Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Cells “The Building Blocks of Life”
Document related concepts
Transcript
Cells “The Building Blocks of Life” What is a Cell? • The structural and functional units of all living organisms. • Living matter enclosed by a barrier that separates it from the exterior environment. • What is a theory? – A set of statements or principles devised to explain a group of facts or phenomena – Based on limited information or knowledge – Verified or falsified through experimentation History of Cell Theory • Robert Hooke - 1665 – Used microscope to study cross-sections of cork which he called “cells”. • Anton van Leeuwenhoek 1674 – Used a simple microscope to describe tiny cells and bacteria • Theodor Schwann - 1839 – Concludes that all animals are made of cells Cell Theory 1) All living things are composed of cells 2) Cells are the basic units of structure and function in living things 3) All cells come from pre-existing cells Exceptions: Viruses - Not composed of cells - Cannot survive without a host More about cells… • Cells fall into two categories – Eukaryotes – Plants, animals, fungi • Cells that contain organized nuclei (nucleus) – Prokaryotes - Bacteria • Cells that contain a non-organized nuclei (nucleus) Nuclues • Nucleus is a large membrane-enclosed structure that contains the cell’s genetic material (DNA) • The Nucleus controls most of the cell’s activities!!! • DNA is like the instructions for your cell
