The Discovery of Cells

All living things are made of cells!

Could be one

Could be many

unicellular

multicellular

The Discovery of Cells

Robert Hooke (1665)

Looked through a very simple microscope at a thin slice of cork

Saw “little boxes” and named them cells

The Discovery of Cells

Anton van Leeuwenhoek (1675)

Discovered tiny creatures swimming around in pond water using a simple microscope

Named them animalcules

Life in Water The Hidden Life of Pond Water

It took more than 150 years for scientists to develop microscopes that would allow them to really study cells.

The Discovery of Cells

Matthias Schleidan (1838)

Found that all parts of a plant are made of cells

The Discovery of Cells

Theodor Schwann (1839)

Found that animals were made of cells

Determined that all the tissues of the body form from a single cell.

The Discovery of Cells

Rudolph Virchow (1858)

Found that new cells come from the division of existing cells

The Discovery of Cells

Cell Theory

All living things are made of one or more cells.

Cells are the basic units of structure and function in organisms.

All cells arise from existing cells.

The Two Types of Cells

Two types of cells

Prokaryotes

Eukaryotes

Prokaryotic Cells

Prokaryote – a unicellular organism that:

has one loop of DNA floating in the cytoplasm

does not have membrane-bound organelles

Have a cell wall that protects and provides structure and support

SOME have a capsule that allow them to stick to things and avoid being broken down.

Prokaryotes

Very large and diverse group of cells

Includes Eubacteria and Archaebacteria

Prokaryotic Cell

Capsule Cell Wall

Cell Membrane

Cytoplasm

Ribosome

DNA

Eukaryotic Cells

Eukaryote – an organism made of cell(s) with:

DNA in a nucleus

DNA arranged into linear chromosomes

Membrane-bound organelles

Eukaryotes

Eukaryotes can be unicellular or multicellular

Includes protists, fungi, plants, and animals

Eukaryotic Cell

NucleusDNA

Cytoplasm

Cell Membrane

Organelles

Ribosomes

Eukaryotes

Eukaryotic cells are compartmentalized which allows them to be:

Larger than prokaryotes

Allows them to carryout specialized processes (differentiation)

o muscle cells, blood cells, nerve cells

Eukaryotes

Organelle – a structure that carries out a specific activity inside the cell

Membrane-bound organelles are surrounded by a membrane just like the cell membrane

Nucleus – the structure that stores and protects the DNA

Two types of cells

Prokaryotes

Eukaryotes

What structures are common to ALL cells?

Cell Membrane

Cytoplasm

Ribosomes

DNA

What structures are common to ALL cells?

Cell Membrane A barrier between

the environment and the inside of the cell

What structures are common to ALL cells? Cytoplasm

the fluid (cytosol) and all the structures inside the cell

What structures are common to ALL cells? Ribosome cellular structure where proteins are made

What structures are common to ALL cells? DNA genetic material that provides the instructions to

make proteins

The shape of a cell is a result of its function.

What is the function of each cell type?

Cells vary in size and shape

Cells vary in shape and size

All the nutrients and waste must pass through the cell membrane!

the larger a cell gets the more nutrients and waste must pass through the membrane

Surface area to Volume ratio