HISTORY AND TYPES OF CELLS

Cells Unit

LEVELS OF ORGANIZATION Biome Ecosystem Community Population Organism Organ System Organs Tissue Cells Organelle Molecules

Discuss in Ecology

We will focus on these areas

Properties of Life1. Cellular Organization2. Metabolism3. Homeostasis4. Growth & Development5. Reproduction/Heredity6. Responsiveness/Interaction7. Evolution

Cells:Organize to form…

Tissues:Collect &

work together to form…

Organs:Work

together to form a structure

that form…

Org

anis

mOrgan Systems:

Work together to perform

major bodily Functions. Work withothers to

create an…

ORGAN SYSTEM A group of organs working together for a

particular function

ORGANS

A defined group of tissues that work together for one purpose

TISSUE

A layer of the same kind of cell

CELL The basic unit of

“living” things.

ORGANELLE = a structure that carries out specific

activities in the cell.

MOLECULES

Groups of atoms; the smallest unit of most chemical compounds

THINK ABOUT IT??? Question: What is a cell? Answer: the most basic unit of life that

can perform all life processes.

SO, WHAT ARE CELLS? Cells are very small. Cells make up all living things (from

bacteria to elephants). They are the building blocks of all things

living.

LOOKING AT CELLS Cells can vary greatly in their size and

shape.

But they are all still very small.

Just how big are cells?

Cell size is limited for a reason.

http://learn.genetics.utah.edu/content/begin/cells/scale/

http://htwins.net/scale2/

Fig. 4-2a, p. 54

This is the business end of a needle.This one’s infested with E. coli.

200µm = 0.2mm

Bacteria

Finger width= 16mm

Fig. 4-2b, p. 54

40µm = 0.04mm

Fig. 4-2c, p. 54

1µm = 0.001mm

HOW DO WE KNOW THEY ARE THERE? Hooke Leeuwenhoek Virchow Schleiden

WHO CAME UP WITH THE NAME, CELL Robert Hooke in 1655. Looked at oak cork through a magnifying

glass. Thought the compartments looked like the

rooms monks lived in…cells.

Fig. 4-3b, p. 55

oil lamp water flask

specimen

focusing knob

WHO SAW THE FIRST LIVE CELLS Anton van Leeuwenhoek (1660’s)

Looked at all kinds of stuff through the first “microscope”.

Called what he saw “animalicules”, which would later be discovered to be bacteria.

OTHERS Schleiden (1838)… Discovered cells in

plants. Virchow (1858)… Was the first to

discover cellular division.

HISTORY OF THE CELL, THE TOOL OF THE TRADE Microscope observations of

organisms led to the discovery of the basic characteristics common to all living things.

Scientists first discovered cells in the 1600s using crude microscopes.

There has been many versions, the most recent being very sophisticated electron scanning microscopes.

THE DISCOVERY OF CELLS LED TO THE…CELL THEORY…WRITE THIS DOWN IN YOUR NOTES.

CELL THEORY: 1. All living things are made up of one or

more cells.This is universal. All living things are made of

cells. 2. Cells are the basic units of structure and

function in organisms. Just like amino acids are the basic unit of

proteins, cells are the basic unit of life. 3. All cells arise from other cells.

EXPLORING CELLS If cells are so small,

how do we see them?We use microscopes.

CELL TYPES Cells come in a variety of

shapes and sizes.Some are very, very tiny like

bacteriaSome are relatively large like

the amoeba

SIMILARITIES All cells share 4 common features: Copy off the

board.

1. The cell membrane is the outer layer that covers a cell’s surface and acts as a barrier between the outside environment and the inside of the cell.

2. The cytoplasm is the region of the cell within the cell membrane. The cytoplasm includes the fluid inside the cell called the cytosol.

3. A ribosome is a cellular organ that makes proteins.

4. The DNA of a cell provides instructions for making proteins, regulates cellular activities, and enables cells to reproduce.

CELLS CAN BE DIVIDED INTO TWO MAJOR GROUPS

Prokaryotes Eukaryotes

MAJOR DIFFERENCE

Prokaryotes Eukaryotes

No nucleus Nucleus

WHAT’S A NUCLEUS? A large membrane-enclosed structure

that contains the cell’s genetic information (DNA)

Controls many of the cell’s activities

PROKARYOTES Quick definition: Genetic material (DNA)

is NOT contained in a nucleus More info: Generally smaller and less

complicated Examples include bacteria Are prokaryotes still living if they are

less complicated and microscopic? How do you know this?

PROKARYOTES

ANTHRAX, STAPHYLOCOCCI, C. DIFFICILE Gram positive organisms have a cell

wall that allows them to be stained to see.

E. COLI & MENINGOCOCCUS Some bacteria don’t have a cell wall but

they can be stained with a different stain.

TESTING TOGETHER When you get sick a lab can run a test

to see if you have an infection and what kind of infection you have.

PARTS OF A PROKARYOTE

A

B

CD

E

F

Click to animate the image.

EUKARYOTES Quick definition: cells that store DNA in

a nucleus More info: inside these cells, parts are

separated from the rest of the cell by membranes

Examples: plants, animals, fungi, amoeba

HOW DO YOU KNOW? Look for a nucleus!

Bacterial cell Animal CellVery basic Complex

COMPARING PROKARYOTIC AND EUKARYOTIC CELLS

COMPARING PROKARYOTES AND EUKARYOTES

100x bigger!

2 billion years older!

More complex

PROKARYOTE OR EUKARYOTE?

Read each example and decide if it is a prokaryote or a eukaryote.

1. You scrape the inside of your cheek and make a slide of the cells that come off.

2. In an amoeba cell, there are many complex cell parts and a membrane wrapped around the DNA.

3. A bacteria cell has a clump of DNA that looks like a pile of spaghetti.

ANSWERS 1. Eukaryote 2. Eukaryote 3. Prokaryote

PROKARYOTIC CELLEUKARYOTIC CELL

CLOSURE… What did you learn today?

1/31/13Objective Label common parts of an

animal cell and describe their functions

Warm-Up What is the major difference

between a eukaryotic cell and a prokaryotic cell?

Part II: Cell Organelle.

TYPICAL PROKARYOTIC CELL

TYPICAL PROKARYOTIC CELL

Cell wall

TYPICAL PROKARYOTIC CELL

Cell membrane

TYPICAL PROKARYOTIC CELL

DNA

TYPICAL PROKARYOTIC CELL

cytoplasm

TYPICAL PROKARYOTIC CELL

ribosome

TYPICAL PROKARYOTIC CELL

flagella

BUT WHAT DO THE PARTS DO?

CELL MEMBRANE Controls what moves in and out of a cell

REGULATOR!

CELL WALL Protects the cell and gives it shape

CYTOPLASM A jellylike material that fills the cell

DNA Instructions to run the cell. The “brain”.

FLAGELLA Helps the cell move (one direction only)

RIBOSOMES Follows instructions to make proteins

ACTIVITY 1: FOLDABLE