Slide 1

CELL STRUCTURE AND FUNCTION Life Science Chapter 2 Slide 2 Chemistry of Life All matter is made up of atoms Matter is anything that has mass and takes up space Gas, liquid, solids Atoms have a nucleus Center of atom Contains protons (+) and neutrons (0) Around the nucleus are electrons (-) The number of protons in the atom determines what element it is The number of electrons determines its chemical properties Slide 3 Organization is a characteristic of living things Atoms molecules Molecules organelles Organelles cells Cells tissues Tissues organs Organs organ systems Organ systems organisms Slide 4 Elements Periodic Table An element is an atom with a certain number of protons All atoms in the universe with 1 proton are called Hydrogen The number of protons an atom has is called its atomic number Hydrogen is then atomic number 1 If the number of protons changes, the element changes It is no longer the same element Electron and neutron numbers can change in an element A neutral atom has equal numbers of protons and neutrons If an atom loses or gains electrons, it gains a charge If it gains an electron, it becomes more negative (more of a negative charge) If it loses electrons, it becomes positive (less negative charges) Slide 5 Example Sodium (Na) is atomic number 11 because it has 11 protons When neutrally charged, it will have 11 electrons However, Sodium really wants to lose an electron When it loses that electron, it will have 11 protons and 10 electrons It will be positively charged Charged atoms are called ions Chlorine (Cl) is atomic number 17 because it has 17 protons Has 17 electrons when neutral However, it really wants one more electron (again, not discussed here) When it gains an electron, it will have 17 protons and 18 electrons It is negatively charged Like magnets, charged atoms attract Sodium and chlorine attract and form sodium chloride (NaCl) Also called table salt Slide 6 Elements in Organisms Oxygen~61% Carbon~23% Hydrogen~10% Nitrogen~2.6% Calcium~1.5% Phosphorus~1.1% Other-Less than 1% Called Trace elements Still important, but found in lower amounts How to remember: Our Cooks Have No Cakes or Pies 1 st letters are the chemical symbol of the element Slide 7 Atoms to molecules Salt is an example of a molecule Molecules are made up of atoms bonded together Water is the most important molecule to organisms Water is required for many of the chemical reactions that take place in organisms Cells are mostly water. Large molecules are called macromolecules 4 important ones for life Lipids Proteins Carbohydrates Nucleic Acids Slide 8 Properties of Water Water is a polar molecule It has areas of positive charge (the hydrogen atoms) and areas of negative charge (the oxygen atom) This charge attracts ions Sodium and chloride break apart easily in water Salt water As do sugar molecules Water molecules also like to bond to other water molecules (called cohesion) Causes surface tension Slide 9 Slide 10 Structure of Macromolecules The 4 main macromolecules are large molecules Made up of chains of smaller molecules Think train made up of carts The large molecules are called polymers (poly=many)-The train The smaller molecules are called monomers (mono=one)-The carts The monomers are held together by bonds Slide 11 Lipids Fats, oils, steroids Do not dissolve in water Make up the cell membrane Energy storage Slide 12 Proteins Important for many cell processes Also help build cell structures Monomers are amino acids Proteins have a unique 3-D structure that determines their role Enzymes are important proteins that assist with chemical reactions Slide 13 Carbohydrates Provide energy Sugars, starches Slide 14 Nucleic Acids The most important macromolecules Monomers are nucleotides DNA, RNA, and ATP are all nucleic acids DNA is the material passed from parents to children and contains the instructions for the organisms features RNA is used to manufacture proteins ATP provides the cell with energy to do nearly everything Much, much more to come on these 3 molecules, so learn them now! Slide 15 The Cell Theory Recall: Theory in science=explanation Explains what cells are, what they do, and where they come from 4 scientists contributed: Robert Hooke, Matthias Schleiden, Theodor Schwann, and Rudolf Virchow (Guaranteed Matching question on Test) Slide 16 Robert Hooke 1635-1703 (You will not need to know dates) English philosopher and scientist Looked in a microscope at cork and discovered small spaces Called them cells Laid the foundation for cell theory more than 100 years before others Slide 17 Matthias Schleiden 1804-1881 German botanist (studied plants) Discovered that plants are all made up of cells Slide 18 Theodor Schwann 1810-1882 German physiologist (studied how the body works) Discovered that all animals are made up of cells Slide 19 Rudolf Virchow 1821-1902 German doctor Discovered that all cells come from other cells Slide 20 Recap Hooke-Named cells Schleiden-Plants are made of cells Schwann-Animals are made up of cells Virchow-Cells come from cells Slide 21 How do we see cells? Microscopes The ones we use are called Light Microscopes Pass light through the image The light is then collected by 2 different lenses and becomes magnified Antonine van Leeuwenhoek Improved the microscope so that it could be used in biology First to observe microorganisms that can not be seen without one Slide 22 Slide 23 1. Ocular Lens (Eyepiece) This is what you look through to see the image. It contains a lens (usually 10x magnification) Slide 24 2. Arm Structural