Exam (elaborations) BIOLOGY 101 Cell Types Gizmos

Exam (elaborations) BIOLOGY 101 Cell Types Gizmos Vocabulary: ATP, bacteria, carbon dioxide (CO2), cell, cellular respiration, compound light microscope, eukaryote, multicellular, muscle cell, neuron, organelle, photosynthesis, prokaryote, protist, red blood cell, root hair cell, tissue, unicellular, white blood cell Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. How do you know if something is alive? Describe some of the characteristics of living things. All living things move, plants track the sun, humans and animals run. All living things require food and therefore anything that is living eats or creates food. All living things grow, plants grow in size and humans do too. these are some of the characteristics that define a living thing. 2. Humans, plants and mushrooms are all alive. What do these organisms have in common? These organims are always in need of nutrition. Humans require food as energy, plants create food using energy from the sun and so do mushrooms. These organisms are growing. Humans, plants and mushrooms grow to a certain extent. The listed organisms all fulfill the characteristics of a living thing. Gizmo Warm-up In the Cell Types Gizmo, you will use a light microscope to compare and contrast different samples. On the LANDSCAPE tab, click on the Elodea leaf. (Turn on Show all samples if you can’t find it.) Switch to the MICROSCOPE tab to observe the sample as it would appear under the microscope. By default, this microscope is using 40x magnification. 1. Drag the Coarse focus slider until the sample is focused as well as possible. Then, improve the focus with the Fine focus slider. What do you see? Under 40x magnification, you see several small rectangular shapes which are lined up compactly. When the labels are turned on, we see that these chambers are cells. 2. Select the 400x magnification. If necessary, adjust the fine focus. Now, what do you see? Under 400x magnification, we are able to see certain parts of this cell. We also see the chloroplast, vacuole, nucleus, etc. The individual chambers you see are cells, the smallest functional unit of an organism. BIOLOGY 101 Cell Types Gizmos 2018 Activity A: Observing cells Get the Gizmo ready:  On the LANDSCAPE tab, click on the woman’s right arm to choose the Human skin sample.  Select the MICROSCOPE tab. Introduction: Complex organisms are made up of smaller units, called cells. Most cells are too small to be seen by the naked eye. Microscopes are used to magnify small objects, so here you will use a compound light microscope to observe the cells of different organisms. Question: What are similarities and differences between cells from different organisms? 1. Match: Read about each microscope part. Match the description to the part on the diagram. B Stage: Platform where a slide is placed. A Eye piece: Lens at the top of the microscope that the user looks though. This lens most commonly magnifies a sample by 10x. C Coarse focus knob: Large knob that moves the stage up and down to focus the sample. D Fine focus knob: Small knob that moves the stage over a short distance to refine the focus. E Objective lens: A second lens that further magnifies the sample. Microscopes usually have several objective lenses with different magnifications. The total magnification is the product of the eyepiece magnification and the objective lens magnification. F Slide: A rectangular piece of glass upon which a sample is mounted for viewing under a microscope. 2. Manipulate: With 40x selected, use the Coarse and Fine focus sliders to focus on the sample. Then, choose 400x and focus on the sample using the Fine focus slider. A. Which focus knob is easier to use at 40x? Coarse 400x? Fine B. Turn on Show labels. What structures can you see in human skin cells? Cytoplasm, Nucleus and Cell Membrane C. Turn off Show labels and turn on Show scale bars. The scale bar has a width of 20 micrometers, or 20 μm. (There are 1,000 micrometers in a millimeter.) Using the scale bar, about how wide is a human skin cell? 30 (Activity A continued on next page) Activity A (continued from previous page) 2018 3. Observe: An organelle is a cell structure that performs a specific function. Observe the samples below under the highest magnification. Click the Show labels checkbox to label the organelles. List the organelles and approximate size of the cells in each sample. Sample Organelles Estimated size (μm) Mouse skin Nucleus, Cytoplasm and Cell Membrane 15 Fly muscle Nucleus, Cytoplasm, Cell