25 POINTS2018E. 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?B. Do you think sand or silt is alive? Explain. 2018Activity B: Specialized cellsGet the Gizmo ready:On the LANDSCAPEtab, 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. SampleEstimatedsize (μm)(s)Human neuronHuman skinHuman muscleHuman blood2.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? B. What is the function of the cytoplasm? C. What is the function of the cell membrane? 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?
2018B. What is the function of a dendrite? 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? B. What is a striation and how does it help muscle cells function? 5.Compare: Select the human blood sample. Observe at 400x. Look under Show informationon the right-hand side of the Gizmo. A.What is the function of red blood cells? B. What is the function of white blood cells? C. What organelle is missing from the red blood cells? 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.
2018B. What organelle do frog RBCs have that human RBCs do not? 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.
2018Activity C: Plants and unicellular lifeGet the Gizmo ready:On the LANDSCAPEtab, select the Microalgaesample. 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: MicroalgaeElodea Maple leaf Root hairA. What structures do all of these cells have in common? B. What structures are missing from the root hair cells? C. What is the purpose of this structure, and why do you think it is missing from the root hair cells? 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? Microalgae are examples of unicellular organisms. Each cell is a single organism.
20182.Explore: Which other samples in the Gizmo do you think represent unicellular organisms? (Activity C continued on next page)
2018Activity 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: Euglena: Paramecium: B. In the table below, draw the structures that allow the protists to move on their imageson the left and describe the structures in the spaces on the right:AmoebaEuglenaParameciumC. Which protist is photosynthetic? How do you know?4.