The Cell Cycle

POINT > Describe three reasons cells divide POINT > Identify the three parts of the cell cycle POINT > Identify three stages of interphase POINT > Identify four stages of mitosis POINT > Describe how cytokinesis is different in plant and animal cells

POINT > Describe three reasons cells divide 20 µm 100 µm 200 µm (1) Reproduction Unicellular organisms divide as a way to reproduce (2) Growth and development. The cells of multicellular organisms divide for growth (3) Tissue repair. Damaged or old cells need to be replaced

POINT > Describe three reasons cells divide 20 µm 100 µm 200 µm (1)Reproduction Unicellular organisms divide as a way to reproduce (2) Growth and development The cells of multicellular organisms divide for growth (3) Tissue repair. Damaged or old cells need to be replaced

POINT > Describe three reasons cells divide 20 µm 100 µm 200 µm (1) Reproduction Unicellular organisms divide as a way to reproduce (2) Growth and development The cells of multicellular organisms divide for growth (3) Tissue repair Damaged or old cells need to be replaced

CHECK: What are 3 reasons cells must divide? What is produced during cell respiration? What are the products of photosynthesis? What are the reactants of cell respiration? What is a eukaryote? What are stomata? What is osmosis?

POINT > Identify 3 parts of the cell cycle The cell cycle consists of 1) Interphase – normal cell activity 2) Mitosis– the nucleus divides into two 3) Cytokinesis – the cell divides into two new cells Growth G 1 (DNA synthesis) Growth G2 Cell Divsion

POINT > Identify three stages of interphase Cells spend most of the cell cycle in interphase The purpose of interphase is for cell growth and DNA replication By the end of interphase a cell has two sets of DNA (chromosomes) and is large enough to divide

POINT > Identify three stages of interphase Interphase is divided into three phases 1. G1 (Gap 1) phase: the cell grows and makes more proteins and organelles

POINT > Identify three stages of interphase Interphase is divided into three phases 2. S (Synthesis) phase the DNA replicates, so both “daughter” cells will receive a full copy of the DNA

POINT > Identify three stages of interphase Interphase is divided into three phases 3. G2 (Gap 2) phase, cells continue to grow and produce the proteins necessary for cell division

CHECK: What happens during the S phase of interphase? What are the 3 parts of interphase? What happens during G1 phase? What do ribosomes do? What is a eukaryote? What is active transport?

POINT > Identify the four phases of mitosis Mitosis is the division of the nucleus Mitosis is divided into four phases. Each phase is characterized by specific processes involving different structures Prophase Metaphase Anaphase Telophase

POINT > Identify the four phases of mitosis 1. Prophase: 1) DNA wraps up tightly with proteins to form chromosomes 2) The nuclear membrane disappears DNA during interphase DNA during mitosis DNA double helix DNA and histones Chromatin Supercoiled DNA

POINT > Describe the structure of chromosomes The DNA was replicated during S-phase of interphase. During prophase it condenses into chromosomes The two copies of the DNA are called sister chromatids Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Metaphase chromosome Kinetochore microtubules Centromere region of chromosome Sister Chromatids

CHECK: What are the 4 phases of mitosis? What are 2 things that happen in prophase? What is an autotroph?

POINT > Identify the four phases of mitosis 2. Metaphase: chromosomes line up in the middle of the cell

POINT > Identify the four phases of mitosis 3. Anaphase: sister chromatids separate to opposite sides of the cell

POINT > Identify the four phases of mitosis 4. Telophase: the new nuclei form and chromosomes begin to uncoil

CHECK: What happens during metaphase? What happens during anaphase? What happens during telophase? What are the two types of fermentation? What is produced during alcoholic fermentation? What types of cells use lactic acid fermentation?

POINT > Describe how cytokinesis is different in plant and animal cells Cytokinesis is the physical division of the cell into two “daughter” cells Cytokinesis is different in plant and animal cells

POINT > Describe how cytokinesis is different in plant and animal cells In animal cells the cell membrane pinches in half to create two new cells

POINT > Describe how cytokinesis is different in plant and animal cells In plant cells a cell plate grows between the two new daughter cells. This makes a new cell wall

POINT > Review the basics of the cell cycle Mitosis results in two genetically identical daughter cells

CHECK: What is cytokinesis? How many cells are produced by mitosis? What happens during cytokinesis in plant cells? What are the subunits proteins are made of? What are the 3 Domains of living things?

Homework: Complete Study Guide Read pages 95-100 S.A. page 100 #1a-c GRAS pp. 51-52 #1-11