GED Science Study Guide

Points to remember! --All living things have several things in common. The cell is the basic functional unit of a living organism. Ecosystems are home to thousands of organisms, each playing a necessary role. ABOUT 40% THE GED SCIENCE QUESTIONS WILL BE ABOUT LIFE SCIENCES. Cell --the basic functional unit of an organism DNA --contains all the instructions needed to direct a cell's activities Mitosis --replication of a cell & its DNA Life science (or biology) --is the study of all living things, from plants to animals and humans. A biologist is someone who- --studies organisms, or living things, of which there are over 1.5 million different types. Biologist study their structures, their life cycles, and their relationship to their environment. Scientist have come up with a way to separate the living from the non-living: ---Has a life cycle (from birth to death) -Has the ability to move or grow -Has the need to find sources of energy as in feeding -Has the ability to respond to stimuli, or something in the environment, that causes a change in behavior -Has the ability to reproduce -Made up of cells Life science covers --every organism from the smallest, single-celled bacterium to the largest animal on earth, the blue whale All organisms have similarities, --such as needing energy to grow, interacting with their surroundings, and producing offspring. (No matter how big or small, all of these organisms are alike in that they are composed of cells. The Cell --the cell is the basic functional unit of an organism, meaning that each cell has the potential to fulfill all the functions of that organism. Cells also must arise from other pre-existing cells 4 pts of a Cell --1. The first part of a cell is the membrane 2. The second part of a cell is the cytoplasm 3. The third part of a cell is the nucleus 4. The fourth part consists of the many organelles (ALL CELLS HAVE FOUR DISTINCT PARTS) Cell mambrane --cells are surrounded by a thin covering, which separates the cell from its environment.This membrane is called the "cell membrane" (or plasma membrane) it acts as a barrier or wall. Cell membranes are semipermeable, --meaning that they will allow some substances to move both into and out of cells through the cell membrane. This allows the cell to take in the required nutrients and expel any waste products. Cytoplasm --the inside of the cell, is the semi-liquid substance in which all of the internal "organs" of the cell are dissolved. (this is where much of the biochemical activity of the cell occurs) The main component of cytoplasm is --WATER Nucleus --Cells must create DNA, the genetic material which allows a cell to replicate, & this DNA in a specific region in the cell called the nucleus. The nucleus & its DNA hold inside --All of the information needed to function & create another cell. Cells have "Organelles" --Which are structures (of which the nucleus is one) within the cytoplasm that preform certain specialized duties.