Mitosis – Asexual Reproduction

Cell Cycle

Cell Cycle Mitosis Cytokinesis Period of time from one division to the next Unicellular division results in formation of new individuals of the species Cell Cycle Multicellular division results in replacement of old or damaged cells Process by which the nucleus divides while maintaining number of chromosomes Mitosis Cytokinesis Division of the cytoplasm Asexual Reproduction Reproduction that only involves one parent so therefore no special reproductive organs are needed

Interphase Prophase Metaphase Anaphase Telophase Nuclear DNA wound around proteins known as histones Chromatin Chromosomes Condensed rolls of chromatin that are able to be seen during mitosis (rod-like structures) There are 5 phases in MITOSIS Interphase Prophase Metaphase Anaphase Telophase

Draw Interphase Interphase Known as “resting phase” Cells grow in size by producing more nucleic acids, proteins, and cellular organelles Chromosomes make copies of themselves, but they can’t be seen Nucleus of the cell is contained within the nuclear envelope Centrioles are present and duplicate themselves Draw Interphase

Draw a Chromosome One Double Chromosome Prophase Double chromosomes become visible - Chromatid Chromosomes are 2 sister chromatids connected by a centromere Draw a Chromosome Centromere Sister Chromatids One Double Chromosome

Draw Prophase DON’T DRAW At the beginning, centrioles move to opposite poles Aster (star shaped fibers) extend = microtubules Spindle fibers attach (to centromere to pull away chromatids to opposite sides of the cell) By the end, the nuclear envelope and nucleus have disappeared Draw Prophase EARLY LATE DON’T DRAW

Draw Metaphase Metaphase Centromeres line up on the equator (middle= metaphase plate) By the end, the centromeres divide and pull the daughter chromosomes to opposite sides of the cell Half of each chromosome goes to the opposite side of the cell Draw Metaphase

Draw Anaphase Anaphase Daughter chromosomes move to opposite sides of cell (poles) Movement is accomplished by the microtubules Movement occurs by shortening of the microtubules Draw Anaphase

Draw Telophase Telophase Chromosomes uncoil and return to previous shape (threadlike) Nuclear membrane and nuclei reform Draw Telophase NOTE: Cytokinesis begins during late anaphase and finishes during telophase

I PUNCHED MY AUNT TILLY!! Mnemonic Device She had it coming!! An easy way to remember the order of the phases in mitosis is to think: I PUNCHED MY AUNT TILLY!!

Mitosis in Plants Same as mitosis in animals except: Plants have no centrioles – spindle fibers take their place Asters do not form Cell wall does not pinch because it is too rigid Cell plate divides the cell into two

D. Protein that causes cells to go through cell cycle is called cyclin * Asexual Reproduction Occurs only through the process of mitosis Each offspring has the same genetic information Where can asexual reproduction be found? BACTERIA YEAST PLANTS

There are 5 different types of asexual reproduction. 1. Budding Parent divides unequally; new individuals develop from buds ex – yeast & hydra 2. Binary Fission Most simple form of asexual reproduction; Parent divides equally and results in two separate individuals Ex.-paramecium 3. Spore Formation Single specialized cells that germinate when released from parent. Usually covered by a protective coating for preservation.

4. Regeneration/fragmentation Ability to regrow new body parts/ability to grow new Organism from parts. ex – hyrda, planaria, starfish, the bad guy from Terminator 2 5. Vegetative Reproduction/Propagation Refers to roots, stems, and leaves. Cells divide then differentiate to produce the same organism Ex.- strawberry plant, pick-a-back plant