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Cell Reproduction and Inheritance. Duplicating Genetic Information. The Cell Cycle. Cancer and the Cell Cycle. Mitosis. Meiosis. When Cell Division is not perfect. Duplicating Genetic Information. Information about you is in the sequence of nucleotides in the DNA molecule.
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Cell Reproduction and Inheritance Duplicating Genetic Information The Cell Cycle Cancer and the Cell Cycle Mitosis Meiosis When Cell Division is not perfect
Duplicating Genetic Information Information about you is in the sequence of nucleotides in the DNA molecule In each of your cells, there is about 2 meters of DNA per nucleus How does the DNA condense into such as small area? DNA histones chromatin
Duplicating Genetic Information Chromatin can condense into a chromosome Telomere Centromere Telomere
Duplicating Genetic Information Humans have 46 chromosomes Chromosomes are characterized by length Position of the centromere Banding pattern
Duplicating Genetic Information So humans have 46 chromosomes with 23 pairs. You can see stained chromosomes and these can be arranged in pairs. The picture of arranged chromosomes is called a karyotype.
Humans Have 46 Chromosomes 23 pairs 2n = 46 2 is the number of copies of each chromosome n = the number of different chromosomes 46 is the total number of chromosomes in the cell
Let’s Try Some! 2n = 8 3n = 15 4n = 8
The Cell Cycle • Phases include: • Interphase – Preparation phases for mitosis • Mitosis – Cell division or splitting • Interphase • G1 (Growth) • S • G2 (Growth) The Cell Cycle
Cancer and the Cell Cycle A cancer cell has unregulated cell growth Often, the cell cycle checkpoints do not exist. What is cancer? Can you catch cancer? What are the treatments for cancer? What should I look for? http://www.cancer.org/ 1- 800 – 4 CANCER
Why Mitosis Growth and Repair Products are identical copies
Meiosis – a process that reduces the chromosome number in such a way that the daughter nuclei only receive one member of each homologous pair of chromosomes. Think of it as a double mitotic division with only a single S phase • Phases of meiosis • Prophase I 6. Prophase II • Metaphase I 7. Metaphase II • Anaphase I 8. Anaphase II • Telophase I 9. Telophase II • Interkinesis
Prophase I Crossing over of non-sister chromatids During prophase I, non-sister chromatids can undergo synapsis, in which the chromatids line up side-by-side & exchange genetic information between them This allows new combination of genetic material which will become part of a new offspring
Prophase I & Metaphase I Independent assortment As the chromosomes are pushed around during prophase I, eventually lining up along the metaphase plate during metaphase I, their orientation is different from that of mitosis metaphase Instead of lining one on top of the other, the replicated chromosomes line up side by side according to their homologous characterstics
Meiosis I Mitosis Prophase IProphase Pairing of chromosomes No pairing Metaphase IMetaphase Homologous chromosomes at Duplicated chromosomes at Metaphase plate metaphase plate Anaphase IAnaphase Homologous chromosomes separate Sister chromatids separate, becoming Daughter chromosomes Telophase ITelophase Daughter cells are haploid Daughter cells are diploid