Cell Theory. Two scientist, named Schlieden and Schwann, proposed the first cell theory in Cells come from other cells when cells divide.

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1 Cell Theory Two scientist, named Schlieden and Schwann, proposed the first cell theory in Modern Cell Theory The Modern Cell Theory can have up to 9 statements, but we will use 6. These are on the 8 th grade EOG test. 1. All living things are made of cells. ~ALL Animals, ALL Plants, Bacteria, Mold, Fungus, are all included in this. 7 th Grade Science Kline 2. Cells are the most basic structural and functional unit of living things. ~Structure = How something is put together. ~Function = How something works. ~Cells determine how an organism is put together, what it looks like, and everything it is capable of doing. 3. Cells come from other cells when cells divide. ~Cells (life) cannot be created spontaneously. -Mitosis 4. Cells contain DNA, which passes information from one generation to the next. ~DNA is the blueprint for life instructions for how you are made given to you by your parents cells. 5. All cells are basically the same in chemical composition. ~Cells are made out of mostly the same stuff and are put together in mostly the same ways. 6. All energy flow of life occurs at the cellular level. ~Digesting of food, all types of movement, and anything that your body does which requires energy, begins at the cellular level. Cell Theory 1. All living things are made of cells. 2. Cells are the most basic structural and functional unit of living things. 3. Cells come from other cells when cells divide. 4. Cells contain DNA, which passes information from one generation to the next. 5. All cells are basically the same in chemical composition. 6. All energy flow of life occurs at the cellular level. 1

2 Cell Organelles Cell Wall Cell Membrane PLANTS ONLY! Organelle found only in plants that forms a hard, protective coating around the cell Plants AND animals Organelle found in both plant and animal cells that protect the cell from the outside world Lets good things enter the cell and bad thing leave (like a window screen) Cytoplasm Everything in between the membranes Clear, thick, jelly-like Holds organelles in place Nucleus Organelle that holds the information that tell how to build, operate, and repair the cell The brain of the cell Nuclear Membrane skin that hold all the chromosomes together inside the nucleus Lets things in and out of the nucleus through pores Chromosomes Found within the nucleus and contains all the genetic materials Nucleolus Found within the nucleus Makes ribosomes Endoplasmic Reticulum Maze of passageways that carry proteins and other materials from one part of the cell to another End-o-the hall 2

3 Ribosomes Organelles that produces protein RIBS=red meat=protein Mitochondria Organelle that converts sugar from food into energy that can be used within the cell Energy=power=Power House of the Cell Mighty Mitochondria Lysosomes Breaks down old cell parts and food Lysosomes=Lysol *Lysol breaks down germs and bacteria Vacuole Chloroplasts Golgi Complex Organelles that provide storage (food, water, waste) Vacuum ONLY IN PLANTS The location where plant cells make sugar out of water and carbon dioxide Organelle that turns simple chemicals into more complex chemicals Packages, stores, and secrets energy for the cell The Cell Cycle Lesson Objectives: Explain why cells need to divide. List the stages of the cell cycle and explain what happens in each stage. List the stages of Mitosis and explain what happens at each stage. Quick Review What is the cell theory? In what part of your cells is the genetic information located? Sexual Reproduction Budding Mitosis Sexual Reproduction Cell Cycle Vocabulary Mitosis Parent cell Prophase Telophase 3

