Gizmo Answer Key: Cell Types

University
Virtual High School
Course
Biology
Pages

11

Academic year

2022
Author

Scott Haley
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12

Name: Kaleigh Best Date: 03-24-2022 Student Exploration: Cell Types Directions: Follow the instructions to go through the simulation. Respond to the questions andprompts in the orange boxes. Vocabulary: ATP, bacteria, carbon dioxide (CO 2 ), 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 growth energy and development, eats, drinks, reproduces 2. Humans, plants and mushrooms are all alive. What do these organisms have in common? the same as question number one 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 40xmagnification. 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 observe many cells clustered together. 2. Select the 400x magnification. If necessary, adjust the fine focus. Now, what do you see? I see one cell, and inside and outside of it, I can see green objects. The individual chambers you see are cells, the smallest functional unit of an organism. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

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. F Stage : Platform where a slide is placed. A Eye piece : Lens at the top of the microscope that the user looks through. This lens most commonly magnifies asample 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 objectivelenses with different magnifications. The totalmagnification is the product of the eyepiece magnificationand 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? 400x? Coarse, coarse B. Turn on Show labels . What structures can you see in human skin cells? Nucleus, Cytoplasm, and membran 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? About 33 um Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

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 Cytoplasm, nucleous, cell membrane, 20 um Fly muscle Nucleous, cell membrane, cytoplasm, striation 20 um Maple leaf Cell Mem, chloroplast, vacuole, nucleous, cytoplasm, cell wall 20 um Elodea Cell wall, nucleus, chloroplast, vacuole, cell mem, cytoplasm 20 um Fungus Septum, nucleus, vacuole, cytoplasm, cell mem,cell wall 20 um What do all of these samples have in common? Each one has a cell wall, cytoplasm, and a nucleus. 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 um B. What organelles are present in E. coli ? Nucleus, pilus, flagella, cytoplasm, cellmem, 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. It is incapable of using energy orreproducing, two essential functions only Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

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 anorganelle, list it in the Special structure(s) column. Sample Estimated size (μm) Nucleus Cell membrane Cytoplasm Special structure(s) Human neuron 20 um yes yes yes Axon, dendrite Human skin 20 um yes yes yes axon Human muscle 20 um yes yes yes striation Human blood 20 um yes yes yes White and red blood cells 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 allowing it to turnthe genes on and off B. What is the function of the cytoplasm? Maintains the organelles' position. C. What is the function of the cell membrane? It is a layer that encircles and shields thecell. 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 transports signals out of the body. B. What is the function of a dendrite? A nerve cell's extension is what allowsimpulses to be delivered 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. 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 Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

B. What is a striation and how does it help muscle cells function? They employ chemicalenergy. 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 deliver oxygen to the rest of our bodyand to our lungs. B. What is the function of white blood cells ? They guard against getting sick. 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? Nucleus Most mammalian red blood cells have no nucleus. This allows the red blood cell to use all of its volumeto 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 ofskin, nerve, muscle, and blood tissue. You can write your answer on another sheet of paper. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Activity C: Plants andunicellular life Get the Gizmo ready: ● On the LANDSCAPE tab, select the Microalgae sample. 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. ✏ Hand draw in the circles below or click on the circles and select EDIT to use the drawing tool. Microalgae Elodea Maple leaf Root hair A. What structures do all of these cells have in common? A cytoplasm, chloroplast, nucleus, and vacuole are present in every one of them. 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 cell? Plants can absorb solar energy, but since they lack chloroplasts, they are unable toengage in 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 smaller cells with more room in them Microalgae are examples of unicellular organisms. Each cell is a single organism. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

2. Explore: Which other samples in the Gizmo do you think represent unicellular organisms? Human blood 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: pseudopodiu m Euglena: flagellum Paramecium: cillium 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 tiny dots, as well as circles of various colors, arepresent. Euglena It resembles a leaf with pills inside of it. Paramecium It appears to be a container that contains rocks. C. Which protist is photosynthetic? How do you know? euglena, only one with 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 itattach to other cells Name: Flagellum Description: A tail that allows the cell toswim/move around B. Do protists (amoeba, Euglena , Paramecium ) use similar structures to move? Explain. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

yes, they all move about and attach to other cells using either the pilus or the flagellum. Activity D: Are cells alive? Get the Gizmo ready: ● On the LANDSCAPE tab, select the worm to choose the Worm neuron sample. ● Select the TEST FOR LIFE tab. 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 (CO 2 ). 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. Eachrow 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 phenol red positive turned orange while the ATP positive was blazing green. B. Does the worm neuron sample produce ATP? Yes How do you know? It began to light, indicating the presence of ATP. C. What happens to the phenol red? orange D. When CO 2 combines with water it forms carbonic acid. How does this explain the phenol red result? Theres CO2 in the neutrons 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? Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Positive turns orange In the light, plant leaves undergo photosynthesis, using CO 2 , 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? Beginning to light green, the phenol control has turned orange. D. Based on the test results, are maple leaves alive? yes 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 andperform the experiment again in the dark. Record the results below. Sample Light - ATP Light Respiration Dark - ATP Dark - Respiration E. coli yes yes yes yes Fungus yes yes yes yes Human skin yes yes yes yes Maple leaf yes no yes yes Root hair yes yes yes yes Protists yes yes yes yes Sand/silt no no no no 4. Discuss: Based on the results of the experiment, which samples from the table above are likely to undergo photosynthesis? Maple leafs How do you know? No light can get through. 5. Analyze: Small particles of silt are about the same size and shape as a cell. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved