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Ch. 9: The Cellular Basis of Inheritance (Mitosis & Meiosis) -Describe how cell reproduction contributes to repair and growth. -Analyze growth in three different organisms. -Contrast two ways that organisms reproduce (sexual/asexual). 9.1 -Draw and describe chromosome structure. -List, explain, and sketch the important events of each stage of the cell cycle. -Distinguish between chromatin, chromosome, and chromatids. 9.2 -Understand that mitosis (& its stages) is part of the cell cycle. -List, summarize, and sketch the major events that occur during each phase of mitosis. -Explain how cytokinesis differs in plant and animal cells. 9.3 –Relate cancer to the lack of control of the cell’s cycle. -Compare benign and malignant tumors. -Identify several probable causes of cancer. -Explain how cancer treatments, and their side effects, work at the cellular level. 9.4 -Describe how homologous chromosomes are alike and how they differ. -Contrast haploid and diploid cells in words and sketches. -Explain how the alternation of meiosis and fertilization keeps a species’ chromosome number constant from generation to generation. -Understand how the sex chromosomes of human females and males differ. -Sketch and write a summary of the process of meiosis. 9.5 -Explain how chromosome assortment during meiosis increases genetic variation. -Explain how crossing over contributes to genetic variation. -Connect sexual reproduction to genetic variation. -Explain how genetic variation affects the survival of species over time. -Understand the history behind the discovery of chromosomes. -Compare mitosis to meiosis via Venn diagram. 9.6 Ch. 9: The Cellular Basis of Inheritance (Cell Division: Mitosis & Meiosis) Mitosis -Describe how cell reproduction contributes to repair and growth. -Analyze growth in three different organisms. -Contrast 2 ways that organisms reproduce (sexual vs. asexual). All organisms reproduce their own kind. The 5 Characteristics of Life 1. Made of cells 4. Reproduce 2. Grow & develop 3. Acquire energy 5. Respond to environment Cellular Reproduction/Division Like all life processes, reproduction has a cellular basis. Rudolf Virchow, a German physician, put it this way in 1855: "Where a cell exists, there must have been a preexisting cell . . ." Cell Division The dividing of cells into more cells enables organisms to: 3. Produce offspring 1. Repair damaged cells 2. Grow Morula Repair Take a moment to look at the skin on your arm. You might be surprised to learn that the outermost layer of skin is actually a layer of dead cells. Underneath the surface layer are living cells busily carrying out the chemical reactions you studied in Unit 2. The living cells are also engaged in another vital activity: They are reproducing. The new cells gradually move outward toward the skin's surface, replacing dead cells that have rubbed off. This renewal of your skin goes on throughout your life. Repair When your skin is injured, additional cell reproduction helps heal the wound. Repair Scar tissue If the wound is too deep or too wide, scar tissue may form Growth Another role of cell division is growth— simply increasing in size from a baby to a child to an adult. Growth All of the trillions of cells in your body result from cell reproduction, a series of cell divisions that began with a single fertilized egg cell. Cell division •repairs damaged cells and replaces dead cells •causes growth and development in the organism •creates new organisms (asexual or sexual reproduction) Asexual Reproduction While the production of new cells can result in growth and repair within organisms, cell division also has an essential role in the reproduction of entire organisms. Some organisms reproduce by simple cell division, in which a single cell or group of cells each duplicates its genetic material and then splits into 2 new genetically identical cells (clones). This process, which is known as asexual reproduction, produces offspring that inherit all their genetic material from just 1 parent. -2 daughter cells form -the cells are clones Asexual Reproduction the production of 2 new daughter cells (clones) Asexual Reproduction As a result, the offspring are genetically identical to one another and to their parent. They are clones. Single-celled organisms such as Paramecium usually reproduce this way. One scientist calculated that if all the progeny of a single Paramecium survived, assuming a division rate of once a day, then after 113 days, the mass of paramecia would equal the volume of the Earth! Asexual Reproduction Many multicellular organisms can also reproduce asexually at certain times. For example, some sea stars, when divided into two pieces, can regrow into two whole new individuals through simple cell division. And if you've ever grown a geranium from a leaf cutting, you've taken advantage of the plant's ability to reproduce asexually. Asexual Reproduction Leaf Cutting Sexual Reproduction In contrast, when 2 parents are involved in the production of offspring, the process is called sexual reproduction. In sexual reproduction genetic material from each of 2 parents combines, producing offspring that differ genetically from either parent. Sexual Reproduction Sexual reproduction involves the union of sex cells, such as an egg and a sperm. These cells are produced by a specialized kind of cell division that you'll read about later in the chapter (MEIOSIS). Asexual Reproduction Sexual Reproduction •Growth •Repair •2 parents & their gametes •1 parent •Involves meiosis •“Clones” •Cells •Utilizes haploid egg & sperm •Involves mitosis •5 C’s of life •Unique new organism •Produces diploid cells 9.1 Online Review 5 Characteristics of Life; Biology Overview Bottle Biology Activity Characteristics of Life Quiz Cell Division: Growth & Repair: 1, 2, 3, 4 Asexual Reproduction Leaf Cutting Animation Sexual Reproduction Sexual Reproduction Quiz Back to Mr. Belmonte’s Biology