4 Asexual reproduction produces offspring that are identical to the parent. Budding - a form of asexual reproduction in which a new organism grows on another one. The new organism remains attached as it grows, separating from the parent organism only when it is mature. Mitosis division of the nucleus Sexual reproduction produces offspring that have genetic information from two parents. Fertilization sex cells if different organisms if the same species combine to produce a new organism. Why Cells Divide Think about humans. A sperm cell fertilizes and egg, which makes the first cell the forms a human. How many cells is a human made up of? Think about the cell theory all cells must come from existing cells. From the one initial fertilized cell, a baby will develop. But how does this one cell turn into the trillions that make up a human? The original cell divides into 2 cells. Then those 2 cells divide again giving a total of 4 cells. Then those 4 cells divide giving a total of eight cells, ect. Embryo Division Diagram SearchBox&biw=1280&bih=575&tbm=isch&tbnid=6mLy5CkctHaE7M:&imgrefurl= 0lHVXO2M&imgurl= ck4biology.info/c4b/11/11.4/blastocyct.gif&w=454&h=277&ei=7ob_ujrtgo2u8aton4h4cg&zoom=1&iact=rc&dur=313&sig= &page=2&tbnh=135 &tbnw=222&start=25&ndsp=29&ved=1t:429,r:47,s:0,i:226&tx=142&ty=52 Other Reasons Cell Division is Necessary 1. To grow and develop, people must form new cells. 2. Cell division is needed to repair damaged cells. (ie: when you skin your knee) 3. Cells wear out over time and must be replaced. The Cell Cycle The cell cycle is the life cycle of a cell, with cell division at the end of the cycle. These steps can be divided into 3 main components: 1. Interphase- the 1 st stage where the cell mostly performs is everyday functions. 2. Mitosis- the 2 nd stage when the cell prepares to become 2 cells. 3. Cytokinesis- the 3 rd stage when the cell actually divides into 2 separate cells. The original cell is called the parent cell. Once the cell divides into 2 identical cell these cells are called daughter cells. Phase 1 of the Cell Cycle - Interphase Most of the cell cycle consists of interphase, the time between cell divisions. 1. Stage 1: Interphase (21 hours) Interphase is the longest of the 3 stages of the Cell Cycle Interphase is divided into 3 stages: 1. G 1 (1 st gap) the cell doubles in size and doubles the number of organelles 2. S phase (synthesis) the DNA is replicated (an identical copy of all the cell s DNA is made) 3. G 2 (2 nd gap) Proteins are synthesized that will help the cell divide. The cell begins to grow & enlarge during all 3 stages of Interphase At the end of interphase, the cell is ready to enter mitosis. Phase 2 of the Cell Cycle - Mitosis During mitosis, the nucleus of the cell divides. 2 nuclei must form so that when the cell divides into 2 daughter cells each cell has its own nucleus. To begin mitosis, the DNA in the nucleus wraps around proteins to form chromosomes. Different organisms have a unique number of chromosomes. After the DNA is replicated during the S phase of Interphase, each chromosomes has 2 identical copies of DNA which are called sister chromatids. Mitosis continued 2. Stage 2: Mitosis (<50 minutes) During Mitosis, 2 nuclei are created and 1 copy of the DNA created during Interphase is distributed to each of the nuclei. This process is divided into 4 primary phases: Phase 1: Prophase the chromosomes condense so that you can see them under a microscope Phase 2: Metaphase the chromosomes line up in the MIDDLE of the cell. Phase 3: Anaphase the 2 sister chromatids of each chromosome separate (pull APART) Phase 4: Telophase the spindle dissolves and nuclear membranes form around the chromosomes. 4

5 The Cell Cycle 4/25/2015 Phase 3 of the Cell Cycle - Cytokinesis Cytokinesis is when the cytoplasm of the cell divides, producing 2 separate cells. Stage 3: Cytokinesis (< 15 minutes) The cytoplasm divides. The 1 st sign of cleavage is the appearance of a cleavage furrow. A cleavage furrow is shallow groove in the cell surface near the old metaphase plate. 2 new cell membranes form around the 2 new cells. The new cells have an identical set of chromosomes and half of the organelles. SearchBox&biw=1280&bih=575&tbm=isch&tbnid=afoT1dIHacXA7M:&imgrefurl= yydj16vpa7wm&imgurl= &zoom=1&iact=hc&vpx=2&vpy=30&dur=62&hovh=152&hovw=331&tx=160&ty=64&sig= &page=1&tbnh=116&tbnw=252&start=0&ndsp=19&ved =1t:429,r:0,s:0,i:83 Review 1. In what phase of mitosis are chromosomes moving towards opposite sides of the cell? 2. In what phase of mitosis do the duplicated chromosomes condense? 3. What stage of the cell cycle is the longest? 4. What is the term for the division of the cytoplasm? 5. What happens during the S stage of interphase? - General Overview Human body cells have 46 chromosomes Each parent contributes 23 chromosomes Takes place in sex cells (gametes): egg and sperm One cell becomes 4 NON-IDENTICAL cells Homologous Chromosomes Chromosomes and Chromosome Number Same length Same centromere position Carry genes that control the same inherited traits One is from mother, one is from father = a matching set Haploid and Diploid Cells An organism produces gametes to maintain the same number of chromosomes from generation to generation. Human gametes contain 23 chromosomes. A cell with n chromosomes is called a haploid cell. A cell that contains 2n chromosomes is called a diploid cell. 5

