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The Cell Cycle & Cell Division Basic Understanding • Structure – An arrangement or organization of parts to form an organ, system, or living thing. • Characteristics – pertaining to, constituting, or indicating the character or peculiar quality of a person or thing Basic Understanding • Response –any behavior of a living organism that results from an external or internal stimulus. • Stimulus - Something that can elicit or evoke a physiological response in a cell, a tissue, or an organism • Species –composed of related individuals that resemble one another, are able to breed among themselves Basic Understanding • Development – the act or process of growth or progress • Function – to perform a specified action or activity; work • Mobility – The ability to move from place to place, job to job, or level to level. Basic Understanding • Extinction – a coming to an end or dying out • Hierarchy –any organized system of things ranked one above another in successive order Robert Hooke • English Naturalist • Was the first to use the term cell. • Was looking at CORK under a compound microscope. What is a cell? • It is the smallest unit of life that carries out life functions The Cell Theory • The cell is the basic unit of structure and function (a.k.a. – life) • All living things are made up of 1 or more cells • Cells come from other, preexisting cells (a.k.a. – reproduction) Francesco Redi – The Italian Doctor • It was previously thought that maggots spontaneously grew. Redi disproved this theory. • He took 8 jars of rotting meat and covered 4 with muslin (fabric). The jars with muslin developed no maggots but the open jars had maggots. • This is important because cells come from other cells. Prokaryote • Are unicellular - 1 • Have no formed nucleus • Are very disorganized. • Have a cell wall, cytoplasm, ribosomes, bacteria have cell membrane • Bacteria are prokaryotes Eukaryote • Have a Nucleus • Have cell membrane bound organelles • Are very organized. • Can be singular or multicellular. • Have these other organelles; nuclei, mitochondrion, lysosome, golgi apparatus, ribosomes What’s Inside? • Organelles – tiny structures within a cell that perform specific jobs to keep the cell alive Cytoplasm - gel-like material inside cells Cytoplasm Cytoplasm • Contains materials involved in cell metabolism. • Gives the cell its shape Cell Membrane - protects cell and controls what enters and leaves the cell. Cell Membrane The Cell Membrane • Is semipermeable, or selectively permeable. • Is made of a phospho-lipid bilayer. • Helps maintain the shape of the cell. Nucleus - directs cell activities (brain) Nucleus The Nucleus and The Nucleolus • Serves as the control center of the cell and contains Deoxyribonucleic Acid (DNA) • Nucleolus- Contains RNA • Nuclear membrane – Control what goes in or out of the Nucleus. Endoplasmic Reticulum (ER) - movement of materials throughout cell ER Endoplasmic Reticulum •Rough ER contains Ribosome's. •Smooth ER has no Ribosome's Ribosome - makes proteins Ribosomes Ribosome's • Grain like Structures • Sites of protein synthesis Mitochondria - the powerhouse of the cell (converts food into energy for the cell) Mitochondria Mitochondria • Makes ATP/ Energy • These organelles are more plentiful in active cells Chromatin/Chromosomes (DNA) contains genetic information (inside the nucleus) Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell Chromosomes • Contains code that guides all cell activities • They are found in the nucleus. • Chromosomes contain the genes that determine an organisms characteristics. The Centrioles • Involved in cell division • Produce Microtubules that pull chromosomes apart. • Microtubules also give the cell structure. • Are found inside the nucleus. Golgi Body - packages and moves proteins Golgi Body Golgi Bodies • Look like stacks of pancakes. Lysosome - digests wastes Lysosome Lysosomes • Powerful chemicals that break things down. Vacuole - storage of food and water Vacuole Vacuoles • Plays a role in intercellular digestion • Store food and water. • Are much larger in plant cells. Cells Plant Cells • Have two main differences from animal cells • 1. Cell wall = a tough, usually flexible but sometimes fairly rigid layer that surrounds a cell • 2. Chloroplasts = organelles found in plant and other eukaryotic organisms that conduct photosynthesis Cell Wall - supports and protects PLANT cells (not found in animal cells) Cell Wall Chloroplast - takes energy from the sun and makes food for the PLANT cell (not found in Animal Cells) Chloroplast Cell Reproduction • All organisms REPRODUCE. • Why? – This allows for growth, development and the survival of the species Gamete – The male or female reproductive cell that contains half of the DNA Egg Cell – The Ovum; the female reproductive cell (gamete); usually not mobile Sperm – The male reproductive cell (gamete) ; usually mobile There are 2 types of reproduction 1. Asexual Reproduction – Requires A single parent!!! (sorry, just ONE). Asexual Reproduction (cont)… • Results in the offspring having the same hereditary material (DNA) Asexual Reproduction (cont)… • In other words, the new cells are an exact copy of its parent (allow for little variation among species) Types of Asexual Reproduction • Fission – cell splits in half (ex: Amoeba) Types of Asexual Reproduction (cont)… • Budding – a new organism grows off from the side of an adult (ex: Hydra) Types of Asexual Reproduction (cont)… • Regeneration – a new organism grows from a severed body part (ex: starfish) The