1. CHAPTER 4  A TOUR OF THE CELL 4.2  Most cells are microscopic Objectives:1) Be able to explain why cell size is limited. III. Surface area-to-volume ratio A. Surface Area(SA) 1. The measurement of the exterior of the cell 2. To calculate  take the # of sides and multiply by the length and width of sides B. Volume 1. The measurement of the internal contents of the cell 2. To calculate  multiply the length x width x height I. Diffusion A. One of many ways cells transport materials throughout the cell B. Cell parts must not be too far from the cell membrane 1. Diffusion is very fast and efficient over short distances 2. Diffusion becomes slow and inefficient as distances become larger II. DNA limits cell size A. DNA contains the directions for all cell activity 1. For example  Proteins a. If cell is too large the DNA cannot make proteins fast enough to support the cells needs

2. L=1 W=1 H=1 SA= 6X1X1=6 Volume= 1X1X1=1 C. As a cell grows so to does its SA and volume 1. The problem  the volume increases faster than the SA W=2 H=2 L=2 SA=24 Volume=8 4X the SA 8X the volume

3. 2. How does the SA-to-volume ratio affect the function of the cell a. If cell size doubles, the cell would require 8x more nutrients & would have 8x more waste to excrete 1. SA would only increase by 4x 2. The plasma membrane could not accommodate this increase

4. 4.3  Prokaryotic cells are structurally simpler than eukaryotic cells Objective:1) Be able to briefly explain the difference between a prokaryotic cell and a eukaryotic cell. I. Prokaryotic vs. Eukaryotic ProkaryotesEukaryotes No Nucleus (have a Nucleoid)Nucleus No membrane bound organellesMembrane bound organelles Cell membrane Cytoplasm Ribosomes I. Organelle Intro A. A specialized compartment that carries out 1 or more specific functions B. 4 basic functional groups 1. Manufacturing a. Nucleus, ribosomes, endoplasmic reticulum, golgi apparatus 4.4  Eukaryotic cells are partitioned into functional components Objective:1) Be able to explain the importance of organelles

5. C. How do organelles benefit a eukaryotic cell 1. Allows specialized activities that require different environments to be carried out simultaneously 2. Hydrolysis of molecules a. Lysosomes & vacuoles 3. Energy processing a. Mitochondria & chloroplast 4. Structural support, movement, communication a. Cytoskeleton, plasma membrane, cell wall

6. 4.6-4.13  Cell structures involved in manufacturing and breakdown Objectives:1) Be able to describe structure and functions of organelles I. 4.6-The nucleus is the cells genetic control center A. The brains 1. Directs all cell activity a. Tells all other organelles what to do by directing protein synthesis 2. Storage center for cells DNA 3. Nuclear envelope a. Bilayer membrane that surrounds the cell controlling what comes in and out

7. II. 4.7- Ribosomes make proteins for use in the cell and export A. Site were proteins are assembled B. 2 types of ribosomes 1. Free ribosomes a. Suspended in the cytoplasm b. Manufacture proteins that function within the cytoplasm 2. Bound ribosomes 1. Attached to the endoplasmic reticulum or nuclear envelope 2. Manufacture proteins that will be inserted into the plasma membrane, exported from the cell

8. III. 4.9-The endoplasmic reticulum is a biosynthetic reticulum A. Smooth endoplasmic reticulum 1. No ribosomes attached to 2. Synthesizes lipids (mainly oils) 3. Calcium ion storage B. Rough endoplasmic reticulum 1. Ribosomes attached to 2. Synthesize phospholipids & proteins

9. IV. 4.10-Golgi apparatus finishes, sorts, & ships cell products A. The packaging and distribution center of the cell B. Receives & modifies products from endoplasmic reticulum 1. As products travel through the golgi apparatus they will be modified before being shipped out to the cell or other cells

10. V. 4.11-Lysosomes are digestive compartments within a cell A. The digestive system and recycler of the cell 1. Cleans up waste and damaged cell structures & recycles their organic components 2. Breaks down nutrient material for the cell to utilize B. Structure: Demonstrating the importance of compartmentalization 1. Membrane enclosed compartment containing digestive enzymes a. Enzymes are potent enough to digest the entire cell b. Membrane contains enzymes so as to not harm the rest of the cell 1. Except under certain curcumstances C. Function 1. Digest food providing nutrients to the cell 2. Digest worn out or damaged organelles recycling their organic compounds 3. Digest harmful pathogens like bacteria and viruses & recycle

12. I. 4.14-Mitochondria harvest chemical energy from food  The power plant A. Creates the energy needed by the cell by cellular respiration 1. Converts food (sugar) into ATP 4.14-4.15  Energy-converting organelles Objective:1) Be able to describe structure and functions of organelles B. Structure 1. Outer membrane/Intermembrane space/Inner membrane/Matrix a. Matrix 1. Contains the mitochondrial DNA and necessary ribosomes

13. II. 4.15-Chloroplasts convert solar energy to chemical energy A. Provides the necessary sugar that is needed by the mitochondria B. Structured very similar as mitochondria 1. Outer membrane/intermembrane space/inner membrane/ stroma a. Stroma 1. Contains the chloroplast DNA and necessary ribosomes

14. READ 4.16 ON YOUR OWN 4.17  Internal support I. Cytoskeleton A. A network of protein fibers that provides the support allowing the cell to maintain its shape and provide locomotion.

15. IV. Plant cells vs. Animal cells PlantsAnimals Plasma membrane Nucleus Golgi ApparatusGolgi apparatus Mitochondria ChloroplastNO chloroplast Cell WallNO cell wall