Presentation on theme: "Just what does a cell do with all its time?"— Presentation transcript:
1Just what does a cell do with all its time? Honors Biology Chapter 8Cell CycleJust what does a cell do with all its time?
2Cell Division Cell undergoes reproduction Makes “daughter cells” Has to first duplicate its chromosomesWHY?To keep the same number of chromosomes after division
3gb Asexual Reproduction Sexual Reproduction 2 parents One parent Types of Asexual ReproductionSexual Reproduction2 parents4 offspringOffspring most likely different from parentsMeiosis (multicellular eukaryotes)Makes sex cellsOne parent2 offspringOffspring identical to parents (if no mutations)Mitosis (eukaryotes)Binary fission (prokaryotes + unicellular organisms)Makes somatic cells (non sex cells)
4Types of Asexual Reproduction BuddingRegenerationan offspring grows out of the body of the parent.Hydrabudding hydra (10 secs)Budding in Hydra (1:27)SpongebobStarfish regeneration Regrowth of a limb or organ after damage (not a form of reproduction of whole organism)
5Asexual Reproduction Parthenogenesis growth and development of embryos occur without fertilization.Aphid Parthenogenesis (Gotta see this one!!!!!!!)Eviction of Drone Bees (5:13)Komodo Dragon Parthenogenesis Reproduction
6Asexual Reproduction Fragmentation Planaria Regeneration Body of parent breaks into distinct pieces, each of which can produce an offspring (is a form of reproduction)
7Asexual Reproduction Gemmules (internal buds) -Sexual reproduction of the sponge-Sponges: Factsinternally-produced, asexual bud (new sponge – even if adult does not survive)- usually under stressInternal budding of coral (mushroom coral 55 secs.)
8Asexual Reproduction: Vegetative (no seeds or spores) In PlantsRhizomesTubersBulbCormTUBERSAsexual Vegetative Propagation
9Asexual Reproduction Paramecium (a protist) Amoeba (a protist) Paramecium Binary fissionBinary Fission in amoebaAmoeba division (1:55)
10Asexual Reproduction Spores in Plants and Fungi Mold spore dispersal Mold spore dispersal youtubeLittle black dots of bread mold are spores (becomes an organism)Powder inside a puffball is actually the spores
11Bacteria Binary Fission Yeast buddingBacteria Binary FissionSmall growth becomes full yeast cellyeast budding time lapseCell enlarges and splits in halfbinary fission of bacteria
12Recap: Asexual Reproduction MitosisBinary FissionDivision of a cell (prokaryotes and unicellular organisms) into two identical cellsa eukaryotic cell separates the chromosomes in its nucleus into two identical nuclei.
13For prokaryotes and unicellular protists BINARY FISSIONFor prokaryotes and unicellular protists1-Chromosomeduplicates2-cell elongatesas chromosomesmove to poles3-plasma membranemoves inward and cell wall is madeYou Tube Binary Fission
14Mitosis: How eukaryotes divide Must divide the genetic material
15ALL DNA + Protein Not visible with light microscope CHROMATIN Loose During non-divisionCHROMOSOMESingle strandedSomewhat coiledVisible with microscopeCHROMATIDPaired homologous chromosomes during cell divisionDensely coiledVisible with microscope
16Chromosomes and centromeres Each chromosome strand has its own centromere
17Centromere: constricted area of two sister chromatids
18Sister Chromatids: Identical copies of Genetic Material Happens during S phase
19During cell division, the DNA replicates During cell division, the DNA replicates. The replicating DNA molecules attach to the plasma membrane. As the cell elongates, the chromosomes are pulled apart.
