BIOL 1543 Custom Edition Lecture 10 Outline of Last Lecture I Viruses and genetic material II The lytic cycle III The lysogenic cycle IV Phage reproductive cycles V Viruses and disease VI Emerging viruses VII AIDS a retrovirus VIII To clone or not to clone IX Differentiation X DNA packing XI Animal Cloning XII Cloning XIII Stem cells have medical potential Outline of Current Lecture I Like begets like more or less II Cells arise only from preexisting cells III Binary Fission IV THE EUKARYOTIC CELL CYCLE AND MITOSIS V The cell cycle consists of two major phases VI In the mitotic phase These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute VII Interphase VIII Prophase IX Prometaphase X Metaphase Anaphase Telophase Cytokinesis XI Cytokinesis XII Review of the functions of mitosis XIII Anchorage cell density and chemical growth factors XIV Apoptosis XV Cancer XVI THE GENETIC BASIS OF CANCER XVII Carcinogen Current Lecture I Like begets like more or less a In sexual reproduction fertilization of sperm and egg produces offspring b In asexual reproduction offspring are produced by a single parent without the participation of sperm and egg Their offspring are genetic copies of the parent and of each other c Other organisms reproduce sexually creating a variety of offspring II Cells arise only from preexisting cells a Cell division is at the heart of the reproduction of cells and organisms because cells come only from preexisting cells b Prokaryotic cells reproduce asexually by cell division binary fission III Binary Fission a As the cell replicates its single chromosome the copies move apart and the growing membrane then divides the cells i in most prokaryotes and protists IV THE EUKARYOTIC CELL CYCLE AND MITOSIS a The large complex chromosomes of eukaryotes duplicate with each cell division i A eukaryotic cell has many more genes than a prokaryotic cell and they are grouped into multiple chromosomes in the nucleus b Individual chromosomes contain a very long DNA molecule associated with proteins and are visible only when the cell is in the process of dividing i chromo colored some body c If a cell is not undergoing division chromosomes occur in the form of thin loosely packed chromatin fibers d Before a cell starts dividing the chromosomes replicate producing sister chromatids joined together at the centromere e Cell division involves the separation of sister chromatids and results in two daughter cells each containing a complete and identical set of chromosomes V The cell cycle consists of two major phases a drawn in relative time spent in each section b Know the phases and what happens in each VI In the mitotic phase a Cell division is a continuum of dynamic changes i In mitosis after the chromosomes coil up a mitotic spindle moves them to the middle of the cell ii The sister chromatids then separate and move to opposite poles of the cell where two nuclei form iii Cytokinesis in which the cell divides in two overlaps the end of mitosis b Two parts i mitosis the division of the genetic material ii Cytokinesis the movement of the cytoplasm to the new cells VII Interphase a three sections within i G1 growth 1 ii DNA Synthesis S iii G2 growth 2 VIII Prophase a in mitosis b early mitotic spindle an array of micro tubials and proteins that form between the opposite poles of the cell during mitosis c Centrosome the regulator IX Prometaphase a the centrosomes move to the poles of the cell X Metaphase Anaphase Telophase Cytokinesis a Metaphase i spindle fully formed ii metaphase plate the chromosomes have moved to the middle of the cell b Anaphase i the chromosomes split c Telophase i starts to reform d Cytokinesis i cytoplasm moves to the two cells XI Cytokinesis a Cytokinesis differs for plant and animal cells i In animals cytokinesis occurs by a constriction of the cell cleavage 1 complete cleavage separation of the cells ii In plants a membranous cell plate splits the cell in two do not totally separate incomplete cleavage XII Review of the functions of mitosis a Growth cell replacement and asexual reproduction i When the cell cycle operates normally mitotic cell division functions in 1 Growth of the different tissue 2 Replacement of damaged or lost cells 1and2 in both eukaryotes and prokaryotes 3 Asexual reproduction in prokaryotes and protists only Cells anchor to dish surface and divide When cells have formed a complete single layer they stop dividing densitydependent inhibition If some cells are scraped away the remaining cells divide to fill the dish with a single layer and then stop density dependent inhibition XIII Anchorage cell density and chemical growth factors a Most animal cells divide only when stimulated and some not at all i In laboratory cultures most normal cells divide only when attached to a surface called anchorage dependence ii They continue dividing until they touch one another called density dependent inhibition b Growth factors are proteins polypeptides secreted by cells that stimulate other cells to divide can lead to cancer XIV Apoptosis a Programmed cell death b Occurs billions of times daily c Cleaned up by other cells phagocytosis phase eat cytosis cell i phagocytosis is a specialized type of endocytosis d example being an unfertilized female egg XV Cancer a Growing out of control cancer cells can produce malignant tumors i Cancer cells divide excessively to form masses called tumors ii Malignant tumors can invade other tissues iii Radiation and chemotherapy are effective as cancer treatments because they interfere with cell division b Two types i malignant 1 severe and can metastasize meaning they can move to a different location in the body ii benign 1 do not grow in an unlimited and aggressive manor do not metastasize do not invade other tissues c Biopsy i two types of testing 1 excisional a remove the whole tumor mass b not always done because the tumor may be too big or aggressive 2 incisional a take just a piece of the tumor and test it ii Three types of cancer treatment can be one or all three depending on how bad it is 1 radiation 2 chemotherapy 3 surgical removal iii The key to success is early detection and treatment iv Etiology 1 the study of what causes a disease 2 Can be divided into a genetic issues b environmental issues XVI THE GENETIC BASIS OF CANCER a Cancer cells result from mutations in genes whose protein products affect the cell cycle b