1. Cell Study

2. Microscope History Robert Hooke
First described cells in 1665.
He viewed thin slices of cork and compared the boxy partitions he observed to the cells (small rooms) in a monastery.
(1635–1702)

3. Microscope History Anton van Leeuwenhoek
In 1676 the Dutch scientist observed single- cell organisms ("little animalcules“).
He was likely the first person to observe a red blood cell and a sperm cell.
(1632–1723)

5. Microscope History Robert Brown
In 1831, Scottish scientist Robert Brown gave the nucleus of a cell its name.
(1773–1858)

6. Methods of Cell Study
Advances in instruments has led to a better understanding of the structure and function of cells.
Compound Light Microscope
A. Two lenses (ocular and objective)
B. Specimen must be transparent

7. The Compound Light Microscope

8. Function of the Compound Light Microscope
Ocular – (eye piece) look through, magnifies the image
Body Tube - holds lenses
Nosepiece - rotates the objectives (lenses)

9. Function of the Compound Light Microscope
Stage – platform for slide
Stage Clips - holds slide in place
Diaphragm - controls the amount of light passing through the specimen

10. Function of the Compound Light Microscope
Mirror or Light Source (illuminator) - lights the specimen so it is easier to observe
Arm – used to carry the microscope
Base - supports the microscope

11. Function of the Compound Light Microscope
Coarse Adjustment Knob - used for preliminary focusing, NEVER used on high power.

12. Function of the Compound Light Microscope
Fine Adjustment Knob – used to focus on high power, and to fine tune low power.

13. Function of the Compound Light Microscope
High Power Objective: This objective has a magnification of 100x (maximum magnification)

14. Function of the Compound Light Microscope
Low Power Objective: This objective has a magnification of 10x (minimum magnification)
Scanning objective – has a magnification of 4x

15. Magnification & Resolution
C. Magnification power is equal to the product of the ocular lens times the objective lens.
Ocular
Objective
Total Magnification
10x
100x
40x
400x
15x
600x
Resolution - ability to distinguish between (separate) two objects very close together.
The properties of light limit the resolving power of the light microscope.
If you can’t read this, it is because you can’t distinguish between the letters

16. Resolution

17. Electron Microscope
Uses a beam of electrons instead of light to get greater resolution and magnification (up to 250,000X).

18. Electron Microscope

19. Dissecting Microscope
Used for viewing opaque (not see- through) specimens. Provides a 3-D view. Does not reverse or invert the image

20. Phase Contrast Microscope
Provides contrast without stains (stain kills specimens)

21. Phase Contrast Microscope

22. Ultracentrifuge
Separates cell parts (organelles) by spinning them in a test tube at high speed (denser parts sink to the bottom of the test tube).

24. 8.Measurements with the microscope
Millimeter = mm Micrometer = µm 1000 µm = l mm 1 µm = 1/l000 mm

25. Measuring with a Microscope
Measuring the Field of View (FOV)
Place a ruler on the stage, and line up one measurement line at the edge of the FOV
Measure/estimate the size of FOV

26. Measuring with a Microscope
Estimate the size of the object:
Size of object = FOV
# object that fit across the FOV
How big is this cell?

27. Cells

28. Structure of Living Organisms
The cell is the basic unit of life.

29. I. The Cell Theory All organisms are made up of one or more cells.
These cells working individually, or together in tissues or organs, perform all life functions.
All cells come from pre-existing cells.

30. II. Exceptions to the Cell Theory
The first cell could not have come from a pre-existing cell.
Viruses - which are not cells have hereditary material and can reproduce.
Organelles such as mitochondria and chloroplasts have genetic material (DNA) and can reproduce.

31. Two types of Cells
Prokaryotic
Eukaryotic

32. Prokaryote Do not have structures surrounded by membranes
Few internal structures
One-celled organisms (ex: bacteria)

33. Eukaryote Contain organelles surrounded by membranes
Most living organisms

34. Examples of Cells Amoeba Proteus Plant Stem Bacteria Red Blood Cell
Nerve Cell

35. Cell Organelles
Organelles are small specialized structures that carry out life functions within cells.

36. Animal Cell

37. Plant Cell

38. 1. Plasma (Cell) Membrane
Regulates the movement of materials into or out of cells.
Semi-permeable
Selectively-permeable
Composed of a lipid bilayer with embedded proteins.
It is “fluid” – meaning it is flexible and the parts can move around within the membrane.

40. 2. Cytoplasm Jelly like environment of the cell (mostly H2O)
Cyclosis: Movement of the cytoplasm (transports materials within the cell)

41. Nucleus and Nucleolus Nucleus – controls cell activities
surrounded by nuclear membrane.
- Contains genetic material (DNA and RNA)
- Involved in Reproduction
Nucleolus – dense region in the nucleus.
involved in the synthesis of ribosomes.

42. 5. Mitochondrion
Site of cellular respiration Produces ATP (energy) for metabolism

43. 6. Golgi Complex
Synthesizes, packages and secretes (releases) cellular products.

44. 7. Ribosomes
Site of protein synthesis (ex: enzymes are proteins)

45. 8. Endoplasmic Reticulum (ER)
Forms passages throughout the cell for intracellular (within the cell) transport.
Connects the nuclear membrane to the plasma membrane

46. 8. Endoplasmic Reticulum (ER)
Two Types of Endoplasmic Reticulum
Rough Endoplasmic Reticulum- covered in ribosomes
Smooth Endoplasmic Reticulum (no ribosomes)

48. 9. Lysosome
Contains digestive enzymes (breaks down damaged organelles or pathogens)

49. 10. Vacuole
Space in a cell surrounded by a membrane. Food vacuole - stores food to be digested. Contractile vacuole – helps to maintain water balance within a cell

50. Organelles in Animal Cells Only
Centrioles – Play a role in cell division

51. Organelles in Plant Cells Only
Chloroplast – Perform photosynthesis (produce nutrients)

52. Organelles in Plant Cells Only
Cell Wall– non-living structure that surrounds, supports and protects the cell. Made of cellulose (a polysaccharide)