Deck 2: How We See the Invisible World

Question 1

Which of the following has the highest energy?

A) light with a long wavelength
B) light with an intermediate wavelength
C) light with a short wavelength
D) It is impossible to tell from the information
Given.

Answer 1

The light waves have a characteristic property, i.e. the wave length. The distance between two successive peaks is known as "wave length." Amplitude is the height of each peak. The waves with the higher frequency has the highest energy. And the waves with the lower frequency has the lowest energy.
Frequency is the number of waves that are passes through a point in a period of time. The frequency of light wavelength or sound wavelength is measured in "hertz (Hz)".
Thus, the options (a), (b), and (d) are incorrect.
The waves with the higher frequency has the shorter wavelength. Hence, has the highest energy.
Hence, the correct answer is
.

Question 2

You place a specimen under the microscope and notice that parts of the specimen begin to emit light immediately. These materials can be described as _____________.

A) fluorescent
B) phosphorescent
C) transparent
D) opaque

Answer 2

Phosphorescent materials are those that absorb radiation and re-emit after a short delay. The absorbed radiation undergoes energy state transitions. These transitions undergo at a slower rate, so the radiation is emitted slowly for a long duration of time.
Transparent materials are those that does not allow the transmission of light easily. Tissue paper is an example of transparent material.
On the other hand, the opaque materials does not allow the passage of light through them. Metals and wood are the examples of opaque materials.
Thus, the options (b), (c), and (d) are incorrect.
Fluorescent materials are those that absorb radiation and start emitting the radiation immediately.
Hence, the correct answer is
.

Question 3

Who was the first to describe "cells" in dead cork tissue?

A) Hans Janssen
B) Zaccharias Janssen
C) Antonie van Leeuwenhoek
D) Robert Hooke

Answer 3

Zaccharias Janssen and his father Hans Janssen are Dutch spectacle-makers. During the late 1500s or early 1600s, they may have invented telescope, simple microscope and compound microscope.
However, most of the credit for the advances in microscopy was given to Antonie van Leeuwenhoek and Robert Hooke.
Thus, the options (a), (b), and (c) are incorrect.
Robert Hooke was first used the word "cell" to describe the (In Latin, Cellula = small compartment) structure of dead cork when he observed under microscope. His observations were published in the book "Micrographia" in 1665 by the Royal Society.
Hence, the correct answer is
.

Question 4

Who is the probable inventor of the compound microscope?

A) Girolamo Fracastoro
B) Zaccharias Janssen
C) Antonie van Leeuwenhoek
D) Robert Hooke

Question 5

Which would be the best choice for viewing internal structures of a living protist such as a Paramecium ?

A) a brightfield microscope with a stain
B) a brightfield microscope without a stain
C) a darkfield microscope
D) a transmission electron microscope

Question 6

Which type of microscope is especially useful for viewing thick structures such as biofilms?

A) a transmission electron microscope
B) a scanning electron microscopes
C) a phase-contrast microscope
D) a confocal scanning laser microscope
E) an atomic force microscope

Question 7

Which type of microscope would be the best choice for viewing very small surface structures of a cell?

A) a transmission electron microscope
B) a scanning electron microscope
C) a brightfield microscope
D) a darkfield microscope
E) a phase-contrast microscope

Question 8

What type of microscope uses an annular stop?
a. a transmission electron microscope
b. a scanning electron microscope
c. a brightfield microscope
d. a darkfield microscope
e. a phase-contrast microscope

Question 9

What type of microscope uses a cone of light so that light only hits the specimen indirectly, producing a darker image on a brighter background?
a. a transmission electron microscope
b. a scanning electron microscope
c. a brightfield microscope
d. a darkfield microscope
e. a phase-contrast microscope

Question 10

What mordant is used in Gram staining?

A) crystal violet
B) safranin
C) acid-alcohol
D) iodine

Question 11

What is one difference between specimen preparation for a transmission electron microscope (TEM) and preparation for a scanning electron microscope (SEM)?

A) Only the TEM specimen requires sputter coating.
B) Only the SEM specimen requires sputtercoating.
C) Only the TEM specimen must be dehydrated.
D) Only the SEM specimen must be dehydrated.

Question 12

When you see light bend as it moves from air into water, you are observing _________.

Question 13

A microscope that uses multiple lenses is called a _________ microscope.

Question 14

Chromophores that absorb and then emit light are called __________.

Question 15

In a(n) _______ microscope, a probe located just above the specimen moves up and down in response to forces between the atoms and the tip of the probe.

Question 16

What is the total magnification of a specimen that is being viewed with a standard ocular lens and a 40? objective lens?

Question 17

Ziehl-Neelsen staining, a type of _______ staining, is diagnostic for Mycobacterium tuberculosis.

Question 18

The _______ is used to differentiate bacterial cells based on the components of their cell walls.

Question 19

Explain how a prism separates white light into different colors.

Question 20

Why is Antonie van Leeuwenhoek's work much better known than that of Zaccharias Janssen?

Question 21

Why did the cork cells observed by Robert Hooke appear to be empty, as opposed to being full of other structures?

Question 22

What is the function of the condenser in a brightfield microscope?

Question 23

Label each component of the brightfield microscope.

Question 24

How could you identify whether a particular bacterial sample contained specimens with mycolic acid-rich cell walls?

Question 25

In Figure 2.7 , which of the following has the lowest energy?
a. visible light
b. X-rays
c. ultraviolet rays
d. infrared rays
Reference Figure 2.7:

Question 26

When focusing a light microscope, why is it best to adjust the focus using the coarse focusing knob before using the fine focusing knob?

Question 27

You need to identify structures within a cell using a microscope. However, the image appears very blurry even though you have a high magnification. What are some things that you could try to improve the resolution of the image? Describe the most basic factors that affect resolution when you first put the slide onto the stage; then consider more specific factors that could affect resolution for 40? and 100? lenses.

Question 28

You use the Gram staining procedure to stain an L-form bacterium (a bacterium that lacks a cell wall). What color will the bacterium be after the staining procedure is finished?