Week 9 Lecture Notes
Week 9 Lecture Notes EBIO 1210-001
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This 4 page Class Notes was uploaded by Tatiana Tabares on Thursday November 12, 2015. The Class Notes belongs to EBIO 1210-001 at University of Colorado taught by Dr. Barbara Demmig-Adams in Fall 2015. Since its upload, it has received 28 views. For similar materials see General Biology 1 in Biology at University of Colorado.
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Date Created: 11/12/15
Week 9 Lecture Notes Cell Cycle Mitosis Cell Cycle and Mitosis 1 What are the functions of miotic cell division The vast majority of cells in the adult body are not dividing To renew naturally used up cells To replace cells after injury During development During reproduction of single celled organisms What happends when cell division goes WRONG Cancers o A tumor grows from a single cancer cell 0 Cancer cells invade neighboring tissue 0 Cancer cells spread through lymph and blood vessels to other parts of the body 0 A small of cancer cells may metastasize to another part of the body iClicker Question If an adult human being loses an arm in an accident it does not regrow Why not D Developmental processes for growing limbs are not reactivated when a limb is lost later in life 2 When cells are not dividing interphase Cell cycle from the time a cell is formed from the division of its parent cell to the time it undergoes its own division into two cells Most of the time is spent in interphase G1 growth S synthesis G2 growth then Mitotic phase Most cells in your body never go past G1 they go to GO part of interphase 0 These cells are not going to progress through the cycles 0 Are performing specialized functions 0 Doing things for you to keep you alive iClicker Question Which of the following statements about interphase is FALSE Very few of our cells ar ein interphase at any one time Week 9 Lecture Notes Cell Cycle Mitosis iClicker Question Who has the highest percentage of cells in S phase synthesis C A Fetus 3 The Mitotic Phase where division actually happens Mitotic Phase M Phase When the cell divides Has 2 parts 0 Mitosis division of nucleus and nuclear material 0 Cytokinesis Division of rest of cell The organization of genetic material in animal cells Nucleus 0 Multiple chromosomes 46 in most during G1 1 DNA molecule accessoy proteins During Replication of DNA happens during S phase of interphase Duplication of genetic material One DNA molecule is made into 2 DNA molecules Seperation of the sister chromatids the duplication of DNA is still stuck together and considered to be 1 chromosome occurs in Mitosis phase First stage of mitosis Prophase 1 Chromosomes condense gt they become supercoiled for efficient movement during subsequent processes 2 Preparation of the mitotic spindle gt a molecular scaffold that will help guide chromosomes Second stage of mitosis Prometaphase 1 Nuclear membrane breaks down 2 Spindle attaches to chromosomes Third stage of mitosis Metaphase Chromosomes line up in the middle of the cell Week 9 Lecture Notes Cell Cycle Mitosis Fourth stage of mitosis Anaphase Sister chromatids separate pulled by spindle Fifth stage of mitosis Telophase 1 Nuclear membranes reform 2 Cytokinesis can begin at the same time B Regulation of the Cell Cycle 1 Checkpoints Mitotic checkpoints move on to the next phase only if conditions are right Prevents sick or precancerous cells from dividing and maintains proper cell number Checkpoint sensing mechanisms monitor 0 Progression of the current phase 0 DNA integrity 0 Cell density 0 Cell anchorage what you are anchored to or attached too Multiple checkpoints within the cell cycle to regulate going foward 0 G1 checkpoint sends things that need to remain in GO back they have important functions that keep you alive 0 G2 checkpoint o M checkpoint Like stoplights or gates 2 The cell cycle is regulated by proteins in the cytoplasm Cyclin Accumulation Cyclin 0 protein 0 sounds like cycle is a protein that has a readout or determines where it is in the cycle Week 9 Lecture Notes Cell Cycle Mitosis 0 during 8 and G2 0 can bind to other proteins like CDK CDK enzyme that binds with cyclin 0 becomes active which makes it a quotmitosis promoting factorquot 0 happens during 8 and G2 Cyclin is degraded during M and G1 Important takehome message of the Cyclin accumulation Concentrations of proteins in the cytoplasm regulate the cell cycle Cyclins are ONE EXAMPLE gt there are other checkpoints and other molecules at work Cyclin and checkpoints If anything is outof whack the cell cycle is stopped by 0 increasing rate of cyclin degradation 0 inhibiting interaction of cyclin and CDK Both of these processes act to prevent the cell from crossing the checkpoint between G2 and the mitotic phase