Transcript Ch 4 Cells
Chapter 4 - Cell Structure and Function The printed out notes are more detailed than these slides, you are expected to read the chapter and your notes - anything is fair game on the test, but the cell chapter is largely review. Lab: microscopes and membranes Thurs: 10/9 A. The Cell Theory 1. Every living organism is made of one or more cells. 2. The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions. 3. All cells arise from preexisting cells. *Why is the Cell Theory called a Theory and not a Fact? Cells need a large surface area to volume ratio If there a person was at the very center of each house and accidently started a fire, the person in which house would have a better chance of escaping? Figure 4.3 Early Contributions Hooke Leeuwenhoek Schleiden Schwann Virchow http://htwins.net/scale2/ B. ALL CELLS HAVE: 1. Cell Membrane a) Phospholipid Bilayer (double layer) b) Proteins c) Carbohydrates 2. Genetic Material 3. Cytoplasm (cytosol) ORGANELLES float within cytoplasm and perform specific functions Prokaryote Cells Figure 4.4a Eukaryotes Endosymbiosis : All organelles seem to share many properties with bacteria. Lynn Margulis proposed: endosymbiosis hypothesis: that ancient colonization of large bacteria (became the eukaryotic cell) engulfed smaller bacteria (became the mitochondria, chloroplast, etc.) Symbiosis = "living together". *Mitochondria & Chloroplasts have their own DNA Animation at Microbiological Concepts https://www.youtube.com/watch?v=3ESXvLHceDc Endosymbiosis Theory that ancient colonization of large bacteria (became the eukaryotic cell) engulfed smaller bacteria (became the mitochondria, chloroplast, etc.) http://www.youtube.com/watch?v=-FQmAnmLZtE In your notes: Create a diagram comparing prokaryotic and eukaryotic cells. Include examples of each and anything you can remember When done, use ch 4 to label the pictures on your notes outline handout pg 65 and 68 Prokaryote No Organelles Simple Mostly single cells Archaea and bacteria both Cells DNA Cytoplasm Plasma Membrane Ribosome Cell wall Eukaryote Membrane Bound Organelles Nucleus Complex Specific in function Multicellular Plants, Animals, fungi Quick Recap....... 1. What are the two main types of cells? 2. Which one is larger? 3. Which one does not have a membrane bound nucleus? 4. What are the three main parts of the cell (that all cells have)? 5. What are the 3 components of the cell theory? 6. What theory best explains how eukaryotes evolved? Label the pictures on the top of your notes outline: use 65, 68-69 to help Prokaryotic or Eukaryotic? 1 2 1. Has membrane bound organelles 2. Includes plant and animals cells 3. Bacteria P 4. E 5. P 6. Has no organelles P E E cell biology is a huge area, and is divided into many branches that biologists specialize in... 1) Oncology 2) Microbiology 3) Genetics 4) Paleobiology 5) Pathology ............to name a few Here's an older video that compares prokaryotes and eukaryotes and discusses how cells evolved, film by the Phoenix Learning Group (17 minutes) And a shorter video on the main parts of The Cell The Parts of the Cell Cell Diagram Directions: 1. You will get a picture of a animal or plant cell, label the cell. 2. label as many parts as you can remember 3. Then look in your book to label the rest 4. Write a 2-5 word description of the function of each part II. Nucleus: • Nucleoplasm: semifluid matrix • Chromatin: uncoiled, fluid DNA and proteins • Chromosomes: coiled, rodlike DNA structures • Gene: unit of heredity located on DNA • Nucleolus: dark region of chromatin where rRNA joins with proteins to form ribosomal subunits (parts to make ribosomes) • nuclear envelope contains nuclear pores for some things to enter and exit III. Endomembrane System: Includes: a.Nuclear envelope b.Membrane of the ER c.Golgi apparatus d.Several types of lysosomes I am a reticulated python. Ask me what I have to do with the endoplasmic reticulum. A. Nuclear Envelope/ Membrane: RNA leaves nucleus to instruct production of proteins B. Endoplasmic Reticulum (endoplasm= "within cytoplasm", reticulum= "little net" --divides cell into compartments --channels molecules through the cell's interior, like a little highway, make vesicles Figure 4.10a Rough ER --has ribosomes --functions in protein synthesis -- ER transports newly assembled proteins to the Golgi Apparatus Smooth ER --no ribosomes --mostly contains enzymes that act in lipid synthesis (such as hormones like estrogen and testosterone) Vary depending on location C. Golgi Apparatus: Delivery System -flattened stacks of membranes -functions in collection, modifying, packaging and distribution of molecules made in the cell and used elsewhere -unprocessed proteins enter the front end (cis) near the ER, and are exported near the cell membrane, at the back end (trans) --the folded stacks are called cisternae Jobs of the Golgi Apparatus (aka Golgi Complex) 1. separates proteins according to their destinations 2. modifies proteins (adds sugar and makes glycoproteins) 3. packages materials into vesicles which are exported outside the cell - secretion Lysosomes - Intracellular Digestion Centers --contain high levels of degrading enzymes (to "lyse" means to dissolve) --recycle old and worn out cell parts - apoptosis "suicide sac” -digest other particles taken in by phagocytosis --this "food" is stored in food vacuoles, the lysosomes fuse with the vacuoles and release digestive enzymes Lysosomes - Intracellular Digestion Centers TAY-SACHS disease – What do lysosomes have to do with this deadly disease? Article and Video on Tay Sachs http://6abc.com/archive/9036458/ https://www.youtube.com/watch?v=RzEpkBU-ITA