1. Chapter 7: Cell Structure and Function

2. Robert Hooke (1635-1703) English Scientist
First to use the microscope to observe cells
Coined the term “cell”
Looked at cork cells

3. Anton van Leeuwenhoek 1632-1723
Dutch scientist
Invented the first compound microscope
First to observe LIVING cells
Blood cells and protists

4. Robert Brown 1773-1858 Scottish botanist
In 1831 he was the first person to observe the nucleus of a cell

5. Schleiden & Schwann

6. Developing Cell Theory 1838
Schleiden
Said “all plants are made up of cells”
Schwann
Said “all animals are made up of cells”

7. Johannes Rudolph Purkinje Virchow
Coined the term “protoplasm” to refer to the jellylike material that fills the cell.
Said “all cells arise only from preexisting cells”

8. Cell Theory Overview All organisms are made of one or more cells.
All cells carry on life activities.
New cells arise only from other living cells.

9. Prokaryotic vs Eukaryotic
Simplest form
Lack membrane bound structures
Example: bacteria and some protists
EUKARYOTIC
Most common
Possess membrane bound structures and a nucleus
Found in most living things

10. Sizes of Cells Eukaryotic are usually larger than prokaryotic
Both nutrients and wastes are constantly entering and exiting cells
Vary in size and shape

11. Cell Structures and Organelles
Organelles = specialized internal structures of eukaryotic cells

12. CELL WALL Found in most bacteria and all plant cells
Gives cell its shape and provides protection
Allows passage of materials
In plant cells, it is made of cellulose

13. THE NUCLEUS Control center or “ city hall ” of cell. Largest organelle
Controls metabolism and cell reproduction

14. Structure of nucleus
Nuclear envelope = membrane that surrounds the nucleus that acts in manner similar to the cell membrane
Nucleolus = dense are in center of nucleus where DNA,RNA, and proteins are found.
*site where ribosomes are produced

15. Picture of nucleus:

16. MICROFILAMENTS Long, solid, threadlike structures Made of actin
Involved in muscle contraction and cyclosis
Movement of cytoplasm

17. MICROTUBULES Hollow, cylindrical structures
Helps to give cell its shape
Made of tubulin
Involved in mitosis
More information

18. Cytoplasm
Watery material lying within the cell between the cell membrane and the nucleus
Formally called the protoplasm by Purkinje
Contains all the other organelles

19. RIBOSOMES Very small “mini factories” of the cell
Responsible for protein synthesis with the help of RNA
Examples: John Morrell, Gateway

20. ENDOPLASMIC RETICULUM (ER)
Fluid filled canals
Continuous paths for transport of materials
Divides the cell into compartments

21. ER continued
Acts as a “street system” in a city or conveyer at a factory
Rough ER = surface lined with ribosomes
Smooth ER = no ribosomes

22. GOLGI BODIES Packaging, storage and processing of proteins
“ Post Office ” of the cell
Protein arrives from the ER to be packaged in vesicles.

23. ER, Ribosome, & Golgi

24. LYSOSOMES Many strong digestive enzymes Produced by Golgi Bodies
Involved in digestion of food in the cell
Helps break down worn out organelles and wastes
“ Garbage Truck ”
Recycles cell materials

25. VACUOLES Found mainly in plants but a few are found in animal cells
Many different types
Examples: Food and contractile
Act as a storage unit

26. Contractile vacuoles
Location in plant cells where excess water collects

27. Chloroplasts A special type of chromoplast that contains chlorophyll
Most important
Contains grana and stroma
Contain their own DNA
Site of photosynthesis

28. Chloroplast Structure

29. MITOCHONDRIA Release energy used by the cell “power plant”
Double membrane for extra surface area
Responsible for cellular respiration
Process by which energy is released using oxygen

30. Mitochondria structure

31. Mitochondria (powerhouse)
Act similar to electric power plant
Upto 300 to 800 per cell
What advantage is their to having its own DNA?
Can replicate itself

32. Organelle DNA
The only two organelles that contain their own DNA are mitochondria and chloroplasts
In animals, all of an organisms organelle DNA is maternal in origin.
Why?

33. CELL MEMBRANE Controls what materials move in and out
Helps to maintain homeostasis
Similar to the “city limits”
Made up of three substances :
Lipids, proteins, and carbohydrates

34. Fluid-Mosaic Model

35. Protein functions Transport proteins = control movement of materials.
Receptors = act to signal cell when to begin or stop metabolizing.
Enzymes = start chemical rxns.
Binding site for internal structures.

36. Selectively permeable
Some substances pass through while others may not.
Regulates chemical composition
Maintains homeostasis

37. Diffusion
Movement of molecules from a region of high concentration to a region of low concentration

38. Osmosis
Diffusion of WATER across a selectively permeable membrane from a region of high water concentration to a region of low water concentration.
Osmotic pressure =
Increased pressure resulting from osmosis

39. Isotonic solution
Same concentration of dissolved substances in solution as there is in the cell
Same water concentrations
Net result
No net gain or loss of water

40. Hypotonic solution
Lower concentration of dissolved substances in solution than in the cell
More water outside the cell than inside the cell
Net result :

42. Hypertonic pressure
A high concentration of dissolved substances outside the cell
More water in the cell than outside the cell
Net result :

44. Facilitated diffusion vs Active transport
No energy needed
Concentration gradient determines movement
Uses protein channels
ACTIVE
Usually works against the conc. Gradient
Often a transport protein helps the movement (ATP)

45. Sodium-potassium pump

46. Endocytosis Transport of material into the cell by means of a vesicle
Pinocytosis = small amounts of liquid engulfed
Phagocytosis = small amounts of solid ingested

47. Exocytosis Transport of material out of the cell by means of a vesicle
Exocytosis movie

48. Cellular organization
Simplest form of life: unicellular Ex. bacteria, protists, algae
Multicellular:
The simplest form is that of a colony
Little if any cellular specialization
Example: Volvox (algae)

49. Organization
CELLS TISSUES
ORGAN SYSTEM ORGANS
ORGANISM

50. Tissues:
A group of cells which are structurally similar and perform the same function.

51. 1. Epithelial Tissue
Tissue that covers surfaces inside and outside the body
Example: skin
Sheets of closely packed cells

52. 2. Connective Tissue Supports and binds tissues and organs together
Widely separated cells
EX. bone, blood

53. 3. Nervous Tissue Specialized for electrical impulse transport
Ex. brain, spinal cords, nerves

54. 4. Muscle Tissue
Specialized for contraction
Lots of mitochondria

55. Organs
Group of tissues that work together to perform a specific function
Ex. heart, stomach, flower

56. Organ system Group of organs that perform a specific task
Ex. digestive, skeletal, circulatory

57. Assignment
Pages
1-10,11,12,15,17,18,22,26,27
Page