1. Structure and Function
Cells
Structure and Function

2. Fig. 3.2

3. Life on Earth All living things are made of one or more cells
There are two major types of cells
Prokaryotic cells
Eukaryotic cells

4. Fig. 3.5

5. Prokaryotic and Eukaryotic Cells
Prokaryotic cells have:
DNA
Cell wall and plasma membrane
Cytoplasm and ribosomes
Prokaryotic cells DO NOT have:
A nucleus
Compartmentalized specialized structures (organelles)

6. cell membrane
Cell wall
DNA

7. Prokaryotic and Eukaryotic Cells
Bacteria are prokaryotic cells and are generally much smaller than eukaryotic cells
Figure 2.15 Bacterial cell being engulfed by a human immune system cell.
Prokaryotic cells are much smaller than eukaryotic cells, as this electron micrograph demonstrates.

8. Prokaryotic and Eukaryotic Cells
Eukaryotic cells include cells of
Plants
Protozoa and Algae
Fungi
Animals
Eukaryotic cells have
A plasma membrane
Ribosomes
DNA enclosed in a nucleus
Compartmentalized specialized structures (organelles)

9. Cell Structure
All cells are enclosed by a structure called a plasma membrane
The function of the plasma membrane is to control what enters and leaves the cell

10. Cell Structure
All membranes in a cell have similar structural components: phospholipids and proteins
The phospholipids arrange themselves to form phospholipid bilayers with water both on the inside and the outside of the bilayer

11. Cell Structure
Since the phospholipids have two hydrophobic tails at one end and a hydrophilic head at the other end, they tend to gather in a specific arrangement
Two layers with the hydrophilic heads pointing out and the hydrophobic tails on the inside.

12. A Fluid Mosaic of Lipids and Proteins

13. A Fluid Mosaic of Lipids and Proteins
Because lipids and proteins can move about laterally within the membrane, the membrane is a fluid mosaic of lipids and proteins

14. A Fluid Mosaic of Lipids and Proteins
Cell membranes are semipermeable
Allow some things through but not others
Water freely crosses the membranes
This can be a problem
If too much water enters the cell, it may swell or burst
If too much water leaves the cell, it may shrink
All organisms have ways of regulating how much water is in their cells.
In most animals (except some simple marine invertebrates) the water content of tissues is regulated by the kidneys, so this isn’t normally a problem.

15. A Fluid Mosaic of Lipids and Proteins
Cell membranes are semipermeable
Allow some things through but not others
Gases such as oxygen and carbon dioxide pass freely
But substances such as glucose and proteins require the help of the proteins in the cell membrane in order to enter the cell.

16. A Fluid Mosaic of Lipids and Proteins
Some cells (like plant cells and fungal cells) have a cell wall outside of the plasma membrane that give the cell structure and protect against water damage
The cell wall is purely structural and has no control over what enters or leaves the cell

17. Page 64

18. Page 66

19. Fig. 3.7

20. Fig. 3.8

22. Fig. 3.10

23. Fig. 3.11

24. Fig. 3.12

25. Fig. 3.14

26. Figure: 03-15a
Title:
Golgi complex.
Caption:
(a) Diagram of the Golgi complex. This organelle serves as the site for protein processing and packaging within the cell.

27. Fig. 3.16

28. Page 59

29. Fig. 3.18

30. Page 60

31. Mitochondria are organelles that carry out the process of aerobic respiration, which converts food energy to ATP, the type of energy a cell can use.
Table 2.1 Cell components.
Illustrations and descriptions of cell components and their functions.

32. Fig. 3.19

33. Page 61

34. Fig. 3.20

35. The nucleus is a membrane bound structure that encloses the DNA
Table 2.1 Cell components.
Illustrations and descriptions of cell components and their functions.

36. Cytosol and Cytoplasm
The cytoplasm is made up of the watery mixture inside the cell (called the cytosol) and the organelles
The cytoplasm is contained by the plasma membrane.
Organelles are membrane bound structures that carry out specific jobs for the cells.
Cellular functions are more efficient when the work is compartmentalized in organelles.

37. Chloroplasts are organelles found in plant cells
Chloroplasts are organelles found in plant cells. Chloroplasts can convert sunlight energy into chemical energy stored in the chemical bonds of glucose.

38. Lysosomes are small membrane sacs that contain digestive enzymes which break down food and other materials for the cell.

39. Ribosomes are small structures that act like workbenches
Ribosomes are small structures that act like workbenches. Proteins are assembled at the ribosomes. Some ribosomes are free in the cytoplasm and some are bound to a structure called the endoplasmic reticulum.

40. Some subcellular structures help cells divide and maintain their shape
Some subcellular structures help cells divide and maintain their shape. Centrioles are involved in moving genetic material around when a cell divides

41. Figure: 03-01a
Title:
A eukaryotic cell.
Caption:
Eukaryotic cells, such as (a) the generalized animal cell shown here, have internal membrane-bound organelles.

42. Figure: 03-14t
Title:
Endoplasmic reticulum.
Caption:
Top: The endoplasmic reticulum in a cell.

43. Figure: 03-01a
Title:
A eukaryotic cell.
Caption:
Eukaryotic cells, such as (a) the generalized animal cell shown here, have internal membrane-bound organelles.

45. Plant Cell Wall Table 2.1 Cell components.
Illustrations and descriptions of cell components and their functions.