1. Organelles
Ribosomes - sites of protein synthesis

2. Organelles
Endoplasmic reticulum - network of membranes in the shape of flattened sacs or tubules
- Rough ER - connected to the nuclear envelope, a series of flattened sacs, surface is studded with ribosomes, produces various proteins
-Smooth ER - a network of membrane tubules, does not have ribosomes, synthesizes fatty acids and steroids, detoxifies certain drugs

3. Organelles
Golgi complex - consists of 3–20 flattened, membranous sacs called cisternae.
- Modify, sort, and package proteins for transport to
different destinations.
- Proteins are transported by various vesicles .

4. Golgi Complex

5. Processing and Packaging

6. Organelles
Lysosomes - vesicles that form from the Golgi complex and contain powerful digestive enzymes

7. Organelles Peroxisomes Proteasomes Smaller than lysosomes
Detoxify several toxic substances such as alcohol
Abundant in the liver
Proteasomes
Continuously destroy unneeded, damaged, or faulty proteins
Found in the cytosol and the nucleus

8. Organelles Mitochondria - the “powerhouses” of the cell Generate ATP
More prevalent in physiologically active cells: muscles, liver and kidneys
Have inner and outer mitochondrial membranes similar in structure to the plasma membrane
Cristae - the series of folds of the inner membrane
Matrix - the large central fluid-filled cavity
Self-replicate during times of increased cellular demand or before cell division
Contain own DNA
Inherited only from your mother

9. Mitochondria

10. Organelles - Nucleus Spherical or oval shaped structure
Usually most prominent feature of a cell
Nuclear envelope - a double membrane that separates the nucleus from the cytoplasm
Nuclear pores - numerous openings in the nuclear envelope, control movement of substances between nucleus and cytoplasm
Nucleolus - spherical body that produces ribosomes
Genes - the cell’s hereditary units, control activities and structure of the cell
Chromosomes - long molecules of DNA combined with protein molecules

11. Nucleus

12. Packing of DNA into a Chromosome of a Dividing Cell

13. Overview of Gene Expression

14. Transcription

15. Translation

16. Translation

17. Translation

18. Translation

19. Translation

20. Translation

21. Translation

22. Translation

23. Protein Synthesis Interactions Animation
You must be connected to the internet to run this animation.

24. Somatic Cell Division - Mitosis
The cell cycle is a sequence of events in which a body cell duplicates its contents and divides in two
Human somatic cells contain 23 pairs of chromosomes
(total = 46)
The two chromosomes that make up each pair are called homologous chromosomes (homologs)
Somatic cells contain two sets of chromosomes and are called diploid cells

25. Cell Division Interphase - the cell is not dividing
- The cell replicates its DNA
- Consists of three phases, G1, S, and G2, replication of DNA occurs in the S phase Mitotic phase - consists of a nuclear division (mitosis) and a cytoplasmic division (cytokinesis) to form two identical cells

26. The Cell Cycle

27. DNA Replication

28. Nuclear Division: Mitosis
Prophase - the chromatin fibers change into chromosomes.
Metaphase - microtubules align the centromeres of the chromatid pairs at the metaphase plate.
Anaphase - the chromatid pairs split at the centromere and move to opposite poles of the cell; the chromatids are now called chromosomes.
Telophase - two identical nuclei are formed around the identical sets of chromosomes now in their chromatin form.

29. Cytoplasmic Division: Cytokinesis
Division of a cell’s cytoplasm to form two identical cells
Usually begins in late anaphase
The plasma membrane constricts at its middle, forming a cleavage furrow
The cell eventually splits into two daughter cells.
Interphase begins when cytokinesis is complete .

