ATP, Bacteria, Carbon Dioxide (CO2) Answer Key

Cell Types 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. Uses energy, growth and development, made of cells, eat, reproduce 2. Humans, plants and mushrooms are all alive. What do these organisms have in common? Same thing that was listed above. 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? I see a lot of cells all grouped together. 2. Select the 400x magnification. If necessary, adjust the fine focus. Now, what do you see? I see one cell very clearly and I can also see that it has other green things in it. The individual chambers you see are cells, the smallest functional unit of an organism. 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. F 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. B 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? Coarse B. Turn on Show labels. What structures can you see in human skin cells? Nucleus, Cytoplasm, 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? Around like 35 μm (Activity A continued on next page) Activity A (continued from previous page) 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, Cell membrane, Cytoplasm 20 μm Fly muscle Cell membrane, Striation, Nucleus, Cytoplasm 20 μm Maple leaf Nucleus, Chloroplast, Vacuole, Cytoplasm, Cell membrane, Cell wall 20 μm Elodea Chloroplast, Vacuole, Nucleus, Cell membrane, Cell wall, Cytoplasm 20 μm Fungus Cytoplasm, Septum, Nucleus, Vacuole, Cell membrane, Cell wall 20 μm What do all of these samples have in common? They all have a nucleus, cytoplasm, and cell wall 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? 4 μm B. What organelles are present in E. coli? Nucleus (DNA), Pilus (pili), Flagellum (flagella), Cytoplasm, Cell membrane, Cell wall 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 B. Do you think sand or silt is alive? Explain. No because it can’t use energy or reproduce which is two things living things can do. 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 20 μm Yes Yes Yes Axon, dendrite Human skin 20 μm Yes Yes Yes … Human muscle 20 μm Yes Yes Yes Striation Yes White blood cell, Red blood call Human blood 20 μm Yes Yes 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? It controls the cell by regulating when the genes are turned off and on B. What is the function of the cytoplasm? It’s a fluid like substance that holds the organelles in place C. What is the function of the cell membrane? It’s a bi layer that surrounds and protects the cell, regulating 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? It carries electrical signals away from the body B. What is the function of a dendrite? It’s a branched extension of a nerve cell that lets impulses be transmitted to the cell body 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? They use chemical energy for physical work 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? They carry oxygen from our lungs to the rest of our bodies. B. What is the function of white blood cells? They protect you from illnesses and other things (immunity cells). 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. The only difference is with the frog. The frog’s red blood cells have a nucleus. B. What organelle do frog RBCs have that human RBCs do not? A nucleus Most mammalian red blood cells have no nucleus. This allows the red blood cell to use all of its volume to transport oxygen. 7. Extend your thinking: Many types of cells, such as the ones in this activity, live together in groups, called tissues. A tissue is a group of similar cells that together carry out a specific function. Describe how the skin cells, neurons, muscle cells, and blood cells you have observed relate to the functions of skin, nerve, muscle, and blood tissue. You can write your answer on another sheet of paper. Introduction: Most of the animals and plants we are familiar with are multicellular, they are made up of many cells. However, many living things only consist of a single cell. These microscopic organisms are unicellular. Question: How are unicellular organisms similar to multicellular organisms? 1. Observe: Compare the microalgae, the Elodea leaf cells, the maple leaf cells, and the root hair cells at 400x. Sketch each below: Microalgae Elodea Maple leaf Root hair A. What structures do all of these cells have in common? They all have a nucleus, cytoplasm, vacuole, and chloroplast. B. What structures are missing from the root hair cells? Chloroplast C. What is the purpose of this structure, and why do you think it is missing from the root hair cells? To let plants capture the energy released from the sun. They don’t have a chloroplast because they don’t carry out photosynthesis. Photosynthesis is the ability of some organisms to generate food from sunlight. Cells that are not exposed to sunlight will not take part in photosynthesis. D. How are the algae cells different from the other cells? They have many smaller cells with more room and the other compact cells. Microalgae are examples of unicellular organisms. Each cell is a single organism. 