20Prokaryotes Eukaryotes No membrane around nucleus Simpler Smaller Single chromosomeDivide by binary fissionEukaryotesMembrane around nucleusMore complexLargerMany chromosomesDivide by mitosis or meiosis
21How many genes? Genes: working subunits of DNA. In a human cell~21,000In a bacterial cell~3,000
22Sexual ReproductionAsexual Reproduction-Used to make egg and sperm (that will join later) -Increases diversityUsed to replace dead cellsGrowth of new parts (size)New organism identical to parent
23Cell Cycle Game Enter the Cell Cycle Game Nobelprize.org (use Firefox )“Educational Games”Scroll down toCell cycle gameFUN!!!!!!!!!!!!!!!!!Top 10 most visited educational games1. The Blood Typing Game2. The Laser Challenge Game3. The DNA - the Double Helix Game4. The Pavlov's Dog Game5. The Diabetic Dog Game6. The Lord of the Flies Game7. The Electrocardiogram Game8. The Immune System Game9. The Control of the Cell Cycle Game10. The Split Brain Experiments Game
24Cell Cycle= Time from when a cell is first formed from its dividing parent cell to its own division into daughter cells.Cell Division and Cell Cycle Sit back and relax and enjoy the big picture of cell division (5.5 mins)
25Cell CycleTime from first formed from a dividing parent to until its own cell divisionmcgraw-hill cell cycle
26Get out your worksheet to fill out what happens in each phase (back of Nobelprize.org “cell cycle game”Eukaryotic Cell Cycle You Tube (4:20)Interphase = G1, S, G2 = 90% of timeMitosis= cell divides = 10% of time
28G1Growth of the CellMakes more organelles (mitochondria and ribosomes)Plasma membrane got larger (needs more lipids, carbos, proteins)High energy activity (cell resp.)FYI Typical cell 8-10 hours
29Go Resting or Permanently no division Maximum Surface area/volume EXAMPLES: Nerve (brain) cellsMuscleOR * Liver (will exit Go if damaged)Go
30S Phase DNA synthesis (replicates, makes a copy) At the end the chromosomes consist of sister chromatidsFYI Typical cell 6-8 hours
31G2 Growth for mitosis Check for DNA accuracy Final prep before mitosis Centrosome Doubles (MTOC)FYI Typical cell 4-6hours
32McGraw-Hill: How the cell cycle works Which of the following represents the correct order of the phases of the cell cycle?A) G1 -> G2 -> S -> MB) G1 -> G2 -> M -> SC) G1 -> S -> G2 -> MD) G1 -> S -> M -> G2E) G1 -> M -> G2 -> S
33Can you tell what goes on in each? Cell Cycle MovieTry this one…"The Cell Cycle" - multimedia animation by Yannick Mahe and Bernard Ducommun
42Control of the Cell Cycle Control of the Cell Cycle *McGraw-Hill animation__control_of_the_cell_cycle.htmlLike a control knob of an automatic washing machine…Get analogy handout
43Cell Cycle Checkpoints (get out your cell cycle handout) Cell cycle checkpoints = regulatory pathways that control the order and timing (starting/stopping) of cell cycle transitions(at G1, G2, M)
44Block outIf there is an error at any area, it will be fixed or the cell cycle will stop.
45(see analogy handout) Checkpoints: will give the cell a signal to proceed to next phase G1 Cell growth (big enough? Proteins for DNA synthesis? Nutrients?) to replication or G0G2 DNA synthesis (any DNA repair?) Size?M Mitosis (chromosome attachment to spindles)
54Cyclins build/break-down Cdk’s stay in cell phosphateactivates the cdkP
55cdk + cyclin = MPF “maturation promoting factor” (add to your diagram) Green cyclin attaches to blue kinase – note phosphate is the site of attachment
56Cyclins bind to a Cdk Animation of cyclins, cdk's (shows cdk + cyclin = MPF)Nobel Prize winner 2001: discovered the key regulators of the cell cycle, cyclin dependent kinase (CDK) and cyclin.
57CDK and CYCLINSEach cyclin-dependent kinase (cdk) forms a complex with a particular cyclin, a protein that binds and activates the cdk.The kinase part of the complex is an enzyme that adds a phosphate (makes the molecule unstable to cause it to be more reactive)
58*The Cell Cycle: Cyclins and Checkpoints (cyclins and kinases) Major control switches of the cell cycle are cyclin-dependent kinases.
59Checkpoints: Cyclins and Cdk’s Checkpoints in the Cell Cycle AnimationCyclins, Cdk's, and the Cell Cycle Animation
61P53: a “tumor suppressor gene” REGULATES THE CELL CYCLERediscovering Biology - Animation Archivep53 can stop and check a damaged DNA strand + repair it“the guardian of the genome”DNA tube action of p53 (5:18)Chromosome 17
63p53White = p53common mutation changes arginine 248, colored red here.DNA is blue and greenOther key sites of mutation are shown in pink, including arginine residues 175, 249, 273 and 282, and glycine 245.p53 video (p53-DNA complex) (1:32)
64How does p53 protect the cells? 1. start DNA repair2. stop the cell cycle3. initiate apoptosis = cell death, if DNA cannot be repairedMcGraw-Hill Tumor Suppressor Gene BIOL 230 Lecture Guide - ADCC Apoptosis by NK Cells (animation)
65ApoptosisSevere defects in chromosomes block progression through the cell cycle, and can lead to cell suicide, or apoptosis.Apoptosis You Tube Apoptosis Video
66What if… If the cell cycle does not work properly? CELL APOPTOSIS=cell death(A-pop-toe-sis)Apoptosis (40 secs) by Cancer QuestApoptosis Video (1.33 mins)You Tube Apoptosis Video (4 mins)THEN GO TO THE CANCER POWER POINT TO FIND OUT (“cells gone wild”)
67p27p27 is a protein that binds to cyclin and cdk blocking entry into S phase.Recent research (Nature Medicine 3, 152 (1997)) suggests that breast cancer prognosis is determined by p27 levels.
68What types of inhibition are these? Competitive or non-competitive?