1. Chapter 3 The Cell (part 1)

2. The Cell Theory Three Principles All organisms are composed of cells
Cells are the smallest living units of life
All cells arise from pre-existing cells (by cell division)

3. Cells Are Highly Structured
Eukaryotic (“with nucleus”) cells are highly “compartmentalized”
plasma membrane
nucleus: information center
cytoplasm: fluid within membrane
organelles: structures with specialized functions
Prokaryotes have no nucleus or true organelles

4. FIGURE 3.1 part 1
Eukaryotic cells, such as the generalized animal cell shown here, have internal membranebound organelles.

5. FIGURE 3.1 part 2
Eukaryotic cells, such as the generalized animal cell shown here, have internal membranebound organelles.

6. Prokaryotes have no nucleus or true organelles
FIGURE 3.2 part 1
Prokaryotic cells, such as a bacterium, lack internal membrane-bound organelles.

7. FIGURE 3.2 part 2
Prokaryotic cells, such as a bacterium, lack internal membrane-bound organelles.

8. TABLE 3.1
REVIEW OF FEATURES OF EUKARYOTIC AND PROKARYOTIC CELLS

9. The Plasma Membrane
Structure of the plasma membrane

10. FIGURE 3.5
The structure of the plasma membrane of a cell according to the fluid mosaic model.

11. Structural Features of the Plasma Membrane
Lipid bilayer
Phospholipids: polar head and nonpolar tail
Cholesterol: makes membrane a bit more rigid
Proteins: provide means of transportation through membrane
Carbohydrates: provide recognition for cells and organisms

12. TABLE 3.2
REVIEW OF PLASMA MEMBRANE FUNCTIONS

13. Movement Across the Plasma Membrane
Diffusion
Movement from area of high concentration to low
Passive transport: no energy required

14. FIGURE 3.7
Diffusion is the random movement of a substance from a region of higher concentration to a region of lower concentration.

15. Facilitated Diffusion
Diffusion that uses transport (carrier) proteins in membrane to assist moving molecules across the membrane both:
Down the concentration gradient
Without expending energy

16. FIGURE 3.8
Facilitated diffusion is the movement of a substance from a region of higher concentration to a region of lower concentration with the aid of a membrane protein that acts as a channel or a carrier protein.

17. Active Transport
Active transport uses proteins and energy to move substances from an area of lower concentration to an area of higher concentration

18. Active Transport Proteins Use Energy
FIGURE 3.10
Active transport is the movement of molecules across the plasma membrane from an area of lower concentration to one of higher concentration with help from a carrier protein and energy, usually in the form of ATP.

19. Osmosis
Osmosis: net diffusion of water across a semi-permeable membrane

20. FIGURE 3.9
Osmosis is diffusion of water across a selectively permeable membrane. The drawings show what happens when a membranous bag through which water but not sugar can move is placed in solutions that are (a) hypertonic, (b) isotonic, or (c) hypotonic to the solution inside the bag. The width of the arrows corresponds to the amount of water moving into and out of the bag. The photographs show what happens to red blood cells when placed in the three kinds of solutions. Red blood cells are normally shaped like flattened disks, as in part b.

21. Osmosis and Tonicity

22. Endocytosis (Phagocytosis) Moves Materials in Bulk
Endocytosis moves material into cell
Example: WBC engulfs bacteria

23. FIGURE 3.11a
Endocytosis—phagocytosis or pinocytosis—occurs when a localized region of the plasma membrane surrounds a bacterium, large molecule, or fluid containing dissolved substances and then pinches off to form a vesicle that moves into the cell.

24. Exocytosis Moves Materials in Bulk
Exocytosis moves material out of the cell
Example: secretion of hormones

25. FIGURE 3.12
Cells package large molecules in membrane-bound vesicles, which then leave by exocytosis.

26. TABLE 3.3
REVIEW OF MECHANISMS OF TRANSPORT ACROSS THE PLASMA MEMBRANE

27. FIGURE 3.13a
The nucleus contains almost all the genetic information of a cell.

28. FIGURE 3.13b
The nucleus contains almost all the genetic information of a cell.

29. Structure and Function of the Nucleus
Functions:
Contains the genetic information of the cell
Controls the function & the operations of the cell
Structural features:
Double-layered nuclear membrane
Nuclear pores
Chromosomes/chromatin
Nucleolus (synthesizes ribosomes)

30. Our Cells Are Highly Structured
Chromosomes contained in the nucleus are made of DNA

31. FIGURE 3.14a
Chromosomes are composed of DNA and associated proteins.

32. FIGURE 3.14b
Chromosomes are composed of DNA and associated proteins.

33. Endoplasmic Reticulum (ER)

34. FIGURE 3.15
The endoplasmic reticulum (ER), shown in this electron micrograph, is continuous with the plasma and nuclear membranes and consists of two regions: rough ER and smooth ER.

35. Endoplasmic Reticulum (ER) and Ribosomes
Ribosomes: used in synthesis of proteins
Free and membrane bound
Endoplasmic Reticulum (ER): packages the proteins
Smooth ER: no ribosomes, lipid synthesis & detoxifies alcohol and drugs
Rough ER: has ribosomes, protein synthesis