Living Environment Unit 3 Study Outline PDF

# Honors Living Environment Unit 3 (Cells and Cell Transport) Study Outline ## A. Scientists - Be able to identify the contributions of the following scientists to the knowledge we have of the cell and the cell theory. 1. **Anton Van Leeuwenhoek** - first microscope, "animalcules" 2. **Robert...

# Honors Living Environment Unit 3 (Cells and Cell Transport) Study Outline ## A. Scientists - Be able to identify the contributions of the following scientists to the knowledge we have of the cell and the cell theory. 1. **Anton Van Leeuwenhoek** - first microscope, "animalcules" 2. **Robert Hooke** - first compound microscope, studied cork cells, "cell" 3. **Matthias Schleiden and Theodor Schwann** - all plants and all animals are made up of cells 4. **Rudolf Virchow** - cells come from preexisting cells ## B. Microscope - Be able to identify the following parts of the microscope and state their function: 1. **Ocular Lens/Eyepiece** - magnifies image 2. **Objective Lenses (scanning, low, high power)** - magnifies image 3. **Body Tube** - connects eye piece to objective lenses 4. **Nosepiece** - contains the objective lenses 5. **Coarse Adjustment** - used to bring image into focus under scanning power only 6. **Fine Adjustment** - takes fuzziness out image 7. **Arm** 8. **Base** - to carry the microscope safely, use one hand to hold it by the arm and the other under the base. 9. **Stage** - place slide on this platform 10. **Stage clips** - holds slide on stage 11. **Diaphragm** - adjusts the amount of light passing through the specimen ## 2. Procedure for using microscope 1. Always start under the lowest power (scanning power). 2. Use the coarse adjustment knob to bring image into focus. 3. Center your image before switching to the next power. 4. Under low and high power use the fine adjustment knob ONLY. 5. Remember that the image will appear UPSIDE DOWN and BACKWARDS under the microscope. ## 3. Calculating total magnification 1. Multiply the power of the ocular lens by the power of the objective lens. - Scanning 10x X 4x = 40x - Low 10x X 10x = 100x - High 10x X 40x = 400x ## 4. Troubleshooting 1. Know what to do in the following situations: - Image is too dark - adjust the diaphragm. - Image is fuzzy - use the fine adjustment knob. - You can only see part of the image under high power - center the image before rotating to the higher power objective lens. ## 5. Technique 1. Wet mount- apply coverslip at a 45 degree angle to reduce trapping air bubbles. 2. Applying a stain or solution - place paper towel on one side of the coverslip and the stain/solution to the opposite side. ## 6. Invention of Microscope → Discovery of Cells → Advances in Microscope → Advanced knowledge of cells ## C. Cell Theory 1. All living organisms are composed of one or more cells. 2. The cell is the basic unit of structure and organization in organisms. 3. Cells come from preexisting cells. ## Exceptions to the Cell Theory 1. Mitochondria and Chloroplast - they have their own DNA and can replicate independently within a cell, essentially acting like small cells within a larger cell. - supported by the endosymbiotic theory of evolution 2. Viruses - can make us sick and can be transmitted from person to person, but viruses cannot replicate on their own or maintain homeostasis. Viruses are not composed of cells. 3. First Cell - the first cell could not have arisen from another cell. ## D. Cells and Organelles 1. Prokaryote vs. Eukaryote - Prokaryotes - first cells, simple, fewer organelles, no nucleus - BACTERIA - Eukaryotic cells - came later, more complex, membrane-bound organelles, nucleus - Plants, animals, fungi, protists 2. Animal vs. Plant Cell - Animal cells only - centrioles - Plant cells only - cell wall, large vacuole, chloroplasts 3. Organelles - Know the structure and function of the organelles. - Nucleus - contains DNA, controls cell processes - Nucleolus - where ribosomes are made - Nuclear membrane - controls what exits and enters the nucleus - Ribosome - site of protein synthesis - Endoplasmic Reticulum - transportation route within cell - Rough ER - contains ribosomes, makes proteins - Smooth ER - makes lipids - Golgi Apparatus - modifies, packages and transports proteins - Lysosome - contains digestive enzymes to