1. HB p. 25
Cells

2. Since every living thing is made of cells, does that mean bigger organisms (like whales or elephants) have bigger cells?
Not really!
All organisms, no matter how tiny or how large are composed of cells.
There are different TYPES of cells (ex. Skin, bone, muscle, nerve), but all cells of a particular type are essentially the same size.
Therefore, the difference in cells in large vs. small organisms is the NUMBER of cells, not the SIZE!

3. How Were Cells Discovered?
New technologies lead to new discoveries
Robert Hooke - invented the first microscope and was the first to observe and name the small units that make up organisms. He called those small units cells because of the appearance of the structures in the dead cork he observed.

4. How Were Cells Discovered?
Anton van Leeuwenhoek - improved the microscope and procedures for observing cells. He was able to clearly see living cells when observing the scrapings from his teeth.

5. Fill It In …
Cells observed by …
Hooke:
Leeuwenhoek:

6. The Cell Theory
Through the cooperative efforts of many individual scientists, a unifying cell theory developed:
All organisms are made of cells
Cells are the structural & functional units of organisms
Cells come from pre-existing cells

7. The Cell Theory

8. Prokaryotic vs Eukaryotic Cells
Are all cells alike?
Two main types of cells ….

9. Prokaryotic Cells Simplest type of cell Includes only bacteria.
Structure of a prokaryotic cell
No nucleus
No membrane-bound organelles
Includes: circular chromosome (DNA), plasmids (smaller rings of DNA, and ribosomes

10. Prokaryotic Cells- MYP
Thought to have a symbiotic relationship with Eukaryotic Cells
Nucleus
Mitochondria
Chloroplasts

11. Eukaryotic Cells More complex than prokaryotic cells
Includes protist cells, fungi cells, plant cells, and animal cells (i.e. - everything EXCEPT bacteria cells)
Structure of a eukaryotic cell
Chromosomes contained within a nucleus
In addition to ribosomes contains membrane-bound organelles
Cells :)

12. Fill It In …
Prokaryotic
Eukaryotic

13. Check Yourself! Who first to observed dead cells?
Who first to observed living cells?
What are the two main types of cells?
How is the location of the DNA different in prokaryotic and eukaryotic cells?

14. What do cells share? Structures found in ALL cells

15. DNA/Chromosome(s)
DNA organized as chromosome(s). DNA directs cell activity 15

16. Cytoplasm
Cytoplasm is the “filling” of the cell and is made of up to 90% water. Water provides the necessary environment for all the chemical reactions the cell needs 16

17. Ribosomes
Ribosomes are organelles that are the site of protein synthesis. Proteins are essential for enzymes, structure, and communication
Uses DNA code to synthesize proteins 17

18. Cell Membrane
Also called the Plasma Membrane

19. Fill It In …
4 structures found in ALL cells: 1. 2. 3. 4.

20. Cell Membrane
Composed of a phospholipid bilayer with embedded proteins. The fluid mosaic model describes the structure of the cell membrane 20

21. Cell Membrane
Fluid - individual phospholipids and proteins can move past each other; they are not fixed in one position
Mosaic - the membrane has more than one type of molecule (phospholipids & proteins) 21

22. Cell Membrane- MYP Flexible/strong barrier
Some proteins from channel or pumps to allow things to go in and out of the cell
Carbohydrates are attached to membrane
These are used as chemical identification markers for the cell

23. Functions of the Cell Membrane
Selectively permeable - regulates what enters and leaves the cell. This helps maintain homeostasis
Gives the cell (cytoplasm) shape

24. Fill It In … The cell membrane is also called …
And is S____________ P_____________

25. Structures (organelles) found in EUKARYOTIC cells25

26. Fill It In …
Organelle means …

27. 1. Nucleus
Nucleus - surrounds the chromosomes for additional protection; is made of a phospholipid bilayer

28. Nucleus- MYP Surrounded by nuclear envelope (lipid bilayer)
Nuclear pores
Chromatin- DNA bound to proteins
Chromosomes are condensed chromatin
Nucleolus- dense region where ribosomes are synthesized

29. 2. Mitochondria
Mitochondria - site of cellular respiration which produces cell energy (ATP)
Active cells (muscle) -> hundreds of mitochondria
Inactive cells (fat) -> few mitochondria
Structure contains folded membranes which increases surface area allowing more space for more reactions
(MYP)-inherited through the ovum

30. 3. Vacuole
Vacuoles - store food, waste or water to be used inside the cell or excreted from the cell.
Size differs in plant vs. animal cells
Much, much larger in plant cells … why? 30

31. 4. Lysosomes
Lysosomes - contain digestive enzymes which digest food contained in vacuoles as well as old or damaged cell parts
(contain lipid bilayer) 31

32. 5. Endoplasmic Reticulum (ER)
ER - a series of interconnected folded membranes that function in modifying (changing) proteins, detoxification of alcohols, and communication

33. ER (MYP) Lipid components of the cell membrane are made here
Proteins and other material are exported or inserted into the cell membrane

34. Two Types of ER
Rough ER
Covered in ribosomes
Modify proteins

35. Two Types of ER
Smooth ER
Lacks ribosomes
Detoxification

36. 6. Golgi Complex
Golgi Complex - packages materials for export from cells
(MYP)- Modify, Sort, and Package
“finishing touches”

37. Plant Cell versus Animal Cell

38. Structures found ONLY in plant and plant-like cells
Chloroplasts - organelles full of chlorophyll that are the site of photosynthesis which produces sugars (C6H12O6)
Composed of folded membranes for more surface area 38

39. Structures found ONLY in plant and plant-like cells
Cell Wall - provides extra support, protection, and shape for the cell
Found outside the cell membrane and made of cellulose 39

40. Structure found ONLY in animal cells
Centrioles -organelle that helps with cell division in animal cells

41. Cytoskeleton (MYP) Protein filaments to help maintain shape
May help with movement (amoeba)
Microtubules help with cell division (pulling the chromosomes)

43. Fill It In … Summary of structure/function: Nucleus - Mitochondria -
Vacuole -
Lysosome -
ER -
Golgi -
Chloroplast -

44. Fill It In …
Plant only
Animal only

45. Check Yourself! What four structures are found in all cells?
What is the function of the mitochondria?
What is the function of the ribosome?
What term refers to small cell structures?
What two structures are found in plant and plant-like cells?