Biology 30 Cell Division Curriculum Outline PDF

Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline Specific Outcome 1.1 Define and explain the significance of chromosome number in somatic and sex cells....

Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline Specific Outcome 1.1 Define and explain the significance of chromosome number in somatic and sex cells. p.550-552 Cell Division and the Cell Cycle § Cell cycle – the life cycle of the cell § Somatic cells – body cells o Some examples include blood cells, skin cells, nerve cells o The parent cell will pass on genetic information to its daughter cell § Sex cells- cells that contain half of the genetic information in humans Genetic information in Eukaryotic Cells ( organized membrane bound nucleus ) § Deoxyribonucleic Acid (DNA) – nucleic acids that control all processes of heredity in cells § Chromosomes – DNA and associated proteins are found in these in the nucleus o Single human cell = 3 m DNA that is organized into chromosomes using proteins (histones) to compact the material within the cell o Chromatin – long intertwined strands that condense to make chromosomes visible to a microscope o Centromere – specialized region where the chromosome is pinched in that helps in the cell division process GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline Chromosome Number § Humans – 22 homologous chromosomes (similar looking) as well as 2 sex chromosomes o Diploidy (Homologous chromosomes) § A cell containing pairs of homologous chromosomes § carry the same genes at the same location(locus) § They appear to look the same yet they carry different forms of genes (alleles) § Eg. Humans – the diploid number is 46 or 23 pairs o Haploidy (Sex Chromosomes) § A cell that contains unpaired chromosomes § Eg. Human gametes (eggs or sperm) are haploid § Haploid number is represented by, n. EXAMPLE: Humans: § All species differ in numbers of chromosomes § n=23 and diploid cells have 2n chromosomes (2n=46) o Polyploidy § Sets of more than two homologous chromosomes o assessing results. Specific Outcome 1.2 Explain, in general terms, the events of the cell cycle. p.553-559 Stages of the Cell Cycle § Mitosis is a process produces diploid cells from diploid cells that ARE identical. § Interphase o This is the growth stage and the cells spends most time here o Cell continues metabolic functions and prepares for its next division o G1 (Gap 1) § Cells grows quickly here o S (Synthesis) § New genetic material is synthesized here § DNA in the chromatin replicates to create a second identical set of DNA (sister chromatids joined by the centromere forming the chromosome) o G2 (Gap 2) § Second growth phase to allow the cell to rebuild its reserve energies to prepare for cell division § Also produces proteins and structures required for division GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline § Phases of Mitosis § This is the division of the genetic material and the contents of the nucleus into two complete and separate sets § Purpose: o Growth o Maintenance o Repair § Prophase o Chromatin condenses into tightly packed chromosomes o Nuclear membrane breaks down, releasing the chromosomes into the cytoplasm o Nucleolus disappears o Centrioles (cylindrical organelles) will move part to opposite sides of the cell o Network of spindle fibres (spindle apparatus) will form to help facilitate movement of chromosomes within a cell § Metaphase o Spindle fibres guide the chromosomes to the equator or centre line o Spindle fibres will attach to the centromere of each chromosome o The fibres will align so that the sister chromatids will be pulled to opposites sides (centromeres) § Anaphase o Each centromere is splits apart and the sister chromatids separate from one another o The spindle fibres connected to the centromeres begin to shorten thereby pulling sister chromtids to opposite sides o One diploid set of chromosomes has been gathered at each pole GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline § Telophase o Chromatids begin to unwind into longer and less visible strands of dna o Spindle fibres break down o Nuclear membrane forms around each set of new chromosomes and a nucleolus forms within each new nucleus § Cytokinesis o The division of the cytoplasm and the organelles into two separate daughter cells o Indentation depends until the cytoplasm and organelles pinch into two identical cells o The cells are now in G1 phase. Specific Outcome 1.3 Describe the process of meiosis and the necessity for the reduction of chromosome number. p.563-565 GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline Meiosis § The purpose of meiosis is for female and male gametes to come together to produce a unique zygote (sexual reproduction) § The zygote is NOT identical to either parent but has genetic information from both § Meiosis is a process produces haploid gametes from diploid cells in the ovaries and testes Reduction division § Meiosis § Cell division that produces daughter cells with fewer chromosomes than