1. Chapter 3 Cellular Structure This is what this chapter is about, cells!!!

2. Cells under the microscope Robert Hooke saw these cork cells under the microscope in 1665. He saw a lot of little boxes, so he called them cells. Anton van Leeuwenhoek used a microscope to view water from a pond, and he discovered many living creatures. Let’s look at page 50-51 and discuss The measuring of cell structures.

3. Microscopes Light microscopes-Light passes through one or more lenses to produce an enlarged image of what you are looking at, such as hair, cells, and underwater specimens. Electron microscopes-Forms an image of a specimen using a beam of electrons rather than light.

4. Magnification and Resolution Magnification-The quality of making an image appear larger than its actual size. A magnification value of 200X indicate the image is 200 times larger than the original size. – RerererResolution-Measuring the clarity of the image, is it clear clear? Is it fuzzy. Some microscope do a great job at at keeping thing clear and perfect.

5. Types of microscopes Compound light microscope-Uses two lenses, a light bulb from the bottom shines up thorough the specimen, like our microscopes! – Can look at live specimens or slides. Electron microscopes-Can magnify images up toe 200, 000X. The electron beam and the specimen must be placed in a vacuum chamber, so the electrons in the beam will not bounce off gas molecules in the air. – No living tissue. – Called TEM

6. Some example of light microscopy

7. Scanning electron microscope or SEM Uses a needle like probe to measure differences in voltage caused by electrons that leak, or tunnel, from the surface of the object being viewed. End of section 1!!! Know your images!!!

8. Cell Features Mattias Schleiden and Rudolph Virchow formed the cell theory 1. All living things are made of one or more cells. 2. Cells are basic units of structure and function in organisms. All cells arise from existing cells.

9. Cellular size 100 trillion cells in the human body, most ranging from 5 um. To 20 um. in diameter. How much is a um? A thousand um = 1 mm. Small cells can exchange substances more readily than large cells because small objects have a higher surface area-to-volume ratio.

10. Common features of cells Cellular membrane-Outer boundary found in all cells. – Regulates what comes into and out of the cell, including gases, wastes, and nutrients. Cytoplasm-Cellular interior Ribosomes-Cellular structures in which proteins are made. DNA-Provides instructions for making proteins, regulates cellular activities, enables cells to reproduce.

11. Prokaryotes Single-celled organism that lacks a nucleus and other internal compartments. They CANNOT carry out many specialized functions. INTERESTING FACTS- Grow and divide very rapidly Some do not need oxygen to survive Genetic material is a single circular molecule of DNA Have a cell wall, providing structure and support Lack an internal supporting skeleton, depend on strong cell wall Some cells wall have a capsule to cling to anything, teeth, skin, food…..YUCK!!!!! Flagella enables movement, looks like a rat’s tail!!!

12. Eukaryotic cells (that’s us) Cells have a nucleus, what is a nucleus? It houses the cell’s DNA. Organelle-Structure that carries out specific activities in the cell. Vesicles-Move proteins and other molecules from one organelle to another. Cilia-hair-like structure used for movement. Help propel the cell.

13. The Cytoskeleton, the bones of the cell!! Protein fibers anchored to the inside of the plasma membrane. Like steel beams anchoring a building, or our own skeleton keeping us upright and not a big blob. Three kinds of cytoskeleton fibers 1.Long, slender microfilaments made of the protein actin. 2.Hollow tubes called microtubules. 3.Thick ropes of protein called intermediate fibers.

14. Actin fibers-Determine shapshape by pulling the plasma plasma membrane in somesome places, and pushing it out in others. This is a cow endothelial blood cell with actin fibers. The yellow color is the actin fibers.

15. Microtubules within the cytoskeleton act as a highway system for transportation of information from the nucleus to different parts of the cell. RNA molecules are transported along microtubular rails that extend throughout the cell like train tracks. This slide is of a embryonic mouse cell with the nucleus and extensive microtubule network.

16. Intermediate fibers-Provide a frame on which ribosomes and enzymes can be confined to particular regions of the cell.

17. Cellular membranes Some facts about cell membranes – They are not hard like a eggshell, but very soft like a bubble (though they do not break like one). – Lipids make up the membrane (as you remember last chapter). – Selectively permeable, so it will determine what substances leave and what will stay.

18. Phospholipids Lipid made of a phosphate group and two fatty acids. Polar head and two non-polar tails. The non-polar tails of the phospholipid make up the interior of the lipid bilayer. Because water both inside and outside the cell repels the non-polar tails, they are forced to the inside of the lipid bilayer.

19. Membrane Proteins The motion and fluidity of phospholipids enable some membrane proteins to move around within the lipid bilayer. Transport proteins aid the movement of substances into and out of the cell. End of section 2-

20. Cells organelles The nucleus Most functions of the eukaryotic cell are controlled by the cell’s nucleus. The nuclear envelope is made of two lipid bilayer that separate the nucleus from the cytoplasm. Nuclear pores are found a at the left. What else? Hereditary information of a eukaryotic cell is coded in the cell’s DNA, which is found in the nucleus.

21. Ribosomes and the Endoplasmic Reticulum Cells make proteins on ribosomes. Productions of proteins – Endoplasmic reticulum-The ER, is an extensive system of internal membranes that move proteins and other substances through the cell. The ER with attached ribosomes is called rough ER because it looks rough. As each protein is made, it crocrosses the ER membrane and entersenters the ER.

22. Vesicles-Small membrane-bound sac that transports substances in cells. Smooth ER lacks ribosomes, it can make lipids and break down toxic substances.

23. Packaging of proteins Golgi apparatus-Flattened, membrane-bound sacs that serves as the packaging and distribution center of the cell. It modifies the proteins that are received in the vesicles from the ER. Lysosome-Which are small, spherical organelles that contain the cell’s digestive enzymes. Step 1-Ribosomes make proteins on the rough ER. The proteins are packaged into vesicles. Step 2-The vesicles transport the newly made proteins from the rough ER to the Golgi apparatus.

24. Step 3-In the Golgi apparatus, proteins are processed and then packaged into new vesicles. Step 4-Many of these vesicles move to the cell membranes and release their contents outside the cell. Step 5-Other vesicles, including the lysosomes, remain within the cytoplasm. Lysosomes digest and recycle the cell’s used components by breaking down proteins, nucleic acids, lipids, and carbohydrates.

25. Mitochondria-Powerhouse of the Cell Harvest energy from organic compounds to make ATP, the main energy currency of the cell. Note the inner membrane folded and large surface area. Mitochondrial DNA-Mitochondria make some of their own DNA, independent upon nuclear DNA and similar to the circular DNA of prokaryotic

26. Plant cells Cell wall-Cell membrane of plant cells is surrounded by a thick cell wall. This is composed of proteins, carbohydrates, and the polysaccharide cellulose. Chloroplasts-Organelle that uses light energy to make carbohydrates from CO₂ and H₂O. Central vacuole-Stores water and may contain many substances, including ions, nutrients, and wastes. » End of section 3!!!