1. Structure and Function of the Cell
Chapter 4
Structure and Function of the Cell

2. 4-1 Introduction to the Cell
Biology – The study of life
Bio – life
Ology – study of
Cell – smallest unit of matter that can carry on all life functions

3. I. Discovery of the cell
Early 17th century (a.k.a. 1600’s) – discovery of the microscope
1665:

4. ROBERT HOOKE The man the discovered cells! Looked at a slice of cork
Plant cells

5. Saw “little boxes”
Reminded him of small rooms that monks lived in called cells
So that is how cells got their name!

6. Cell Theory 150 years later …. Cell theory – 3 parts
All living things are composed of at least one cell
Cells are the basic unit of structure and function in an organism
Cells come from other cells

7. II. Cell diversity

8. A. Size Most are microscopic few are seen by the naked eye
Size is limited by:
Ratio of surface area to volume
Nutrients must enter the cell
If it is too large – materials won’t enter the cell fast enough

9. B. Shape
Shape reflects function
Examples:

10. Nerve cell
Branched and long
Job: Transmit information

11. Skin cells
Flat and layers of dead cells
Job: Protection

12. White Blood Cells Blob – move through small openings and eat bacteria
Job: kill bad things

13. C. Internal Organization
Organelles – cell component that performs a specific function
Like organs of the body – “Itty bitty baby organs”

14. EUKARYOTIC CELL
Eukaryotic cell – has a nuclear membrane and membrane- bound organelles
Just like you and me!!
All cells that are not bacteria

16. PROKARYOTIC CELL No membrane – bound organelles No nuclear membrane
Example: bacteria cells

18. 4-2 Parts of the eukaryotic cell

19. Eukaryotic cells are different
Three main parts
Cell membrane
Organelles
Nucleus

20. I. Cell Membrane Holds everything inside the cell
Semipermeable – (selectively permeable) – Only allows some things through

21. Cell Mem. Make-up Made of:
Phospholipid bilayer – fat with a phosphate group attached
Proteins – allows certain things through

22. The phospholipid Hydrophilic end Hydrophobic end Latin:

23. The cell membrane Proteins
Some proteins go all the way through the mem.
These serve as channels or pores

24. Fluid Mosaic Model of cell mem
What is a mosaic?

25. Fluid Mosaic Model of cell mem
For many years scientists thought that proteins were static
(stuck in 1 place)
The phospholipid bilayer behaves more like a fluid than a solid
Proteins can move
Cell membrane is always changing

26. II. Organelles of eukaryotic cells
Organelles – Parts that make-up the cell

27. 1. Cytoplasm
Area between cell mem. and nucleus
Also called cytosol

28. 2. Mitochondria (MIGHTY)
Powerhouse of the cell (Makes energy)
Makes ATP (adenosine triphosphate) -molecule that gives us energy
Double membrane with series of folds (Cristae)
Highly active cells= lots of mitochondria
Has own DNA
Comes from your mama

29. Mitochondria

30. 3. Ribosome Help make proteins Most numerous
NOT membrane bound (in bth eukaryotic and prokaryotic cells)
Some are free others are attached to the endoplasmic reticulum

31. Ribosome

32. 4. Endoplasmic Reticulum
System of tubules and sacs
Function= path for molecules
Two types:
Rough E.R. – has ribosomes
Smooth E.R.- no ribosomes

33. Smooth Endoplasmic Reticulum
Forms channels within the cell
Breaks down and make lipids
Helps detoxify chemicals

34. Rough Endoplasmic Reticulum
Rough b/c of ribosomes on the outside
Ribosomes help make proteins
RER connects to the nucleus and helps make proteins

35. E.R.

36. 5. Golgi Body (apparatus)
Processing, packaging, and shipping proteins
Stacked membranes
Vesicles (membrane bound bags) carry materials.

37. Golgi

38. Protein from rough E.R to golgi

39. 6. Lysosome Latin: Lys – to break or split
Sac filled with digestive enzymes
Digests anything bad – like the garbage disposal of the cell.
Suicide sac-can kill a cell
Human hand begins as a solid and lysosome kills cells to make spaces btwn fingers

40. Lysosome

41. 7. Cytoskeleton Provides support Move organelles within the cytoplasm
Two types:
Microfilaments – play a role in cellular movement
Microtubules – form spindle fibers (attach to centrioles and chromosome during cellular division

42. Microtubules/Spindle fibers

43. 8. Cilia
Short hair like extensions that help with movement (made of microtubules)
Single-celled organisms use it to move
Multi-cellular organisms use it to clean
Ex: Respiratory system

44. Paramecium w/ cilia

45. 9. Flagella One up to a few long whip – like extensions
Whip around to move a cell

46. Flagellum example:
A SPERM CELL!!!

47. Cilia and Flagella

48. III. Nucleus
Filled with Nucleoplasm

49. Three main parts
Surrounded by semi permeable membrane (Nuclear membrane/ envelope)
Double mem. That surrounds the nucleus
Has pores
Nucleolus
Helps make ribosomes
DNA

50. DNA (Deoxyribonucleic acid)
Two forms of DNA
Chromosome )( - DNA is condensed around proteins – ONLY during cellular reproduction
Chromatin – DNA is all spread out like a plate of spaghetti

52. Nucleus

53. The Cell

54. IV. Plant Cell

55. Plant cells have all the other organelles + three others

56. 1. Cell Wall
Outside the cell membrane
Helps support and protect

57. 2. Vacuole Storage for water and food Much larger in plant cells
May not exist in some animal cells

58. 3. Chloroplasts Contain chlorophyll
Chlorophyll is the pigment that allows plants to make food