structure of a chromosome Chromatid arm Centromere Chromosome Gene How do we replace old cells? • Mitosis – The process in which the newly duplicated chromosome pairs are separated from each other MITOSIS Mitosis The process of cell division which results in the production of two daughter cells from a single parent cell. The daughter cells are identical to one another and to the original parent cell. Mitosis can be divided into stages • Interphase • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis Interphase The cell prepares for division • Animal Cell – DNA replicated – Organelles replicated – Cell increases in size • Plant Cell – DNA replicated – Organelles replicated – Cell increases in size Interphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Prophase The cell prepares for nuclear division • Animal Cell – Packages DNA into chromosomes • Plant cell – Packages DNA into chromosomes Prophase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Metaphase The cell prepares chromosomes for division • Animal Cell – Chromosomes line up at the center of the cell – Spindle fibers attach from daughter cells to chromosomes at the centromere • Plant Cell – Chromosomes line up at the center of the cell – Spindle fibers attach from daughter cells to chromosomes at the centromere Metaphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Anaphase The chromosomes divide • Animal Cell – Spindle fibers pull chromosomes apart – ½ of each chromosome (called chromotid) moves to each daughter cell • Plant Cell – Spindle fibers pull chromosomes apart – ½ of each chromosome (called chromotid) moves to each daughter cell Anaphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Telophase The cytoplasm divides • Animal Cell – DNA spreads out – 2 nuclei form – Cell wall pinches in to form the 2 new daughter cells • Plant Cell – DNA spreads out – 2 nuclei form – New cell wall forms between to nuclei to form the 2 new daughter cells Telophase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm What happens to a cell after Mitosis is complete? • Cytokinesis – Cell splits into two identical daughter cells with complete set of organelles Mitosis Animation http://www.cellsalive.com/mitosis.htm Animal Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase How did you get here? • Sexual Reproduction – Reproduction in which two (2) parents are involved – Sex cells are called gametes (egg and sperm cells are gametes) What is sexual reproduction? • Sexual reproduction – starts with the formation of gametes and ends when one gamete joins another gamete. The joining of egg and sperm is called fertilization, resulting in the production of a zygote zygote How are gametes produced? • Meiosis – A process whose purpose is to reduce the chromosome number in the cells – Produces 4 new cells with half the number of chromosomes as the parent Meiosis – two divisions of the nucleus Parent Cell 1st Division 2nd Division – 4 new daughter cells with ½ the # of chromosomes Meiosis continued • Diploid Cells: have two of every chromosome (body cells) • Haploid Cells: have just one chromosome from each pair (gametes) MEIOSIS Meiosis Meiosis is the type of cell division by which germ cells (eggs and sperm) are produced. One parent cell produces four daughter cells. Daughter cells have half the number of chromosomes found in the original parent cell Meiosis During meiosis, DNA replicates once, but the nucleus divides twice. Meiosis Four stages can be described for each division of the nucleus. Meiosis I First division of meiosis First Division of Meiosis • Prophase 1: Each chromosome duplicates and remains closely associated. These are called sister chromatids. • Metaphase 1: Chromosomes align at the center of the cell. • Anaphase 1: Chromosome pairs separate with sister chromatids remaining together. • Telophase 1: Two daughter cells are formed with each daughter containing only one chromosome of the chromosome pair. Prophase I http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Prophase I http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Metaphase I http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Telophase I http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Meiosis Second Division of Meiosis Second Division of Meiosis • Prophase 2: DNA does not replicate. • Metaphase 2: Chromosomes line up at the center of the cell • Anaphase 2: Centromeres divide and sister chromatids move separately to each pole. • Telophase 2: Cell division is complete. Four haploid daughter cells are formed. Prophase II http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Metaphase II http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Telophase II http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Meiosis http://www.biosci.uga.edu/almanac/bio_103/notes/apr_3.html. Meiosis Animation http://www.rothamsted.bbsrc.ac.uk/notebook/courses/guide/movie/meiosis.htm Differences in Mitosis & Meiosis • Mitosis – – – – Asexual Cell divides once Two daughter cells Genetic information is identical • Meiosis – Sexual – Cell divides twice – Four haploid daughter cells – Genetic information is different Comparison Animations http://www.pbs.org/wgbh/nova/baby/divi_flash.html http://www.usoe.k12.ut.us/curr/science/sciber00/7th/gen etics/sciber/animatin.htm Cells (basic unit of life) Tissues (A group of cells performing a similar function) Organs (A group of tissues performing a similar function) Organ System (A group of organs performing a similar function) Organism An individual living thing made up of smaller parts that work together (You and Me)