Determining the Basis of Life Unit 2 Chapter 6 Lesson 2

Lesson Introduction  What is the difference between prokaryotic and eukaryotic cells?  Why is a virus structure not truly a cell?  Differentiate between a cell membrane and a cell wall.  Why is cell specialization important to human, animal, and plant life?

Structural Basis of Life  What are cells? –Structural unit that makes up all living things  Many variations that all appear similar but have different cell structure –General pattern of organization and relationship in a cell

Bacteria cell Plasma Membrane Cytoplasm Cell wall DNA Flagella Pili Ribosomes

Virus Structure Head Tail sheath Tail fiber DNA

Prokaryotic Cell (Single Celled Organisms) Cell Membrane DNA Ribosomes Cell Wall

Cell Membrane Eukaryotic Cell (Animal) Lysosome Vacuole Golgi Body Nucleus Ribosome Rough ER* Mitochondria Smooth ER* Chromatin *ER = Endoplasmic Reticulum Nucleolus Cytoplasm Nuclear Membrane

Eukaryotic Cell (Plant) Golgi Body Chloroplast Vacuole Nucleus Ribosome Rough ER* Mitochondria Smooth ER* Chromatin *ER = Endoplasmic Reticulum Nucleolus Cytoplasm Nuclear Membrane Cell Wall

Cell Membranes  What is a cell membrane? –Surrounds the animal cells –Gives shape and flexibility to cell –Controls movement of material in and out of the cell – very selective  Plants have a cell wall that provides structure to the plant and protects the cell  Animals don’t need structure from cell walls- they have skeletons to provide structure Video Clip

Nucleus  Near the center of the cell  Surrounded by the nuclear membrane –Gives shape and flexibility to nucleus –Controls movement of material in and out of the nucleus – very selective  Command center for the cell  Stores genetic information on chromatin –Structure found in the nucleus that carries genetic information on DNA  Holds the nucleolus –Synthesizes ribosomes –Holds the cells RNA Video Clip

Cell Parts  Cytoplasm –Thick, semi-fluid (like hair gel) material that surrounds the nucleus. –Holds organelles in place –Provides protection to the nucleus –Helps to rid the cell of waste.  Microfilament –Help shape and support the cell –Provide movement  Microtubules –Also help provide shape and support –Main component in cilia and flagella –Move liquids across cell membrane Video Clip 1 Video Clip 2 Video Clip 3 Video Clip 4

Other organelles…  Centrioles –Move chromosomes when the cells divide –Produce microtubules  Cilium –Short hairlike extensions made of microtubules found on a cell’s surface –Function as a group (up to 50,000) to move the cell  Flagella –Long whip like structure that is made of microtubules –Found singly or in pairs like a tail –Moves the cell

Cellular Organisms  What are multicellular organisms? –Any organism made of two or more cells  What are unicellular organisms? –Any organism made up of only one cell  What is cell specialization? –The development of a cell for a particular life function –Needed for multicellular organisms to have separate organs and tissues Video Clip 1 Video Clip 2

Cell Specialization  Tissues –Group of cells that are alike in structure and activity  Organs –Collection of tissues that work together to perform a specific function  Organ systems –Several organs that work together to perform an activity  Organism –Group of organ systems that form one body