Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
NOTES CHAPTER 8 – MITOSIS AND MEIOSIS ZOOLOGY I. II. Chromosomes a. Objectives i. Describe the structure of a chromosome ii. Identify the differences in structure between prokaryotic chromosomes and eukaryotic chromosomes iii. Compare the numbers of chromosomes in different species iv. Explain the differences between sex chromosomes and autosomes v. Distinguish between diploid and haploid cells b. Chromosome structure i. Chromosomes are rod-shaped structures made of DNA and protein ii. In eukaryotes, DNA wraps around proteins call histones to help maintain the compact structure of chromosomes iii. Chromosomes in prokaryotes are simpler in structure than chromosomes in eukaryoties c. Chromosome numbers i. Each species has a characteristic number of chromosomes in each cell ii. Sex chromosomes and autosomes 1. Sex chromosomes are chromosomes that determine the sex of an organism 2. All of the other chromosomes in an organism are autosomes iii. Diploid and haploid cells 1. Cell having two sets of chromosomes are diploid (2n) 2. Haploid cells (1n) have only one set of chromosomes Cell division a. Objectives i. Describe the events of cell division in prokaryotes ii. Name the two parts of the cell that are equally divided during cell division in eukaryotes iii. Summarize the events of interphase iv. Describe the stages of mitosis v. Compare cytokinesis in animal cells with cytokinesis in plant cells vi. Explain how cell division is controlled b. Cell division in prokaryotes i. Cell division is the process by which cells reproduce themselves III. ii. Binary fission is the process of cell division in prokaryotes c. Cell division in eukaryotes i. Cell cycle 1. The cell cycle is the repeating set of events in the life of a cell 2. The cell cycle consists of cell division and interphase 3. Cell division in eukaryotes includes nuclear division, called mitosis, and the division of cytoplasm, call cytokinesis ii. Interphase 1. Interphase consists of growth (G1), DNA replication, and preparation for cell division (G2) iii. Stages of Mitosis 1. Mitosis is divided into stages: prophase, metaphase, anaphase, and telophase 2. Mitosis results in two offspring cells that are genetically identical to the original cell iv. Cytokinesis 1. During cytokinesis in animal cells, a cleavage furrow pinches in and eventually separates the dividing cell into two cells 2. In plant cells, a cell plate separates the dividng cell into two cells v. Control of cell division 1. Cell division in eukaryotes is controlled by many proteins 2. Control occurs at three main checkpoints 3. When control is lost: cancer a. Cancer may result if cells do not respond to control mechanisms Meiosis a. Objectives i. Compare the end products of meiosis and those of mitosis ii. Summarize the events of meiosis I iii. Explain crossing-over and how it contributes to the production of unique individuals iv. Summarize the events of meiosis II v. Compare spermatogenesis and oogenesis vi. Define sexual reproduction b. Formation of haploid cells i. Meiosis includes prophase I, metphase I, anaphase I, and telophase I ii. Crossing-over, which is when portions of homologous chromosomes exchange genetic material, occurs during prophase I and results in genetic recombination c. d. e. f. iii. Meiosis is a process of nuclear division that reduces the number of chromosomes in new cells to half the number in the original cell iv. Meiosis leads to four haploid cells (gametes) rather than two diploid cells as in mitosis Meiosis I i. Meiosis I includes prophase I, metaphase I, anaphase I, and telophase I ii. Crossing over occurs Meiosis II i. Meiosis II includes prophase II, metaphase II, anaphase II and telophase II ii. Four new haploid cells result Development of gametes i. Spermatogenesis is the process by which sperm cells are produces ii. Oogenesis is the process that produces mature egg cells Sexual reproduction i. Sexual reproduction is the formation of offspring through meiosis and the union of a sperm and an egg ii. Offspring produced by sexual reproduction are genetically different from the parents