point. |
| Prophase II: | (Chromosomes are likely still condensed, if not, the recondense here), and bipolar spindle forms |
| Metaphase II: | Duplicated chromosomes line up single file at the equator in metaphase II |
| Anaphase II: | Chromatids separate and are pulled toward opposite poles. |
| Telophase II | The nucleus reorganizes as new nuclear envelopes enclose each cluster of chromosomes. Chromosomes decondense back to chromatin. |
| Cytokinesis: (after meiosis 1 and 2) | after this second cytoplasmic division, each of the resulting daughter cells has a haploid number of unduplicated chromosomes. |
| Crossing over in prophase I: | When chromosomes synapse, non-sister chromatids of homologous pairs exchange segments in a process called crossing over |
| Segregation of chromosomes into Gametes - | When homologous pairs line up at the spindle equator and then separate into two haploid cells, each of new gamete has a random mix of maternal and paternal chromosomes. |
| ToF: every time a human sperm or egg forms, there are 8,388,608 (2^23) possible combinations of chromosomes.t | true |
| Gamete formation in plants: | Sporophytes produce haploid spores by meiosis: spore-mitosis->haploid gametophyte. Gametophytes produce gamets. |
| what happens when plants fertilize gametes???? | Fertilization (the joining of a male and female gamete) results in a diploid zygote. In plants, zygotes undergo mitosis to produce diploid sporophytes |
| gametogenisis | is the development of (diploid) germ cells into (haploid) gametes, either eggs or sperm, via meiosis. Gametogenesis can more specifically be called either oogenesis (egg formation) or spermatogenesis (sperm formation). |
| spermatogenesis | A germ cell going through "this" = primary spermatocyte(2n): Primary spermatocytes - meiosis I -> secondary spermatocytes (n)- meiosis II -> spermatids (n). Spermatids change in form and develop a tail to become mature sperm |
| Oogenisis - | A germ cell going through "this" = primary oocyte (2n): primary oocyte(2n)-Meiosis I -> secondary oocyte (n) and one polar body (n)-Meiosis II -> ovum (n) and three polar bodies (n) |
| the variation present at Fertalization is from what? | crossing over random alignments at metaphase I (leading to millions of combinations of maternal and paternal chromosomes in each gamete) the randomness of which gametes meet during fertilization. |
Created by:
jseekins
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