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 TerminologyProkaryoticEukaryoticNucleoid Membrane-boundPlastidCytoplasmProtista

Discovery of CellsCame with the invention of the microscopeKey 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 TheoryThree 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 CyanobacteriaConsidered the simplest cellular organism

Prokaryotic Cell StructureDistinguishing 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 fungiDivided into three regions Outer membrane Nucleus Cytoplasm

occupies volume between nucleus and outer membrane

Eukaryotic Cell StructureDistinguishing 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-ShareUse 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-ShareDraw 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