Transcript The Cell
Chapter 1 Cells: The Basic Units of Life Levels of Organization 1.) Cells – smallest living thing 2.) Tissues – many cells working together 3.) Organ – many tissues working together (stomach, heart, lungs, skin) 4.) Organ systems – many organs working together (nervous & digestive system) 5.) Organism – many organ systems 6.) Population- same organisms living in same area 7.) Community- two or more different populations. 8.) Ecosystem- a community & all the nonliving things that affect it. • Terrestrial • Aquatic Vocabulary • Organism-anything that can live on its own. • Unicellular-a single cell living on its own (ex. bacteria) • Multicellular- many cells living as a group of cells (ex. plants & animals) Discovery of Cells Robert Hooke • Hooke was the first to discover cells in 1665 by looking at a piece of cork. • The invention of the microscope was necessary and lead to the discovery of cells because they are too small to see with the naked eye. Image of Cork Cells Discovery of Cells Anton von Leeuwenhoek • Dutch merchant • He looked at: pond scum, blood, & yeast in 1673. • He saw small “animals” in pond scum and called them “animalcules” Other Facts: – Made own microscope – First to see bacteria – Discovered yeast is unicellular Cell Theory The three people to discover the cell theory are: Matthias Schleiden Theodor Schwann Rudolf Virchow 3 Parts of the Cell Theory 1. All organisms are composed of one or more cells. 2. The cell is the basic unit of life in all living things. 3. All cells come from existing cells. Two Types of Cell Prokaryotic Cells Eukaryotic Cells No Nucleus Nucleus No membrane-covered organelles Membrane-covered organelles Circular DNA Linear DNA Example: Bacteria Example: All cells other than bacteria Eukaryotic Cell Prokaryotic Cell Parts of a Cell Animal Cell Animal Cell Plant Cell Plant Cell Organelles • Structures in the cell that perform specific functions within the cell Cell Membrane • Protective layer that surrounds all cells • Separates cells from their environment • Controls materials going into & out of the cell Cytoplasm • Jelly-like fluid in the cell • Holds the organelles in place Cytoskeleton • Web of proteins in the cytoplasm • Maintains structure of cell Smooth Endoplasmic Reticulum • A system of folded membrane that is used for lipid (fat) transport. • There are no ribosomes Ribosomes • • • • Smallest & most numerous organelles Some float freely in cytoplasm Some are attached to the Rough ER Their function is to make proteins out of amino acids Rough Endoplasmic Reticulum • A system of folded membranes which are covered in ribosomes • Used for protein transport Golgi Complex • Packages lipids and proteins in small bubbles which may be used somewhere else inside or outside of the cell • Looks like smooth ER Vesicle • Bubbles that form from the Golgi complex’s membrane • Surrounds material to be moved into or out of a cell Mitochondria • Power house of the cell that breaks down sugar to produce energy in the form of ATP (Adenosine triphosphate) • * All The Power Vacuoles • Stores water • Much larger in plant cells than in animal cells Lysosome • Contain digestive enzymes • Responsible for digestion and getting rid of waste Nucleus • Controls the cell • Contains DNA (deoxyribonucleic acid) which is the genetic material that carries information • Surrounded by a nuclear membrane that contains pores Nucleolus • Dark area in the nucleus • Produces ribosomes DNA • Inside the nucleus • Contain genes in two forms: – Chromatin: (thread-like substance) that DNA is typically shaped like – Chromosomes: (X-shaped substance) that DNA takes the form of when the cell is dividing Chromatin Chromosomes Cell Wall • Outermost layer of PLANT cells (as well as fungi and some prokaryotes) • Gives shape & support to cells • Contains cellulose Chloroplasts • Green organelle in plant cells only • Responsible for photosynthesis – process by which plants use sunlight, carbon dioxide, & water to make sugar & oxygen • Contain chlorophyll Cells Alive!