Chapter 4

1. 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: • Hydro=__________ • Philic=__________ • Phobic=__________

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