the parent cells § Recombination division § Products of meiosis have different combinations of genes § Offspring are not identical to parents (unlike mitosis) GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline Phases of Meiosis § Meiosis I o Interphase § Growth and synthesis § Chromosomes are replicated in the S phase of interphase allowing the germ cell to begin meiosis with duplicated chromosomes Identical sister chromtids held together by a centromere o Prophase I § Homologous chromosomes does not mean identical (same genes different alleles) § Synapsis – aligning of homologous chromosomes (4 sister chromatids line up = tetrad) § Non-sister chromatids – homologous chromosomes that are non-identical lies side by side o Metaphase I § Spindle fibres from each pole attach to the centromeres of each homologous chromosome § They line up at the equator of the cell as homologous chromosomes (not single file like mitosis) o Anaphase I § Spindle fibres shorten causing the homologous chromosomes to separate to opposite poles of the cell § A single homologous chromosome (two sister chromatids) move to each pole o Telophase I § Homologous chromosomes will begin to uncoil and spindle fibres disappear § Cytoplasm is divided, nuclear membrane forms around each group of homologous chromosomes § Each of the two cells is haploid but with duplicated sister chromatids GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline § Meiosis II o The phases to this cell division are very similar to mitosis o Each cell enters as haploid (n) but with duplicated chromatids o Each cell that leave will also be haploid with unreplicated chromosomes Gamete Formation in Animals o Mitosis is also happening to keep a supply of germ cells o Spermatogenesis § Testes § Begins with a diploid cell (spermaogonium) which will split at puberty creating two cells: One cell will replenish the spermatogonia cell population One cell will form a primary spermatocyte (undergoes meiosis I) that undergoes meiosis I to form two secondary spermatocytes The secondary spermatocytes will undergoes meiosis II to form 4 spermatids Spermatids will develop into mature sperm by: o Head region = Nucleus and certain enzymes o Midsection = many mitochondria (energy source) o Long tail flagellum = locomotion GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline Oogenesis § Ovaries § Begins with a diploid cell (oogonium) which will undergo mitosis to form two primary oocytes § One primary oocyte (diploid) will undergo meiosis and an unequal splitting of cytoplasm and two cells are formed: Polar body – not functional and will soon degenerate Secondary oocyte - most cytoplasm § Secondary oocyte (haploid) undergoes meiosis II again dividing cytoplasm unequally Mature egg – contains large amount of nutrients for implantation Second polar body – not a viable gamete GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline Specific Outcome 1.4 Compare the processes of meiosis and mitosis. p.568 Specific Outcome 1.5 Describe the process of crossing over and non-disjunction and evaluate their significance to organism inheritance and development. p.566-567 Genetic Recombination § Independent Assortment o Metaphase I, the chromosomes will align so that the paternal chromosomes will move in opposite directions to allow for exchange of genetic information § Crossing Over o Prophase I; homologous chromosomes pair up o Crossing over – sister chromatids will exchange pieces of chromosomes o May contain 100’s to 1000’s of genes Nondisjunction § Nondisjunction occurs when chromosomes or chromatids do not separate as they should producing too many (trisomy – down syndrome) or too few (monosomy – turner syndrome) chromosomes § Occurs in anaphase I and II of meiosis § Anaphase I – homologous chromosome pairs do not separate to opposite poles § Anaphase II – when sister chromatids are pulled toward the same pole together o Prophase I § Homologous chromosomes does not mean identical (same genes different alleles) § Synapsis – aligning of homologous chromosomes (4 sister chromatids line up = tetrad) § Non-sister chromatids – homologous chromosomes that are non-identical lies side by side o Metaphase I § Spindle fibres from each pole attach to the centromeres of each homologous chromosome § They line up at the equator of the cell as homologous chromosomes (not single file like mitosis) GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline o Anaphase I § Spindle fibres shorten causing the homologous chromosomes to separate to opposite poles of the cell § A single homologous chromosome (two sister chromatids) move to each pole o Telophase I § Homologous chromosomes will begin to uncoil and spindle fibres disappear § Cytoplasm is divided, nuclear membrane forms around each group of homologous chromosomes § Each of the two cells is haploid but with duplicated sister chromatids § Meiosis II o The phases to this cell division are very similar to mitosis o Each cell enters as haploid (n) but with duplicated chromatids o Each cell that