1. History of the Cell Theory
1665, Robert Hooke made a simple microscope
Cell-the basic structural and functional unit of all living organisms
Late 1600’s Anton Van Leeuwenhoek designed his own microscope

2. The Cell Theory
Fundamental idea of modern biology that includes these three principles:
All living organisms are composed of one or more cells
Cells are the basic unit of structure and organization of all living organisms
Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells

3. Basic Cell Facts Cells exists in various shapes and sizes
Cells differ based on their function they perform for the organism
All cells have at least one physical trait in common - the plasma membrane

4. Categories of Cells Prokaryotic Cells
Cells without specialized internal structures
Unicellular
Similar to the first organisms on Earth

5. 2. Eukaryotic Cells More complex than prokaryotic cells
Contain a structure called a nucleus (a distinct central organelle that contains the cell’s genetic material in the form of DNA) and other organelles (specialized structures that carry out specific cell functions)
Generally one to one hundred times larger than prokaryotic cells

6. 7.2 The Plasma Membrane
Main idea: The plasma membrane help’s to maintain a cell’s homeostasis
Objectives:
Describe how a cell’s plasma membrane functions (in left column of Cornell notes)
Identify the roles of proteins, carbohydrates, and cholesterol in the plasma membrane
(in left column of Cornell notes)
Review Vocabulary
Ion: an atom or group of atoms with a positive or negative electric charge

7. Plasma Membrane Found in all cells
Primarily responsible for homeostasis in the cell
A thin, flexible boundary between a cell and its environment that allows nutrients into the cell and allows waste and other products to leave the cell

8. Selective Permeability
A key property of the plasma membrane which allows some substances to pass through while keeping others out
Controls the substances in and out of the cell

9. Plasma Membrane Structure
The plasma membrane is composed of the phospholipid bilayer.
Phospholipid is a molecule that has a glycerol backbone, two fatty acid chains, and a phosphate-containing group
Phospholipid bilayer is two layers of phospholipids arranged tail to tail

10. Plasma Membrane Structure

11. Plasma Membrane Structure
Phosphate group makes the head polar and are hydrophilic (mix with water)
The two fatty acid tails are non-polar and hydrophobic (repel, not mix with water)
The phospholipids are arranged in such a way that the polar heads can be closest to the water molecules and the non-polar tails can be farthest away from the water molecules

12. Components of the Plasma Membrane
A. Proteins
Transmit signals inside the cells (receptor proteins)
Acts as a support structure to give the cell its shape
Provide pathways for substances to enter and leave the cell (transport proteins)

13. B. Cholesterol
Prevents fatty acid tails of the phospholipid bilayer from sticking together
Helps maintain cell homeostasis

14. C. Carbohydrates
Help cells identify chemical signals

15. Eukaryotic Cell Structures & Organelles
Main idea: Eukaryotic cells contain organelles that allow the specialization and the separation of functions within the cell.
Objectives
Identify the structure and function of the parts of a typical eukaryotic cell (add to left column of Cornell Notes)
Compare and contrast structures of plant and animal cells (add to left column of Cornell Notes)
Review vocabulary
Enzymes: a protein that speeds up the rate of a chemical reaction.

16. Cytoplasm and Cytoskeleton
Cytoplasm - a semi-fluid material that constitutes the environment inside the plasma membrane (Plant & Animal Cells)
Cytoskeleton - a supporting network of long, thin protein fibers that form a framework for the cell and provide an anchor for the organelles inside the cell (Plant & Animal Cells)

17. Cytoskeleton
A framework for the cell within the cytoplasm that rapidly assemble and disassemble and slide past one another. This allows cells and organelles to move.
Microtubules-long, hollow protein cylinders that form a rigid skeleton for the cell and assist in moving substances within the cell
Microfilaments-thin protein threads that help give the cell shape and enable the entire cell or parts of the cell to move

18. Cytoskeleton

19. Cell Structures
Nucleus - brain of the cell; directs the cell processes (Plant & Animal Cells)
Contains most of the cell’s DNA, which stores information used to make proteins for cell growth, function, and reproduction
Nuclear envelope - double membrane with nuclear pores that surrounds the nucleus
Nuclear pores - allow larger-sized substances to move in and out of the nucleus
Nucleolus – site of ribosome production
Chromatin – the complex DNA attached to protein; spread throughout the nucleus

20. Nucleus

21. Ribosomes
Ribosomes - are the most numerous of the cell’s organelles (Plant & Animal Cells)
The ribosome is the site of protein synthesis. (Protein factories)
Composed of RNA & protein
The concentration or distribution of ribosomes in the cells depends on how the proteins they produce will be used.
Proteins used by the cells are made by free floating ribosomes.
Exported proteins are made by ribosomes that are attached to the ER.

22. Ribosomes

23. Endoplasmic Reticulum (ER)
The “ER” is a membrane system of folded sacs and tunnels (Plant & Animal Cells)
Rough ER are covered with ribosomes
Smooth ER have little or no ribosomes and function primarily as an intercellular highway, a path which molecules can move from one part of the cell to another
Also the site of carbohydrate and lipid synthesis

24. ER

25. Golgi Apparatus
The processing, packaging and secreting organelle of the cell (Plant & Animal Cells)
Notice that the Golgi Apparatus consists of a stack of membranes.
It operates like a production line in a factory, where a product is assembled at one end, then packaged, and finally shipped out.
The protein vesicle is modified as it passes from sac to sac. Finally it is released to be sent out of the cell.

26. Golgi Apparatus

27. Vacuole
A membrane-bound vessicle for the temporary storage of materials
Plant cells-one large; Animal cells-a few small

28. Lysosomes
organelles that contain powerful digestive enzymes (Animal Cells Only)
They destroy foreign bodies that get into the cell
They also digest food vacuoles to help feed the cell
They destroy the cell when it is too old or damaged. This is why they are sometimes called the “suicide sacs of the cell”

29. Lysosomes

30. Centrioles
tiny t-shaped structures in the cell that function in helping the cell when it divides to form two new cells (Animal Cells and most Protists)
Protists – single celled organisms

31. Mitochondria They provide energy for the cell.
respiration centers of the cell (Plant and Animal Cells)
They are called the “powerhouse of the cell”
Mitochondria have their own DNA.
The number of mitochondria in a cell depends on the needs of the cell.

32. Mitochondria

33. Chloroplasts organelle responsible for making food (Plants Cells Only)
This process is called photosynthesis.
They use sunlight + Water + Carbon dioxide and make glucose (sugar).
The waste product of this is oxygen and water vapor.

34. Cell Wall
rigid covering of a plant cell that provides shape and protection (Plant Cell Only)
It is made primarily of cellulose (carbohydrate)
Pores in the cell wall allow ions and molecules to pass to and from the cell membrane.