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CELL DIVISION Mitosis and Meiosis

CELL DIVISION Mitosis and Meiosis. ASEXUAL (EUKARYOTES ONLY). SEXUAL. I CAN: Compare the advantages of sexual reproduction and asexual reproduction in different situations. This is a model of the double helix shape of DNA.

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CELL DIVISION Mitosis and Meiosis

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  1. CELL DIVISION Mitosis and Meiosis ASEXUAL (EUKARYOTES ONLY) SEXUAL I CAN: Compare the advantages of sexual reproduction and asexual reproduction in different situations.

  2. This is a model of the double helix shape of DNA. DNA is the molecule that transfers hereditary information from one cell to the next. Pg 233

  3. When a cell is dividing, DNA winds up tightly and forms chromosomes in the nucleus of the cell. A Copy of DNA is needed in all cells. A specific portion of the DNA code is called a gene, which has genetic information. Pg 139 The genes are contained within the chromosome.

  4. A karyotype is a picture showing the arrangement of a full set of human chromosomes. Humans have 46 (or 23 pairs) of chromosomes

  5. Biologists use “2N” to symbolize diploid. Biologists use “N” to symbolize haploid. In animals… Somatic cells (cells of the body) are diploid. This means that each cell has two chromosomes of each type. They are in PAIRS. Gamete cells (egg, sperm) are haploid. This means that each cell has only one of each type of chromosome. HAPLOID vs DIPLOID PRACTICE

  6. When somatic (body) cells reproduce themselves the process is called MITOSIS. Somatic Cell 2N Mitosis leads to the production of two “daughter cells”. Each daughter cell has the same number of chromosomes as the parent cell. 2N 2N Daughter Cells • Main purposes of mitosis: • Growth • Repair • Asexual reproduction (bacteria) MITOSIS Pg 141 Mitosis In Action

  7. Haploid Diploid

  8. The steps of Mitosis: PAGE 141 INTERPHASE - DNA replicates PROPHASE - chromatin condenses into chromosomes/nuclear membrane breaks down METAPHASE - chromosomes are lined up in the middle.. ANAPHASE - Sister chromatids separate and migrate to opposite poles. TELOPHASE - chromosomes decondense CYTOKINESIS.division of cytoplasm

  9. WEEKLY TEST – CELL REPRODUCTION AND ENERGY • IT’S TIME TO TAKE YOUR EDUCATION MORE SERIOUSLY… • FRESH …MEN AND WOMEN!!!

  10. UNDERSTANDINGMEIOSIS • STEP 1: GET A LINELESS SHEET OF PAPER • ON THE FRONT – GIVE TITLE MY BODY AND HOW IT GROWS AND REPAIRS ITSELF! • DRAW AND DESCRIBE THE PHASES OF MITOSIS! (PAGE 175)

  11. UNDERSTANDINGMITOSIS VIDEO • STEP 2: ON THE BACK!!! • NUMBER TO 1- 10 • GIVE THE ANSWERS (letter only) to VIDEO QUESTIONS!!!

  12. The steps of Meiosis I and Meiosis II: Pg. 175

  13. Pg 175 When gamete (sperm or egg) cells reproduce themselves the process is called MEIOSIS. Meiosis reduces chromosome #to half. Gamete Cell 2N During meiosis, a single diploid cell divides and produces FOUR genetically different haploid cells. N N In Meiosis there is one chromosome duplication followed by two cellular divisions (into four cells) so Meiosis is broken down into Meiosis I and Meiosis II. N N Upon fertilization, a “N” sperm meets a “N” egg and a zygote (2N) is formed. 1 N sperm 1 N egg 2N zygote Crossing Over, pg 190 MEIOSIS

  14. MEIOSIS IN ACTION

  15. 1 Cell Division Produces Body Cells Produces 2 daughter cells Daughter Cells are Diploid 2N Daughter cells IDENTICAL to parent cells 2 Cell Divisions Produces Sex Cells Produces 4 daughter cells Daughter cells are haploid N Daughter cells are GENETICALLY different from parent cell due to CROSSING OVER of chromosomes Meiosis Mitosis Compare & Contrast

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