Chapter 10 Lecture Presentation on Cell Division PDF

Chapter 10 Lecture Presentation: How Cells Divide Dr. Katelyn Jones [email protected] © 2023 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent o...

Chapter 10 Lecture Presentation: How Cells Divide Dr. Katelyn Jones [email protected] © 2023 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC. 1 Lecture Outline 10.1 Bacterial Cell Division 10.2 Eukaryotic Chromosomes 10.3 Overview of Eukaryotic Cell Cycle 10.4 Interphase: Preparation for Mitosis 10.5 M Phase: Chromosome Segregation and Division of Cytoplasmic Contents 10.6 Control of the Cell Cycle 2 Student Learning Outcomes 1. Explain binary fission. 2. Relate the structure of eukaryotic chromosomes. 3. Distinguish between homologues and sister chromatids. 4. Contrast replicated and nonreplicated chromosomes. 5. Relate the eukaryotic cell cycle. 6. State events that occur during interphase. 7. Illustrate the connection between sister chromatids after S phase. 8. Describe the phases of mitosis. 9. State the importance of metaphase. 10. Compare and contrast cytokinesis in plants and animals. 11. Identify the role of checkpoints in the control of the cell cycle. 12. Identify checkpoint controls in the cell cycle. 13. Describe cancer in terms of cell-cycle control. 3 Section 1: Bacterial Cell Division 1. Explain binary fission. 4 Bacterial Cell Division Bacteria divide by binary fission No sexual life cycle Reproduction is clonal Single, circular chromosome is replicated Escherichia coli – DNA is 500 times longer than cell Replication begins at the origin of replication and proceeds bidirectionally to site of termination New chromosomes are partitioned to opposite ends of the cell by unknown mechanisms Septum forms to divide the cell into two cells 5 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Binary Fission 6 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Binary Fission 7 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle The FtZ protein Septation Production of septum separates cell components Begins with formation of ring of FtsZ proteins – Accumulation of other proteins follow – Structure contracts radially = pinch cell into two cells FtsZ protein found in most prokaryotes Shows a high degree of similarity to tubulin – FtsZ role in binary fission different from tubulin in mitosis 8 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Comparison of organisms: Cell Division Assemblies 9 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Binary Fission 10 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Section 2: Eukaryotic Chromosomes 2. Relate the structure of eukaryotic chromosomes. 3. Distinguish between homologues and sister chromatids. 4. Contrast replicated and nonreplicated chromosomes. 11 Eukaryotic Chromosomes Characteristics Every species has a different number of chromosomes Humans have 46 chromosomes in 23 nearly identical pairs – Additional/missing chromosomes usually fatal 12 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Eukaryotic Chromosomes Characteristics Eukaryotic Chromosomes Are linear Vary in number depending on species – Cats - 38 chromosomes – Humans - 46 chromosomes in 23 nearly identical pairs – Chimpanzees - 48 chromosomes – Dog - 78 chromosomes Missing or extra chromosomes usually fatal 13 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Chromosomes Chromosomes Composed of chromatin – Complex of DNA (40%) and protein (60%) Site of RNA synthesis Has DNA in one long continuous double-stranded fiber for each linear chromosome – Typical human chromosome 140 million nucleotides In nondividing nucleus – Heterochromatin – DNA is not expressed – Euchromatin – DNA can be expressed 14 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Structure of Eukaryotic Chromosomes Monosomy- Trisomy- missing 1 pair of Has extra chromosome chromosomes added to chromosome pair CC BY-SA 3.0 Nami-ja - public domain, https://commons.wikimedia.or https://commons.wikimedia.or g/w/index.php?curid=1285283 g/w/index.php?curid=6094574 15 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Structure of Chromosomes Nucleosome Refers to complex of DNA and histone proteins to promote / guide coiling of DNA Composed of 200 DNA nucleotides coiled around a core of eight histone proteins Has electrical attraction – Most proteins negatively charged – Histone proteins are positively charged – PO4- groups on DNA are negatively charged 16 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Nucleosomes A nucleosome has 200 DNA nucleotides coiled around a core of 8 histone proteins 17 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Structure of Chromosomes Chromatin in nondividing nucleus or interphase – Has nucleosomes wrapped into higher order coils called solenoids – Leads to fiber 30 nm in diameter = 30 nm fiber Chromatin during mitosis – Arranges solenoids around scaffold of protein for maximum compaction – Radial looping to scaffold protein aided by condensin proteins 18 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Chromosomal Organization 19 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Chromosomal Organization Chromatin compaction during mitosis = inactive 20 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Chromosomal