Information for Prelim I

Information for Prelim I - 1 Chapter 13: Meiosis and Sexual...

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Chapter 13: Meiosis and Sexual Life Cycles 1. the transmission of traits from one generation to the next is called inheritance or heredity 2. offspring acquire genes from parents by inheriting chromosomes a. genes are segments of DNA made up of nucleotides 3. reproductive cells are called gametes a. male gametes are sperm b. female gametes are egg 4. Except for tiny amounts of DNA in mitochondria and chloroplasts, the DNA of a eukayotic cell is subdivided into chromosomes with in the nucleus a.each chromosome consists of a single long DNA molecule b.one chromosome includes several 100 to a few thousand genes c.a gene’s location is called the gene’s locus 5. Asexual reproduction- a single individual is the sole parent and passes copies of all its genes to its offspring (mitotic division-in which DNA is copied and allocated equally to 2 daughter cells) a. the hydra is an example of a multicellular organism that is capable of reproducing asexually b. asexual reproduction gives rise to a clone 6. sexual reproduction- two parents give rise to offspring that have unique combinations of genes inherited from the two parents a. offspring resemble parents but their DNA is different 7. In humans, each somatic cell (any cell other than a gamete) has 46 chromosomes a. homologous chromosome are two chromosome that form a pair and have the same length, centromere position, and staining pattern 1. both chromosome of each pair carry genes controlling the same inherited characters (ex. Eye color) 2. females have homologous pairs XX, males have XY 3. The X, Y chromosomes are sex chromosomes and all the others are autosomes 4. one chromosome from the homologous pair is from the mother (maternal) and the one from the father (paternal) b. any cell with two chromosome sets is called diploid (2n) c. there are two sister chromatids on one chromosome d. gametes contain a single chromosome set so they are haploid (n) 8. the human life cycle begins when a haploid sperm cell from the father fuses with a haploid egg cell from the mother and is called fertilization a. a zygote is formed (diploid) b. mitosis occurs to generate all the somatic cells of the body 9. in animals meiosis occurs only in the ovaries or testes 10. life cycle in animals a. two haploid gametes fuse during fertilization > forming a zygote > then mitosis occurs > then meiosis occurs to produce more gametes 11. life cycles in plants and some algae – alternation of generations a. a diploid multicellur organism (sporophyte) undergoes meiosis > haploid spores > undergo mitosis to get a halpoid multicellular organism (gametophyte) > undergoes mitosis again to produce gametes > fertilization of gametes > zygote which does mitosis > sporophyte 12. life cycle in most fungi and some protists a. fertilization of gametes > zygote which does meiosis right away instead of mitosis ( so no diploid offsring develops) > haploid spores which undergo mitosis > haploid multicellular organism > mitosis to produce haploid gametes
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Information for Prelim I - 1 Chapter 13: Meiosis and Sexual...

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