NAME___________________________________ Period__________ CHAPTER 10 REVIEW SHEET Give the chromosome number in different organisms. Humans 46, Carrots 18, Fruit Flies 8, Pea Plant 12 When dos the majority of cell growth occur? The majority of cell growth occurs during G1. As a cell increases in size, what happens? Volume increases faster than surface area. If the cell gets too large (SA/V ratio decreases) it is unable to take in nutrients fast enough to support its metabolism or get rid of wastes fast enough. Also, there is an information crisis. The DNA cannot keep up with the needs of the cell How are the cells of a rat and a cat alike? They are both eukaryotic cells that are about the same size and have contain basic genetic information. What happens as the SA/V ratio is high? A smaller cell has a high SA/V. The higher the ratio, the faster or more efficient the transport of substances across the cell membrane. The faster the exchange the more effectively the cell functions. What is the result of cell division? 1 parent = 2 genetically identical daughter cells (mitosis & cytokinesis) What happens when you cut yourself? The cells that no longer touch other cell divide rapidly until the touch or contact other cells (healing). Define Cancer. Cancer is a disorder where cells have uncontrolled or unregulated growth within an organism. Contrast Malignant vs Benign cells. Malignant cells have the ability to spread into surrounding tissue and cells may break off and spread to other tissues/organs with the body. Benign tumors lack the ability to spread within the body. What are the two main stages of cell division? Mitosis (nucleus) and Cytokinesis (cytoplasm) What are the stages of the cell cycle (know order and be able to recognize each stage). Cell Cycle G1 Interphase S G1 Growth, Replication G2 P Mitosis M Nuclear division A M M phase T Cytokinesis Cytoplasm division G2 S Do all cells divide at the same rate: If not, give some examples Under ideal conditions some bacteria (Ecoli) can divide in 20 – 30 minutes. Liver cells in humans divide 2-3 years. Cells growing in a Petri Dish will stop dividing when the touch other cells. Nerve and brain cells do not divide. How is cell division different in plant and animal cells? Plant cells do not contain centrioles and the form a cell plate that becomes the cell walls. In animal cells a cleavage furrow forms that pinches inward. Chromatin consists of ____DNA_____________ and __Protein (nucleosomes)_______. Visible chromosomes are made up of _condensed DNA_ and _centromere_. Define Nucleosomes. Nucleosomes are proteins that are used to condense DNA. Chromatin becomes chromosomes. Where are chromosomes found? Chromosomes are found in the nucleus of a cell during Interphase. Which cells of the body rarely divide (if they divide at all)? Nerve, Brain A duplicated chromosome is made up of _2 sister chromatids. Sister chromatids are joined at the _centromere. Which stage of the cell cycle does cytokinesis occur? M phase (Cell Division) Calculate the SA:V ratio of a cube 4cm per side (SHOW WORK!!) 4x4x6 = 96 (SA) 4x4x4 = 64 (V) 96:64= 3:2 What is occurring during G1, S. and G2? G1: Cell Growth, production of organelles and proteins involved in normal cell functions S: Genetic material duplicated G2: Production of organelles and proteins necessary for processes during Mitosis Phases of Mitosis (nuclear division) What is happening at each phase? Prophase Nucleolus disappears, Nuclear membrane breaks down, chromosomes condense, Spindle fibers attach to centromeres Metaphase Chromosomes align in the middle of the cell, Spindle fibers attach to centrioles Anaphase Centromeres break, sister chromatids separate. Telophase Spindle fibers disperse, Events of prophase reverse Followed by Cytokinesis (cytoplasm division).