leave will also be haploid with unreplicated chromosomes § Gamete Formation in Animals o Mitosis is also happening to keep a supply of germ cells o Spermatogenesis § Testes § Begins with a diploid cell (spermaogonium) which will split at puberty creating two cells: One cell will replenish the spermatogonia cell population One cell will form a primary spermatocyte (undergoes meiosis I) that undergoes meiosis I to form two secondary spermatocytes The secondary spermatocytes will undergoe meiosis II to form 4 spermatids Spermtids will develop into mature sperm by: o Head region = Nucleus and certain enzymes o Midsection = many mitochondria (energy source) o Long tail flagellum = locomotion o Oogenesis § Ovaries § Begins with a diploid cell (oogonium) which will undergo mitosis to form two primary oocytes § One primary oocyte (diploid) will undergo meiosis and an unequal splitting of cytoplasm and two cells are formed: Polar body – not functional and will soon degenerate Secondary oocyte - most cytoplasm § Secondary oocyte (haploid) undergoes meiosis II again dividing cytoplasm unequally GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline Mature egg – contains large amount of nutrients for implantation Second polar body – not a viable gamete Specific Outcome 1.6 Compare the formation of fraternal and paternal offspring in a single birthing event. p.570-571 Specific Outcome 1.7 Describe the different reproductive strategies by comparing the alternation of generations a range of organisms p.573-579 Sexual reproduction – production of gametes by meiosis followed by fertilization between genetically different individuals to produce genetically distinct offspring Reproduction in Prokaryotes (bacteria) § Binary fission – asexual reproductive process of cell division in bacteria producing genetically identical offspring (instead of mitosis) o Single circular chromosome and nonucleus o Exponential growth (cells can divide in as little as 20 minutes and then each daughter cell doubles in another 20 minutes o BENEFIT: Huge population growth in little time o DOWNFALL: genetically identical individuals could be wiped out by toxins or viruses § Conjunction – transfer of genetic material from one cel to another by cell-to-cell contact through a pilus (bridging structure) o Creates cells with new genetic information o BENEFIT: creates fenetically unique daughter cells o DOWNFALL: new cell can reproduce through binary fission to create colony Asexual reproduction § reproductive process in which a parent organism produces genetically distinct offspring § Budding – a complete but minature version of the parent will grow out from the parents body o Example - hydra § Vegetative reproduction – spreading of stems across an area that will eventually develop roots and separate from its parent. o Example – strawberry plants GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.  Biology 30 Unit C: Cell Division, Genetics & Molecular Biology Curriculum Outline § Fragmentation – creation of new plants from a fragment of a parent plant o Example - Cultivation of potatoes using tubers(fragments) or gardeners cuttings’ § Parthenogenesis – a form of asexual reproduction in which an unfertilized egg develops into an adult o Example – honeybees lay both fertilized and unfertilized eggs; fertilized eggs develop into female worker bees; unfertilized eggs will develop into male drones § Spores – structure that will contain genetic information and can be spread over large distances o Enables the offspring to take advantage of a favourable environment, limits the organism’s ability to spread quickly to more distant environments o Also has a protective covering that will protect the spore until a favourable environment o Spores may be haploid or diploid Alternation of Generations § Life cycle of plants consists of two alternate generations; a haploid generation as well as a diploid generation § Sporophyte o Diplod generation o meiosis will produce one or more haploid spores § Gametophyte o Haploid generation o gamete making body o produces female and male gametes that fuse at fertilization and develop another sporophyte … on and on… § one generation is usually dominant over the other generation § Vascular plants – diploid sporophyte § Non-vascular plants – haploid gametophyte § Mosses o Gametophyte – leafy green mat produces sperm and egg; sperm swim to eggs in moist environments o Sporophyte – stalk that grows up from the mat (only a few times a year) § Conifers o Sporophyte – tree itself (diplod) o Gametophyte – male cones (smaller releases pollen to fertilize female cones) and female cones (larger) Alternation in Sexual Cycles § Found only in plants § Alternation between sexual reproduction and asexual reproduction § Example – phylum cnidaria (jellyfish, sea anemones, corals) o Polyp – adult form (non-motile) o Medusa – adult form (motile) Describe Advantages and Disadvantages of Reproductive Strategies: GENERAL OUTCOME 1 You will be able to describe the processes of mitosis and meiosis.