Organization Chromatin during interphase = active 21 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Karyotype Karyotype – A particular array of chromosomes of an individual organism – Arranges chromosomes by size, staining properties, location of centromere, etc. Humans are diploid (2n) – Two complete sets of chromosomes = 46 in humans Haploid (n) – Refers to one set of chromosomes = 23 in humans Homologous chromosomes – Pair of same kind of chromosome – Each one is a homologue 22 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Human Karyotype Homologous chromosomes 23 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Replication Prior to replication, each chromosome composed of a single DNA molecule After replication, each chromosome composed of 2 identical DNA molecules – Held together by cohesin proteins Visible as 2 strands held together as chromosome becomes more condensed – One chromosome composed of 2 sister chromatids 24 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Homologous Chromosomes vs Sister Chromatids Replicated homologous chromosomes Non-replicated homologous chromosomes 25 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Section 3: Eukaryotic Cell Cycle 5. Relate the eukaryotic cell cycle. 26 Eukaryotic Cell Cycle 1. G1 (gap phase 1) – Primary growth phase, longest phase 2. S (synthesis) Interphase – Replication of DNA 3. G2 (gap phase 2) – Organelles replicate, microtubules organize 4. M (mitosis) – Separation of nucleus – Subdivided into 5 phases M phase 5. C (cytokinesis) – Separation of cytoplasm for 2 new cells 27 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Duration of Cell Cycle Time it takes to complete a cell cycle varies greatly Fruit fly embryos = 8 minutes Mature cells take longer to grow – Typical mammalian cell takes 24 hours – Liver cell takes more than a year Growth occurs during G1, G2, and S phases – M phase takes only about an hour Most variation in length of G1 – Resting phase G0 – cells spend more or less time here 28 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cell Cycle 29 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cell Cycle 30 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle  Section 4: Interphase 6. State events that occur during interphase. 7. Illustrate the connection between sister chromatids after S phase. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.vecteezy.com%2Fvector-art%2F14047272-interphase-is-the-portion-of-the-cell- cycle&psig=AOvVaw1JLKIB679Uoue8ITCr_Idm&ust=1711243108046000&source=images&cd=vfe&opi=89978449&ved=0CBQQjhxqFwoTCN 31 jRvL6biYUDFQAAAAAdAAAAABAx Interphase G1, S, and G2 phases – G1 – cells undergo major portion of growth – S – replicate DNA – G2 – chromosomes coil more tightly using motor proteins; centrioles replicate; tubulin synthesis (building block of microtubules) Centromere – point of constriction – Kinetochore – attachment site for microtubules – Each sister chromatid has a centromere – Chromatids stay attached at centromere by cohesin 32 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Kinetochores 33 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Interphase G2 34 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle  Section 5: The M phase 8. Describe the phases of mitosis. 9. State the importance of metaphase. 10. Compare and contrast cytokinesis in plants and animals. https://teachmephysiology.com/biochemistry/cell-growth-death/mitosis/ 35 M Phase Mitosis is divided into 5 phases: 1. Prophase 2. Prometaphase 3. Metaphase 4. Anaphase 5. Telophase 6th image? Cytokinesis https://www.sciencephoto.com/media/623749/view/plant-cell-mitosis-light-micrograph 36 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Prophase Individual condensed chromosomes first become visible with the light microscope – Condensation continues throughout prophase – Ribosomal RNA synthesis ceases Spindle apparatus assembles – 2 centrioles move to opposite poles forming spindle apparatus (no centrioles in plants) – Asters – radial array of microtubules in animals (not plants) Nuclear envelope breaks down 37 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Prophase 38 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Prometaphase Transition occurs after disassembly of nuclear envelope Microtubule attachment – 2nd group grows from poles and attaches to kinetochores – Each sister chromatid connected to opposite poles Chromosomes begin to move to center of cell – congression – Assembly and disassembly of microtubules – Motor proteins at kinetochores 39 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Prometaphase 40 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Metaphase Alignment of chromosomes along metaphase plate – Not an actual structure – Future axis of cell division 41 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Metaphase 42 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Anaphase Begins when centromeres split Key event is removal of cohesin proteins from all chromosomes Sister chromatids pulled to opposite poles 2 forms of movements – Anaphase A – kinetochores pulled toward poles – Anaphase B – poles move apart 43 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Anaphase 44 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Telophase