1. Use the magnifying lens in front of you to ---------
Let’s have some fun…
Use the magnifying lens in front of you to
the specimens in front of you. Start with number 1
Specimen 1 cork
Specimen 2 blood smear or animal cell
Specimen 3 plant cell slide
What do you see?

2. Use the _________ in front of you to observe
the specimens in front of you. Start with number 1
What do you see?

3. What is a Cell?

4. Cell theory
Activity

5. Year of Discovery
Scientist
Contribution
1595
Hans and Zacharias Janssen
produced the first compound microscope by combining two convex lenses within a tube
1665
Robert Hooke
Discovered the cellular composition of cork and introduced the word cell to science
1674
Anton van Leeuwenhoek
Improved magnification of microscopes by polishing lenses
1676
"animacules" were discovered
1683
discovered bacteria from a sample of saliva from his mouth
1838
Matthias Schleiden
discovered the plants were made up of cells
1839
Theodor Schwann
discovered that animals were made up of cells
1855
Rudolph Virchow
stated that all living things come from other living things

7. 1. State the 3 main ideas of
the cell theory.
2. Explain one of these ideas.

8. C E L T H O R y

9. Questioning the cell theory using atypical cells as:
striated muscles, giant algae and fungal hyphae)

10. Questioning the cell theory using atypical cells as:
striated muscles, giant algae and fungal hyphae)

11. Questioning the cell theory using atypical cells as:
striated muscles, giant algae and fungal hyphae)

12. What is a L.O?

13. MR H GREN Metabolism Response Homeostasis Growth Reproduction
Excretion
Nutrition

15. Do we have different types of L.O?
What is the difference between unicellular
and multicellular organisms?

16. Let’s get to know unicellular organisms and
their activities to stay alive
Paramecium
Chlorella
Draw a table to compare between both organisms and how they
maintain different life processes

17. Paramecium

19. Paramecium
Chlorella
Draw a table to compare between both organisms and how they
maintain different life processes

20. Characteristics of life
Paramecium
Chlorella
Metabolism
Burning food that is ingested
Photosynthesis making sugar and burning it
Response (sensitivity)
Responds to food in water and moves towards it
Responds to lack of sunlight and starts to divide to reach it
Homeostasis
Contractile vacuole control the water content of the cell to maintain a stable environment
Growth
The grows in size then divides into 2 cells
The cell grows then the cell divides into spores
Reproduction
Nucleus divides then cytoplasm and cell membrane
The cell gives 4 autospores that form a cell wall around them and then mother cell wall disappears
Excretion
Loss the wastes from the cell surface
Nutrition
Ingests microorganisms in the water
Photosynthesis

21. Cell size Why does it matter? Which is better to be made
up of one big cell or many cells?
NOTE:
Gases and food molecules dissolved in water must be absorbed and waste products must be eliminated. For most cells, this passage of all materials in and out of the cell must occur through the plasma membrane 

22. The cell is very small so we use micrometers (or micron)to measure
the size of a cell
1 Micron = mm = mm

23. Elephant weighs 5000 Kgs
Food intake Kgs /day
Mouse weighs 35 gms
Food intake 54 gms/day

24. Egypt and over population
Resources?
Wastes?
Services?

25. Surface area- volume ratio
Activity 3
Surface area- volume ratio
activity

26. Each internal region of the cell has to be served by part of the cell surface. As a cell grows bigger, its internal volume enlarges and the cell membrane expands. Unfortunately, the volume increases more rapidly than
does the surface area, and
so the relative amount of
surface area available to pass materials to a unit volume
of the cell steadily decreases.

27. The surface area to the volume ratio gets smaller as the cell gets larger. Thus, if the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume. When this happens, the cell must divide into smaller cells with favorable surface area/volume ratios, or cease to function.

28. How can cells overcome this problem?
1. Cells divide
2. Compartments within cells
3. Cells have folds to increase SA:V
4. Cells have organelles with
their own membranes

29. Homework

30. If cells are so small then
how can we see them?
microscopes

31. Mention the differences..

32. Microscope Vocabulary
Magnification VS Resolution
Magnification: increase of an object’s apparent size
Resolution: power to show details clearly
Both are needed to see a clear image

33. 1. Compound Light Microscope 1st type of microscope, most widely used
Types of Microscopes
1. Compound Light Microscope
1st type of microscope, most widely used
light passes through 2 lenses
Can magnify up to 2000x

35. Types of Microscopes
2. Electron Microscopes
Used to observe VERY small objects: viruses, DNA, parts of cells
Uses beams of electrons rather than light
Much more powerful

36. Types of Electron Microscopes
Scanning Electron Microscope (SEM)
Can magnify up to 100,000x

38. Types of Electron Microscopes
Transmission Electron Microscope (TEM)
Can magnify up to 250,000x

40. Mention the differences..

41. Three advantages of using light microscopes include:
Colour images instead of monochrome,
A larger field of view,
Easily prepared sample material with the possibility of examining living material and observing movement.
Advantages of Electron microscopes (Scanning and transmission electron microscopes)
Higher resolution and magnifications