1. Cell Structure and Function
Chapter 7
Cell Structure and Function

2. 7-1 Life is Cellular

3. 7-1 Life is Cellular Objectives Explain what the cell theory is.
Describe how researchers explore the living cell.
Distinguish between eukaryotes and prokaryotes

4. 7-1 Life is Cellular The Discovery of the cell
The study of the cell was made possible by the invention of microscopes

5. 7-1 Life is Cellular
Robert Hooke was the first person to see cells through a compound microscope.
All he saw was the cell wall

6. 7-1 Life is Cellular
German scientists Matthias Schleiden and Theodore Schwann developed the CELL THEORY.

7. 7-1 Life is Cellular CELL THEORY:
All living organisms are composed of one or more cells.
Cells are the basic units of life.
New cells come from pre-existing cells.

8. 7-1 Life is Cellular Cell theory is significant! Why?
All living things are made of cells.
Differences in the structure and function of different life forms are reflected in differences in their cell structure.

9. 7-1 Life is Cellular
Prokaryotes and Eukaryotes – the 2 basic kinds of cells

10. 7-1 Life is Cellular Prokaryotic
Primitive cells that lack membrane bound organelles.
Lack nucleus
Most are single-celled.
bacteria

11. 7-1 Life is Cellular
Prokaryotic Bacteria

12. 7-1 Life is Cellular

13. 7-1 Life is Cellular

14. 7-1 Life is Cellular Eukaryotic More complex developed cells
Have membrane bound organelles
Distinct nucleus
Both single and multiple-celled organisms

15. 7-1 Life is Cellular

16. 7-1 Life is Cellular
A Stained Yeast Cell

17. Eukaryotic PLANT Cell (notice the cell wall)
7-1 Life is Cellular
Eukaryotic PLANT Cell (notice the cell wall)

18. A comparison of Prokaryotic and Eukaryotic Cells
7-1 Life is Cellular
A comparison of Prokaryotic and Eukaryotic Cells

19. A comparison of Prokaryotic and Eukaryotic Cell
7-1 Life is Cellular
A comparison of Prokaryotic and Eukaryotic Cell

20. 7-1 Life is Cellular Objectives Explain what the cell theory is.
Describe how researchers explore the living cell.
Distinguish between eukaryotes and prokaryotes
End of Section 7-1

21. 7-2 Eukaryotic Cell Structure
Objectives
Describe the function of the cell nucleus.
Describe the functions of the major cell organelles.
Identify the main roles of the cytoskeleton.

22. 7-2 Eukaryotic Cell Structure
Divided into two major parts that work together:
Nucleus
Cytoplasm – outside the nucleus

23. 7-2 Eukaryotic Cell Structure
Organelles (“little organs”) - Specialized
Nucleus (Both)
Ribosomes (Both)
Endoplasmic Reticulum (Both)
Golgi apparatus (Both)
Lysosomes (Both)
Vacuoles (Both, but mostly plants)
Mitochondria (Both) and Chloroplasts (Plants)
Cytoskeleton (Both)
Cell membrane (Both)
Cell wall (Plants)

24. 7-2 Eukaryotic Cell Structure
Nucleus
Directs most of cell’s activities
Contains information needed to make proteins
Stores genetic material - DNA
Chromatin
chromosomes
Surrounded by the nuclear envelope
Nucleolus – small, dense region where assembly of ribosomes begins

25. 7-2 Eukaryotic Cell Structure
Ribosomes
In cytoplasm
Small particles of RNA and protein
Make proteins following coded instructions from the nucleus

26. 7-2 Eukaryotic Cell Structure
Endoplasmic Reticulum
Rough – ribosomes on surface
Smooth – no ribosomes on surface

27. 7-2 Eukaryotic Cell Structure
Endoplasmic Reticulum
Membrane system
Lipid parts of cell, proteins and other materials that are exported are assembled
Moves proteins & Carbohydrates to the Golgi Body.

28. 7-2 Eukaryotic Cell Structure
Golgi apparatus
Stacks of flattened sacs
Modify proteins made by the cells
Package, sort & export proteins from the ER

29. 7-2 Eukaryotic Cell Structure
Lysosomes
Break down compounds into small particles that the cell can use.
Remove “junk” that clutter cell

30. 7-2 Eukaryotic Cell Structure
Vacuoles
Saclike structures
Store materials:
Water
proteins,
Salts
carbohydrates

31. 7-2 Eukaryotic Cell Structure
Mitochondria and Chloroplasts
Sources of energy
From food and/or from the sun

32. 7-2 Eukaryotic Cell Structure
Mitochondria
Releases energy in the cell. (The powerhouse of the cell)
Produce ATP (high energy compound) from food.
Plants DO have these.

33. 7-2 Eukaryotic Cell Structure
Mitochondria
The powerhouse of the cell.

