Cells Chapter 4
Discovery of the Cell 1665 Robert Hooke used a microscope to examine a piece of cork. He saw little boxes in the cork and called them cells. 1673 Anton van Leeuwenhoek was the first person to observe living cells. (Cheek cells) 1838 Matthias Schleiden concluded that all plants are made of cells. 1839 Theodor Schwann concluded that all animals are made of cells. 1855 Rudolf Virchow reasoned that cells come only from other cells.
Schleiden, Schwann, and Virchow helped to create what is known as the cell theory: 1. All living things are made of cells. 2. Cells are the basic units of structure and function in living organisms.(meaning anything smaller is not alive) 3. Cells come from other cells.
How do we know cells are alive? 1. They grow and develop 2. They are organized 3. They ARE cells 4. They maintain homeostasis 5. They use energy 6. They reproduce
The Cell (School Building) Cell- The basic unit of function and structure in living things. Cells come in many shapes and sizes.
Cellular Organization Cells are composed of many parts, including: Organelles, which are made of Macromolecules (lipids, carbohydrates, proteins, nucleic acids), which are made of Molecules and smaller compounds, which are made of»atoms (carbon, hydrogen, oxygen, nitrogen, and phosphorous)
Cell Wall (Outer Gate) Strong, rigid wall that protects the cell and gives it shape. Made of cellulose (a carbohydrate) Plants, bacteria, fungi and some protists have Cell Walls.
Cell Membrane (Outside walls, roof, foundation) The outer covering of a cell. Used for protection and support. Made of a phospholipid bilayer Remember, lipids help to repel water. Controls what enters into the cell.
Cytoplasm A gel-like substance found inside the cell. Used to support the organelles. They float around in it
Cytoskeleton Long strands of protein that provide support for the cell. Located within the cytoplasm Acts kind of like scaffolding.
Organelles Structures within a cell with special functions. There are many types of organelles, with different functions!
Nucleus (Main Office) Regulates and controls all the activities within a cell. Contains chromosomes- Thick strands of DNA that do not leave the nucleus. DNA is a nucleic acid
Plastids Plastids store food or pigment. Pigments give plants their color. One type (chloroplast) transfers energy from light to organic compounds known as glucose. Only found in photosynthetic organisms. (plants, some protists, and some bacteria)
Chloroplast (Cafeteria) Green organelle that makes sugar for plants and other photosynthetic organisms. Chloroplast is used in photosynthesis. Contain chlorophyll- Green pigment that captures the sun s light. Plants, plant-like protists and some bacteria contain chloroplast.
Mitochondria (Generator) Rod-shaped organelle that provides energy for the cell. The POWERHOUSE of the cell!
Ribosomes (Students) Are made out of RNA. RNA is a nucleic acid. Ribosomes are tiny organelles that are used to make proteins. Some float throughout the cytoplasm, some are stuck to other organelles.
Vacuoles (Lockers) Organelles that are used for storage. Vacuoles store food, water and waste. Only plant cells have very large vacuoles.
Lysosomes (Custodians) Small round organelles that contain digestive chemicals called enzymes. Enzymes are a type of protein. Used to break down food, waste and dying organelles.
Golgi Body or Golgi Apparatus (mail room) Organelle that is responsible for sorting and packaging materials within the cell. They are stacked, flattened membranes.
Endoplasmic Reticulum (hall ways) A group of folded membranes that extend from the nucleus to the cell membrane. Used to move materials around the cell. Can be rough (with ribosomes attached) or smooth (without ribosomes attached)
Nucleus Chloroplasts and Other Plastids Ribosomes Organelles Mitochondria Golgi body Endoplasmic Reticulum Lysosomes Vacuoles
From Cell to Organism Groups of cells combine to form tissues. Groups of tissue combine to form organs.
From Cell to Organism (Cont) Groups of organs combine to form organ systems. Groups of organ systems combine to form an organism.
Organelles Cells Tissue Organism Organ