Cell Structure and Function
Prokaryote vs. Eukaryote Prokaryotic cells: Pro- Before, Karyot- Center or Nucleus Very Basic Cells with no membrane bound organelles. DNA is not separate from the rest of the Cell (no nucleus) Bacterial cells
Prokaryote vs. Eukaryote Eukaryotic cells: Eu True, Karyot Nucleus Complex unicellular organisms and all multicellular organisms. Cells that contain membrane bound organelles. The DNA is separated from the rest of the cell by a nucleus. Much larger than Prokaryotic cells.
Why are cells so small? As the size of a cell increases, its volume increases by the cube of the side, whereas the surface area only increases by the square of the side. Therefore, as the cell size increases the surface area to volume ratio decreases. There is less surface area per unit of volume in a larger cube. (More total surface area total but increase in surface area
Importance of Surface Area Many substances have to be transported in or out of the cell and reach all parts of the cell. For example, food molecules and oxygen have to be transported into the cell. Waste materials such as carbon dioxide have to be removed from the cell. The cell needs to have an adequate amount of surface area per unit of volume to support the needs of the cell.
The Cell: Structure and Function of Eukaryotic Cells
Organelle Little organ of cells A structure inside a cell that has a specialized function. They are the machinery of a Cell Example: Nucleus, chloroplasts, etc.
Found in all cells Function: Protection Allows something to pass through it, both in and out. Communicationreceives and responds to outside signals Semi-permeable: Only certain molecules can pass through The Cell Membrane
Cell walls Made of cellulose in Plants Made of Chitin in Fungus Bacteria and Some Protists have cell Walls Provide support and structure
Cytoplasm Fluid that surrounds the organelles and fills the cell Function: Provides a medium for chemical reactions to occur
Nucleus The Cell s command center. Contains the DNA of the cell Function: Control the activity of the cell and stores genetic information. DNA/Genes: Provide instructions for the production of proteins. (One gene provides the instructions for making 1 protein)
Found in the Nucleus Chromatin: Structure of DNA found in the nucleus. Slightly coiled Chromosome: tightly coiled DNA. Forms right before cell division DNA/Genes: The genetic message used to make proteins. Chromatin
Also Found in the Nucleus Nucleolus: Where the ribosomes are made. Stores RNA to manufacture mrna mrna- Messenger RNA. Copies and carries the instructions for making protein from the DNA to the Ribosome.
Ribosomes Reads the mrna and makes the proteins One of the few organelles also found in Prokaryotic Cells. Not a membrane bound organelle.
The Powerhouse of the cell. Respiration occurs here: Biomolecules (esp. Glucose) broken down into CO 2 and water to produce energy Present in all Eukaryotic Cells Mitochondria
Chloroplasts Found in Plant Cells and some Protists The site where photosynthesis occurs: Producing sugar from CO 2, Water, and Sunlight. Contain Green Pigment called Chlorophyll Two parts: Stroma and Thylakoids
Endoplasmic Reticulum Rough ER: Ribosomes on the surface. -transports Proteins Smooth ER: Produces and Transports Lipids
Golgi Bodies Flattened membrane sacs Packages, modifies, and transports the protein for specific uses.
Vacuole Vacuole: Storage in the cell. Plants cells have Large Water Vacuoles. Animal Cells are smaller Vesicle: Small Vacuole that contains Proteins. Found in both Plants and Animals Vacuole
Lysosomes Suicide Sacs Used to digest food and old parts. When the cell gets worn out the lysosymes will burst and digest the whole cell. The process is called apoptosis.
Cytoskeleton Function: Maintains cell shape and directs traffic within the cell. Done By Microtubules Microskeleton
Movement: Microtubules Cilia: Short and numerous hair-like structures that move a cell Ex. Paramecium Flagella: A long threadlike structure used to propel the cell Ex. Dinoflagellates, Euglena
Level of organization within an organism 1. Cell: The Basic Unit of Life 2. Tissue: A collection of cells that work together for a common purpose. 3. Organ: Two or more tissues acting together. (Lung) 4. Organ System: A group of organs that work together in a system. (Respiratory System)
List Three differences between Plant and Animal Cells: 1. Plant Cells have a cell wall, animal cells do not 2. Animal Cells lack a chloroplast 3. Plant cells have a large vacuole
Label Me and describe my function 1. 2. 3. 4. 5. 6. 7. 8. Cell mem. Nucleolus Nucleus Mitochondria E R Golgi Vacuole Vesicle
Applying the Concepts Some cells have a large number of mitochondria. What type of cell might it be and why? A cell with high energy needs since mitochondria provide usable energy for the cell. Example: Muscle cells