BIO 140: OBJECTIVES OF THE COURSESlide 2Slide 3Slide 4Introduction to Cell DivisionContrasting Mitosis and MeiosisWhat Is a Chromosome?Slide 8Chromosomes Change before and during MitosisChromosome ReplicationSlide 11Interphase – S PhaseInterphase – Gap PhasesSlide 14Mitosis OverviewSlide 16Events in MitosisSlide 18Slide 19Slide 20Slide 21Slide 22Control of the cell cycle:Microinjection Expt:Mitosis-Promoting Factor Induces MitosisSlide 26MPF DeactivationCell-Cycle CheckpointsCell cycle check points: G1 CheckpointSlide 30Slide 31Cancer: Out-of-Control Cell DivisionCancer Involves Loss of Cell-Cycle ControlSlide 34Slide 35Properties of Cancer CellsSlide 37Cancer Is a Family of DiseasesSlide 39Different Cell Types Undergo Cytokinesis DifferentlySlide 41The Cell Cycle: Key Concepts LearnedSlide 43© 2011 Pearson Education, Inc.BIO 140: OBJECTIVES OF THE COURSE •1. √ Cells: working units of life -Bio-molecules: structure-function, Enzymes, Dynamic Cell membrane – Structure/function- transport•2. Inside the cell– Structure/function- transport, cell communication, and adhesion, cell signaling and hormones•Harvesting energy- Discuss the main metabolic pathways in the cell Photosynthesis: light Energy into Chemical energy •3, 4: Heredity and the genome: Cell cycle and cell division. How genes work? – Synthesis of nucleic acids and proteins. Regulation of gene expression. Defective proteins and diseases, Recombinant DNA Techniques© 2011 Pearson Education, Inc.•All living things are made of similar sub-components, which are evolved to have related/different functions in different life forms (Structure and Function)•All living things rely on chemical reactions to process matter and acquire energy for cellular functions. Some energy transformations are nearly universal while some are restricted to certain species (Pathways and Transformations of Energy and Matter)•DNA is the instruction code or the blue print for life; how it is used and exchanged within and among life forms is the basis of life (Information Flow, Exchange and Storage)•Organisms and their cellular components have changed over time (biodiversity) through both selection (mutations) and random evolutionary processes (Evolution)•Life is predictably interconnected - from cells within an organism to interactions between global communities (Systems)FBI:© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.Bio 140:Organization AndFunction Of the CellNew Cells arise through the division of pre-existing cells that is CELL DIVISION!© 2011 Pearson Education, Inc.Introduction to Cell Division•Cells arise through the division of preexisting cells. There are two types of cell division: meiosis and mitosis (only in eukaryotes).•Both forms of cell division are usually accompanied by cytokinesis, in which the cytoplasm of the cell divides into two distinct daughter cells.In multicellular organisms, uncontrolled cell division may lead to cancer. Different types of cancer result from different types of defects in control over the cell cycle.In eukaryotes, most dividing cells go through a cycle that consists of four phases.© 2011 Pearson Education, Inc.Contrasting Mitosis and Meiosis•Meiosis leads to the production of gametes (eggs and sperm).–Daughter cells have half the amount of genetic material as the parent cell.•Mitosis leads to the production of all other cell types, referred to as somatic(body) cells.–Genetic material is copied and then divided equally.–Daughter cells are genetically identical to the parent cell.Mitosis and cytokinesis are responsible for three key events in multicellular eukaryotes:1. Growth2. Wound repair3. Asexual reproduction© 2011 Pearson Education, Inc.What Is a Chromosome?•Chromosomes contain a single long double helix of deoxyribonucleic acid (DNA) wrapped around proteins. –DNA encodes the cell’s genetic information. –A gene is a section of DNA that encodes a specific protein or RNA.Chromosomes can be stained with dyes and observed under the light microscope.© 2011 Pearson Education, Inc.•Eukaryotic chromosomes consist of DNA associated with histone proteins. –In eukaryotes this DNA-protein material is called chromatin.© 2011 Pearson Education, Inc.Chromosomes Change before and during Mitosis•The purpose of mitosis is to distribute chromosomes to daughter cells during cell division.–To this end, each chromosome is replicated prior to mitosis.•As mitosis starts, the chromosomes condense from long, thin filaments into compact structures that can be moved around the cell efficiently.•At the end of mitosis, one of the chromosome copies is distributed to each of two daughter cells.© 2011 Pearson Education, Inc.Chromosome Replication•Prior to mitosis, each chromosome is replicated. –Each of the DNA copies in a replicated chromosome is called a chromatid.–Chromatids are joined together along their entire length as well as at a specialized region of the chromosome called the centromere.–Chromatids from the same chromosome are referred to as sister chromatids.•Even though a replicated chromosome consists of two chromatids, it is still considered a single chromosome.© 2011 Pearson Education, Inc.Unreplicated ReplicatedSister chromatidsCentromere© 2011 Pearson Education, Inc.Interphase – S Phase•The cell cycle is the orderly sequence of events that occurs from the formation of a eukaryotic cell through the duplication of its chromosomes to the time it undergoes cell division.Chromosome replication occurs only during interphase and not during M phase. The stage in which DNA replication occurs is called the synthesis (S) phase.DNA REPLICATION: Chapter 14© 2011 Pearson Education, Inc.Interphase – Gap Phases•Interphase also includes two gap phases, during which no DNA synthesis occurs. –The first gap, G1 phase, occurs before the S phase. –The second gap, G2 phase, occurs between S phase and mitosis.•During the gap phases, organelles replicate and additional cytoplasm is made in preparation for cell division.•It takes a cell about 24 hours to complete one cell cycle. Vary–G1 phase lasts 7–9 hours.–S phase lasts 6–8 hours.–G2 phase lasts 4–5 hours.© 2011 Pearson Education, Inc.The purpose of mitosis is to produce daughter cells that are identical to the parent cell.© 2011 Pearson Education, Inc.Mitosis Overview•Mitosis results in the division of replicated chromosomes and formation of two daughter