Tay-Sachs disease is caused by the absence or significantly reduced level of a enzyme called beta-hexosaminidase (Hex-A). Normally, Hex A is a digestive enzyme that is part of the lysosome. Without the correct amount of the Hex-A enzyme, a fatty substance or lipid called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain. Ribosomes - Sites of Protein Synthesis -each is composed of two subunits, one large and one small -mRNA is "read" by the ribosomes and amino acids are assembled into proteins -ribosomes are manufactured by the nucleolus, assembles by ER --polyribosomes – strings of ribosomes in the cytoplasm that work to make a protein Free vs Bound Ribosome Free ribosomes: produce proteins that are used by the cell. - ex: for metabolism of food. Bound ribosomes: produce proteins that are transported out of the cell. - ex: for a specific function, such as digestive enzymes and polypeptide hormones. Mitochondria --contains its own DNA, support for Endosymbiosis Theory • mitochondria divide before cell division, they are not synthesized like other cell parts --function: store energy for cell use. Energy is stored in the form of ATP adenosine triphosphate -2 membranes, one smooth outer membrane, and an inner membrane folded into layers called cristae --Cristae has two compartments: the matrix and the intermembrane space What happens if your mitochondria don’t work? Mitochondrial Disease Video Why is mitochondrial disease so devastating to children? Consider the mitochondria have their own DNA separate from the parental DNA. How could you cure this disease? https://www.youtube.com/watch?v=6_ylLEhRG30 Focus on Plant Cells Chloroplasts - Where Photosynthesis Takes Place Plants only --has its own DNA, like mitochondrion --functions: to convert light energy to carbohydrates --carbohydrates then broken down in mitochondria to produce ATP Parts of chloroplast --thylakoids are the individual disk shaped compartments -- Grana: stack of thylakoids --stroma is the fluid surrounded the thylakoids *Chloroplasts are a type of plastid Chromoplasts – red, yellow and orange pigment Leucoplasts – colorless (potatoes) Cytoskeleton- support system a. Microfilaments (now called actin filament) – occur in bundles, form tracks within the cell for the movement of organelles, used to form pseudopods (ameba) b. Intermediate filaments - support membrane, cell to cell junctions c. Microtubules - (little pipe) radiate from the centrosome - form the spindle during cell division Centrioles – used during cell division to move and separate chromosomes, only found in animal cell Cytoskeleton How do cells maintain their shape? How do they move? - pseudopod - cilia - flagella Pseudopod – extensions of the cell that allow for movement (ameba), depend on actin filaments Cilia (hair) & Flagella (whip) --function in movement -- 9 + 2 Arrangement of microtubules http://www.youtube.com/ watch?v=7pR7TNzJ_pA Hey....remember enzymes? The Peroxisome Found in plant and animal cells, this organelle plays a critical role in normal cell functioning. In human cells, peroxisomes house some sixty enzymes, involved in metabolic processes such as bile acid, cholesterol, and plasmalogen biosynthesis, as well as ß-oxidation peroxisome produces hydrogen peroxide as a by-product of its normal function. -To neutralize this potentially toxic compound, a peroxisome imports the hydrogen peroxidemetabolizing enzyme catalase, from the cytosol of the cell. Catalase converts hydrogen peroxide to water and oxygen Vacuole -- mainly storage or specific functions (contractile vacuole, fat vacuole) -- Plant cells have a CENTRAL VACUOLE - used for storage and help to maintain hydrostatic pressure QOD: 1. What does the cell theory state? 2. Explain why cells are so small using the idea surfacearea- to- volume ratio. 3. Compare and contrast plant and animal cells use a graphic organizer: (venn, tree map, etc) •Plant Cell •Animal cell •Eukaryote •Plasma Membrane •Nucleus •Ribosome •ER •Mitochondria •Chloroplast •Cell wall •Cytoplasm •Golgi Apparatus •Vacuole •Centrioles •Fern Cells •Muscle Cells •Human Cells Plant Animal Tree Map Double Bubble (like a venn diagram) Cell wall Eukaryote vacuole centrioles Nucleus Mitochondria Plant Cell Chloroplast Fern Cytoplasm Animal Cell Muscle cells Plasma Membrane Ribosome ER lysosome Golgi apparatus humans Eukaryote Plant Cell Animal Cell vacuole centrioles Nucleus Cell wall Chloroplast Fern Mitochondria Muscle cells Cytoplasm Plasma Membrane Ribosome ER lysosome Golgi apparatus humans QOD: Proteins in the Cell What parts of the cell are involved with protein production and what role does each part play? Most of the Endomembrane: • Nucleolus • Rough ER • Golgi • Vesicles • Free Ribosome Mini Quiz 1. What part of the cell produces vesicles for export? 2. What part of the cell makes proteins? 3. What part of the cell produces ATP? 4. What part of the cell transports materials throughout the cytoplasm? 5. What part of the cell has a cis and a trans face? https://www.youtube.com/watch?v=1Z9p qST72is&feature=youtu.be a. ________________ b. ________________ c. _________________ d. _________________ e. _________________ f. __________________ f. Find the: a. Nucleolus b. Centriole c. Vesicle d. Smooth ER e. Lysosome Figure 4.7b What is this structure? What is this structure? Terms / Concepts for Show, Don't Tell cell_theory mitochondria chloroplast prokaryote protein_synthesis eukaryote nucleus lysosome ribosome endoplasmic_reticulum cytoskeleton golgi_apparatus enzyme messenger_RNA chromatin phospholipid_bilayer cilia flagella microscope peroxisome Single Cheek Cell - at different illuminations