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REVIEW OF MITOSIS.

REVIEW OF MITOSIS. CELL DIVISION/REPRODUCTION. Mitosis is _____________________________________ It refers to the process of replication of ___________ cells. Two purposes of mitosis: ____________ and __________ It results in __________________________________

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REVIEW OF MITOSIS.

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  1. REVIEW OF MITOSIS. CELL DIVISION/REPRODUCTION • Mitosis is _____________________________________ • It refers to the process of replication of ___________ cells. • Two purposes of mitosis: ____________ and __________ • It results in __________________________________ (_______________________________________) BODY REPAIR GROWTH TWO IDENTICAL DAUGHTER CELLS 2 CELLS WITH THE SAME DNA AS ORIGINAL CELL Meiosis - Chapter 3

  2. sex cells (egg) body cells sex cells (sperm) You have body cells and gametes. somatic • Body cells are also called _________________ cells. • Germ cells develop into ______________. • Germ cells are located in the _________ and ________. • Gametes are sex cells: ______________________. • Gametes have _______ that can be passed to offspring. gametes ovaries testes Egg and sperm DNA

  3. KEY CONCEPT Gametes have ______________________ of ______________________ that body cells have. ½ the number chromosomes

  4. 2 • Your cells have __________ different type of chromosomes:- ___________________ - Chromosomes that carry • _____________ body traits- ________________ - chromosomes that carry • genes specific to the ___________ of an organism AUTOSOMES ONLY SEX CHROMOSOMES SEX/GENDER

  5. Your cells have autosomes and sex chromosomes. • Your body cells have _______ pairs of chromosomes. • Chromosome pairs • # 1-22 are ________________. • Sex chromosomes, # ______determine gender in humans. They are referred to as _________________ 23 Homologous pairs 23 X and Y

  6. Understanding Homologous Chromosomes AUTOSOMES • ____________________of chromosomes have the same structure. • For each homologous pair, one chromosome comes _____________________. from each parent Allele for straight hair From Mom Gene for hair texture From Dad Allele for curly hair

  7. Understanding Sex Chromosomes • ____________________do _________ always have the same structure. • Each parent still contributes one sex cell, BUT depending upon the parent, they can give either an _____________________. Sex Chromosomes NOT X or a Y

  8. Body cells are diploid; gametes are haploid. • Fertilization between egg and sperm occurs in sexual reproduction. • Diploid (2n) cells have two copies of every chromosome. • n represents the “pairs of chromosomes” • Human = 2n = __46___________________________ • Goldfish = 2 n = _96___________________________ • Pea = 2n = __18______________________________ • Body cells are diploid. • Half the chromosomes __haploid_______________________.

  9. GAMETES Sex cells, (______________) are haploid. ONLY ONE • Haploid (n) cells have ________________ of every chromosome. • Only contain DNA from ______________________ ONLY ONE PARENT • - Gametes have ___ autosomes and __ sex chromosome. 22 1

  10. MAINTAINED • Chromosome number must be _____________ in animals. • Many plants have more than two copies of each chromosome. • Mitosis and meiosis are types of nuclear division that make _________________ types of cells. • Mitosis makes more _________________ cells. (____________) • Meiosis makes more __________________ cells.(____________) 2 DIFFERENT SOMATIC/BODY DIPLOID GAMETES/SEX HAPLOID

  11. HAPLOID • Meiosis makes _______________ cells from diploid cells. SEX • Meiosis occurs in _______________ cells. • Meiosis produces _______________. (_________________) GAMETES SPERM & EGG

  12. Steps of Meiosis PROPHASE 1 METAPHASE 1 ANAPHASE 1 TELOPHASE 1 / PROPHASE 2 METAPHASE 2 ANAPHASE 2 TELOPHASE 2 ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________

  13. PROPHASE I Shorten and Thicken. “Double File” Find their “match” or pair up, (one from mom with one from dad) Move apart from one another Form between centrioles Begins to break down

  14. METAPHASE I Stretch between two ends of the cell Become attached to the fibers, pulled to middle of cell move to opposite ends of cell Remains dissolved

  15. ANAPHASE I Pairs pulled apart by fibers. Pairs are separated… Sisters/copies are still connected Still at cell’s poles Pull matching pairs apart Remains dissolved

  16. TELEPHASE I DO NOT disappear Each end of cell has HALF the number of chromosomes. Chromosomes DO NOT unwind. Begins to pinch in until the cytoplasm is divided in half forming two new cells DOES NOT reform

