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 Ribosomes Pili Flagella

Virus Structure Head DNA Tail sheath Tail fiber

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

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

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

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 Microfilament Microtubules 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 Cilium Flagella 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 Organs Organ systems Organism 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