breakdown nutrients and worn out organelles - Cytoskeleton - internal scaffolding, provides structure and support - Mitochondria - site of cellular respiration - Vacuole - stores materials - Chloroplast (plants only) - site of photosynthesis - Centrioles (only animal cells) - involved in cell division - Cell Wall - provides support, made up of cellulose - Cytoplasm - jelly-like fluid within cell, where chemical reactions take place - Cell (Plasma) Membrane - semi permeable, controls what exits and enters cell ## E. Cell Membrane 1. Fluid mosaic model - describes the structure of a cell membrane as a flexible, fluid bilayer of phospholipids with various proteins and other molecules embedded within it. 2. Selective Permeability - lets some things through but not all things (size determines what is able to pass through the cell membrane). - Small, uncharged molecules CAN easily pass through. - Large, charged molecules CANNOT easily pass through. 3. Structure - **Phospholipid Bilayer** - two layers of phospholipids, hydrophilic heads on the outside and hydrophobic heads on the inside. - **Proteins** - **Receptor Proteins** - involved in cell communication. - **Transport Proteins** - involved in transport (materials entering/exiting the cell). - **Enzymes** - speed up chemical reactions. 4. Transport - absorption and distribution of materials - **Passive Transport** - No Energy Required because molecules diffuse from high concentration to low concentration. - **Dynamic equilibrium** - when the concentration of molecules remains equal on both sides of the membrane. - **Simple Diffusion** - molecules diffuse between the phospholipids. - Small nonpolar molecules such as CO2 and O2. - **Facilitated Diffusion** - uses transport proteins. - Small, polar molecules such as glucose and water. ## d) Osmosis - diffusion of water - **Solution** - when one substance is dissolved in another. - **Solvent** - what is doing the dissolving (water). - **Solute** - what is being dissolved (sugar/salt). - **Hypertonic Solution** - (placing cells in a higher concentration solution such as a salt/sugar solution) - Causes shriveling, plasmolysis - **Hypotonic Solutions** - (placing cells in a lower concentration solution such sa distilled water) - Causes swelling, (turgid plant cells) - Animals cells can burst because they do not have a cell wall. - **Isotonic Solutions** - (placing cells in a solution that is equal in concentration) - There is no net change in water concentration. - Plant cells are considered flaccid. ## ii. Active Transport - Energy (ATP) Required because molecules go against the concentration gradient from low concentration to high concentration. - Contractile Vacuoles - pump out excess water in freshwater unicellular organisms. - Endocytosis - take materials into cells. - **Phagocytosis** - engulfing large solid particles (food). - **Pinocytosis** - engulfing liquids. - **Receptor-mediated endocytosis** - taking in specific molecules (must bind with receptors). ## d) Exocytosis - materials leaving cell ## F. Diffusion Through A Membrane State Lab - See Your Unit 3 Packet for a more detailed outline. ## 1. Part I (Artificial Cell) - **PROCEDURE (summary):** - Dialysis Tubing represented selectively permeable cell membrane. - STARCH and GLUCOSE went inside the cell. - IODINE (starch indicator) went outside the cell in the beaker. - **RESULTS:** - Starch DID NOT diffuse through the cell membrane (too large). - Glucose and iodine DID diffuse through the cell membrane (small enough). - Cell turned blue/black (positive result for starch). - Beaker stayed amber (negative test result for starch). - Beaker tested positive with Benedict's (positive for glucose). *Benedict's solution must be heated in hot water bath ## 2. Part II (Osmosis in Red Onion Cells) - Be able to draw a simple diagram of a plant cell and label the following: - Cell membrane - Cell wall - Cytoplasm - Know the procedure for preparing a wet mount and adding solution without removing the cover slip. - Recall the changes you observed when you... - **Added distilled water to slide** - water enters the cells causing the cells to swell - **Added salt water to slide** - water leaves the cells causing the cells to shrink - **Added distilled water again** - water to enter the cells causing the cells to swell