CELLS

Videos:

The invention of the microscope Anton von Leuwenhoek, invented the microscope and observed pond scum and discovered single celled organisms

The Compound Light Microscope Lenses Light Up to x1500 bigger

Our Microscope…

Basic Parts of a Cell 1. Nucleus- contains DNA 2. Cytoplasm –jelly like egg white of an egg 3. Plasma membrane/wall – like the shell of egg 4. Organelles- small structures in the cytoplasm

Discovery of Cells English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork (bark of tree)

What are cells? Definition: Basic unit of a living thing

Where do cells come from? Rudolf Virchow, concluded that cells must come from preexisting cells. Biogenesis – Life can only be formed from existing life.

The Cell Theory 1. All organisms are composed of 1 or more cells. 2. Cell is the smallest working unit of living things. 3. All cells come from pre-existing cells through cell division.

Organelle Specialized structure within an Eukaryotic Cell that has its own function.

Prokaryotic Two Types of Cells Eukaryotic

MULTI cellular Multi = Many Definition: Many Cells UNIcellular Uni = one Definition: One Cell

A. Prokaryotic Cells Do not have a membrane-bound nucleus or organelles Few organelles Usually unicellular Ex: Bacteria

B. Eukaryotic Cells Do contain a membrane-bound nucleus and organelles that are more complex. Unicellular or multicellular 1. Plant 2. Animal

Plasma Membrane (Animal and Plant) Outer membrane boundary of cell that controls movement in and out of the cell Double layer with pores (holes)

“Typical” Animal Cell

“Typical” Plant Cell

Cell Wall (Plant/Bacteria) Found in plant cells & bacteria Supports & protects cells Rigid (tough), located outside of the cell membrane

Nucleus (Plant and Animal) Directs cell activities- the brain of the cell Contains DNA

Ribosomes (Plant and Animal) Make proteins Found on ribosomes, nuclear envelope & floating throughout the cell

Endoplasmic Reticulum (Animal and Plant) Flattened sacs and tubes Where communication happens between chemical reactions Smooth type: lacks ribosomes (SER) Rough type: ribosomes on surface (RER)

Golgi Apparatus (Plant and Animal) Protein 'packaging plant' Moves materials within the cell Moves materials out of the cell

Vacuoles (Plant and Animal) Sacs for storage, digestion, and waste removal Contains water Help plants maintain shape Many small in animal, 1 big one in plant cells

Lysosomes (Animal) Digestive factory and breaks down waste (proteins, fats, and carbohydrates) with enzymes

Chloroplast (Plant) Found only in plants Contains chlorophyll (gives color green to plants) Where photosynthesis takes place (plants make own food from light energy)

Mitochondria (Plant and Animal) Produces energy (ATP) through chemical reactions Highly folded membranes Has its own DNA

Cytoskeleton (Plant and Animal) Gives cell support, structure and shape Most of the work of a cell happens here Involved in cell division (mitosis) and transport

Centrioles (Animal) Only in animal cells Play role in cell division (mitosis)

Cillia and Flagella (Animal and Prokaryotic) For movement and fluid transport Cilia = little hairs on the cell body Flagella = few/one tail(s)

GOAL for today Understand how prokaryotic cells, eukaryotic cells differ in complexity and structure Prokaryotes are organisms whose cells lack nuclei. They are usually small and unicellular Eukaryotes are organisms whose cells have nuclei and membrane bound organelles

Prokaryotes No nucleus Circular DNA No membrane bound organelles Have ribosomes (make protein) Have RNA Eukaryotes Nucleus that contains DNA Linear DNA Mitochondria and chlroplast present Have ribomes (make protein) Have RNA