Mrs. Hobbs introducing Cells BELL RINGER: What do you already know about cells? What types of cells have you heard of? Brainstorm a list of at least 5 questions that you think will be answered as we study cells.

A cell is the smallest unit capable of carrying out life functions. -Scientist everywhere agree, cells are small & carry out life processes. Cell Definition:

THE THEORY OF SPONTANEOUS GENERATION Before Cell Theory, There was… Aristotle added to helped form the theory of spontaneous generation in the 4 th century BC What is this Theory?? The idea that inanimate objects could “become” a living thing… Rope left laying around became snakes Straw produced mice Rotting food became maggots

 Francesco Redi conducted experiments in 1668  Redi developed “controls” in experiments  Louis Pasteur's 1859 experiment is widely seen as having settled the question.  Pasteur developed “germ theory” after viewing germs under a microscope  Developed vaccines Debunking Spontaneous Generation

Who found cells? Hans & Zacharias Janssen (1590’s): credited with the invention of the 1 st compound microscope. Robert Hooke (1665): O bserved a thin slice of cork (dead plant cells) with a microscope. He described what he observed as “little boxes” (cells). Anton Van Leeuwenhoek (1673) : made huge improvements to the microscope. He was the first person to observe LIVING cells. He called them animalcules.

Cell Theory Cell theory is used to explain all aspects of cells 1 All living things are composed of 1 or more cells. 2 Cells are the smallest working units of all living things. 3 Cells come only from existing cells.

 Matthias Schleiden (1838): concluded that all plants are composed of cells  Theodor Schwann (1839): concluded that all animals are composed of cells  Rudolph Virchow (1855): determined that cells come only from other cells Development of Cell Theory

Cell Diversity Cells differ in these three areas 1Size 2Shape 3 Internal Structure

Cell Size The longest cell, giraffe nerve (2m long) to the smallest bacteria mycoplasma Cell size ranges from the largest bird egg (ostrich, 6 inches long, 5 inches wide, 3lbs)

Cell Shape Diversity Cell shapes  Cells differ widely in shape.  Most cells are roughly cuboidal or spherical.  Examples: Rod shaped, sphere shaped, rectangular, spiral shaped

Internal Cell organization Internal cell organization is used to classify cells into two groups. Prokaryote and Eukaryotes

Prokaryotic Cells  Do not have structures (organelles) surrounded by membranes  Few internal structures  One-celled organisms  Have flagella to move themselves  Cells WITHOUT internal organelles are called prokaryotes (bacteria, archaea)

Eukaryotic Cells Cells WITH internal organelles are called Eukaryotes (animals, plants, fungi, protists) Contain organelles surrounded by membranes Some have flagella and some have cilia Can be unicellular or multicellular Most living organisms Plant Animal

All Together Now…

Typical Animal Cell

Typical Plant Cell

Eukaryotes VS Prokaryotes ProkaryotesEukaryotes NucleusNOYES Membrane bound organelles NOYES Size1-10 um10-50 um CytoplasmYES Cell MembraneYES Cell wallSome do RibosomesYES DNACircular Free FloatingChromosomes in nucleus ExamplesBacteria, archeaPlants, animals, fungi & protists um= micrometers 1 meter = 1/1,000,000 micrometers 1 nanometer is 1/1,000,000,000 micrometer

What’s Your Message? Part 2: Cells Organelles Mrs. Hobbs

Function: selectively permeable boundary that determines what moves in or out of the cell Structure: phospholipid bilayer (two layers, tail to tail of phospholipids) Location: Outside of cell Cell membrane

Function: provides structure and support Structure: Rigid wall made up of cellulose Location: Outside of cell membrane (surrounds all of cell) Cell Wall

Structure: Contains 3 parts: 1) nuclear membrane 2) chromatin (loose DNA) 3) nucleolus (produces ribosomes) 4) nuclear pores Function: Function: -storage for all of cell’s DNA (nucleus) -manages cell functions (DNA/RNA) -Produces ribosomes (nucleolus) Location: central part of cell Nucleus

Structure: gelatin-like fluid that lies inside the cell membrane Function: - - contains organic molecules - surrounds the organelles Location: F ills the interior of the cell. Cytoplasm

Structure: consist of two subunits Function: location of protein production Location: Floating throughout cell & on the rough endoplasmic reticulum Ribosomes

Structure: a system of membranous tubules and sacs (like a maze) Function: intercellular highway (a path along which molecules move from one part of the cell to another) Location: surrounding the nucleus Two types: – Rough Endoplasmic Reticulum: produces & distributes proteins – Smooth Endoplasmic Reticulum: Breaks down toxins & makes lipids Endoplasmic Reticulum

Structure: stacked flat sacs (kind of looks like stacked pancakes) Function: receives proteins from the rough ER & distributes them to other organelles or out of the cell (receiving, packaging, & shipping) Location: Near rough ER Golgi Apparatus

Structure: folded membrane within an outer membrane – inner membrane is called cristae Function: converts energy stored in food (glucose) into usable energy (ATP) – cellular respiration Location: several throughout cells Mitochondria

Structure: spherical organelles that contain enzymes Function: - breaks down: - food particles - invading objects - worn out cell parts Location: Several throughout cell Lysosomes

Structure: composed of nine sets of triplet microtubules arranged in a ring – Exist in pairs Function: centrioles play a major role in cell division (mitosis) Location: usually on one side of the cell, before & during mitosis one on each side. (animal only) Centrioles

Structure: fluid surrounded by a membrane - Very large in plants Function: used for temporary storage of wastes, nutrients, & water Location: In plants it is the largest internal structure. In animal cells they are very small depending on cell there could be 0- several. Vacuole

Structure: stacked sacs (thylakoids) that contain chlorophyll Function: photosynthesis (conversion of light energy to chemical energy stored in the bonds of glucose) Location: Cytoplasm of a plant cell, in cell wall of some archea and bacteria Chloroplast

Structure: -Flagellum are long structures made from the cells microtubules -Pili long & narrow made of proteins Function: -Flagellum: for locomotion -For surface attachment/DNA transfer Location: -Located on outer surface of cells Pili & Flagellum (prokaryotes) (Eukaryotes)