Solar-powered sea slug harnesses stolen plant genes

1. Solar-powered sea slug harnesses stolen plant genes http://www.newscientist.com/article/dn16124-solarpowered-sea-slug-harnesses-stolen-plant-genes.html Green Sea Slug Is Part Animal, Part Plant http://www.wired.com/wiredscience/2010/01/green-sea-slug/

2. Online Refresher • You are going to visit two websites to refresh you organelle knowledge. We will cover them in more detail later. • You may want to jot some notes on some of the organelles you remember very little about.

3. 11/12 ATB • Which has more energy, carbs or lipids? • Today: • Labs due • Go over tests • Group test • Begin discussing cellular organelles

4. 11/13 ATB What is the basic unit of life? Today: Discuss the cell theory Start our discussion on the cell and it’s organelles

5. Amazing Cells – Univ of Utah http://learn.genetics.utah.edu/content/begin/cells/ http://library.thinkquest.org/12413/structures.html Cells Alive – Eucaryotic Cell Interactive Animation http://www.cellsalive.com/cells/cell_model.htm

6. Organelle Interactive • Amazing Cells – Univ of Utah • http://learn.genetics.utah.edu/content/begin/cells/ • Click “Inside a cell” and explore some of the organelles. • Cells Alive – Eukaryotic Cell Interactive Animation • http://www.cellsalive.com/cells/cell_model.htm • Choose “Plant Cell” • Scroll over the diagram and click to learn more about each organelle

7. Chapter 4 - Cells

8. What are cells? Cell Basic unit of structure and function of life

9. Cellular Organization • Organelle • Intracellular structures with specific functions • Tissue • Group of similar cells with a specific funtion • Organ • A groups of tissues with a particular job • Organ system • A group of organs that accomplish a task • IE: • Digestive system • Respiratory System • Nervous System • Endocrine System • Cardiovascular System

11. The study of cells… What hindered the study of cells for previous scientists? They are very small We didn’t have the technology (microscopes to see them) Your body is a habitat for a variety of cells (vid)

12. Robert Hooke (1665) • Used light microscope to view cork cells (first to see cells – however they were dead) • Named tiny boxes he saw “cells” • Under the microscope, cork seemed to be made of thousands of tiny, empty chambers that Hooke called “cells”. The term cell is used in biology to this day.

13. Aton van Leeuwenhoek (1673) • First person to observe living cells • Used simple microscope(only one lens) • In Holland, Anton van Leeuwenhoek examined pond water and and other things, including a sample taken from a human mouth. He drew the organisms he saw in the mouth—which today we call bacteria.

14. Matthias Schleiden • Concluded that all plants made of cells (1838) • German botanist

15. Theodor Schwann • Concluded that all animals were made of cells (1839) • German zoologist

16. Rudolf Virchow • Concluded that new cells could be produced only from the division of existing cells • German physician (1821 – 1902)

17. The cell theory states: • What is the cell theory? • All living things are made up of cells. • Cells are the basic units of structure and function in living things. • New cells are produced from existing cells.

18. Cell Diversity • Cell Shape • Shape reflects function Function of Nerve cell? Shape? Function ofSkin Cells? Shape?

19. 11/14 ATB • What are the three parts of the cell theory? • Today: • Finish discussion on cell size. • Page 3 in cell packet • Discuss microscopes

20. Cell Size • Cell Size • Cells vary greatly in size • Nerve cells in giraffe neck vs. Human egg cell - size of a . • Wide range of sizes:0.2 – 1000 micrometers • Average is from 5-50 micrometers • Eukaryotic Cell 10-100 micrometers • Prokaryotic Cell 1-5 micrometers • Cell Size: http://learn.genetics.utah.edu/content/begin/cells/scale/

21. Cell Size • Cell size is limited by its surface area to volume ratio

22. What is the problem with increasing cell size? • Volume increases faster than surface area as a cell grows • PROBLEM: • needed materials can’tget in fast enough (O2, glucose) and wastes out fast enough (CO2) • Notice SA increasedonly 25 times and thevolume increase125 times

24. Light Microscopes and Stains • Uses two lenses to magnify the object / organism • Stain allow us to see cell structures that may otherwise not be visible • PRO • Can be used to study living specimens • Inexpensive (we can use them) • CON • Only able to magnify an object 1000 times

25. Light Microscopes and Cell Stains A typical light microscope allows light to pass through a specimen and uses two lenses to form an image. The first set of lenses, located just above the specimen, produces an enlarged image of the specimen. The second set of lenses magnifies this image still further. Because light waves are diffracted, or scattered, as they pass through matter, light microscopes can produce clear images of objects only to a magnification of about 1000 times. Another problem with light microscopy is that most living cells are nearly transparent, making it difficult to see the structures within them. Using chemical stains or dyes can usually solve this problem. Some of these stains are so specific that they reveal only compounds or structures within the cell.

