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Mr. Wills Ch11.4
Question | Answer |
---|---|
Reproduction | the process of creating offspring |
Asexual reproduction | process of creating off spring that are genetically identical to the parent |
Sexual reproduction | process of creating offspring using the DNA of two parents to produce offspring that have the traits of both parents. |
What are the four types of asexual reproduction? | Binary fission, fragmentation, budding, parthenogenesis. Genetically identical to parent. |
Binary fission | occurs in bacteria and other single celled organisms. Ex. Starfish. Genetically identical to parent. |
Fragmentation | when an offspring is created by breaking off a piece of that organism the becomes a new independent organism. Ex. Starfish. Genetically identical to parent. |
Budding | when a new organism grows off of an existing organism. Ex. Hydra Genetically identical to parent. |
Parthenogensis | when a viable egg is produce by a female without fertilization by a male. Ex Komodo dragon. |
Gamete | a haploid reproductive cell; in humans sperm and egg |
Zygote | the resulting cell after a sperm and an undergo fertilization. The first cell of an offspring. Diploid. |
Fertilization | when an egg and a sperm form a zygote. |
What are the advantages of sexual reproduction? | genetic variation that may allow certain offspring to survive changes in environment. |
What is the disadvantage of sexual reproduction? | It takes a lot of time and energy to make gametes and find a mate. |
What is an advantage to asexual reproduction? | Can produce offspring more quickly and using less energy. |
What is a disadvantage to asexual reproduction? | There is very little genetic variation between individuals reducing the ability of an organism in general to survive changes in their environment. |
Germ cell | a cell that undergoes meiosis; in humans produce sperm or eggs; found in testes and ovaries. |
Somatic cell | all cells of an organism that are not germ cells. |
Chromosome number | the number of chromosomes that contains one entire set of genes for an organism represented by the letter n. |
Diploid | a cell that has two sets of genes/chromosomes for every trait. 1mom/1dad. Diploid orgainisms are represented by 2n. In human all cells except the egg and sperm. |
Haploid | when a cell has only one set chromosomes/genes. In humans this results from meiosis and is only the sperm and egg. |
Homologous chromosomes | chromosomes that contain the same genes as another. Humans have 2 sets(1mom/1dad) of 23 chromosomes for a total of 46. Homologous chromosomes pair during prophase 1. |
Tetrad | two homologous chromosomes attached at he centromere |
Crossing over | exchange of genetic material between homologous chromosomes increasing genetic diversity. |
How many chromosomes(2n) do humans have? | 46 |
How many chromosomes does a human egg have? | 23 |
Autosomes | chromosomes that do not determine the sex of an organism |
Sex chromosomes | chromosomes that determine the sex of and organism |
Male sex chromosomes | XY |
Female sex chromosomes | XX |
Meiosis | the process that sexually reproducing organisms produce four haploid genetically different gametes from a diploid cell |
Prophase 1 | homologous chromosomes form tetrads and become visible, crossing over occurs |
Metaphase 1 | homologous pairs line up in the cell. |
Anaphase 1 | homologous pairs separate two opposite sides of cell |
Telophase 1 | two new nucleuses form separating homologous pairs making two haploid cells |
Prophase 2 | new spindles form to move chromosomes of haploid cells |
Metaphase 2 | chromosomes line up at center of cell |
Anaphase 2 | sister chromatids are separated and move to poles of cell |
Telophase 2 | four genetically different nucleuses form |
Spermatogenesis | four genetically different haploid sperm made |
Oogenesis | 1 viable(usable) haploid egg and 3 polar bodies are formed. |
Compare mitosis and meiosis | mitosis produces 2 genetically identical cells and is used to make cells for growth, development, repair and asexual reproduction. Meiosis produces four genetically different haploid (1/2chromosomes) cells called sperm or eggs. The starting point of sexu |
Why is genetic variation/diversity important? | So that organisms are different enough to survive changes in the environment. |
What are three cause of genetic variation? | crossing over, independent assortment, and random fertilization. |
Independent assortment | the random separation of homologous chromosomes during meiosis; this gives you a random selection of each of your grandparents DNA. |
Random fertilization | you are never sure which egg or sperm will be fertilized. Because every sperm and egg are different it is like playing Russian roulette with your genes. |
How many different combinations of chromosomes can two individual have? | 64 trillion, this doesn’t even include crossing over!! |