6 I The sexual life cycle in animals involves meiosis. produces gametes. When gametes combine in fertilization, the number of chromosomes is restored. I Interphase Chromosomes replicate. Chromatin condenses. Interphase I Prophase I Pairing of homologous chromosomes occurs. Prophase I Each chromosome consists of two chromatids. The nuclear membrane breaks down. Spindles form. I Prophase I Crossing over produces exchange of genetic information. Crossing over chromosomal segments are exchanged between a pair of homologous chromosomes. I Metaphase I Chromosome centromeres Metaphase I attach to spindle fibers. Homologous chromosomes line up the middle of the cell. I Anaphase I Homologous chromosomes separate and to move opposite poles of the cell. Anaphase I I II II Telophase I The spindles break down. Chromosomes uncoil and form two nuclei. The cell divides. Telophase I Prophase II A second set of phases as begins the spindle apparatus forms and the chromosomes condense. Prophase II Metaphase II A haploid number of line chromosomes up in the middle. Metaphase II 6

7 II Anaphase II The sister chromatids are pulled apart at the centromere by spindle fibers and move toward the opposite poles of the cell. Anaphase II II Telophase II The chromosomes reach the poles, the andnuclear membrane and nuclei reform. Telophase II II Cytokinesis Division of the cytoplasm Results in four haploid cells, each with n number of chromosomes. Cytokinesis The Importance of consists of two sets of divisions Produces four haploid daughter cells that are not identical Results in genetic variation Provides Variation Depending on how the chromosomes line up at the equator, four gametes with four different combinations of chromosomes can result. Genetic variation also is produced during crossing over and during fertilization, when gametes randomly combine. Mitosis vs Scientists Cell Parts Fluid Mov t in Cells Parts & Functions Cell City Analogy Hodge Podge This scientist looked at cork cells under a microscope and gave cells their name

8 Who is Robert Hooke? This scientist was the first to use these instruments (called microscopes) because of his great skill of grinding lenses Who is Leewenhoek? This was Virchow s contribution to the Cell Theory. What is that all cells come from preexisting cells; plant cells come from plant cells and animal cells come from animal cells. This was Schwann s contribution to the Cell Theory. What is that cells are the basic unit of life? These are the three parts of the cell theory. What is 1. Cells are the basic unit of life 2. All living things are made up of one or more cells 3. All cells come from preexisting cells? 8

9 These are three examples of organelles. Which is mitochondria, nucleus, lysosomes, ribosome, golgi body, vacuole, endoplasmic reticulum, nucleolus, This is the semi-jelly like environment in which most of the cell s activities take place. What is the cytoplasm This organelle only occurs in the plant cell and provides support for the cell What is the cell wall? This is the name of the organelle where the process of photosynthesis takes place and contains a green pigment called chlorophyll. What is the Chloroplasts? These balloonlike spaces within the cytoplasm store waste and food and other substances the cell cannot use right away. 9

10 What are vacuoles? This type of membrane only allows certain materials to cross it. What is an selectively permeable? This type of membrane lets nothing cross it. What is impermeable? This process happens when an ink blob spreads apart from a concentrated area into area where there are fewer ink particles. What is diffusion? The movement of water from an area of high concentration to an area of low concentration What is Osmosis? 10

11 These are the three types of cell membranes. What is 1. Selectively Permeable 2. Permeable 3. Impermeable This is the function of the nucleus. What is it controls all of the functions of the cell? This is the function cell wall. What is support? This tough material makes cell walls thicker and more rigid than cell membranes. What is cellulose? These green pigment absorbs sunlight. 11

12 What is chlorophyll? This organelle distributes materials such as oxygen and food to different parts of the cell. What is Cytoplasm? This could be described as the power plant of the city Which is the mitochondria This organelle can represent the Post Office or the UPS station What is a golgi body? What kind of city analogy can you find for the Lysosome? Which is the Waste disposal, Recycler or Refinery 12

13 What does the Nucleus resemble in the city analogy? City Hall What is a vacuole in the city analogy of cell city? Which is warehouses, water tower, or garbage dumps Which cell structure is found in a plant cell, but not in an animal cell? Which is the cell wall, or the chloropasts Name the structure which is surrounding all cells that regulates what enters and leaves the cell Which is the cell membrane Name the organelle where the DNA is found? 13

14 What is the nucleus What is the cell city model for the endoplasmic reticlum? What are the road systems or high ways Name the wood like boundary that plant cells use for support and protection Which is the cell wall in plant cells. 14