Cells contain organelles that carry out specific functions. The cytoplasm contains organelles like mitochondria, which produce energy, and the endoplasmic reticulum and Golgi apparatus, which process and package proteins and lipids. The cytoskeleton is made of microtubules, microfilaments, and intermediate filaments that help maintain cell shape and allow movement. The nucleus houses the cell's DNA and directs protein production. Organelles are surrounded by membranes and transport materials throughout the cell.

1. Cells are the Structural and Functional
Units of an Organism

3. Cells are Diverse in Size, Shape,
and Length

4. Parts of a Cell: Nucleus, Cytoplasm, and Plasma Membrane

5. The Cytoplasm
The major functional area of the cell.
Consists of:
Cytosol
Organelles
Inclusions

6. Inclusions: Stored Nutrients
Glycogen
Lipid (brown fat)

7. Melanin Secretory Granules
Substantia Nigra Pancreas

8. Mitochondria - Structure

9. Mitochondria
The site of ATP production.
Metabolically active cells have more mitochondria.
Are self-replicating.
May have evolved from purple bacteria.

10. Ribosomes
Composed of protein and rRNA.
May be free in the cytoplasm or bound to
endoplasmic reticulum.

11. Rough Endoplasmic Reticulum

12. Endoplasmic Reticulum

13. Smooth Endoplasmic Reticulum

14. The Golgi Apparatus

15. The Golgi Apparatus
Plasma Cells

16. Lysosomes
Sites of digestion.
Lysosomal enzymes are produced by the RER.
The lysosomal membrane has special adaptations.
Lysosomes function in:
1. Digestion of ingested particles
2. Digestion of worn-out organelles
3. Metabolism of stored glycogen
Lysosomal rupture results in autolysis.

17. Lysosomes Phagocytosis

18. Peroxisomes
Convert free radicals to H2O2
Required for detoxification
Self-replicate

19. Peroxisomes

20. The Cytoskeleton

21. Cytoskeletal Elements
Microtubules:
* Hollow tubes formed by proteins called tubulins
* Comprise the centrosome and other structures (e.g., cilia &
flagella)
* Variable stability (mitotic spindle is labile)
* Maintain cell shape and rigidity

22. Structure of a Microtubule

23. Cilia
Basal bodies control the assembly of the
axoneme.

24. Structure of Cilia
Axoneme

25. Cytoskeletal Elements
Microfilaments:
consist of thin strands of actin
form the core of microvilli, allow amoeboid
movement, produce the cleavage furrow
most highly developed in muscle cells
labile
are attached to the cytoplasmic side of the
plasma membrane

26. Cytoskeletal Elements
Intermediate Filaments:
Intermediate in size
Have tensile strength
Most stable
Specific names in certain cell types
(see table 2-4)

27. The Nucleus
The largest organelle and has 3 regions:
nuclear membrane
nucleolus – protein and rRNA
chromatin – DNA and histone proteins
euchromatin - active
(vesiculate nucleus)
heterochromatin - inactive
(pachychromatic nucleus)

28. The Nucleus

29. Nuclear Pores
200,000 X 48,000 X

30. Nucleosomes – the fundamental units of chromatin

31. Intracellular Pigments
* Endogenous or exogenous (environmental)
* Exogenous pigments include carbon and other
dusts
* Endogenous pigments: lipofuscin, melanin,
hemosiderin.
Apoferritin + iron = ferritin
hemosiderin = large amounts of ferritin

32. Endogenous Intracellualr Pigments - Hemosiderin

33. Exogenous Intracellular Pigments
Silicosis
Asbestosis

34. Endogenous Intracellular Pigments
Lipofucsin