Microscopes and Cells

1. Microscopes and Cells

2. Microscopes • Light microscope (LM) works by passing light through the specimen. Specimen must be thin. - Magnification - the increase in apparent size of the object. - Resolution – a measure of the clarity of the image. • We use these in lab • Know all parts and functions

3. Stereo Light Microscope Used when 3 dimensional imaging is needed.

4. Microscopes cont. • Electron Microscope (EM) instead of light it uses a beam of electrons. - 2 types of EM: - Scanning electron microscopes (SEM) used to study surfaces - Transmission electron microscope (TEM) used to study internal details - can’t be used to study living specimens

5. SEM- left TEM-right

8. Microscopes

11. Cell Theory • Microscopes advances led to the “cell theory” – All living things are composed of cells and all cells come from other cells.

12. Two types of Cells • Prokaryotes - no internal membranes therefore no nucleus and not many organelles - Domains Bacteria and Archaea - 1-10 μm • Eukaryotes - have internal membranes therefore a distinct nucleus and many organelles.

13. Similarities • Both Prokaryotes and Eukaryotes have: - plasma membrane – surrounds the cell - ribosomes – tiny structures that make proteins - DNA – passes on hereditary information

14. Prokaryotes

15. Eukaryotes

17. Eukaryote Cell Structure • Plasma membrane – surrounds cell - made of phospholipid bilayer - is selectively permeable - carbohydrates & proteins protrude from surface & have many functions: - cell to cell recognition - transport proteins - signal receptors

20. Nucleus & RibosomesGenetic control of cell • Nucleus – genetic control center, contains: - chromatin which is DNA and proteins that help keep it spiraled. This is the genetic code. - Nucleolus – makes ribosomes • Nuclear envelope – surrounds nucleus - is a semi-permeable double membrane

21. Ribosomes • Protein synthesis • Made in nucleus, do their work in cytosol • Can be attached to endoplasmic reticulum • Can be attached to outside of nucleus • Can be suspended in cytosol DNA directs protein production DNA-> RNA-> Protein Nucleus-> cytoplasm-> ribosome

23. Endomembrane system • Internal network made up of endoplasmic reticulum, Golgi apparatus and vesicles. • Two types of endoplasmic reticulum - smooth - rough

24. Rough ER • Has ribosomes on outside of membrane • Makes more membrane throughout cell • Proteins from ribosomes inserted into ER for transport to other organelles • Transport vesicles-sacs made of membrane bud off ER

25. Smooth ER • Lacks ribosomes • Contains enzymes • Synthesize lipids including steroids • Detoxify drugs HOMEWORK: HOW DOES THE LIVER DETOXIFY DRUGS FROM THE BLOOD?

26. GOLGI APPARATUS • Receives, refines, stores and distributes chemical products of cell • One side receiving end, one side ships • Pathway of a protein: ribosome, ER, vesicle, golgi, vesicle, cell membrane

30. lysosomes • Develop from vesicles that bud off golgi • Contain enzymes in acid env • Not found in most plant cells • In simple cells, fuse with food vacuoles to add enzymes-digest • Help destroy harmful bacteria- WBC ingest bacteria into vacuoles, enzymes cause lyses

31. Lysosomal storage diseases • Person missing an enzyme of lysosome • Abnormal lysosome engorges with indigestible substances, interferes with other cell functions • Usually fatal • Tay Sachs- nerve cells & brain

32. Vacuoles & vesicles • Vacuoles- large sacs of membrane that bud from ER, Golgi, or plasma membrane • Storage- water, food, waste • Small-vesicle • Central vacuole in plants-store • water, chemicals, poisons • Can act as lysosome for plant

33. Mitochondria-converting energy • Cell respiration-converts chemical energy in food to ATP energy of cell • Structure: • Outer membrane • Matrix contains thick fluid in the space • Inner membrane folds- cristae

35. chloroplast • Perform photosynthesis- converts light energy (sun) into chemical energy (food) • Only in plant cells • Structure: • Outer membrane • Inner membrane organized into stacks called grana • Space between grana called stroma

36. cytoplasm • Area between nucleus and cell membrane-2 parts • Cytosol- liquid part • Cytoskeleton-several fibers-protein • Microtubules-straight hollow tubes-shape, support • Intermediate-ropelike for cell shape • Microfilaments- thin, solid- movement

37. centrioles • Made of microtubules- • Guide movement of chromosomes • Cell division- animal cells-paired • Cilia & flagella- microtubules • Movement- cells-protists • Cilia-shorter, animal & human respiratory cells • Flagella-longer- human sperm, protists

38. Cell walls • Found in plants, bacteria, algae, fungi • Found outside cell membrane • Made of cellulose, ligninn pectin

46. Materials entering and exiting cells membrane function

47. What materials? • Enter: - water needed for hydrolysis - amino acids to build protein - carb’s like glucose for cellular respiration to make energy - oxygen for cellular respiration in mitochondria - cellular respiration equation C6H12O6 + O2 CO2 + H2 O + Energy (glucose)

48. Materials cont. • Exit: - CO2 - from cellular resp. - proteins – produced here needed elsewhere - waste – whatever the cell doesn’t want

49. How materials enter & exit • Most mol’s are liquid when they enter & exit - solution - ie. salt water - solute – the dissolved substance (salt) - solvent – the dissolver (water)

50. Passive transport • Diffusion – mol’s move from area of high concentration to area of low concentration • Molecules move until equilibrium is reached – when conc.is the same on both sides • Molecules always try to reach equilibrium • http://www.indiana.edu/~phys215/lecture/lecnotes/lecgraphics/diffusion.gif