Biology, Cell Cycle Lecture Notes PDF

09-28-2023 07:21 09-28-2023 07:21 The Cell Cycle: Stages...

09-28-2023 07:21 09-28-2023 07:21 The Cell Cycle: Stages Biology 11 Lecture 8 Interphase CELL CYCLE G1 – growth S – growth and DNA synthesis G2 – growth and preparation for cell division Mitotic Phase Mitosis – nuclear division Cytokinesis – division of the cytoplasm Bio 11 1s2324 1 Bio 11 1s2324 2 09-28-2023 07:21 09-28-2023 07:21 The mitotic (M) phase of the cell cycle alternates with Cell division functions in reproduction, the much longer interphase. growth, and repair/tissue renewal Interphase accounts for 90% of the cell cycle. Bio 11 1s2324 3 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings 09-28-2023 07:21 Fig. 12-4 09-28-2023 07:21 0.5 µm Chromosomes DNA molecules Chromo- Chromosome some arm duplication (including DNA synthesis) Centromere Sister chromatids Separation of sister chromatids Centromere Sister chromatids Bio 11 1s2324 6 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings 09-28-2023 07:21 09-28-2023 07:21 Assembly of the spindle microtubules starts in the centrosome. The centrosome (microtubule-organizing center) of animals has a pair of centrioles at the center (but the function of the centrioles is somewhat undefined). Bio 11 1s2324 7 Bio 11 1s2324 8 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings 09-28-2023 07:21 09-28-2023 07:21 Cytokinesis, division of the cytoplasm, typically follows mitosis. In animals, the first sign of cytokinesis During telophase in plants, (cleavage) vesicles from the Golgi is the appearance of a coalesce (phragmoplast) at cleavage furrow the metaphase plate, (contractile ring of forming a cell plate. actin microfilaments, associated with myosin) in the cell surface near the old metaphase plate. Bio 11 1s2324 10 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings 09-28-2023 07:21 09-28-2023 07:21 Key Haploid gametes (n = 23) Haploid (n) Egg (n) Diploid (2n) Sperm (n) MEIOSIS FERTILIZATION MEIOSIS AND SEXUAL LIFE CYCLES Fig. 13-5 Ovary Testis Diploid zygote (2n = 46) Mitosis and development Multicellular diploid adults (2n = 46) Bio 11 1s2324 11  Fig. 13-6 09-28-2023 07:21 09-28-2023 07:21 KARYOTYPE 5 µm Pair of homologous Key Haploid (n) replicated chromosomes Haploid multi- Haploid unicellular or Diploid (2n) multicellular organism cellular organism (gametophyte) n Gametes n n Mitosis n Mitosis Mitosis n Mitosis Centromere n n n n n MEIOSIS FERTILIZATION Spores n n Gametes Gametes n MEIOSIS FERTILIZATION Zygote 2n MEIOSIS FERTILIZATION 2n 2n 2n Diploid Zygote 2n Diploid multicellular Mitosis multicellular Mitosis organism organism Zygote (sporophyte) Sister (a) Animals (b) Plants and some algae (c) Most fungi and some protists chromatids Metaphase chromosome 09-28-2023 07:21 09-28-2023 07:21 Key Maternal set of chromosomes (n = 3) 2n = 6 Paternal set of chromosomes (n = 3) Two sister chromatids of one replicated chromosome Centromere Two nonsister Pair of homologous chromatids in chromosomes a homologous pair (one from each set) Bio 11 1s2324 16 09-28-2023 07:21 09-28-2023 07:21 09-28-2023 07:21 09-28-2023 07:21 Bio 11 1s2324 19 Bio 11 1s2324 20 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings 09-28-2023 07:21 09-28-2023 07:22 Bio 11 1s2324 21 Bio 11 1s2324 22