30. Mitosis 1 Early Late (d) ANAPHASE Pericentriolar material Nucleolus
Nuclear envelope
Chromatin
Plasma membrane
Cytosol
(a) INTERPHASE
Centrioles
Centrosome:
Cleavage furrow
(e) TELOPHASE
(c) METAPHASE 2 3 4 5
Cleavage
furrow
(b) PROPHASE
Fragments of
nuclear envelope
Mitotic spindle
(microtubules)
Kinetochore
Metaphase plate
Chromosome
all at 700x LM
(two chromatids
joined at
centromere
Centromere 1
Early
Late
(d) ANAPHASE
Pericentriolar material
Nucleolus
Nuclear envelope
Chromatin
Plasma membrane
Cytosol
(a) INTERPHASE
Centrioles
Centrosome:
(f) IDENTICAL CELLS IN INTERPHASE
Cleavage furrow
(e) TELOPHASE
(c) METAPHASE
Cleavage
furrow 2 3 4 5 6
(b) PROPHASE
Fragments of
nuclear envelope
Mitotic spindle
(microtubules)
Kinetochore
Metaphase plate
Chromosome
all at 700x LM
Centromere
(two chromatids
joined at
centromere 1
Pericentriolar material
Nucleolus
Nuclear envelope
Chromatin
Plasma membrane
Cytosol
(a) INTERPHASE
Centrioles
Centrosome:
all at 700x LM 1
Early
Late
(d) ANAPHASE
Pericentriolar material
Nucleolus
Nuclear envelope
Chromatin
Plasma membrane
Cytosol
Chromosome
(a) INTERPHASE
Centrioles
Centrosome:
(c) METAPHASE 2 3 4
Cleavage
furrow
(b) PROPHASE
Fragments of
nuclear envelope
Mitotic spindle
(microtubules)
Kinetochore
Metaphase plate
all at 700x LM
(two chromatids
joined at
centromere
Centromere 1
Pericentriolar material
Nucleolus
Nuclear envelope
Chromatin
Plasma membrane
Cytosol
Metaphase plate
(a) INTERPHASE
Centrioles
Centrosome:
(c) METAPHASE 2 3
Late
Early
(b) PROPHASE
Fragments of
nuclear envelope
Mitotic spindle
(microtubules)
Kinetochore
all at 700x LM
Chromosome
(two chromatids
joined at
centromere
Centromere 1
Late
Early
Pericentriolar material
Nucleolus
Nuclear envelope
Chromatin
Plasma membrane
Cytosol
Chromosome
(two chromatids
joined at
centromere
(a) INTERPHASE
(b) PROPHASE
Centrioles
Centrosome:
Fragments of
nuclear envelope
Mitotic spindle
(microtubules)
Kinetochore 2
all at 700x LM
Centromere
Mitosis

31. Mitosis

32. Mitosis

33. Mitosis

34. Mitosis

35. Mitosis

36. Mitosis

37. Reproductive Cell Division
During sexual reproduction, each new organism is the result of the union of two gametes (fertilization), one from each parent.
Meiosis - reproductive cell division that occurs in the gonads (ovaries and testes) that produces gametes with half the number of chromosomes.
Haploid cells - gametes contain a single set of 23 chromosomes.
Fertilization restores the diploid number of chromosomes (46).

38. Reproductive Cell Division
Meiosis occurs in two successive stages: meiosis I and meiosis II .
Each of these two stages has 4 phases: prophase, metaphase, anaphase, and telophase.
Summary - Meiosis I begins with a diploid cell and ends with two cells having the haploid number of chromosomes; in Meiosis II, each of the two haploid cells divides, and the net result is four haploid gametes that are genetically different from the original diploid starting cell.

39. Meiosis and Cytokinesis

40. Comparison
of Mitosis
and Meiosis

41. Cell Division Interactions Animation
The Cell Cycle and Division Processes
Interactions Animation
You must be connected to the internet to run this animation.

42. Cellular Diversity The average adult has nearly 100 trillion cells.
There are about 200 different types of cells.
Cells come in a variety of shapes and sizes.
Cellular diversity permits organization of cells into more complex tissues and organs.

43. End of Chapter 3
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