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We’re Comparing Mitosis from Chapter 8 to Meiosis from Chapter 10. The Human Life Cycle. FROM MOM. FROM DAD. Mitosis Review. ** Mitosis is asexual reproduction & occurs ONLY in regular old body cells called SOMATIC CELLS (skin, nails, your pancreas, etc..) NOT sperm and eggs .
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We’re Comparing Mitosis from Chapter 8 to Meiosis from Chapter 10
The Human Life Cycle FROM MOM FROM DAD
Mitosis Review ** Mitosis is asexual reproduction & occurs ONLY in regular old body cells called SOMATIC CELLS (skin, nails, your pancreas, etc..) NOT sperm and eggs ** These cells contain autosomal chromosomes that are non-sex chromosomes ** 22 from Mom autosomal chromosomes from mom and 22 from dad Diploid (2n) number of chromosomes you have 44 or 22 pair of autosomal chromosomes (2n=44)
Haploid Numbers of Chromosomes **Haploid means 1 (n). You receive a haploid number of chromosomes from mom and a haploid number from Dad that makes YOU diploid!! ( **46 in all; 22 autosomal, an X from mom and an X or Y from dad • **SO there are half as many chromosomes in gametes (sperm and eggs)
Recall in In Mitosis and Homologous Chromosomes…………….. Replicates Same types if genes on each chromosome, just different variations from each parent
Overview of Meiosis • Required for Sexual Reproduction • Similar to Mitosis but there are two sets of phases and the end result are haploid cells (gametes) • **Produces gametes in the ovaries (females) and testes (male) • **Results in 4 NON-IDENTICAL haploid (n) cells • Either sperm or egg • **Diploid to haploid cells **Genetic Recombination Occurs
In Meiosis………………… From Dad From Mom A Tetrad of Homologous Chromosomes They Replicate Prior to Meiosis to form a tedtrad………
Four Haploid gametes are produced!! Look On Page 264 #1-4
Meiosis Phases • **After interphase (DNA replication phase) • **Meiosis I Prophase I, Metaphase I, Anaphase I, telophase I and cytokenisis. • **2 cells • **Meiosis II Prophase II, Metaphase II, Anaphase II, Telophase II and cytokinesis • **4 cells, the gametes!!
Genetic Recombination During Meiosis ** A reassortment of chromosomes and genetic information they carry **crossing over between non-sister chromatids during Prophase 1 **independent segregation of homologous chromosomes
Crossing Over **Pink is from your mom, blue from your dad **Non-sister chromatids exchange genetic information
Non-Disjunction **Nondisjunction BOTH chromosomes of a homologous pair (tetrad) fail to separate and move to the same pole of the cell.
Chromosomal Mutations **Occur in all living organisms, but they are especially common in plants. **Few harmful gene mutations are passed on to the next generation because the zygote usually dies. If it lives, the offspring may have birth defects.
Deletion of part of a chromosome ABCDEFGH A B C E F G H Deletion
Insertion of Part of a Chromosome A B CD E F G H A B CB C D E F G H **When part of a chromatid breaks off and attaches to its sister chromatid Insertion
Chromosomal Mutations **When part of a chromosome breaks off and reattaches backwards onto the same chromosome A D C B E F G H A B C D E F G H Inversion
Translocation of Part of a Chromosome **When part of one chromosome breaks off and is added to a different chromosome, a translocation occurs. F G H E B C D F G A W X B C D E H A X Y Z Y Z W Translocation
Steps Of Meiosis Worksheets – You’ll Need A Book **Cut them out and paste them in the correct order !!!
Mitosis (asexual reproduction) vs. Meiosis (sexual Reproduction) • Meiosis • Occurs in 2 stages • For Sexual Reproduction • Produces genetically variability due to recombination • Occurs in sex cells called gametes or germ cells and four haploid cells (sperm and egg) • n=23 22 autosomal chromosomes and 1 sex chromosome • Forms a tetrad • Mitosis • Occurs in 1 stage • It is Asexual Reproduction • Produces “clones” with no genetic variability • Occurs in body cells (autosomal) and creates two diploid cells • 2n=46 22 pair of autosomal chromosomes and 1 pair sex chromosomes
Meiosis Mitosis
Mitosis (asexual reproduction) vs. Meiosis (sexual Reproduction) Venn Diagram