2. Explore: Which other samples in the Gizmo do you think represent unicellular organisms? E. coil, frog blood, human blood, and protists (Activity C continued on next page) Activity C (continued from previous page) 3. Observe: Switch to the Protist sample. Protists are unicellular organisms common in ponds On the MICROSCOPE tab, select the 100x radio button and focus the image. A. Watch the motion of the protists at 100X and 400X. What structures allow each protist to move? Amoeba: Pseudopodium Euglena: Flagellum Paramecium: Cilium B. In the table below, draw the structures that allow the protists to move on their images on the left and describe the structures in the spaces on the right: Amoeba It looks like a small octopus with only two les that move towards the body and away from it as well. They are also a triangular shape. Euglena It looks like it has a tail on the end of the body, which is away from the point. Parameciu m It looks like little hairs that move back and fourth around the whole body. C. Which protist is photosynthetic? How do you know? Euglena because it is the only one with a chloroplast. 4. Compare: On the LANDSCAPE tab, click on the cow to switch to the E. coli sample. On the MICROSCOPE tab, select 2500x, focus the image and turn on Show labels. A. Find two structures that help E. coli move and describe them below: Name: Pilus Description: Small hairs surrounding it helping it attach to other cells Name: Flagellum Description: A tail that allows the cell to swim/move around B. Do protists (amoeba, Euglena, Paramecium) use similar structures to move? Yes Explain: They all use either the pilus or flagellum to move around and attach to other cells. Introduction: All organisms need energy from food to function. During cellular respiration, cells use glucose from food to produce ATP, a molecule that stores energy for the cell, and carbon dioxide (CO2). You can test for the products of respiration to see if your sample is alive. Question: How can you test if cells are alive? 1. Observe: The first row of the dish contains an ATP reagent that will glow if ATP is in the liquid. The second row of the dish contains phenol red, a reagent that turns orange when the liquid is acidic. Each row of the dish contains an example of a positive test (positive control), an example of a negative test (negative control), and the sample. A. Click Play ( ). What happens? The ATP positive control and sample started glowing green and the Phenol red positive control and sample turned orange. B. Does the worm neuron sample produce ATP? How do you know? It does. This is because the positive control for ATP started to glow which means it has ATP. C. What happens to the phenol red? It turned orange D. When CO2 combines with water it forms carbonic acid. How does this explain the phenol red result? There is CO2 in the neurons E. Based on the test results, are the worm neurons alive? Yes 2. On the LANDSCAPE tab, select the Maple leaf sample. Return to the TEST FOR LIFE tab. A. Click Play. Does the maple leaf sample produce ATP? Yes B. What happens to the phenol red? Only the positive control turns orange In the light, plant leaves undergo photosynthesis, using CO2, water, and light energy to produce food. In the dark, plants cannot perform photosynthesis. C. Click Reset ( ), then click on the light switch to turn off the lights. Click Play to run the experiment in the dark. What happens? The ATP positive control and sample started glowing green and the Phenol red positive control and sample turned orange. D. Based on the test results, are maple leaves alive? Yes E. Activity D (continued from previous page) 3. Collect data: Using the table below, select the sample on the LANDSCAPE tab. Perform the experiment in the light on the TEST FOR LIFE tab. Turn off the light by clicking on the light switch and perform the experiment again in the dark. Record the results below. Sample Light - ATP Light Respiration E. coli Yes Yes Dark - ATP Dark - Respiration Fungus Yes Yes Yes Yes Human skin Yes Yes Yes Yes Yes Yes Maple leaf Yes No Yes Yes Root hair Yes Yes Yes Yes Protists Yes Yes Sand/silt No No Yes No Yes No 4. Analyze: Which of the samples in the above table are alive? E. coil, fungus, human skin, and root hair. How do you know? They all have light ATP and respiration as well as dark ATP and respiration 5. Discuss: Based on the results of the experiment, which samples from the table above are likely to undergo photosynthesis? The maple leaves How do you know? Light respiration doesn’t pass through it 6. Analyze: Small particles of silt are about the same size and shape as a cell. A. Is silt alive? No B. How do you know? This is because they don’t have any energy or respiration