1. CELLS
Chapter 3

2. Nine important landmarks distinguish eukaryotic cells

3. 1. The Nucleus
The nucleus is the largest and most prominent organelle in most eukaryotic cells
The nucleus has two primary functions: 1. 2.

4. 1. The Nucleus
Nucleolus
Chromatin

5. 1. The Nucleus Nuclear membrane (nuclear envelope) 2 bilayers
Nuclear pores

6. Three important structural components stand out in the nucleus (Figure The nucleus: the cell’s genetic control center).  
First is the nuclear membrane, a membrane sometimes called the nuclear envelope that surrounds the nucleus and separates it from the cytoplasm.
Unlike most plasma membranes, however, the nuclear membrane consists of two bilayers on top of each other, much like if you have your groceries double-bagged at the market.
The nuclear membrane is not a sack, though. It is covered with tiny pores, made from multiple proteins embedded within the phospholipid membranes and spanning both of the bilayers. These pores enable large molecules to pass from the nucleus to the cytoplasm and from the cytoplasm to the nucleus. 6

7. 2. Cytoplasm & Cytoskeleton

8. 2. Cytoplasm & Cytoskeleton
Cytosol:
Cytoplasm:

9. 2. Cytoplasm & Cytoskeleton
Cilia
 Flagella

10. 2. Cytoplasm & Cytoskeleton

11. 3. Mitochondria energy converters
consume most of the oxygen used by each cell

12. Mitochondria (singular: mitochondrion) are the cell’s all-purpose energy converters and they are present in virtually all plant cells, animal cells, and every other eukaryotic cells.
Although we consume a variety of foods, our mitochondria allow us to convert the energy contained within the chemical bonds of the carbohydrates, fats, and proteins in food into carbon dioxide, water, and ATP, the molecule that is the energy source all cells use to fuel all their functions and activities. (ATP and how it works are described in detail in Chapter 4.)
Because this energy conversion requires a significant amount of oxygen, organisms’ mitochondria consume most of the oxygen used by each cell. In humans, for example, our mitochondria consume as much as 80% of the oxygen we breathe. They give a significant return on this investment by producing about 90% of the energy our cells use to function. 12

13. 3. Mitochondria - Endosymbiosis

14. 4. Lysosomes
digest and recycle

15. 4. Lysosomes

16. 4. Lysosomes
~ 50 different digestive enzymes and a super-acidic, corrosive fluid

17. 4. Lysosomes – Tay-Sachs Disease
Result of malfunctioning lysosomes

18. Which cellular component would be responsible for the classic shape of a red blood cell?
Nucleus
Cytoskeleton
Lysosome
Mitochondria
Answer: 2 18

19. Endomembrane System smooth endoplasmic reticulum
rough endoplasmic reticulum
golgi apparatus

20. 5. Endoplasmic Reticulum
cells build proteins and disarm toxins

21. 5. Endoplasmic Reticulum (Rough)
completely surrounds the nucleus (usually)
Perhaps the organelle with the most cumbersome name, the rough endoplasmic reticulum or rough ER (from the Greek words for a “within-cell network”), is a large series of interconnected, flattened sacs (they look like a stack of pancakes) that are connected directly to the nuclear envelope. In most eukaryotic cells, the rough ER almost completely surrounds the nucleus (Figure The rough endoplasmic reticulum is studded with ribosomes).  It is called “rough” because its surface is studded with little bumps. These bumps are protein-making machines called ribosomes, and generally cells with high rates of protein production have large numbers of ribosomes. We cover the details of ribosome structure and protein production in Chapter 5.
The primary function of the rough ER is to fold and package proteins that will be shipped elsewhere in the organism. Poisonous frogs, for example, package their poison in rough ER of the cells in which it is produced before transporting it to the poison glands on their skin. Proteins that are used within the cell itself are generally produced on free-floating ribosomes in the cytoplasm.

22. 5. Endoplasmic Reticulum (Rough)
Primary function:
example: poisonous frogs

23. 5. Endoplasmic Reticulum (Rough)

24. 5. Endoplasmic Reticulum (Smooth)
no ribosomes
synthesizes lipids such as fatty acids, phospholipids, and steroids

25. 5. Endoplasmic Reticulum (Smooth)
detoxifying enzymes
alcohol, antibiotics, barbiturates, amphetamines
toxic metabolic waste products produced in our bodies
in cells that are exposed to large amounts of drugs

26. 5. Endoplasmic Reticulum (Smooth)
plasma cells in the blood that produce immune system proteins for export
pancreas cells that secrete large amounts of digestive enzymes

27. 5. Endoplasmic Reticulum (Smooth)
detoxification enzymes.

28. Which cells below would have the smoothest endoplasmic reticulum?
Kidney cells
Kidney cells of an alcoholic
Liver cells
Liver cells of an alcoholic
Answer: 4 28

29. 6. Golgi Apparatus not interconnected packages synthesized molecules
carbohydrate synthesis,

30. 6. Golgi Apparatus bud from the endoplasmic reticulum
~ 4 successive chambers , molecules get passed from one to the next

31. The Golgi apparatus, which is not connected to the endoplasmic reticulum, is a flattened stack of membranes (each of which is called a Golgi body) that are not interconnected.
Figure Golgi apparatus: processing of molecules synthesized in the cell and packaging of those molecules destined for use elsewhere in the body.
After transport vesicles bud from the endoplasmic reticulum, they move through the cytoplasm until they reach the Golgi apparatus. There, the vesicles fuse with the Golgi apparatus and dump their contents into a Golgi body.
There are about four successive Golgi body chambers to be visited and the molecules get passed from one to the next.
In each Golgi body, enzymes make slight modifications to the molecule (such as the addition or removal of phosphate groups or sugars).
The processing that occurs in the Golgi apparatus often involves tagging molecules (much like adding a postal address or tracking number) to direct them to some other part of the organism.
After they are processed, the molecules then bud off from the Golgi apparatus in a vesicle which then moves into the cytoplasm.
If the molecule is destined for delivery and used elsewhere in the body, the transport vesicle eventually fuses with the cell’s plasma membrane and dumps the molecule into the bloodstream via exocytosis. 31

32. Figure 3-35 (The endomembrane system: producing, packaging, and transporting molecules.) shows how the various parts of the endomembrane system work to produce, modify, and package molecules within a cell. 32

33. 7. Cell Wall
Made from polysaccharides, including cellulose

34. 7. Cell Wall
~100 times thicker than plasma membrane,
plasmodesmata:

35. 8. Vacuoles found in plant cells, also protists, fungi, and animals
five different areas of plant life 1. 2. 3. 4. 5.

36. 8. Vacuoles Nutrient storage: Waste management: Predator deterrence:
Sexual reproduction:

37. 8. Vacuoles
Physical support:
turgor pressure

38. 9. Chloroplast
all plants and eukaryotic algae
site of photosynthesis

39. 9. Chloroplast
Circular DNA
Dual outer membrane
Endosymbiosis theory

40. Figure 3-39 (Review of the structures and functions of cellular organelles) summarizes all of the parts of a cell and their functions. 40

41. Which answer below is not found in a eukaryotic cell?
Cell wall
DNA without membrane
Endoplasmic reticulum
Chloroplast
Lysosome
Answer: 2 41