  17. PROPHASE II Move apart from one another Still coiled Has not reformed Re-form between centrioles

  18. METAPHASE II Become attached to the fibers. Are pulled to middle of cell (Single File) stretched between ends of cell. Are attached to center of sister chromatids Move to opposite ends of cells Remains dissolved

  19. ANAPHASE II Pull each chromatid toward opposite ends of cell Still at cell’s poles Remains dissolved Sisters are pulled apart by fibers. Each chromatid is separate from its “sister”

  20. TELEPHASE II Begins to pinch in until the cytoplasm is divided in half forming two new SEX cells, (4 TOTAL) Each end of cell has HALF and SINGLE chromosomes. Begins to reform Begin to disappear

  21. KEY CONCEPT During meiosis, diploid cells undergo _______ cell divisions that result in _______________ cells. 2 HAPLOID

  22. Cells go through two rounds of division in meiosis. • Meiosis reduces chromosome number and creates _______________________________. GENETIC DIVERSITY

  23. Meiosis differs from mitosis in significant ways. 2 • Meiosis has _____ cell divisions while mitosis has one. • In mitosis, _____________chromosomes never pair up. • Meiosis results in ____________ cells; mitosis results in ______________ cells. HOMOLOGOUS HAPLOID DIPLOID

  24. Meiosis I and meiosis II each have four phases, similar to those in mitosis. • Pairs of homologous chromosomes separate in ___________. • Homologous chromosomes are ___________ but not identical. • One from mom One from dad • Brown Eyes - Blue Eyes • Attached Earlobes -Free Earlobes • Type B blood -Type A blood • Sister chromatids divide in _____________. MEIOSIS 1 SIMILAR homologouschromosomes MEIOSIS II sister chromatids sister chromatids

  25. Meiosis I occurs after DNA has been replicated. • Meiosis I divides homologous chromosomes in four phases.

  26. Meiosis II divides sister chromatids in four phases. • DNA is not replicated between meiosis I andmeiosis II.

  27. So What Does The Process of Meiosis Look Like? MORE MEIOSIS EXAMPLES MEIOSIS ANIMATION

  28. The Point of Meiosis Result in four sex cells Each cell will have HALF the number of chromosomes as the original cell. Sex cells develop during puberty.

  29. MEIOSIS MEN VS. WOMEN WHAT IS THE SAME? • 4 CELLS ARE PRODUCED • EACH CELL HAS ONLY HALF THE NUMBER OF CHROMOSOMES AS THE ORIGINAL WHAT IS THE DIFFERENT? • MALES: ALL FOUR CELLS ARE “GOOD” SPERM • FEMALES: 3 CELLS ARE CONSIDERED “POLAR BODIES” ONLY 1 CELL IS A VIABLE EGG • (THIS IS DUE TO AN UNEVEN DIVISION OF CYTOPLASM DURING MEIOSIS)

  30. Haploid cells develop into mature gametes. Gametogenesis • _________________ is the production of gametes. • Gametogenesis differs between ____________ and __________. MALES FEMALES • Sperm become ____________ and _____________. • Sperm primarily contribute ____ to an embryo. STREAMLINED MOTILE DNA • Eggs contribute _______, _____________, and ____________ to an embryo. • During meiosis, the ______ gets most of the contents; the other cells form _________________. DNA CYTOPLASM ORGANELLES DNA POLAR BODIES

  31. Understanding Meiosis Starting with Prophase I, draw a cell undergoing MEIOSIS. Your original cell has 4 chromosomes. Make sure to include the cell membrane, nuclear membrane, chromosome, centrioles, and fibers.

  32. MITOSIS VS. MEIOSIS What is the same? What is different? 1.__________________________________2.__________________________________3.__________________________________4.__________________________________5.__________________________________Process: __________________________________________________________ 1 1.__________________________________2.__________________________________3.__________________________________4.__________________________________5.__________________________________6.______________________7.____________________________________ 2 1 2 1 3 3 4 5 4 6 5 7

  33. DID YOU KNOW? The sperm is the smallest cell in the body, whilst the egg is the largest, it is estimated that it will take 175,000 sperm to weigh as much as a female egg, which is a lot of sperm! Average males produce 150 million sperm daily! Females are born with all the oocytes (eggs) that they will ever have in a lifetime? Infertility: sperm counts drop as low as 20 million per ml

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