CHAPTER FOUR “CELL REPRODUCTION” (p.96) Cell Reproduction - is also known as cell division - or mitosis or fission. REASONS FOR MITOSIS Growth -adding cells to the body. Replace - worn-out or dying cells. Ex. Red blood cells (2-3 million per second). Repair - bruises and cuts. Reproduction * - one celled organisms. -----------------------------------------------Parent cell - the original cell. Daughter cells - the two new cells that are formed Parent Cell Daughter Cell Mitosis - a type of cell division which produces daughter cells exactly like the parent. New cells must have the same number of chromosomes. The DNA must be duplicated. Humans: 46 Fruit Flies: 8 Cat: 32 Potato and Chimp: 48 MITOSIS is a series of changes or phases 1) INTERPHASE WHEN THE CELL IS NOT DUPLICATING. NORMAL CELL ACTIVITIES. MOST OF A CELL’S LIFE IS SPENT IN INTERPHASE. Time spent in the Cell Cycle Growth and DNA Synthesis 4 hours 2 hours 4 hours 10 hours Growth and Preparation for Divison Mitosis Rapid Growth 2) PROPHASE- first real stage of mitosis. Nucleus breaks apart. -nuclear membrane disappears Tube-like structures called spindle fibers appear and attach to the centrioles. 3) METAPHASE Spindle fibers attach to the chromosome at their middle point. - called a centromere. 4) ANAPHASE Centrioles and spindle fibers pull apart the chromosomes to opposite sides of the cell. 5) TELOPHASE Centriole and spindle fibers disappear. Nucleus reforms. Chromosomes have duplicated. Cell membrane pinches in to form two daughter cells. After telophase, cells enter interphase again. INTERPHASE TELOPHASE PROPHASE ANAPHASE METAPHASE IDENTIFY THIS STAGE OF MITOSIS INTERPHASE IDENTIFY THIS STAGE OF MITOSIS METAPHASE IDENTIFY THIS STAGE OF MITOSIS IT’S A TOUGH ONE…. PROPHASE IDENTIFY THIS STAGE OF MITOSIS ANAPHASE IDENTIFY THIS STAGE OF MITOSIS TELOPHASE In plants, a new cell wall - called a cell plate - forms between the daughter cells. ASSIGNMENT: WORKSHEET “MITOSIS” DNA - “deoxyribonucleic acid” - a chemical which makes up the chromosomes. - Key to heredity. - Duplicated during mitosis. It’s structure and how it works was a mystery until 1952. James Watson and Francis Crick -proved the shape/structure of DNA was a double helix. (twisted ladder) p.111 The DNA molecule is made of four chemicals put into a certain order. Base pairs Guanine --- Cytosine Adenine --- Thymine - the sequence forms the hereditary code. - it controls eye color, height, allergies, etc. A section of the chromosome called a gene determines traits. Ex. blonde hair, blue eyes, etc DNA is duplicated during mitosis - called replication. - sometimes an error occurs (caused by pollution or x-rays) called a mutation. - a permanent change in the gene. - most are harmful. ex. deformed frogs in Minnesota. DNA Research Recombinant DNA - new DNA created when DNA from one organism is combined with another organism. - also called “gene splicing”. This has created “new” organisms. 1. oil eating bacteria. 2. Disease resistant potatoes. 3. Insulin producing bacteria. 4. “Round-up ready” corn What if we could replace the DNA strand which causes cancer? Many are against DNA research. We could create a very deadly disease. Cloning - a clone is genetically identical to its parent. - The DNA comes from one parent - not two. - Good? Bad? Dolly 1996 -2003 ASSIGNMENT: WORKSHEET “DNA” CLASSIFICATION (P. 22-26) - methods of grouping things according to similarities or differences. Ex. by size, color, age, etc. Classifying organisms is called taxonomy. - started by Aristotle in 350 BC. Many disagreements about the groupings: -by air? -by sea? -by land? Where to put frogs? Geese? Today’s system is called binomial nomenclature (two-name naming) Ex. Canis lupus - created by Carolus Linnaeus. Ex. Canis familiaris Latin was used by scientists and scholars in the 1700’s. - used today to avoid the confusion of using many different languages. Ex. Spanish moss - not Spanish - not moss The Latin names are an organism’s genus species. Canis Genus grouping Always capitalized familiaris Species grouping Always lower case. Most precise “smallest” Can produce offspring Both italicized Other examples: Felis domesticus Homo sapiens sapiens Acer rubrum ‘red maple’ Bison bison ASSIGNMENT: READ PAGES 22 - 26. CLASSIFICATION CATEGORIES - there are seven different levels of scientific classifications. - it becomes more exact/specific as you “move down”. Ex. Bottlenose Dolphin Tursiops truncatus Kingdom Phylum Class Order Animal Chordate Mammal Cetacea Family Delphinadae Genus Tursiops Species truncatus King Phillip cried out for goodness sake Six Kingdom Classification 1) Kingdom Animal - are multicellular. - can move from place to place. - cannot make their own food. 2) Kingdom Plant - make their own food through photosynthesis. - can be large (redwoods) or unicellular (plankton) 3) Kingdom Fungi -can not move. - can not make their own food. - absorb food from dead material. Ex. mushrooms, mold, yeast. 4) Kingdom Protist -are unicellular. - have traits of both plants and animals. Ex. Euglena - can move but it has chloroplasts. 5) Kingdom Eubacteria Ex. strep. 6) Kingdom Archebacteria Ex. stromatolites -both are prokaryotic. - unicellular. - Archebacteria are ‘older’ and more primitive and can live in harsh conditions. The difference between them is their chemical make-up. These kingdoms were formed when Kingdom Monera was split into two. ASSIGNMENT: WORKSHEET “CLASSIFICATION” Asexual Reproduction New organisms are produced from one parent. DNA is identical to parent. Examples Potato from tuber Strawberries from runners Fission: one celled organism divides to form 2 Budding: new organisms grow from one parent (Hydras) Regeneration: grow back missing parts More organism grow from parts of one organism Sponges, planaria, sea stars DNA (DEOXYRIBONUCLEIC ACID) The structure of DNA was discovered by Watson and Crick The shape of DNA is called a Double Helix DNA IS MADE UP OF BASE PAIRS GUANINE - CYTOSINE THYMINE - ADENINE AN ORGANISM WHICH RECEIVES DNA FROM ONLY ONE PARENT IS CALLED A CLONE.