BIOTEST3

BIOTEST3 - BIOLOGY 1002 Chs. 10-14 Study Guide Ch. 10...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: BIOLOGY 1002 Chs. 10-14 Study Guide Ch. 10 Meiosis Fertilization of two haploid nuclei produces diploid nucleus in the zygote Results of Mitosis: 2 diploid cells; each identical to parent Results of Meiosis: 4 haploid cells; differ from parent & one another Asexual Reproduction: one parent produces offspring and each inherits the same # and kinds of genes as its parent (which means asexually produced offspring can only be clones) Sexual reproduction involves meiosis, gamete formation, & fertilization In sexual reproduction the first cell of a new individual ends up w/ pairs of genes on pairs of homologous chromosomes (one is maternal the other is paternal) Allele: one or two or more molecular forms of a gene that arise by mutation and code for different versions of the same trait (these lead to variations in physical appearance & behavioral traits) First step in sexual reproduction: meiosis (type of nuclear division that reduces the parental chromosome number by half to form gametes) Gamete: haploid cell formed by meiotic cell division of a germ cell (required for reproduction) ex: eggs and sperms Meiosis IS similar to mitosis Before cell proceeds from interphase to mitosis or meiosis is duplicates DNA Each duplicated chromosome consists of 2 sister chromatids linked at the centromere In both mitosis and meiosis, microtubules of the spindle apparatus move the chromosomes in prescribed directions Differences in meiosis and mitosis: mitosis involves single nuclear division & meiosis requires two consecutive divisions (meiosis I and meiosis II) & mitosis maintains the chromosome # whereas meiosis halves it When diploid cell undergoes meiosis: moves through 8 stages and produces haploid cells (4) Meiosis forms gametes (like sperm & eggs) Meiosis I: Prophase I, Metaphase I, Anaphase I, Telophase I Meiosis II: Prophase II, Metaphase II, Anaphase II, Telophase II Remember chromosomes duplicated before meiosis began! Genetic variation is enhanced in 2 ways: crossing over (occurs during prophase I) & each crossover represents a chance to swap alleles & the 2 nd results from the random alignment of chromosomes at metaphase I Gametes form by spermatogenesis in male animals (forms 4 haploid spermatids) each develops into a mature sperm cell Gametes form by oogenesis in female animals (cytoplasmic divisions are unequal) thus giving rise to one mature egg (ovum) & three smaller polar bodies which degenerate so the female germ cell produces only ONE functional gamete Ch. 11 Observable Patterns of Inheritance Ch....
View Full Document

Page1 / 5

BIOTEST3 - BIOLOGY 1002 Chs. 10-14 Study Guide Ch. 10...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online