Biology Partnership (A Teacher Quality Grant) Cell Cycle Mitosis & Cell Cycle Regulation Nancy Dow Jill Hansen Tammy Stundon November 3, 2012 Gulf Coast State College Panhandle Area Educational Consortium 5230 West Highway 98 753 West Boulevard Panama City, Florida 32401 Chipley, Florida 32428 850-769-1551 877-873-7232 1 www.gulfcoast.edu Pre-test Q and A board What is Mitosis? What is Meiosis? When do they happen? What is alike and what is different about them? 2 Bell Ringer Mitosis Rap "Mitosis" - Justin Bieber Baby remix! 3 Florida Next Generation Sunshine State Standards BENCHMARK • SC.912.L.16.14 Describe the cell cycle, including the process of mitosis. Explain the role of mitosis in the formation of new cells and its importance in maintaining chromosome number during asexual reproduction. Moderate complexity Clarifications • Students will describe specific events occurring in each of the stages of the cell cycle and/or phases of mitosis. • Students will explain how mitosis forms new cells and its role in maintaining chromosome number during asexual reproduction. 4 Content Limits • Items may address the presence and location of centrioles but may not require knowledge of the function of centrioles. • Items addressing mitosis or meiosis are limited to identification of phases, structures, and major events of each phase. 5 KEY CONCEPT Cells have distinct phases of growth, reproduction, and normal functions. 6 lung cancer cell undergoing cell division • Activate prior Knowledge: To get students thinking about doubling and division, have them think about baking cookies. •Ask, if you want two batches of cookies, not just one, what do you need to do to the recipe? •Double it. •Discuss that doubling a recipe means doubling all of the ingredients in the original recipe. Have students apply this idea to cell division. •Ask, for cells to be functional after division, what needs to be present? •Complete set of DNA, organelles, cytoplasm, cell membrane, cell wall if a plant. 7 Preview Vocabulary: • Cycle=Latin root Circlus= circle( repeating series of events) • Phase =Greek origin phasis= appearance (Remind students of the phases of the moon. Each phase of mitosis has a distinctive appearance.) • Stage=Latin word status= stand (students can think in terms of stagecoaches and stopping points, or stands, along a journey. A cell must move through the stages in the cell cycle to reach the point where it can successfully divide.) 8 Recall • Cells have 3 main jobs – make energy • need food + O2 • cellular respiration & photosynthesis • need to remove wastes Our organelles do all those jobs! – make proteins • need instructions from DNA • need to chain together amino acids & “finish” & “ship” the protein – make more cells • need to copy DNA & divide it up to daughter cells 9 The cell cycle has four main stages. • The cell cycle is a regular pattern of growth, DNA replication, and cell division. 10 • The main stages of the cell cycle are gap 1, synthesis, gap 2, and mitosis. – Gap 1 (G1): cell growth and normal functions – DNA synthesis (S): copies DNA – Gap 2 (G2): additional growth – Mitosis (M): includes division of the cell nucleus (mitosis) and division of the cell cytoplasm (cytokinesis) • Mitosis occurs only if the cell is large enough and the DNA 11 undamaged. DNA REPLICATION DURING ‘S’ PHASE OF CYCLE Adenine Cytosine Guanine Thymine 1 UNWINDING The coiled, doublestranded DNA molecule unwinds and separates into Free nucleotide two strands. 2 REBUILDING Each of the single strands becomes a double strand again as an enzyme connects the appropriate complementary base to the exposed base. The free nucleotides come from your food. 1 2 Complementary nucleotide bases attached ERRORS (MUTATIONS) CAN OCCUR WITH BASES DURING DNA Replication ____________ Why do Cells need to Divide? • Single cell organisms – Asexual reproduction • Multicellular organisms – Growth – Development – Repair Cells divide at different rates. • The rate of cell division varies with the need for those types of cells. • ~100 Trillion cells in the human body • ~100 Billion of them replicate each day • Some cells are unlikely to divide (G0). 14 Cell size is limited. • Volume increases faster than surface area. Larger cells would either starve to death or be poisoned from the buildup of waste products. 15 WHY ARE CELLS SMALL ?? BECAUSE OF SURFACE AREA- TO- VOLUME RATIO 16 • Surface area must allow for adequate exchange of materials. – Cell growth is coordinated with division. – Cells that must be large have unique shapes. 17 KEY CONCEPT Cells divide during mitosis and cytokinesis. 