26. Light Microscopes and Cell Stains Some dyes give off light of a particular color when viewed under specific wavelengths of light, a property called fluorescence. Fluorescent dyes can be attached to specific molecules and can then be made visible using a special fluorescence microscope. Fluorescence microscopy makes it possible to see and identify the locations of these molecules, and even to watch them move about in a living cell.

27. Electron Microscopes – TEM and SEM • Use beam of electrons that are focused by a magnetic field. • Two types: Scanning (SEM) and Transmission (TEM) electron microscope • PRO’s • Can see very small object • CON’s • Specimen must be dead • Expensive

28. Yeast Cells • Light Microscope • TEM (2D slice) • SEM (3D)

29. Light vs. Electron Microscope • SEM? • TEM? • LM?

31. Electron Microscopes Light microscopes can be used to see cells and cell structures as small as 1 millionth of a meter. To study something smaller than that, scientists need to use electron microscopes. Electron microscopes use beams of electrons, not light, that are focused by magnetic fields. Electron microscopes offer much higher resolution than light microscopes. Because electrons are easily scattered by molecules in the air, samples examined in both types of electron microscopes must be placed in a vacuum in order to be studied. Researchers chemically preserve their samples first and then carefully remove all of the water before placing them in the microscope. This means that electron microscopy can be used to examine only nonliving cells and tissues.

32. TEM and SEM • There are two major types of electron microscopes: transmission and scanning. • Transmission electron microscopes make it possible to explore cell structures and large protein molecules. • Because beams of electrons can only pass through thin samples, cells and tissues must be cut first into ultra thin slices before they can be examined under a transmission electron microscope. • Transmission electron microscopes produce flat, two-dimensional images. • In scanning electron microscopes, a pencil-like beam of electrons is scanned over the surface of a specimen. • Because the image is of the surface, specimens viewed under a scanning electron microscope do not have to be cut into thin slices to be seen. • Scanning electron microscopes produce three-dimensional images of the specimen’s surface.

33. 11/15 ATB • What are some problems that occur when a cell gets too large? • Today: • Page 4 in notes • Discuss prokaryotic and eukaryotic cells • Book Assignment • Bill Nye – Cells (?)

34. Light vs. Electron Microscope • SEM? • TEM? • LM?

35. Prokaryotic vs. Eukaryotic Cells • Eukaryotes are cells that enclose their DNA in nuclei. • Prokaryotes are cells that do not enclose DNA in nuclei.

36. Prokaryotes and Eukaryotes • Although typical cells range from 5 to 50 micrometers in diameter, the smallest Mycoplasma bacteria are only 0.2 micrometers across, so small that they are difficult to see under even the best light microscopes. • In contrast, the giant amoeba Chaos chaos may be 1000 micrometers in diameter, large enough to be seen with the unaided eye as a tiny speck in pond water. • Despite their differences, all cells contain the molecule that carries biological information—DNA. • In addition, all cells are surrounded by a thin, flexible barrier called a cell membrane.

37. Cell Types Prokaryote Do not enclose DNA in a nucleus DNA mass in center of cell No membrane bound organelles Small / more simple than eukaryotic cells Example: Bacteria

39. Cell Types • Eukaryote • DNA found in nucleus • 1 or more cells • Have membrane bound organelles • Larger / more complex than prokaryotes • Examples: • plants, animals, fungi,“protists”(paramecium, amoeba)

42. Eukaryotic vs. Prokaryotic Cells

43. Which do you think is older? • Which type of cells are older? Prokaryotic or Eukaryotic? Why? • Scientists think prokaryotic cells evolved first, since they are less complex

44. 11/16 ATB • What are two differences between a prokaryotic and eukaryotic cell? • Today: • Virtual field trip

45. 11/28 ATB • What is the job of the DNA in a cell? • Today: • Get out your packet – page 4 (review endosymbiosis) • Grade Sheet – (only grade is testing for organic substances lab) • Books – start reading about organelles • Microscopes – start using them tomorrow

46. Endosymbiosis: • As prokaryotic cells evolved they engulfed other prokaryotic cells, which eventually became eukaryotic cells • Scientists think that this is how mitochondria and plastids became incorporated into plant and animal cells • Evidence? • Mitochondria and plastids have DNA that varies from the rest of the cell • Mitochondria have their own DNA and only reproduce from division of preexisting mitochondria • Plastid DNA is very similar to DNA of some photosynthetic bacteria

47. Endosymbiosis

48. Endosymbiosis