Spindle apparatus disassembles The tubulin subunits assemble cytoskeleton for new cells Nuclear envelope forms around each set of sister chromatids – Now called chromosomes Chromosomes begin to uncoil – rRNA genes begin to be expressed – Why? Because we need new proteins translated for the new daughter cells Nucleolus reappears in each new nucleus Results in the completion of mitosis 45 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Telophase Telophase = completion of nuclear division 46 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cytokinesis Cleavage of the cell into equal halves Animal cells – constriction of actin filaments produces a cleavage furrow Plant cells – cell plate forms between the nuclei Fungi and some protists – nuclear membrane does not dissolve; mitosis occurs within the nucleus; division of the nucleus occurs with cytokinesis 47 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cytokinesis in animal cells 48 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cytokinesis in animal cells 49 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cytokinesis in plant cells Cell plate forms Formation of plasma membrane from fusion of vesicles made by Golgi apparatus Secretion of cellulose to form cell wall 50 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Mitosis Overview 51 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle  Section 6: Control of the Cell Cycle 11. Identify the role of checkpoints in the control of the cell cycle. 12. Identify checkpoint controls in the cell cycle. 13. Describe cancer in terms of cell-cycle control. https://en.wikipedia.org/wiki/Cell_cycle_checkpoint 52 Control of cell cycle Current view integrates 2 concepts 1. Cell cycle has two irreversible points – Replication of genetic material – Separation of the sister chromatids 2. Cell cycle can be put on hold at specific points called checkpoints – Process is checked for accuracy and can be halted if there are errors – Allows for high fidelity – What is fidelity? The accuracy of replicating a template (DNA) – Allows cell to respond to internal and external signals 53 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle 3 Checkpoints 1. G1/S checkpoint – Cell “decides” to divide – Primary point for external signal influence 2. G2/M checkpoint – Cell makes a commitment to mitosis – Assesses success of DNA replication 3. Late metaphase (spindle) checkpoint – Cell ensures that all chromosomes are attached to the spindle 54 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle 3 Checkpoints 55 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle G1/S checkpoint 1. G1/S checkpoint – Cell “decides” to divide – The cell will commit to DNA replication (S phase) and thus cell division – Primary point for external signal influence – Growth factors are peptides that signal for the cells to grow/divide – The cell is in a favorable environment – Cell cycle halts at this checkpoint if: – There is DNA damage – Exposure to starvation conditions – Lack of growth factors (GFs) 56 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle G2/M checkpoint 2. G2/M checkpoint – Cell makes a commitment to mitosis – Assesses success of DNA replication – Cell cycle halts if: – DNA damage is present – Lack of accuracy in replication in DNA – What is this called again? Genomic Fidelity 57 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Late metaphase/Spindle checkpoint 3. Spindle checkpoint – Cell ensures that all chromosomes are attached to the spindle – Commits to separation of chromosomes during anaphase – Cell cycle halts if: – Not all kinetochores are attached to spindles 58 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle 3 Checkpoints Is DNA replicated Are all chromosomes accurately? attached to spindles? Is the environment favorable? Are growth factors present? 59 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle  How do we regulate the cell cycle at these checkpoints? 60 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cyclin-dependent kinases (Cdks) Enzymes that phosphorylate proteins Primary mechanism of cell cycle control Cdks partner with different cyclins at different points in the cell cycle For many years, a common view was that cyclins drove the cell cycle – that is, the periodic synthesis and destruction of cyclins acted as a clock Now it is clear that Cdk itself is also controlled by phosphorylation 61 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle  How do cdks control the cell cycle? Phosphorylation 62 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cdk enzyme forms a complex with cyclins Regulates cell cycle Cdk – cyclin complex – Also called mitosis-promoting factor (MPF) Activity of Cdk is also controlled by the pattern of phosphorylation – Phosphorylation at one site (red) inactivates Cdk – Phosphorylation at another site (green) activates Cdk 63 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Control in multicellular eukaryotes Multiple Cdks control the cell cycle Animal cells respond to a greater variety of external signals This allows for more complex control of cell cycle Each checkpoint we have discussed have a corresponding Cdk-cyclin (or MPF) Below are the MFPs for mammalian cells You will only need to know