18 Chromosomes condense at the start of mitosis. • DNA wraps around proteins (histones) that condense it. DNA double helix DNA and histones Chromatin Supercoiled DNA 19 20 Recall chromatid telomere centromere •DNA plus proteins is called chromatin. • One half of a duplicated chromosome is a chromatid. • Sister chromatids are held together at the centromere. • Telomeres protect DNA and do not include genes. telomere Condensed, duplicated chromosome 21 HOMOLOGUES AND SISTER CHROMATIDS Homologues are the maternal and paternal copies of a chromosome. A sister chromatid is a chromosome and its identical duplicated version held together at a centromere. Homologues Homologues Replication (S Phase) Centromere Maternal chromosome Paternal chromosome Sister chromatids Sister chromatids A downside to cell division: TELOMERES Animal cell Every time a cell divides, the telomere gets shorter. After a critical number of cell divisions, functional DNA is lost, which means almost certain death for the cell. Nucleus Chromosome Functional DNA TELOMERE A protective cap at the end of each chromosome TELOMERES HAVE BEEN COMPARED TO THE ENDS OF A SHOELACE. AFTER A LOT OF WEAR, THE END OF THE SHOELACE GETS FRAYED. TELOMERES TELOMERE A protective cap at the Functional DNA end of each chromosome Cell division Cell division Cell division Cell death NOW THE CELL DOES NOT REPLACE ITSELF WHICH CAUSES THE AGING PROCESS TO OCCUR At birth, telomeres in most human cells are long enough to support about 50 cell divisions! Telomere Studies May Explain Rare Aging Disease in Children • Study of children with rare case of genetic mutation that causes drastic early aging and death is now being linked to short or missing Telomeres by top scientists. 25 PROGERIA: BORN WITH SHORTER TELOMERES---THESE ARE HIGHLIGHTED IN YELLOW IN PIC. THE CHILD DIES OF OLD AGE. Mitosis and cytokinesis produce two genetically identical daughter cells. Parent cell • Interphase prepares the cell to divide. • During Interphase, the DNA is duplicated. centrioles spindle fibers centrosome nucleus with DNA 27 • Mitosis divides the cell’s nucleus in four phases. – During prophase, chromosomes condense and nuclear membrane breaks down. – centrioles ‘move’ to the poles and spindle fibers form 28 • Mitosis divides the cell’s nucleus in four phases. – During metaphase, chromosomes line up in the middle of the cell. 29 • Mitosis divides the cell’s nucleus in four phases. – During anaphase, sister chromatids separate to opposite sides of the cell. 30 • Mitosis divides the cell’s nucleus in four phases. – During telophase, the new nuclei form, spindle fibers break down and chromosomes begin to uncoil. 31 • Cytokinesis differs in animal and plant cells. – In animal cells, the membrane pinches closed. – In plant cells, a cell plate forms. 32 Mitosis in plant cells 33 • Mitosis Animation 35 Mitosis in whitefish blastula Mitosis in Onion root tip Cell Cycle Lab 38 See you in the Computer Lab Let’s go to the Computer Lab • Mitosis Virtual Lab – Onion Tip 40 Mitosis Dance • Jill will lead us in this dance 41 Follow up • • • • • • • Mitosis Dance Mitosis animation another mitosis animation Animating Mitosis (flipbook) Mitosis: Read Retrieve Connect & Use Mitosis Puzzle Cell Cycle Project 42 Florida Next Generation Sunshine State Standards Benchmark • SC.912.L.16.8 Explain the relationship between mutation, cell cycle, and uncontrolled cell growth potentially resulting in cancer. (cognitive complexity: Moderate) Clarifications • Students will explain how cancer (uncontrolled cell growth) may result from mutations that affect the proteins that regulate the cell cycle. Content Limits • Items will focus on the relationship between mutations and uncontrolled cell growth, rather than a specific mutation that may result in uncontrolled cell growth. • Items referring to mutation will focus on the general concepts of uncontrolled cell growth and not require specific knowledge of cancers or diseases resulting from that growth. • Items will not assess the specific proteins associated with regulating the cell cycle. 43 KEY CONCEPT Cell cycle regulation is necessary for healthy growth. 44 Internal and external factors regulate cell division. • External factors include physical and chemical signals. • Growth factors are proteins that stimulate cell division. – Most mammal cells form a single layer in a culture dish and stop dividing once they touch other cells. 45 • Two of the most important internal factors are kinases and cyclins. • Kinases- change the activity of other molecules • Cyclins- rapidly made and destroyed at different points in the cell cycle • External factors trigger internal factors, which affect the cell cycle. 46 • Apoptosis is programmed cell death. – a normal feature of healthy organisms – caused by a cell’s production of self-destructive enzymes webbed fingers – occurs in development of infants 47 Cell division is uncontrolled in cancer. • Cancer cells form disorganized clumps called tumors. – Benign tumors remain clustered and can be removed. – Malignant tumors metastasize, or break away, and can form more tumors. normal cell cancer cell bloodstream 48 • Cancer cells do not carry out necessary functions. • Cancer cells come from normal cells with damage to genes involved in cell-cycle regulation. How cancer grows and spreads interactive 49 • Carcinogens are substances known to promote cancer. • Standard cancer treatments typically kill both cancerous and healthy cells. 50 Carcinogens 51 Prevention • 1. don't smoke • 30% of all cancer • 2. don't sunbath/booths • melanoma • 3. avoid alcohol • mouth, liver, larynx cancers • 4. avoid radiation • x rays • 5. get tested • catch it early on • 6. Diet • increase by 55% with obesity • high fiber, Vit. A and C, broccoli, cabbage • HeLa Cell Activity • Khan Academy- cancer 53 Follow up • Q&A • Post Test 54