CELL REPRODUCTION NOTES

Transcription

1 CELL REPRODUCTION NOTES CELL GROWTH AND DIVISION The adult human body produces roughly cells every day. WHY DO CELLS REPRODUCE? So that the organism can and As multicellular organisms grow larger, its cells and in. Replacement of / cells To prevent cell Cell Membrane Overload Cell size is limited by the (surface area) DNA Overload Everything must and through the. If cell get too large, DNA cannot be fast enough to make. Gene a unit of that consists that codes for a The of the cell is by the because it contains the for making. CHROMOSOMES OR CHROMATIN? Both are Chromatin DNA Most of the time DNA exists as because it is easier to the instructions for the proteins when. Chromosome DNA (wrapped) around called When the cell gets ready to, the chromatin condenses into because it is easier to the chromosomes when they are.

2 CHROMOSOME STRUCTURE Chromatid one of the two of a chromosome A single long molecule of Sister chromatids chromosome pairs that are still connected Centromere the region of the chromosome that the sister chromatids during cell When sister chromatids are, they are considered chromosome. When sister chromatids are during cell (mitosis), they are considered individual chromosomes. PREPARING FOR CELL DIVISION All cells are produced by the of cells. The cell must give each cell all the it needs to and PROKARYOTIC REPRODUCTION Once a has in size, the cell will. Prokaryotes copy the and divide the by the process called.

3 What is the cell cycle? The Eukaryotic Cell Cycle Notes Cell cycle a sequence of cellular and during the life of the cell. Part One: Interphase The cell is NOT the cell is and to divide. How long does interphase last? Divided into 3 parts: Part Two: Cell Division Two Processes: and During these phases, the cell s and (includes the and ) divide. Carries out cell Cell by building more DNA exists as so that it can be used to make of a cell s is spent in this phase Cells that do not remain in this phase ( ) like cells DNA (gets ) At the end of S, the holds as much DNA now exists as that are attached at the. Cytokinesis the process of separating the and the Occurs during of mitosis. Mitosis the process of the into daughter Cell continues to and prepares to Special structures ( and ) that help the cell divide are. Divided into phases At the beginning of mitosis (prophase), the is packaged into.

4 Mitosis and Cytokinesis Notes (Ch.10:2) Stage What happens? Picture Interphase (not part of mitosis) Cell and carries out activities ( ), the DNA ( ) and for ( ). and visible. Prophase DNA exists as Mitosis Begins and break down. condenses into ( chromatids) begins to form. move to the. Metaphase Chromosomes move to the or the of the cell. Spindle fibers attach to. Anaphase Sister chromatids and move o After separation, chromatids are now considered individual. At the end, there are numbers of at the. Telophase/ Cytokinesis Nuclear membrane around the reforms. Chromosomes into. Spindle fibers. begins. o develops in animal cells. o develops in plant cells Animal Cells Plant Cells

5 Cell Cycle Regulation Notes HOW DOES A CELL KNOW WHEN IT S TIME TO DIVIDE? Cell growth depends on from other or its. HOW DOES A CELL KNOW IF IT IS READY TO DIVIDE? It must pass through. Checkpoint an to ensure the is ready for the next of the. G1 Checkpoint The cells checks: Its to be sure are favorable for Is there enough and? Is the cell and enough to? If ready, the cell enters the phase. When the cell passes this, it must. G2 Checkpoint The cells checks: For any in the ; if so, they are. Makes sure the cells will get an copy of the DNA. Makes sure the cell is enough to divide When the cell passes this, will begin. Mitosis Checkpoint During, the chromosomes line up at the cell s. The cells checks that all are attached to the. This ensures that each gets exactly the right amount of. SO, WHY DOES ALL THIS MATTER? Cells that checkpoints may lead to!!!!! Cancer - cell and LOSS OF CONTROL to DNA can cause a cell to checkpoints. cells divide and produce more cells Tumor a that arises from normal tissue but grows in rate and structure and a function.

6 MEIOSIS NOTES STAGES WHAT HAPPENS? PICTURE Meiosis I separates Prophase I Metaphase I Anaphase I Telophase I/ Cytokinesis Chromosomes, chromosomes pair up, the membrane breaks down, and may occur. The spindle moves the of homologous chromosomes to the of the cell. pairs line up. The homologous chromosomes. are still held together by the. The spindle fibers pull the to poles of the cell. Chromosomes gather at the, divides, and daughter cells are formed Meiosis II separates Prophase II A new forms around the. Metaphase II The chromosomes line up along the and are attached to the spindle fibers at the. Anaphase II Sister chromatids are and to opposite of the cell. Telophase II /Cytokinesis membranes form around each of chromosomes, the breaks down, the divides, & daughter cells formed

7 Sexual and Asexual Reproduction WHAT ARE CHROMOSOMES? Chromosome a -containing structure that carries information from one to the. o Chromosomes are from cells. o Every has a specific chromosome. Autosomes chromosomes with that do not determine an individual s o How many autosomes do humans have? Sex Chromosomes chromosomes with that determine an individual s o Humans o chromosome contains many vital genes to o How many sex chromosomes do humans have? Homologous chromosomes chromosomes that are the size and have the genes. o Genes sections of that code for. HAPLOID VS. DIPLOID Haploid describes cells containing the number of chromosomes o Which cells in our bodies are haploid? o What is the haploid number for humans? Diploid describes cells containing each of chromosome o Which cells in our bodies are haploid? o What is the diploid number for humans? ASEXUAL REPRODUCTION When a cell reproduces by asexual reproduction, o parent cell provides the genetic information. o daughter cells are produced Asexual Reproduction o Daughter cells are to the original cell and to. o No exists unless occur. Genetic variation differences in the Mutations changes in the o Builds the bodies of organisms. Somatic cells

8 Created by reproduction ( ) Every cell in your body has the exact same. Cells differently based on which are turned. o Some organisms reproduce by asexual reproduction to build. o Examples: Prokaryotes Asexual Reproduction Advantages Eukaryotes o Does not require a Saves and. Occurs. Populations grow and offspring can be produced over time. Asexual Reproduction Disadvantages o genetic variation among. Populations are only in environments with little. o No which limits to the environment. SEXUAL REPRODUCTION Requires parent cells o Each parent cell contributes the information for the. o Gametes reproductive cells ( and ) Formed by in the reproductive organs o Zygote the cell that results from the of the by the Sexual Reproduction Advantages o Produces offspring. among individuals produces a more or better population. Genetic variation allows some organisms to when others cannot. Sexual Reproduction Disadvantages o Requires parent cells, so organisms must find a. Takes and process population growth Sources of Genetic Variation o Crossing over occurs when chromosomes genetic information at the beginning of ( ) o Law of Independent Assortment the distribution of chromosomes during ( ) influences the of in the o Random Fertilization only sperm can fertilize each.