Bellringer 10/07

• What do you think this cartoon is about?

• What do you think is happening?

The Story

of Cells

What are we made of?

What are cells?The Building Blocks of Life

The cell is the smallest structural unit capable of performing life

functions.

Cell Trivia

• The average human being is composed of around 100 Trillion individual cells!!!

• It would take as many as 50 cells to cover the area of a dot on the letter “i”

Discovery of Cells

1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork (bark of tree)– He described the cells as tiny boxes or a honeycomb– He thought that cells only existed in plants and fungi

The Microscope!

1673- Anton von Leuwenhoek, invented the microscope and observed pond scum and discovered single celled organisms

•He called them “animalcules”He called them “animalcules”•He also observed blood cells from fish, birds, frogs, dogs, He also observed blood cells from fish, birds, frogs, dogs, and humansand humans•Therefore, it was known that cells are found in animals as Therefore, it was known that cells are found in animals as well as plantswell as plants

More history…

• 1838- German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells

• 1839- German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all animal tissues are composed of cells.

• 1858- Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must start from preexisting cells (BIOGENESIS)

Where does life come from?

• Old Theory - Spontaneous Generation

• Life spontaneously happens:

Life comes from non-life

• Examples: – Mice from cloth sacks and grains.– Maggots from rotting meat.

REALLY?

Where does life come from?• Much doubt existed around Spontaneous Generation• Conclusively disproved by Louis Pasteur

+

=?

Ummm, I don’t think

so!!!

Where does life come from?• 1858- Rudolf Virchow, German physician, after extensive

study of cellular pathology, concluded that cells must arise from preexisting cells.

Biogenesis – Life can only be formed from existing life.

The Compound Light Microscope

• Lenses• Light• We’ll be

using it!!!• Up to

x1500

Our Microscope…

The Electron Microscope• Biggest magnification (X 2,000,000)• 2 types (SEM and TEM)

The Cell Theory

1. All organisms are composed of one or more cells.

2. The Cell is the smallest working unit of living things.

3. All cells come from pre-existing cells through cell division.

Basic Parts of a Cell

All cells have certain structures in common.

1. Nucleus- contains genetic material (DNA)2. Cytoplasm – a semifluid matrix (like the

eggwhite of an egg)3. Plasma membrane – a phospholipid

bilayer- like the shell of an egg4. Organelles- specialized structures in the

cytoplasm

1st Look at THE CELL!!!

Examples of Cells

Amoeba

Plants

Red Blood Cell

Nerve Cell

Bacteria

Two Types of Cells

•Prokaryotic •Eukeryotic

REMEMBER US

Prokaryotic Cells

• Do not have a membrane-bound nucleus or organelles

• Few internal structures (organelles)

• Usually one-celled organisms like bacterias

Eukaryotic Cells• They do contain a membrane-bound nucleus and organelles and are more complex.

• May be unicellular or multicellular

Plant Animal

“Typical” Animal Cell

“Typical” Plant Cell

BELLRINGER 10/151. WHAT ORGANELLE

PRODUCES ENERGY IN THE CELL?

2. WHAT ORGANELLE CONTAINS CHROLOPHYL?

3. WHAT ORGANELLE PACKAGES SUBSTANCES IN THE CELL?

4. WHAT ORGANELLE CONTAINS RIBOSOMES?

Organelles

Surrounding the Cell

Cell Membrane (Animal and Plant)

• Outer membrane boundary of cell that controls movement in and out of the cell

• Double layer with pores (holes)

Cell Wall (Plant)• Most commonly found in plant cells & bacteria• Supports & protects cells• Rigid (tough), outside the cell membrane• Contains cellulose

Inside the Cell

Nucleus (Plant and Animal) • Directs cell

activities- the brain of the cell

• Separated from cytoplasm by nuclear membrane (envelope)

• Contains chromatin (DNA)

Endoplasmic Reticulum (Animal and Plant)

• Highly folded membrane that produces, transports proteins

• Smooth type: lacks ribosomes

• Rough type: ribosomes embedded in surface

Ribosomes (Plant and Animal)

• Each cell contains thousands

• Make proteins• Found on

ribosomes, nuclear envelope & floating throughout the cell

Mitochondria (Plant and Animal)

• Produces energy (ATP) through chemical reactions

• Highly folded membranes

• Has its own DNA

Golgi Apparatus (Plant and Animal)

• Protein 'packaging plant'

• Move materials within the cell

• Move materials out of the cell

• Flat tube system

Lysosomes (Animal)• Digestive factory and breaks down waste (proteins, fats,

and carbohydrates) with enzymes• Transports undigested material to cell membrane for

removal• Cell breaks down if lysosome explodes

Vacuoles (Plant and Animal)

• Membrane-bound sacs for storage, digestion, and waste removal

• Contains water • Help plants maintain

shape• Many small in

animal, 1 big one in plant cells

Chloroplast (Plant)

• Found in plant cells• Contains chlorophyll

(gives color green to plants)

• Where photosynthesis takes place (plants make own food from light energy)

Centrioles (Animal)

• Only in animal cells • Play role in cell

division (mitosis)• Organize

microtubules in bundles

• Make up the centrosome (near the nucleus)

Cillia and Flagella (Animal and Prokaryotes)

• Mostly in unicellular organisms (animal only) and bacteria • For movement and fluid transport• Cilia = many little hairs on the cell body• Flagella = few/one tail(s)

Cytoskeleton (Plant and Animal)

• Network of rods (microtubule) and filaments (microfilaments)

• Gives cell support, structure and shape• Involved in cell division (mitosis) and transport

The BIG Picture again!QUIZ TIME!!!!

USE THE FOLLOWING SLIDES and your NOTES to answer the following…

1. Identify the cells that follow. 2. Identify 3 organelles that exist in BOTH plant and animal

cells.3. Identify 2 organelles that exist ONLY in an animal cell.4. Identify 2 organelles that exist ONLY in a plant cell.5. What is the difference between cilia and flagella?6. Identify 2 differences between prokaryotes and eukaryotes.

QUIZ TIME

Let’s compare…