mammalian MFPs G1/S- Cdk2/Cyclin E G2/M- Cdk1/Cyclin B Spindle Checkpoint- APC 64 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Control in multicellular eukaryotes 65 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Control in multicellular eukaryotes: Cyclins 66 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Anaphase-promoting complex (APC) Also called cyclosome (APC/C) At the spindle checkpoint, presence of all chromosomes at the metaphase plate and the tension on the microtubules between opposite poles are both important Function of the APC/C is to trigger anaphase itself APC is made of Marks securin for destruction; no MANY proteins hence we will not inhibition of separase; separase be memorizing it destroys cohesin 67 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Growth Factors Act by triggering intracellular signaling systems Platelet-derived growth factor (PDGF) one of the first growth factors to be identified PDGF receptor is a receptor tyrosine kinase (RTK) that initiates a MAP kinase cascade to stimulate cell division Growth factors can override cellular controls that otherwise inhibit cell division 68 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cell proliferation-signaling pathway 69 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cell proliferation-signaling pathway 70 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle  What happens when we don’t have control of the cell cycle? 71 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cell cycle and cancer Unrestrained, uncontrolled growth of cells Failure of cell cycle control Two kinds of genes can disturb the cell cycle when they are mutated 1.Tumor-suppressor genes 2.Proto-oncogenes 72 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Tumor-suppressor genes p53 plays a key role in G1 checkpoint p53 protein monitors integrity of DNA – If DNA damaged, cell division halted and repair enzymes stimulated – If DNA damage is irreparable, p53 directs cell to kill itself Prevent the development of mutated cells containing mutations p53 is absent or damaged in many cancerous cells 73 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Cell division, cancer, and p53 protein 74 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Tumor-suppressor genes p53 gene and many others Both copies of a tumor-suppressor gene must lose function for the cancerous phenotype to develop First tumor-suppressor identified was the retinoblastoma susceptibility gene (Rb) – Predisposes individuals for a rare form of cancer that affects the retina of the eye 75 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Tumor-suppressor genes Retinoblastoma Inheriting a single mutant copy of Rb means the individual has only one “good” copy left – During the hundreds of thousands of divisions that occur to produce the retina, any error that damages the remaining good copy leads to a cancerous cell – Single cancerous cell in the retina then leads to the formation of a retinoblastoma tumor Rb protein integrates signals from growth factors – Role to bind important regulatory proteins and prevent stimulation of cyclin or Cdk production 76 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Proto-oncogenes Normal cellular genes that become oncogenes when mutated – Oncogenes can cause cancer Some encode receptors for growth factors – If receptor is mutated in “on”, cell no longer depends on growth factors Some encode signal transduction proteins Only one copy of a proto-oncogene needs to undergo this mutation for uncontrolled division to take place 77 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Key proteins associated with human cancer 78 Bacterial Cell Division | Eukaryotic Chromosomes | Overview of Eukaryotic Cell Cycle | Interphase | M Phase | Control of Cell Cycle Binary Fission Videos Chromosomal compaction (1 min) – https://www.viddler.com/embed/d4cac474/?f=1& player=arpeggio&secret=59037080 Binary fission – begin at 34 seconds (1 min) – https://www.viddler.com/embed/2a4ffe32/?f=1& player=arpeggio&secret=59037080 Bidirectional DNA replication (36 secs) – https://www.viddler.com/embed/2e0e4017/?f=1 &player=arpeggio&secret=59037080 79 Binary Fission Videos FtsZ Protein – https://www.youtube.com/watch?v=aJrc9mdo-R 8 Bacterial cell cycle (2 mins 18 secs) – https://www.viddler.com/embed/517fab0c/?f=1& player=arpeggio&secret=59037080 80 Cell Division/Cycle Videos Cell division review (2 mins 18 secs) https://www.viddler.com/embed/927b500c/?f=1&player= arpeggio&secret=59037080 Cytokinesis (1 min 22 secs) https://www.viddler.com/embed/fbd2a020/?f=1& player=arpeggio&secret=59037080 Control of the cell cycle (1 min 43 secs) https://www.viddler.com/embed/c6de317b/?f=1&player= arpeggio&secret=59037080 81 Cell Cycle Videos Control of the cell cycle (1 min 43 secs) – https://www.viddler.com/embed/c6de317b/?f=1&player= arpeggio&secret=59037080 Stimulation of cell replication (1 min 4 secs) – https://www.viddler.com/embed/da8663ca/?f=1&player= arpeggio&secret=59037080 Cell proliferation signaling pathway (1 min 21 secs) – https://www.viddler.com/embed/e8a077a7/?f=1&player= arpeggio&secret=59037080 Two examples of how tumor suppressor genes block cell division (2 mins 14 secs) – https://www.viddler.com/embed/e0aa6b96/?f=1&player= 82