Chapter 4.1 - 4.4 PDF

Chapter 4 Section 4.1 – 4.4: Introduction to the Cell  Learning Objectives Today you will learn to: ▪ Describe the key events leading to the development of the cell theory. ▪ Be able to describe the role of the microscope in the discovery of the cell. ▪ Restate t...

Chapter 4 Section 4.1 – 4.4: Introduction to the Cell  Learning Objectives Today you will learn to: ▪ Describe the key events leading to the development of the cell theory. ▪ Be able to describe the role of the microscope in the discovery of the cell. ▪ Restate the tenants of the traditional and modern cell theories. ▪ Compare and contrast characteristics of prokaryotic and eukaryotic cells.  Unit Organizer Cells is about Cell Structure & Function and the two Types that are Prokaryotes Eukaryotes that are divided into Uni- Multi- cellular cellular What is the smallest unit of life? The Cell!!  The Discovery of the Cell ▪ Several scientists work contributed to our understanding of cells. Robert Hooke (1665) ▪ Looked at thin slices of cork and saw tiny empty chambers that he called “cells” after empty cells that monks live in ▪ His early “microscope” only magnified 30x  Leeuwenhoek (1674) ▪ Improved the early microscope designs so much that he saw things no one else had ever seen before ▪ He is accredited with inventing the microscope for improving it so much ▪ His microscope magnified up to 300x ▪ Called the “Father of the Microbiology”  Leeuwenhoek (cont) ▪ Looked at pond water and saw hundreds of tiny living things ▪ Began looking at other things and found microscopic life everywhere (bacteria, yeast, blood, etc) Other Contributions to the Cell Theory ▪ 1838 - Matthias Schleiden ▪ Concluded all plants were made of cells ▪ 1839 - Theodor Schwann ▪ Concluded all animals were made of cells ▪ 1855 - Rudolph Virchow ▪ Concluded all new cells come from preexisting cells These scientists collaborated with others to make the cell theory…  The Traditional Cell Theory 1. Living things are composed of one or more cells and that cells come from other cells by the process of cell reproduction. 2. Cells are the basic unit of structure and function in living things. 3. Cells contain specialized structures to perform functions necessary for life. ▪ After continued research this has been expanded to…..  The Modern Cell Theory 1. Energy flow (metabolism and biochemistry) occurs within cells. 2. Cells contain hereditary information (DNA) that is passed from cell to cell during cell division. 3. All cells are basically the same in chemical composition of similar species. ▪ Important Note: You will need to be able to recognize the tenants of each cell theory for your test and be able to pick them out from among other true statements about cells.  The Cell Theory ▪ The invention of the microscope ALLOWED the Cell Theory to come about!!!  How big are cells? ▪ 1 meter = 1000 mm = 1000 µm ▪ So 1 µm = 1/1000000th of a meter ▪ Organelles within cells are even smaller, measured in nm 1 µm = 1000 nm  Prokaryotes and Eukaryotes Cells are divided into 2 main cell types: 1. Prokaryotic cells 2. Eukaryotic cells All cells are surrounded by a cell membrane and have DNA. Prokaryotes ▪ Smaller, simpler ▪ Most primitive ▪ No nucleus ▪ Evolved before nuclei evolved ▪ Some internal membranes, but no membrane bound organelles  Prokaryotes e_coli e-coli Examples: ▪ Bacteria ▪ Staphylococcus ▪ Escherichia coli (E. coli) ▪ Streptococcus 199812-026-Staph-Bacteria Strep PHIL_3184_lores  Eukaryotes ▪ Larger ▪ More advanced ▪ Have a nucleus ▪ Often highly specialized ▪ Many internal membranes around organelles  Eukaryotes ▪ All cells in multi- cellular organisms are eukaryotic as well as some single celled organisms. ▪ Eukaryotes arose from prokaryotes about 1 billion years ago  79_611 Eukaryotes Examples: ▪ Protists, Fungi, Animals, & Plants 3571-fungi manatee_2356_rockne_knuth  Origin of Eukaryotic Cells ▪The Endosymbiotic Theory ▪The endosymbiotic theory states that eukaryotic cells arose from living communities formed by prokaryotic organisms.  Prokaryote Eukaryote Evolution Endoplasmic Nucleus reticulum Engulfing of oxygen- using prokaryote Ancestor of eukaryotic cells (host cell) Mitochondrion Engulfing of photosynthetic prokaryote At least one cell Nonphotosynthetic Mitochondrion eukaryote Chloroplast Figure 4.15 Photosynthetic eukaryote © 2015 Pearson Education, Inc.  What do Prokaryotes and Eukaryotes HAVE in common?? ▪ Cell membrane ▪ Cytoplasm- liquid or jelly like substance ▪ DNA ▪ Ribosomes ▪ Both carry out all living activities  What is an Organelle? ▪ Organelle = Structure of a cell that act as a specialized organ ▪ Organelle literally means “little organs”  Nucleus ▪ A large membrane surrounded structure that contains a cell’s genetic material in the form of DNA. What are the differences between Prokaryotic and Eukaryotic Cells?  Prokaryotes ▪ Cells that DO NOT contain nuclei or organelles. ▪ Bacteria  Eukaryotes ▪ Cells that DO contain nuclei and organelles. ▪ Plants, animals, fungi and protists.  Useful Hint: Eu Do Pro No Eukaryotes Do have a nucleus Prokaryotics Do Not have a nucleus  Review 1. Describe the key events leading to the development of the cell theory. 2. Be able to describe the role of the microscope in the discovery of the cell. 3. Restate the tenants of the traditional and modern cell theories. 4. Compare and contrast characteristics of prokaryotic and eukaryotic cells.