Cell Structure

Bellwork List some characteristics that distinguish a bacterium from a plant.

Objectives List characteristics common to all cells List characteristics that distinguish prokaryotic and eukaryotic cells Describe differences between plant and animal cells

Key Terminology Prokaryotic Eukaryotic Nucleoid Membrane-bound Plastid Cytoplasm Protista

Discovery of Cells Came with the invention of the microscope Key Findings Robert Hooke, 1665  examined cork with an early compound microscope Leeuwenhoek, 1665  examined pond water with a single-lens microscope Scheiden, 1838  concluded all plants made of cells Schwann, 1839  concluded all animals made of cells

Cell Theory Three principles: All living things are made up of cells Cell is the basic unit of structure and function in living things New cells arise from pre-existing cells

Common features in All Cells Outer membrane separates internal from external environment Cytoplasm makes up the cell interior Ribosomes structures on which proteins are made DNA provides instructions for making proteins, regulates cellular activities and allows cells to reproduce

Prokaryotic Cells Bacteria and Cyanobacteria Considered the simplest cellular organism

Prokaryotic Cell Structure Distinguishing characteristics Enclosed in an outer membrane No internal membrane-bound organelles Interior is one continuous compartment No nucleus  DNA found in the nucleoid region Most prokaryotes contain a cell wall  different composition from plant cells No internal support structure  no cytoskeleton  support comes from cell wall

Prokaryotic Cell

Eukaryotic Cells Found in plants, animals, and fungi Divided into three regions Outer membrane Nucleus Cytoplasm  occupies volume between nucleus and outer membrane

Eukaryotic Cell Structure Distinguishing characteristics Interior compartmentalized  membranous and non-membranous organelles  each have specific functions within the cell Nucleus  Membrane-bound organelle that houses the DNA Cell walls limited to certain types  plant cells, some fungi  some protists (ex. paramecium)

Think-Pair-Share Use a Venn diagram to show how Prokaryotic & Eukaryotic cells are alike and how they are different. (at least 2 concepts in each compartment of the diagram) Be ready to share

Eukaryotic Cell Structure (cont.) Further classified into Plant cells Animal cells

Plant Cells have unique features Plastids Photosynthetic  chloroplast is site of photosynthesis Non-photosynthetic  Storage  Ex. Potatoes - starch Ripe fruit - pigments

Plant Cells Have Unique Features Central Vacuole Storage  Holds reserves of organic compounds  stores byproducts that would be toxic to the cell  Stores pigments Growth  Fills with water that pushes cytoplasm against cell wall  If cell wall has capability to loosen, cell will expand

Plant Cells has unique features Cell Wall Protects the cell Maintains shape of cell

Plant Cell

Animal Cells Have Unique Features Lysosomes Where macromolecules are hydrolyzed Breaks down worn out organelles Defective lysosomes cause diseases  Ex. Tay Sachs disease

Animal Cell

Link to Bellwork Describe at least two important features that are different for Bacteria and Plant Cells.

Think-Pair-Share Draw a simple diagram of a Plant Cell and an Animal Cell, showing the key features that distinguish the two types of cell. Be ready to share