Cell Cycle, Mitosis, & Regulation Chapter 12

Slide 2 of 36 Genome

Slide 3 of 36 Kinetochore – protein attaches to chromosome at centromere + attaches to mitotic spindle

Slide 4 of 36 Haploid –Set of unique chromosomes  Only in gametes  Sperm + Egg Diploid – 2 sets of the unique chromosomes  1 set from Mom  1 set from Dad  ALL cells but gametes Somatic Cells 2,700 base pairs OR 2.7 kbp (MIT – D. Gifford [7.90J]) What percent of chromosomal DNA = genes?

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Slide 8 of 36 “-omes”  Genome – Complete set of genetic information  Transcriptome – set of all the mRNA produced by a cell or an organism  Proteome – entire set of proteins coded for by the genome of a cell or an organism  How many chromosomes in human genome?  Which is larger, genome or transcriptome?

Slide 9 of 36 Central Dogma of Molecular Biology  DNA  RNA  Protein  HIV (Reverse Transcriptase)  cDNA (Complementary DNA library)  Prions – infectious proteins  Genome  Transcriptome  Proteome

Slide 10 of 36 Divisions  Prokaryotes = binary fission  Eukaryotes  Mitosis  ALL cells arise by mitosis EXCEPT zygote (original cell)  Meiosis  ONLY used to produce egg (oocyte) and sperm (spermatocytes)

Slide 11 of 36 This is NOT mitosis!!  Proks do NOT do mitosis

Slide 12 of 36 Mitosis  Occurs in which type of cells?  Occurs where in the body?  Genetically identical (Clone)  Produces diploid daughter cells  Produces clones  Somatic cells

Slide 13 of 36 Meiosis  Occurs in which type of cells?  Occurs where in the body?  Genetically different  Produces haploid daughter cells  Produces eggs or sperm  Produces Gametes

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Slide 15 of 36 Questions?  Which is more common mitosis or meiosis?  What is the main way that prokaryote chromosomes differ eukaryotic chromosomes?  Binary fission or mitosis?  Fungi  E. Coli  Plants  What percent of DNA is non-coding in humans?

Slide 16 of 36 Questions? (Page 2)  What is the genome?  What is larger proteome or genome?  Haploid or Diploid?  Red Blood Cell  Muscle Cell  Sperm  Neuron  Macrophage  CD4 T-Cell

Slide 17 of 36 Cell Cycle  “Life of a cell”  From time it is first formed until it divides into 2 daughter cells

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Slide 20 of 36 Notes on Cell Cycle  G1 – Cell growth  Cells do their cell things  Vast majority of time in the cell cycle  Human cell = 46 chromosomes  S – Chromosomal duplication  Human cell = 46*2 = 92 chromosomes  Cells still grow during this time  G2 – Second Gap  Brief period between S and Mitosis  Mitosis / Cytokinesis

Slide 21 of 36 Watch Videos  Overview.swf  Mitosis.mpg  The_Stages_of_Mitosis_HD.mp4

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Slide 26 of 36 Cytokinesis  Cytokinesis – Cytoplasmic (and contents) division  Cytokinesis Video?  During telophase  G1  Animal cells  Cleavage furrow divides the cytoplasm into 2 cells  Plant cells  Cell plate forms that divides the cytoplasm

Slide 27 of 36 Cell Cycle Control  Some cells divide  Continuously (skin cells)  Occasionally (liver cells)  Never (CNS cells & muscle cells)  Signals to divide are present in cytoplasm  These signals control the rate of cell division  Result of signal transduction pathways

Slide 28 of 36 Cell Cycle Regulation  Involves checkpoints  There are 3 checkpoints: G 1, G 2, and M  G 1 checkpoint - Most important  G 0 – nondividing phase  Most body cells  Neurons & Muscle cells

Slide 29 of 36 Kinase – protein enzymes that control cell cycle Cyclins – proteins that bind to kinases and activate them CdK – cyclin-dependent kinase  Activated kinases  give the Go-ahead signal at the checkpoints

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Slide 31 of 36 Questions?  What are the phases of the cell cycle?  What are the parts of interphase?  What are the parts of mitosis?  What happens during the S-phase?

Slide 32 of 36 Questions (Page 2)  What is a CdK?  What is the G 0 phase?  How is cytokinesis different in animal cells from plant cells?  When does cytokinesis occur in the cell cycle?  How does a kinetochore differ from a centromere?

Slide 33 of 36 Normal Cells  Controlled cell cycle  Density-dependent Inhibition - Too many cells = no division - Once a cell contacts another cell, division ceases - Contact Inhibition  Anchorage Dependence - Division only happens when cell is attached to a substrate - If attached to another cell, no division

Slide 34 of 36 Cancerous Cells  Do NOT adhere to normal cell signals  Divide excessively  Violate density-dependent inhibition & anchorage dependency  Considered “immortal cells”  Normal cells undergo a process of genetic alteration that affects cell cycle regulation  Called Transformation

Slide 35 of 36 Tumor Terms  Tumor = mass of abnormal cells  Abnormal because?  Benign tumor  abnormal cells that remain at the original site  Malignant tumor  abnormal cells that impair functions of one or more organs

Slide 36 of 36 Cancer is characterized by …  Malignant tumors are characterized by anaplasia, invasiveness, & metastasis  Anaplasia  Cells do not undergo differentiation  Invasiveness  Intrusion of cells into and destruction of surrounding tissues  Metastasis  Spread of neoplasms via blood vessels to distant tissues or organs