Chapter 4 Notes

1. Chapter 4 Notes BIOLOGY “The Cell”

2. 4-1 CELLS • Science is not static • World is flat • Planets revolve around the Earth • Only things that we can see, exist

3. 1665 • Robert Hooke- England: looked at a thin slice of cork • Where does cork come from? • He saw chambers, and called them “cells” • Why were the chambers empty?

9. 1665… • Anton Von Leewenhoek • Used a single lens microscope to observe pond water • He probably saw paramecium, euglena, and amoebas

10. Paramecium

11. Metaboly movements of Euglena. • Euglena Amoeba

12. Cells are the basic units of life • Cell Theory has 3 parts that are accepted by all scientists….

13. 1. All living things are made up of cells • 1838 Matthias Schleiden – all plants are made of cells • 1839 Theodor Schwann- all animals are made of cells

14. 2. New cells only come from other cells • 1855 Rudolf Virchow said this …

15. 3. Cells are the basic unit of structure and function of all living things. • Atoms are the smallest part that can exist alone • Cells are the smallest part that can exist alone and be considered “alive”

16. Technology: define each on yr own • Fluorescent Labels • Confocal Light microscope • Hi Resolution Video • Electron Microscope • TEM • SEM • Scanning Probe microscope

17. Prokaryotes/ Eukaryotes

20. 4-2 Eukaryotic Cell Structure • Organelles; the mini organs of the cell

21. In the NUCLEUS • Nucleus- sends out instructions for making proteins “the brain” • Nuclear envelope- separates the nucleus from rest of cell • Nucleolus – dense region of the nucleus where manufacturing of proteins begin

22. Chromatin-DNA + protein • Chromosomes- thickened chromatin that are visible during cell division in nucleus

23. In the CYTOPLASM • Ribosomes- where proteins are assembled • ER- where lipid parts needed for cell membrane are made, also some proteins

24. Rough ER- is involved in making proteins, ribosomes are found on its surface • Proteins made on these ribosomes, go into the rough er and are modified • Most proteins that are made here will be exported out of the cell • Smooth ER- contains collections of enzymes, ready for action • These enzymes perform specialized tasks like detoxification of drugs • Liver cells contain a lot of smooth ER ? Tylenol, alcohol

25. CYTOPLASM… • Lysosomes: clean up crew • Filled with enzymes, that help digest proteins, lipids, carbs- “get the junk out of the cell”. • Tay Sachs Disease: these don’t function properly

26. Vacuoles • Storage place for water, salts, proteins, carbs • In plants, it is VERY LARGE, and holds water and is under pressure – Making it possible for the plant to support structures like leaves and flowers • Paramecium has a contractile vacuole to pump out excess water

27. CYTOPLASM… • Golgi Apparatus: (discovered by Camillo Golgi) modifies, sorts and packages proteins, from the ER for storage or secretion outside the cell • Customization, finishing touches are put on the proteins- then they are packed and leave the factory

28. Mitochondria- “powerhouse” of the cell, converts chemical energy in food, to a compound the cell can actually use- • Mitochondria has its own simple circular DNA • In humans, Mitochondrial DNA is inherited from your mom • Your heart cells many mitochondria in each cell

29. Chloroplasts w/ chlorophyll • Capture energy from sunlight, and convert it into chemical energy • Contain the pigment chlorophyll

30. Cytoskeleton: protein filaments that help maintain cell’s shape- also involved in movement • Centrioles- help to organize cell division (stars) in animals cells only • Microtubules and filaments: help maintain cell shape- help amoeba move

31. Flagellum/ Cilia- • For movement or sweeping – respiratory tract • Sperm cells

33. Cell membrane- both animals and plants • Regulates what enters and leaves • Provides some protection and support

34. Cell wall • Present in plants, algae, fungi, and most prokaryotes • Porous enough to allow water, oxygen and carbon dioxide among other substances through • Fiber- and bowel movement • Strong supporting layer made of cellulose a tough carbohydrate fiber

35. Why don’t cells just grow bigger? • Adults don’t have bigger cells than kids… they just have MORE of them

36. The world's tallest man in 2007 7’9”, Bao Xishun and his 5’6” wife… • most peoplewith acromegalic gigantism eventually die because of complications fromheart problems. • "Keeping the blood going round such an enormous circulationbecomes a huge strain for the heart,"

37. Why don’t cells just grow bigger? • DNA overload….DNA would need extra copies to handle “information demand” • Too difficult to get enough nutrients and oxygen IN and waste products OUT

38. What would happen?Calculate ratio of surface area to volume • L * W * # of sides= surface area • L * W * H= Volume • Practice problem: if cell was a cube and its sides were 1cm each ….figure SA? • Figure V… • What if the cell were 3cm? SA? V? • What is the ratio?

39. Volume increases faster than surface area • 1*1*6=6 SA • 1*1*1=1 V • Ratio 6:1 • 3*3*6=54 SA • 3*3*3=27 V • Ratio 54:27 reduce… 2:1 • The decrease in ratio of SA to V- makes it harder for the cell to move needed products in and out.