34. 7-2 Eukaryotic Cell Structure
Chloroplasts
Uses energy from sunlight to make food molecules (photosynthesis).
Found in plants and some other microscopic organisms

35. 7-2 Eukaryotic Cell Structure
Cytoskeleton
Network of protein filaments that helps the cell maintain shape.
Involved in movement
Made of two different structures:
Microfilaments
Microtubules

36. 7-2 Eukaryotic Cell Structure

37. 7-2 Eukaryotic Cell Structure

38. 7-2 Eukaryotic Cell Structure

39. 7-2 Eukaryotic Cell Structure

40. 7-2 Eukaryotic Cell Structure
Objectives
Describe the function of the cell nucleus.
Describe the functions of the major cell organelles.
Identify the main roles of the cytoskeleton.
End of Section 7-2

41. 7-3 Cell Boundaries Objectives
Identify the main functions of the cell membrane and the cell wall.
Describe what happens during diffusion.
Explain the processes of osmosis, facilitated diffusion, and active transport.

42. 7-3 Cell Boundaries Cell Membrane Thin, flexible barrier Protection
Support
Regulates what enters/leaves the cell

43. The Cell Membrane is known as a “Lipid Bilayer”
7-3 Cell Boundaries
The Cell Membrane is known as a “Lipid Bilayer”
I wonder Why?

44. 7-3 Cell Boundaries Cell Walls
Support
Protection
Plant cellulose cell walls from the ragweed plant anther. The rigid cell wall of plants is made of fibrils of cellulose.

45. 7-3 Cell Boundaries Diffusion Through Cell Boundaries
Particles move from an area of high concentration to an area of low concentration.
Concentration – the mass of solute in a given volume of solution.
Equilibrium – concentration is the same throughout a solution.

46. A simple rule to remember:
7-3 Cell Boundaries
Osmosis – diffusion of water through a selectively permeable membrane.
hypertonic = more solute concentration
hypotonic = less solute concentration
isotonic = same solute concentration
A simple rule to remember:

47. 7-3 Cell Boundaries

48. It lets the water through but not the spaghetti.
7-3 Cell Boundaries
selectively permeable
What?
It lets the water through but not the spaghetti.

49. 7-3 Cell Boundaries Facilitated Diffusion
facilitated diffusion - diffusion through a membrane with help from a transport protein.
Because…some molecules just can’t get across that membrane on their own.
Different proteins allow particular molecules.
Does not require energy.

50. 7-3 Cell Boundaries
Facilitated Diffusion

51. 7-3 Cell Boundaries Active Transport
Transport proteins within the membrane must use energy (ATP) to move substances either to the inside or outside of the membrane. (Against a concentration gradient.)
endocytosis
Phagocytosis
Pinocytosis
exocytosis

52. 7-3 Cell Boundaries
Active Transport

53. 7-3 Cell Boundaries Phagocytosis “CELL EATING” takes in large
particles by
engulfing them

54. pinch off to form vacuoles.
7-3 Cell Boundaries
Tiny pockets form
along cell membrane
fill with liquid,
pinch off to form vacuoles.

55. Vacuole fuses with membrane
7-3 Cell Boundaries
Vacuole fuses with membrane
forces contents out.

56. 7-3 Cell Boundaries Objectives After this section, can you…
Identify the main functions of the cell membrane and the cell wall.
Describe what happens during diffusion.
Explain the processes of osmosis, facilitated diffusion, and active transport.
End of Section 7-3

57. 7-4 The Diversity of Cellular Life Objectives
Describe cell specialization
Identify the organization levels in multicellular organisms.

58. 7-4 The Diversity of Cellular Life
Unicellular Organisms
Single-celled
Performs all of it’s necessary life functions.
Ciliata (up to 3 mm long) are unicellular organisms most abundant in fine sandy sediments. Their body is covered by a felt of cilia which may be modified around the mouth opening

59. 7-4 The Diversity of Cellular Life Unicellular Organisms
Diatoms are a major group of eukaryotic algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular. Not only are there more than species of the cute little critters, they are found everywhere that there’s water including on and in soil.

60. 7-4 The Diversity of Cellular Life Multicellular Organisms
Cell specialization – Each specialized cell performs a specific life function.

61. 7-4 The Diversity of Cellular Life Levels of Organization
(Largest)
(Smallest)

62. 7-4 The Diversity of Cellular Life Levels of Organization
Tissues – similar cells are grouped into units.
Organs – Groups of tissues work together.
Organ System – A group of organs that work together to perform a specific function.

63. 7-4 The Diversity of Cellular Life Levels of Organization continued…
ORGAN SYSTEM
ORGAN
CELL
TISSUE

64. 7-4 The Diversity of Cellular Life Levels of Organization
What level of organization is a tongue???
Hmmm?

65. 7-4 The Diversity of Cellular Life Objectives
Describe cell specialization
Identify the organization levels in multicellular organisms.
End of 7-4