Prokaryote and Eukaryote
Prokaryote ? is the first type of cell to evolve, it has not
internal organelle structures. It has DNA and cytoplasm and most
likely single celled.
Eukaryote ? is more evolved and complex than its predecessor,
it has internal structures (organelles) the largest being the nucleus where
DNA is held. They can be single cell or multi-cellular organisms.
Cell Wall (only in plants)
Cells have to be limited in size by natural laws. It must be
large enough to hold the essential components and small enough to accommodate
nutrients received and disposed.
Large cells have less surface volume relative to its size than small
So the bigger the cell doesnít mean more effective. The smaller
cells can be serviced better by the cytoplasm.
Computer chip technology is a parallel to this natural manifestation.
PLANT AND ANIMAL CELLS, range from 10 micrometers to 100 micrometers
Prokaryotic cells are small and structurally simple
Coiled DNA (Nucleoid Region)
No membrane around nucleoid region
Assemble amino acids into polypeptides
Polymers make protiens.
Bacterial Cell Wall
Eukaryotic cells have functional compartments
The Cell Theory
When Scheiden and Schwann proposed the cell theory in 1838,
cell biology research was forever
changed. The cell theory states that:
1.All life forms are made from one or
2.Cells only arise from pre-existing
3.The cell is the smallest form of life.
Cells Chapter 8
Study of Cells
Microscopes ? magnify things not visible with human eyesight alone.
Anton Van Leeuwenhoek , used a single lens to view cells in
Robert Hooke, used a crude compound microscope to view a cork and seen
honey comb shapes in 1665. He coined the term cells since they reminded
him of the small box cells Monks lived in.
Schleiden and Schwann in the 1830ís view organisms underneath microscopes
and verified that all living things are made of cells.
Compound Microscope ? has a series of lenses that magnifies the object
Electron Microscope ? electrons are aimed in a beam through a
magnetic field to focus them then, through or over a specimen in a vacuum,
and finally onto a screen where it forms a image.