Question Video: Recalling the Reasons for Putting a Coverslip on top of a Specimen before the Specimen Is Viewed under a Microscope | Nagwa Question Video: Recalling the Reasons for Putting a Coverslip on top of a Specimen before the Specimen Is Viewed under a Microscope | Nagwa

Question Video: Recalling the Reasons for Putting a Coverslip on top of a Specimen before the Specimen Is Viewed under a Microscope

The diagram shows how a thinly cut specimen is prepared to be observed under a microscope. Which of the following is not a reason why a coverslip is placed on top of the specimen? [A] To protect the microscope objective from getting into direct contact with the specimen [B] To prevent the glass slide from breaking [C] To hold the specimen in place [D] To protect the specimen during visualization

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Video Transcript

The diagram shows how a thinly cut specimen is prepared to be observed under a microscope. Which of the following is not a reason why a coverslip is placed on top of the specimen? (A) To protect the microscope objective from getting into direct contact with the specimen. (B) To prevent the glass slide from breaking. (C) To hold the specimen in place. Or (D) to protect the specimen during visualization.

This question is asking about the role of the coverslip when making a slide to study a specimen under the microscope. For the specimen to be examined under the microscope, it needs to be mounted onto a slide. This makes it easier to handle, as most specimens are fragile or microscopic. The slide is usually made of glass, as it needs to be transparent to let the light rays from the light source of the microscope pass through it. The specimen will be placed on the slide, usually with a drop of stain, such as iodine solution or methylene blue, to make the transparent cells visible.

A coverslip, which is a thin piece of glass, again to allow light to pass through, will be placed on top of the specimen. The coverslip protects the specimen, stopping it from drying out. It holds the specimen in place and also protects the objective lens from the stain. It has to be placed carefully onto the specimen to prevent trapping air bubbles beneath it, which would spoil the image you see of the specimen.

The technique is to put the coverslip at an angle of about 45 degrees on the edge of the solution on the slide. Then using a mounted needle or your fingernail, gently lower it down to cover the specimen. Any excess solution can be gently wiped off the slide, taking care not to absorb all the stain which is under the coverslip. The specimen is then ready to be observed under the microscope.

Now that we have reviewed the steps of making a slide, let’s return to our question. It asks, which of the following is not a reason why a coverslip is placed on top of the specimen? We now know that the correct answer is option (B): to prevent the glass slide from breaking.

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