Post on 24-Jan-2022
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