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Question 1
The image below shows part of a cell observed using a microscope. |
a) | Name the organelle labelled X in the diagram above.
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b) | Which type of microscope was used to obtain this image? Explain your answer.
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c) | Describe what is meant by the term resolution.
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d) | Compare the resolutions obtained by a scanning electron microscope and a transmission electron microscope. Include the differences between the images produced by each microscope.
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Question 2
A student wanted to investigate the chloroplasts inside a plant cell. The image below shows part of the plant Calypogeia neesiana as seen using an optical microscope. |
a) | Describe how the student would have used the optical microscope to observe these cells using a high power lens.
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b) | Explain why the structures inside the chloroplasts cannot be seen in the image above.
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c) | A transmission electron microscope would enable the student to the chloroplasts in more detail. Describe how a transmission electron microscope works to give a higher image resolution.
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d) | Describe the limitations of using a transmission electron microscope.
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Question 3
A student wanted to investigate the process of cell division. He wasn't sure whether it was best to use a light microscope or an electron microscope. |
a) | Suggest the advantages of using a light microscope rather than an electron microscope to study cell division.
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b) | The student suggested that he could use a light microscope to investigate cell division while also observing the structure of mitochondria. Explain why the student is not correct.
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c) | An electron microscope would give a higher resolution. Explain the difference between magnification and resolution.
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d) | The student decided to investigate cell division using a light microscope. He used a stain called toludine blue when preparing his slides. Describe the advantages of staining specimens before viewing them under a microscope.
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Question 4
A student wanted to investigate the number of chloroplasts in some plant cells. |
a) | Describe how he could make a temporary mount of a piece of plant tissue to observe the number of chloroplasts in the cells when using an optical microscope.
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b) | Describe how the student could use the temporary mounts to determine the mean number of chloroplasts in the leaf cells.
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c) | State two features of a plant cell that would not be visible using medium power of an optical microscope.
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d) | Compare the advantages and disadvantages of optical microscopes and transmission electron microscopes.
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Question 5
The diagram below shows an image of part of a eukaryotic cell as viewed under a microscope. |
a) | Name organelle A shown in the diagram above.
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b) | Describe the function of organelle A.
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c) | The actual size of this organelle is 3.5 µm, whereas its size on the image is 4 mm. Calculate the magnification of this image. Give your answer to the nearest whole number.
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d) | Give one piece of evidence to support that the cell shown above was observed using an electron microscope.
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Question 6
The diagram below shows a breast cancer cell as seen through an electron microscope. Included in the diagram is a graticule in which the markings are 0.1 mm apart. |
a) | Use the graticule to calculate the actual width of the cell labelled X in the diagram above. Give your answer in µm.
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b) | Explain why a transmission electron microscope rather than an optical microscope was used to study the cancer cell.
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c) | Describe one advantage of using a transmission electron microscope rather than a scanning electron microscope.
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d) | Describe one advantage of using a scanning electron microscope rather than a transmission electron microscope.
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Question 7
The diagram below shows some cancer cells when viewed under a microscope. |
a) | Which kind of microscope was used to obtain this image? Explain your answer.
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b) | The image size of the scale bar is 4 mm. Calculate the magnification of the image.
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c) | State the resolution that can be achieved using an optical microscope and a transmission electron microscope.
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d) | Another type of electron microscope is the scanning electron microscope. Compare the benefits and limitations of transmission electron microscopes and scanning electron microscopes.
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Question 8
The diagram below shows an electron micrograph of the bacterium Gemmata obscuriglobus. |
a) | The scale bar shown on the diagram represents a measurement of 10 µm. Calculate the image size of this scale bar.
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b) | Explain why it is possible to see the structure of a prokaryotic cell with an electron microscope but not with an optical microscope.
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