piece Holds the parts of the microscope in the proper places. THE ARM IS NOT A HANDLE Never carry the microscope by the arm alone. One hand around the arm, the other hand underneath the base to support it. Microscopes are very expensive. Use the utmost care when transporting it. Slide 25 3. Stage This is the flat portion where you put the slide. A hole in the stage allows light to pass through the slide Slide 26 4. Course Focus Moves the stage up and down. Doing so brings the object into focus. Move it until the image becomes visible. It will still be a bit blurry. Note about the Course Focus: Using the course focus to try to get a better image could result in the stage moving the slide up into the objective. This could crack the slide and/or objective lens, and could be a VERY expensive mistake. Slide 27 5. Fine Focus Makes tiny adjustments to the stage. Once you have found the image, use the fine focus to make it clear. Slide 28 6. Base Bottom of the microscope. Structural and support. Remember, one hand underneath the base and the other holding the arm. Slide 29 7. Light Source A light bulb Sends light through the slide. Slide 30 8. Diaphragm Allows you to adjust the amount of light that comes through. Slide 31 9. Slide Clips Little metal pieces that hold the slide in place. Make sure that the slide is under the clips. You do not want the slide moving after you have just found the image Slide 32 10. Objectives Each is a different lens that magnifies the image. Most microscopes have several of these ranging from 4x to 200x Begin on the lowest objective to find the image, then increase to zoom it in. Slide 33 11. Rotating Nosepiece Holds the objectives Twist to change magnification. Slide 34 12. Body Tube Holds eyepiece Slide 35 Magnification Magnification is the product of the magnifications of the eyepiece and the objective lenses Eyepiece x Objective= Total Magnification Example: Eyepiece 10x and objective 20x 20x10=200x magnification Slide 36 Cell Types 2 major categories of cells Prokaryotic Cells Bacteria and Archaea No organelles, including nucleus Eukaryotic Cells Protists, Plants, Fungi, and Animals Contains organelles, including nucleus Much more complicated Organelles (small organs) Like organs to our body Each does a job for the cell All work together Slide 37 Protection and Support All cells have a cell membrane Flexible boundary between cell and its environment Made up of proteins and lipids Protects the cell, gives it shape, and allows materials to enter and exit the cell Plant cells, and some fungi, protists, and bacteria, also have a cell wall Outside of the cell membrane Very rigid More protection Slide 38 Slide 39 Slide 40 Cell Appendages Some cells have things attached to them that do a job Flagella are whip-like structures that work as a motor for the cell Spins and allows the cell to move Not common in humans except on sperm, very common in unicellular organisms Usually 1 or 2 Cilia are numerous, hair-like structures Work like a row team and move cell Also work to remove foreign materials Found in respiratory tract. Removes dust, pollen, and other materials before they reach the lungs Hundreds on cells that contain them Slide 41 Slide 42 Slide 43 Slide 44 Cellular Structure Cells are filled with a jelly-like substance called cytoplasm Function: Contains materials for the cell and holds organelles in place Found in: All cells Throughout the cytoplasm are proteins that act as bones Called the cytoskeleton Does similar job to our skeleton Function: Protection, support, allows some cells to move Found in all eukaryotic cells Centrioles Function: help cells divide Found in animal cells (very few plants, fungi, protists have them) Made of the same material as cytoskeleton Slide 45 Slide 46 Slide 47 The Nucleus Function: The control center for the cell Function: Contains DNA The DNA is in the form of chromosomes (more to come later) Found in all eukaryotes Also contains another organelle called the nucleolus Function: forms ribosomes Found in all eukaryotes Slide 48 Slide 49 Manufacturing Organelles Ribosomes Function: Make proteins Can be free-floating in the cytoplasm or attached to the rough endoplasmic reticulum (RER) Made in the nucleolus Found in all cells, prokaryotic and eukaryotic Rough Endoplasmic Reticulum (RER) Studded with ribosomes Function: Site of chemical reactions Found in all eukaryotic cells Smooth Endoplasmic Reticulum (SER) Function: Makes lipids and helps remove toxins from the cell Found in all eukaryotes Slide 50 Slide 51 Slide 52 Slide 53 Energy Organelles Mitochondria The powerhouse of the cell Function: Converts sugars to chemical energy, manufactures ATP for use in other processes Found in all eukaryotic cells Chloroplasts Function: Convert sunlight to sugars These sugars are used in mitochondria to make ATP Found in Plants and some protists (also some bacteria), never in animals GREEN Slide 54 Slide 55 Slide 56 Slide 57 Processing, Transportation, Cleaning Golgi apparatus Post office of cell Function: Packages and ships proteins Found in all eukaryotes Vesicles The mail trucks Function: Transport of proteins and other materials Found in all cells Lysosomes The cells cleaners Function: capture and destroy particles in the cell, clean up wastes and broken down cell parts Found in all eukaryotes Slide 58 Slide 59 Slide 60 Slide 61 Storage and Cell division Vacuoles Function: Store materials such as water, food, wastes Found in all cells Plants usually have one large one Called central vacuole Animals have many small ones