{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture_2_Cell_Division

Lecture_2_Cell_Division - BIO 108 2008 Day 1 Lecture 2...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 BIO 108 2008 Day 1, Lecture 2, Title: Cell Division. Text Readings: Campbell et al. (2005) Chapter 12. Topics to cover: Eukaryotic Cell Cycle Ploidy and Chromosome Issues Cell Cycle Controls Mitosis Cytokinesis Cell Division Variants Prokaryotic Binary Fission Principle of Segregation Eukaryotic Cell Cycle Warning: deceptive, everyone thinks they know cell division and mitosis... Cell cycle Note Replication differs from Reproduction Replication is molecular, makes new molecules not new individuals Reproduction is cellular/organismal; makes new cells and perhaps new individuals cell division is often needed for organism growth Fig. 12.5, cell cycle M phase, has two parts: period of cell division, might be mitosis or meiosis mitosis just separation of genetic material into two nuclei cytokinesis separation of the cytosol and the two nuclei this is when reproduction may occur, sexual or asexual (Many people when they refer to "mitosis" really mean M phase as they include cytokinesis in their thinking...) G1 and G2 "gaps" periods of growth, and organellar production During G2 the centrosomes, with any centrioles, are replicated. S time of most nuclear DNA replication so get sister chromatids in each chromosomes this way Note DNA in organelles can replicate here and at other times... Ploidy and Chromosome Issues Changes in chromosome structure over cell cycle Fig. 19.2, chromosome structure and condensation chromatin is protein and DNA, note changes in condensation across cell cycle Fig. 12.4, chromosome SEM and sister chromatids (note: it does not duplicate while condensed) Have to have double chromatid chromosome at start of normal M-phase note centromere, chromatids, DNAs
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 Normally have single chromatid chromosome at end of cell division consider of number of DNA molecules, one dsDNA per chromatid DNA replication during S phase is then done to get ready again for cell division Note: Mitosis can be done by a haploid or by a diploid cell (Ask students to work through example diploid or haploid cell mitosis) Confusing doubles, note the hierarchy of level of organization over which they occur: double-stranded DNA molecular level Double-chromatid chromosome multi-molecular Homologous pair two similar chromosomes Diploid (2N) two sets of the genome Draw out on board chromosome, haploid/diploid states Show changes with: Mitosis vs. meiosis double vs. single chromatid chromosomes DNA replication meiosis fertilization Cell Cycle Controls Need to slow/halt cell cycle to replicate molecules or make more organelles, repair damaged DNA sections... wait for external signals to trigger entry into M phase, etc... One system of control involves proteins called cyclins, many types of these exist Fig. 12.16, cell cycle controls, cyclins Across cell cycle, note changes in concentrations of cyclin cyclin-dependent kinase Fig. 12.13, cell fusion experiment fuse to form M-phase promoting factor (MPF) if inject MPF into a cell can induce M phase errors in cell cycle controls are associated with cancers Mitosis Note that this is just one part of M-phase.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern