Question

Which of the following is mismatched concerning microscopy.

A) SEM: 3D representation of surface features of cells and other objects, individual components in microbial communities, microbial environment interactions

B) Confocal: uses laser light sources to scan differentially labeled specimens producing #D-like images assembled by a computer.

C) Darkfield: can visualize living spirochetes in wet mounts, motility of cells in wet mounts.

D) Differential Interference Phase Contrast: similar to phase contrast but adds prisms providing additional detail and quasi-3D effect

E) Limit of resolution human eye (conventional light microscopy): 0.2mm (2nm)

Please explain.

Answer 1

A)

SEM

Scanning Electron Microscopy

SEM is a type of electron microscope which is used to visualize the surface features of the specimen. McMullan developed this model of microscope. This microscope uses electrons to interact with the atoms of the specimen to get the image.

*In the given statement it explains the uses of SEM. The Statement is true except the term 3D . 3D SEMs are developing nowadays. Other facts are true. The microscope is used to visualize the surface features of cells and other objects, microbial environment interactions and individual components of microbial communities.

B)

Confocal Microscopy

Confocal Microscopy is a type of Confocal Laser Scanning Microscopy used to visualize specimen. It uses laser light to scan the specimens. Later the image is assembled is using a computer. It helps to get the 3D images of the specimen.

* The statement is correct. There is no correction or error in the statement.

C)

Dark field Microscopy

Dark Field Microscopy visualize bright objects on a dark background. Here the field around the specimen is dark. This type is used to see unstained living cell- here in living spirochetes . Thin cellular organisms like spirochetes are unable to be stained, so this type of microscopy is used. Here light source is blocked, by using a condenser.

* The given Statement is correct.

D)

Differential Interference Phase contrast microscopy

This is very similar to phase contrast microscopy but the difference is that it provide 3D images. The image obtained is similar to that of phase contrast but have no bright diffraction. DIC provide high resolution images than the other.

* The Statement is correct.

E)

Limit of Resolution

The limit of Resolution of human eye ( in light Microscopy) is 0.2 micrometer

* the statement given the question is wrong.

0.2 micrometer = 200 nanometer =200 nm

This means human eyes cannot see objects smaller than 200 nm using a light microscope, this is the limit of resolution.