Membrane and Striation (due to this being a muscle cell) unknown (the cell is horizontal and therefore runs beyond the lens) Maple leaf Nucleus, Cytoplasm, Cell Membrane, Cell Wall, Chloroplast and Vacuole 15 (changes based on the chosen cell) Elodea Nucleus, Cytoplasm, Cell Membrane, Chloroplast, Vacuole and Cell Wall 40 Fungus Nucleus, Cytoplasm, Cell Membrane, Chloroplast, Vacuole, Cell Wall and Septum 5 What do all of these samples have in common? All these samples have cells that contain the Nucleus, Cytoplasm and Cell Membrane. In eukaryotic cells, genetic material is contained inside a distinct, membrane-bound nucleus. Plant and animal cells are classified as eukaryotes. 4. Observe: Click on the cow and observe E. coli under the highest magnification. Notice the microscope magnification is larger for this organism, and notice the scale bar is smaller. A. What is the approximate size of E. coli? 0.5 B. What organelles are present in E. coli? Cell Wall, Cell Membrane, Cytoplasm, Flagellum, Pilus and Nucleoid C. What organelle is missing from E. coli. Nucleus E. coli is an example of a bacteria. Bacteria are classified as prokaryotic cells because their DNA is not contained in a membrane-bound nucleus. 5. Compare: Look at the Sand/silt sample under the microscope. A. Turn on Show labels. Does sand/silt have any internal structures? No 2018 Do you think sand or silt is alive? Explain. No, this is because Sand ad Silt do not contain a cell or any internal structures. A cell is the basic unit of all living things and anythign that does not contain a cell is considered non-living. Activity B: Specialized cells Get the Gizmo ready:  On the LANDSCAPE tab, click on the woman’s head to choose the human neuron sample. Question: How do a cell’s specialized structures relate to its function? 1. Collect data: Use the microscope to observe the samples listed in the table below. For each sample, estimate the cell size and check off the organelles that are present. If there is no column for an organelle, list it in the Special structure(s) column. Sample Estimated size (μm) Nucleus Cell membrane Cytoplasm Special structure(s) Human neuron Axon and Dendrite Human skin Human muscle Striation Human blood 2. Observe: Select the human skin sample. On the MICROSCOPE tab, choose the 400x magnification, focus on the sample, and turn on Show labels. Click on the Nucleus label. If necessary, adjust the Stage sliders to see the full description. A. What is the function of the nucleus? The Nucleus controls the cell by regulating when the genes function. B. What is the function of the cytoplasm? The cytoplasm holds together the organelles. C. What is the function of the cell membrane? Protects the cell, controls what goes in and out. 3. Observe: Select the human neuron sample. Focus the cells at 400x. Turn on Show labels. A. Click on the axon label to read the description. What is its function? Carries electrical signals away from the cell. 2018 B. What is the function of a dendrite? Carries electrical signals to the cell. Neurons transmit messages in the form of electrical and chemical signals, through axons and dendrites, from one part of the body to another. (Activity B continued on next page) Activity B (continued from previous page) 4. Compare: Select to the human muscle sample. Observe the sample at 400x. A. What do muscle cells have that other cell types do not? Striation B. What is a striation and how does it help muscle cells function? Striation is what gives muscles the striated look. It helps with expanding and contracting the muscle. 5. Compare: Select the human blood sample. Observe at 400x. Look under Show information on the right-hand side of the Gizmo. A. What is the function of red blood cells? Carries blood from lungs to different parts of the body. B. What is the function of white blood cells? Protects body against bacterias and viruses. C. What organelle is missing from the red blood cells? Nucleus 6. Compare: Compare the human and animal samples (human and mouse skin; human and worm neurons; human and fly muscle; human and frog blood). A. In general, are there any major differences that you can see? Explain. There are generally no major differences apart from the appearance of some of the cells when compared. Apart from the appearance, all the organelles from the cells of different parts are identical between human and animal samples. B. What organelle do frog RBCs have that human RBCs do not? Nucleus Most mammalian red blood cells have no nucleus. This allows the red blood cell to