Mitosis and Reproduction8_ss_10_crp_cm.swf Chapter review Why reproduce? Too big Growneed to make more cells Hereditypass on the genes to another generation Replace worn out or destroyed parts Blood cells constantly being made to replace used ones. Get destroyed by constant squeezing of heart Stomach cells get destroyed by acid Regeneration: Sea starsif loose leg, grow new ones. Asexual Reproduction Method 1._______ 2._______ 3._______ 4._______ Example 1.__________ 2.__________ 3.__________ 4.__________ Definition 1.___________ 2.___________ 3.___________ 4.___________ https://www.youtube.com/watch?v=DY9DN WcqxI4 Bacterial fission Types of Asexual Reproduction: Budding ex. Yeasts Binary Fission ex. Bacteria Fragmentation ex. Starfish Parthenogenesis ex. Crustaceans (shrimp, lobsters, crabs) Sexual Reproduction: Requires and egg and a sperm (gametes). Egg: XX chromosomes Sperm: XY chromosomes 10.1 Limits to Cell Growth 2 reasons for the limit to how big a cell can get a. The larger a cell gets the more difficult it is for the cell to produce the necessary proteins for the cell b. When the volume of the cytoplasm gets bigger than the cell surface (at a faster rate) there isnt enough cell membrane to exchange O2, H2O, food, and CO2. Think of a city whose population grows too fast for the garbage removal companies. Before a cell becomes too big and dies, it divides to increase the surface area/volume ratio again. This is called Cell Division and produces 2 cells called daughter cells which are identical to the parent cell. Some general concepts: plants: cell division takes place in the tips of roots & stems animals: cell division takes place all over the body to produce many different kinds of cells the timing of cell division is critical to development of tissues & organs DNA must be replicated & equally divided otherwise it can lead to birth defects, cancer or serious disease 10.2 Cell Cycle A. Chromosomes: * organisms have genetic information coded in a molecule called DNA * 2 forms of DNA In dividing cell the DNA coiled into structures called Chromosomes In a nondividing cell the DNA is called Chromatin - the genetic code is the same, just in different forms so the cell can divide easily * organisms have a set number of chromosomes humans have 46! Fruit flies have 8!! * When a cell divides, DNA replicates and chromatin condenses, forming visible strands called chromosomes * Each chromosome is now made of two strands called chromatids attached in the middle by a protein bundle called a centromere * When a cell divides, chromatids separate and each cell gets a copy of the DNA centromere Sister chromatids B.Cell Cycle * The period of time between one cell division, growth of the cell, and the next cell division. * During the cell cycle: a cell grows prepares for division divides to form two daughter cells, each of which begins the cycle again The sequence of the cycle is the same in all cells but some cells spend more time in certain stages Most cells in an adult multicellular organism are in G0 resting. * 2 Phases of the cell cycle each broken further 1. Interphase: the period between cell divisions G1 1 st Gap S DNA synthesis G2 2 nd Gap G0 - resting cell cycle animation 2. Mitosis: nuclear division Prophase Metaphase Anaphase Telophase cytokinesis: division of the cytoplasm Phases 1-3 are together called__________. Draw in the 3 Checkpoints as traffic lights. Actual cell division occurs Only in Phase #_____. 1. G1 2. S 3. G2 4.M 5.C Phases 1-3 are together called__________. Draw in the 3 Checkpoints as traffic lights. Actual cell division occurs Only in Phase #_____. 1. Interphase.a little more Once a cell enters the S phase, it usually completes the rest of the cell cycle * longest part of cell cycle 75%? G1: cells grow & make new proteins & organelles GO: some cells enter a prolonged period where they are just carrying out normal cell processes S: DNA replicates (synthesize) DNA is copied so that each new cell will get a copy. G2: organelles and molecules (enzymes) needed for mitosis are made cell is ready for mitosisdivision Interphase Normal Somatic (body) Cells are DIPLOID (2n) Cell cycle (S phase) in Somatic cells Mitosis of DIPLOID (2n) Somatic cells Prophase Mitosis of DIPLOID (2n) Somatic cells Metaphase Mitosis of DIPLOID (2n) Somatic cells Anaphase Mitosis of DIPLOID (2n) Somatic cells Telophase Mitosis of DIPLOID (2n) Somatic cells Cytokinesis Online/hx/hxcrp_io.swf Mitosis interactivets/nih1/cancer/activities/activity2_animation s.htmhttp://science.education.nih.gov/supplemen ts/nih1/cancer/activities/activity2_animation s.htm cell cycle and cancer