The Cell

1. The Cell

2. Plant and Animal Cells • Every living thing on Earth is composed of cells. • The term cell was first used by Robert Hooke to describe the chambers found in a piece of cork.

4. Cellsare the smallest living unit of which all organisms are composed • Cells are classified in many ways • One of the most important classification methods is by complexity.

5. Cell Complexity • Simple cells are termed prokaryotic. • Complex cells are termed eukaryotic. • On what basis do we classify cells as simple or complex?

6. Prokaryotic and Eukaryotic Cells • There are two general classes of cells: prokaryotic and eukaryotic. • The evolution of prokaryotic cells preceded that ofeukaryotic cells by 2 billion years.

7. The Cell Timeline

8. The major similarities between the two types of cells (prokaryote and eukaryote) are: • 1.They both have DNA as their genetic material. • 2.They are both membrane bound. • 3.They both have ribosomes . • 4.They have similar basic metabolism . • 5.They are both amazingly diverse in forms.

9. The major and extremely significant differences between prokaryotes and eukaryotes are: • eukaryotes havea nucleus while prokaryotes do not. • eukaryotes havemembrane-bound organelles prokaryotes do not.

10. The DNA of prokaryotes floats freely around the cell; the DNA ofeukaryotes is held within its nucleus. • The organelles of eukaryotes allow them to exhibit much higher levels of intracellulardivision of labor than is possible in prokaryotic cells.

11. Eukaryotic cells are, on average, ten times the size of prokaryotic cells. • The DNA of eukaryotes is much more complex and therefore much more extensive than the DNA of prokaryotes.

13. Prokaryotes have a cell wall composed of peptidoglycan, a single large polymer of amino acids and sugar. • Many typesof eukaryotic cells also have cell walls, but none made of peptidoglycan.

14. The size of cells • prokaryotes can vary in size from 0.25 x 1.2 m to 1.5 x 4 m • average size (E. coli 1 x 3 mm) • eukaryotes are generally larger • – 200 mm in diameter

15. Prokaryotic Cell

18. There are many types of eukaryotic cells but the two most common types are plant and animal cells • A eukaryotic cell may be divided into major zones. • These zones are man made divisions used to facilitate the study of cells.

19. Animal cells are the cells found in animals. You are made up of trillions of animal cells. • There are two basic zones of an animal cell: • Nucleus • Cytoplasm

20. Cytoplasm: • Cytoplasm is the watery-like part of thecell where the action takes place. It is where thenutrients are used. • Most chemical activity occurs here

21. Nucleus: • The nucleus is the brain of the cell. • Itcontrols the cell, and tells it what to do. • The nucleus also contains the DNA which is like a blueprint. Ablueprint is a plan that people use when they build.

38. Organelles • In each zone (nucleus or cytoplasm) of an animal cell (or plant cell) are specialized units called organelles. • Organelles perform specialized functions • Most organelles are common to both plant and animal cells but a few are only found in one or the other type.

39. What organelles are inside the cytoplasm: • Organelles in 'higher' eukaryote cells: • Endoplasmic Reticulum (ER) -This organelle resembles a system of parallel membranes similar to a radiator core.

40. The ER isimportant in protein synthesis. • It is also a transport network for molecules destined for specific locations within the cell. • Helps give the cell its shape

41. There are two types: Smooth ER - Does not have ribosomes on its surface and tends to be more of a tubular network. • Rough ER - has ribosomes on its surface , and tends to be more in 'sheets'. Very common in the cell and easily seen with an electron microscope.

50. Ribosomes –are small spherical structures found in the cell cytoplasm. • These are the most common organelle found in cells.