1. Cells and Tissues

2. Cells and Tissues
Carry out all chemical activities needed to sustain life
Cells are the building blocks of all living things
Tissues are groups of cells that are similar in structure and function

3. 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

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

5. The Nucleus
Figure 3.1b

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

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

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

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

10. Plasma Membrane
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Membrane Structure
Figure 3.2

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

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

13. Plasma Membrane Specializations
Figure 3.3

14. Plasma Membrane Specializations
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Tight Junctions
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Desmosomes (Anchoring Junctions)

15. Cytoplasm
Cytoplasm is the material outside the nucleus and inside the plasma membrane

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

17. Cytoplasmic Organelles
Figure 3.4

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

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

20. Cytoplasmic Organelles
Endoplasmic reticulum (ER)
Fluid-filled tubules for carrying substances
Two types of ER
Rough endoplasmic reticulum
Studded with ribosomes
Synthesizes proteins
Smooth endoplasmic reticulum
Functions in lipid metabolism and detoxification of drugs and pesticides

21. Rough Endoplasmic Reticulum
Ribosome
Protein
Protein inside transport vesicle
Transport vesicle buds off
mRNA
Rough ER
As the protein is synthesized on the ribosome, it migrates into the rough ER cistern.
In the cistern, the protein folds into its functional shape. Short sugar chains may be attached to the protein (forming a glycoprotein).
The protein is packaged in a tiny membranous sac called a transport vesicle.
The transport vesicle buds from the rough ER and travels to the Golgi apparatus for further processing or goes directly to the plasma membrane where its contents are secreted.
Figure 3.5

22. Rough Endoplasmic Reticulum
Ribosome
Protein
mRNA
Rough ER
As the protein is synthesized on the ribosome, it migrates into the rough ER cistern.
Figure 3.5, step 1

23. Rough Endoplasmic Reticulum
Ribosome
Protein
mRNA
Rough ER
As the protein is synthesized on the ribosome, it migrates into the rough ER cistern.
In the cistern, the protein folds into its functional shape. Short sugar chains may be attached to the protein (forming a glycoprotein).
Figure 3.5, step 2

24. Rough Endoplasmic Reticulum
Ribosome
Protein
Transport vesicle buds off
mRNA
Rough ER
As the protein is synthesized on the ribosome, it migrates into the rough ER cistern.
In the cistern, the protein folds into its functional shape. Short sugar chains may be attached to the protein (forming a glycoprotein).
The protein is packaged in a tiny membranous sac called a transport vesicle.
Figure 3.5, step 3

25. Rough Endoplasmic Reticulum
Ribosome
Protein
Protein inside transport vesicle
Transport vesicle buds off
mRNA
Rough ER
As the protein is synthesized on the ribosome, it migrates into the rough ER cistern.
In the cistern, the protein folds into its functional shape. Short sugar chains may be attached to the protein (forming a glycoprotein).
The protein is packaged in a tiny membranous sac called a transport vesicle.
The transport vesicle buds from the rough ER and travels to the Golgi apparatus for further processing or goes directly to the plasma membrane where its contents are secreted.
Figure 3.5, step 4

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

27. 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

28. Figure 3.6, step 1 Rough ER Proteins in cisterna Cisterna Membrane
Golgi apparatus
Plasma membrane
Extracellular fluid
Figure 3.6, step 1

29. Pathway 1 Figure 3.6, step 2 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Golgi apparatus
Pathway 1
Plasma membrane
Extracellular fluid
Figure 3.6, step 2

30. Pathway 1 Figure 3.6, step 3 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Golgi apparatus
Pathway 1
Plasma membrane
Extracellular fluid
Figure 3.6, step 3

31. Pathway 1 Figure 3.6, step 4 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Golgi apparatus
Secretory vesicle
Pathway 1
Golgi vesicle containing proteins to be secreted becomes a secretory vesicle
Plasma membrane
Extracellular fluid
Figure 3.6, step 4

32. Pathway 1 Figure 3.6, step 5 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Golgi apparatus
Secretory vesicles
Pathway 1
Proteins
Golgi vesicle containing proteins to be secreted becomes a secretory vesicle
Secretion by exocytosis
Plasma membrane
Extracellular fluid
Figure 3.6, step 5

33. Pathway 2 Figure 3.6, step 6 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Pathway 2
Golgi apparatus
Plasma membrane
Extracellular fluid
Figure 3.6, step 6

34. Pathway 2 Figure 3.6, step 7 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Pathway 2
Golgi apparatus
Plasma membrane
Extracellular fluid
Figure 3.6, step 7

35. Pathway 2 Figure 3.6, step 8 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Pathway 2
Golgi apparatus
Golgi vesicle containing membrane components fuses with the plasma membrane
Plasma membrane
Extracellular fluid
Figure 3.6, step 8

36. Pathway 3 Figure 3.6, step 9 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Pathway 3
Golgi apparatus
Plasma membrane
Extracellular fluid
Figure 3.6, step 9

37. Pathway 3 Figure 3.6, step 10 Rough ER Proteins in cisterna Cisterna
Membrane
Transport vesicle
Golgi vesicle containing digestive enzymes becomes a lysosome
Pathway 3
Golgi apparatus
Plasma membrane
Extracellular fluid
Figure 3.6, step 10

38. Pathway 3 Figure 3.6, step 11 Rough ER Proteins in cisterna Cisterna
Membrane
Lysosome fuses with ingested substances
Transport vesicle
Golgi vesicle containing digestive enzymes becomes a lysosome
Pathway 3
Golgi apparatus
Plasma membrane
Extracellular fluid
Figure 3.6, step 11

39. Pathway 3 Pathway 2 Pathway 1 Figure 3.6, step 12 Rough ER
Proteins in cisterna
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, step 12

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

41. Cytoplasmic Organelles
Peroxisomes
Membranous sacs of oxidase enzymes
Detoxify harmful substances such as alcohol and formaldehyde
Break down free radicals (highly reactive chemicals)
Replicate by pinching in half

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

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

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

45. Cellular Projections Not found in all cells Used for movement
Cilia move materials across the cell surface
Located in the respiratory system to move mucus
Flagella propel the cell
The only flagellated cell in the human body is sperm

46. Cell Diversity
Figure 3.8a

47. Cell Diversity
Figure 3.8b

48. Cell Diversity
Figure 3.8c

49. Cell Diversity
Figure 3.8d

50. Cell Diversity
Figure 3.8e

51. Cell Diversity
Figure 3.8f

52. Cell Diversity
Figure 3.8g

53. A Tour of the Cell
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Tour of the Cell