1. CHAPTER 2.2: CELLS
PART 1: A tour of the Cell

2. Anatomy of the Cell Cells are not all the same
All cells share general structures
All cells have three main regions
Nucleus
Cytoplasm
Plasma membrane
Figure 3.1a

3. The Nucleus Control center of the cell - F
Contains genetic material (DNA) - F
Three regions - D
Nuclear envelope (membrane) - D
Nucleolus - D
Chromatin - D

4. The Nucleus
Figure 3.1b

5. The Nucleus Nuclear envelope (membrane) Barrier of the nucleus - F
Consists of a double membrane - D
Contains nuclear pores that allow for exchange of material with the rest of the cell - D

6. The Nucleus Nucleoli Nucleus contains one or more nucleoli - D
Sites of ribosome assembly - F
Ribosomes migrate into the cytoplasm through nuclear pores - F

7. The Nucleus Chromatin Composed of DNA and protein - F
Present when the cell is not dividing - D
Scattered throughout the nucleus - D
Condenses to form chromosomes when the cell divides - F

8. Plasma Membrane Barrier for cell contents - F
Double phospholipid layer - D
Hydrophilic heads
Hydrophobic tails
Also contains proteins, cholesterol, and glycoproteins - D

9. Plasma Membrane
Figure 3.2

10. Plasma Membrane Specializations
Microvilli
Finger-like projections that increase surface area for absorption - F

11. Plasma Membrane Specializations
Membrane junctions
Tight junctions
Impermeable junctions - D
Bind cells together into leakproof sheets - F
Desmosomes
Anchoring junctions that prevent cells from being pulled apart - F
Gap junctions
Allow communication between cells - F

12. Plasma Membrane Specializations
Figure 3.3

13. Membrane Transport – first page
passive
no energy required
diffusion
active
requires energy
sodium-potassium pump

14. Cytoplasm
Cytoplasm is the material outside the nucleus and inside the plasma membrane – D
Contains three major elements
Cytosol
Organelles
Inclusions

15. Cytoplasm Contains three major elements Cytosol
Fluid that suspends other elements - F
Organelles
Metabolic machinery of the cell
“Little organs” that perform functions for the cell
Inclusions
Chemical substances such as stored nutrients or cell products

16. Cytoplasmic Organelles
Figure 3.4

17. Cytoplasmic Organelles
Mitochondria
“Powerhouses” of the cell - F
Change shape continuously - D
Carry out reactions where oxygen is used to break down food - F
Provides ATP for cellular energy - F

19. Cytoplasmic Organelles
Ribosomes
Made of protein and RNA - D
Sites of protein synthesis - F
Found at two locations - D
Free in the cytoplasm
As part of the rough endoplasmic reticulum

20. Ribosomes
Synthesize proteins from amino acids
(Translation)

21. Endoplasmic Reticulum
Detoxifies
Makes lipids
Stores Ca++
SER
Transports proteins
RER

22. Cytoplasmic Organelles
Golgi apparatus
Modifies and packages proteins
Produces different types of packages
Secretory vesicles
Cell membrane components
Lysosomes

23. Pathway 3 Pathway 2 Pathway 1 Figure 3.6 Rough ER Proteins in cisterna
Membrane
Lysosome fuses with ingested substances
Transport vesicle
Golgi vesicle containing digestive enzymes becomes a lysosome
Pathway 3
Pathway 2
Golgi apparatus
Secretory vesicles
Pathway 1
Golgi vesicle containing membrane components fuses with the plasma membrane
Proteins
Golgi vesicle containing proteins to be secreted becomes a secretory vesicle
Secretion by exocytosis
Plasma membrane
Extracellular fluid
Figure 3.6

24. Common in animals, rare in plants Stores acids & enzymes
Lysosomes
Common in animals, rare in plants
Stores acids & enzymes
Intracellular digesion
Engulfs “foreign”
Recycles
Uncontrolled release = cell death

25. Cytoplasmic Organelles
Lysosomes
Contain enzymes that digest worn-out or nonusable materials within the cell

26. peroxisomes Protects the cell from its own production of H2O2 Example
Secretory vesicle
Protects the cell from its own production of H2O2
Example
White blood cells produce H2O2 to kill bacteria
Peroxisomes produce catalase, which breaks down the H2O2
catalase
H2O2
H20 + ½ O2

27. Cytoplasmic Organelles
Cytoskeleton
Network of protein structures that extend throughout the cytoplasm
Provides the cell with an internal framework
Figure 3.7a

28. Cytoplasmic Organelles
Cytoskeleton
Three different types of elements
Microfilaments (largest)
Intermediate filaments
Microtubules (smallest)
Figure 3.7b–d

29. Cytoplasmic Organelles
Centrioles
Rod-shaped bodies made of microtubules
Direct the formation of mitotic spindle during cell division

30. Life Cycle of a Cell Interphase – cell maintenance and growth
The mitotic phase
Mitosis – The division of the cell nucleus and chromosomes into two nuclei each with its own set of identical chromosomes
prophase
metaphase
anaphase
telophase
Cytokinesis – the division of the cytoplasm into two parts, the final step in cell division

31. Mitosis
prophase
chromatin condenses into chromosomes, cell membrane breaks down
metaphase
chromosomes line up in the center of the cell
anaphase
centromeres are cut in half, sister chromatids pull toward centrioles
telophase
chromosomes “decondense,” new nuclear membrane forms

32. Mitosis

33. Cytokinesis
the cytoplasm divides into two parts, the final step of cell division

34. Cancer cancer cell grows too much grows where it does not belong
does not die when it should

35. Cell Diversity
Figure 3.8a

36. Cell Diversity
Figure 3.8b

37. Cell Diversity
Figure 3.8c

38. Cell Diversity
Figure 3.8d

39. Cell Diversity
Figure 3.8e

40. Cell Diversity
Figure 3.8f

41. Cell Diversity
Figure 3.8g