2 Cell Division At times, cells need to divide Divide = split and make copiesThere are actually different types of cell division
3 Types of Cell Division Binary Fission Only for Prokaryotic cells Binary = twoFission = SplitBinary Fission = Split in twoOnly for Prokaryotic cells
4 Types of Cell Division 2. Mitosis Only for Eukaryotic Cells Makes 2 identical cellsNew cell is exactly the same. Has the same DNA, does the same function (job)Used for:HealingGrowingReplacing old cells
5 Stages of MitosisMitosis occurs in a series of steps. These steps are:InterphaseProphaseMetaphaseAnaphaseTelophaseCytokinesis
6 Stages of Mitosis Interphase Interphase is the longest stage This is when the cell functions normallyThe cell is growing during this timeThe DNA of the cell with replicate (copy itself) and the DNA will condense into chromosomes during this stage
7 Stages of Mitosis Prophase The chromosomes condense even more. Chromosomes can now be seen under a microscopeNucleus dissolves and is no longer visible
8 Stages of Mitosis Metaphase The duplicated chromosomes line up in the middle of the cellSpindle fibers (long proteins) connect to the centre of each chromosome
9 Stages of Mitosis Anaphase The duplicated chromosomes are pulled apart to opposite sides of the sideThe chromosomes are identical and the exact same genetic information is being moved to each side of the cell
10 Stages of Mitosis Telophase The separated chromosomes arrive at opposite ends of the cellThe nucleus begins to reform around the chromosomesChromosomes become less condensed.
11 Stages of Mitosis Cytokinesis When the cell actually splits into 2 daughter cellsAnimal Cells – cell membrane pinches in, in the middle to divide the 2 nucleiPlant Cells – new cell wall forms between nuclei
12 Types of Cell Division Meiosis Only in Eukaryotic Cells Meio = lessen (decrease)osis = actionMeiosis = action that lessensOnly in Eukaryotic CellsMakes sex cellsSperm and eggsMakes 4 different cellsEach cell has different DNAEach cell has half of the original cell’s DNAA human sex cell has 23 chromosomes. No pairs.
13 Stages of MeiosisMeiosis occurs in a series of steps. These steps are:InterphaseProphase-1Metaphase-1Anaphase-1Telophase-1Prophase-2Metaphase-2Anaphase-2Telophase-2
14 Stages of Meiosis Interphase Prophase - 1 Same as Mitosis Chromosomes find their Homologous PairsChromosome #1 pairs up with the other Chromsome #1. Chromosome #2 pairs with Chromosome #2.
15 Stages of Meiosis Metaphase - 1 Anaphase – 1 Homologous pairs line up in the middle of the cell and attach to spindle fibersAnaphase – 1Homologous pairs pulled to opposite sides of the cellOne side has a Chromosome number 1, the other side has the other Chromosome number oneGet different combinations of chromosomes every time meiosis occurs
16 Stages of Meiosis Telophase - 1 Prophase – 2 Cell divides into 2 daughter cells by cytokinesisNucleus reformsProphase – 2Resting periodNucleus dissolves
17 Stages of Meiosis Metaphase 2 Anaphase 2 Chromosomes line up in the middles of the cellsSpindle fibers attachAnaphase 2Chromosomes pulled apart to opposite sides of the cells
18 Stages of Mitosis Telophase - 2 The separated chromosomes arrive at opposite ends of the cellsThe nucleus begins to reform around the chromosomesChromosomes become less condensed.Creates 4 gametes – cells with ½ the DNA of the original cellGametes = sex cells, also called sperm and eggs
19 Types of ReproductionThere are 2 mains types of reproduction that living things can use to reproduceAsexual ReproductionOffspring (child) has same DNA as the parentSexual ReproductionOffspring has a mix of DNA from both the mother and the father.
20 Asexual Reproduction New organism is produced with DNA from 1 parent Done through Binary Fission or Mitosis
21 Types of Asexual Reproduction BacteriaUse Binary FissionSingle Eukaryotic CellsUse MitosisPlantsNew plant starts from old plants leaves, roots, or stemsExample – Starting a bamboo plant from a leafUses MitosisAnimalsCalled BuddingNew living grows off the parent like a ‘bud.’ Eventually develops into a mature, independent living thing.
22 Sexual Reproduction New living thing produced using DNA from 2 parents Only in Eukaryotic living thingsCombines sex cells to make new living thingNew living thing has half DNA from mother, half DNA from fatherWhen sperm and egg combine, it is called FertilizationNew formed cell is called a zygote
23 Types of Sexual Reproduction External FertilizationEgg and sperm combine outside of mother’s bodyNew living things develops outside of body in an eggExamples – fish, coral, octopi, squid, etc. use this method.Most animals that live in water use this method of fertilization
24 Types of Reproduction Internal Fertilization Egg and sperm combine inside mother’s bodyNew living thing sometimes develops inside motherExample – humans, mammalsMother sometimes will lay egg.Example – chicken, reptiles,Most land animals use internal fertilization
25 QuestionsA human embryo (developing baby) starts as one cell. It divides to grow. Would it use binary fission, mitosis, or meiosis?An E.coli bacteria is dividing. What process would it use?A jellyfish can make an exact copy of itself by budding off copies instead of using sexual reproduction. Would a jellyfish need to undergo meiosis? Explain why or why not. (3 marks)What are the differences between mitosis and meiosis?Create an expression to help you remember the phases of Mitosis.Example of an expression – remember the order of the planets by saying: My Very Educated Mother Just Saw Uncle Nick
26 QuestionsWhat are the differences between sexual and asexual reproduction?What are the similarities between sexual and asexual reproduction?A trembling aspen is reproducing using asexual reproduction. What differences would there be between its DNA and its offspring’s DNA? Explain.Which would create more genetic diversity (differences in the offspring's genetic material) amongst species? Asexual or sexual reproduction? Explain.