BIOL 438 Exam #1 2025/2026 Exam
Questions and Answers 100%
1
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After this Gram stain, both Gram-positive bacteria and Gram-negative bacteria are
purple. - 🧠 ANSWER ✔✔Crystal Violet
After this Gram stain step, purple Gram-positive bacteria and purple Gram-
negative bacteria remain purple. - 🧠 ANSWER ✔✔Gram's Iodine
After this Gram stain step, Gram-positive bacteria are purple and Gram-negative
bacteria are red or pink. - 🧠 ANSWER ✔✔Safranin
After this Gram stain step, Gram-positive bacteria are purple and Gram-negative
bacteria are colorless. - 🧠 ANSWER ✔✔Alcohol Decolorizer
Which microscope would be the best to use to view components within a cell? - 🧠
ANSWER ✔✔Transmission Electron Microscope
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,The most commonly used type of microscopy is called ___________ , because the
specimens produce dark images against brighter backgrounds. - 🧠 ANSWER
2
✔✔bright-field
In ______________ microscopy, however, bright images on a darker background
are produced because only light that is refracted by the specimen is captured. - 🧠
ANSWER ✔✔dark-field
The ____________ microscope uses slight differences in refractive indices and an
annular condenser to produce sharper images than simple bright-field microscopy.
- 🧠 ANSWER ✔✔phase-contrast
When polarized light is needed for imaging a ___________ microscope is used. - 🧠
ANSWER ✔✔differential interference contrast
Light at specific wavelengths is used to excite dyes in specimens that then emit
light at specific wavelengths in ____________ - 🧠 ANSWER ✔✔epifluorescence
Laser light is used in _____________, generating three-dimensional images. - 🧠
ANSWER ✔✔confocal
How does the addition of immersion oil provide better magnification than a high
power lens alone? - 🧠 ANSWER ✔✔The immersion oil has the same refractive
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, index as glass; by placing a drop of oil between the glass slide and the lens, this
eliminates two refractive surfaces.
3
Select all that are characteristics of transmission electron microscopes. - 🧠
ANSWER ✔✔-Highest practical magnification over 100,000 times.
-Uses electron beam for radiation source.
-Adjust current to magnetic lenses to change magnification.
What microscope would be the best to use to view cell surface features of a
specimen? - 🧠 ANSWER ✔✔Scanning
Which of the following stains would best determine if a bacterium has a single cell
membrane plus a very thick cell wall or if a bacterium has a very thin cell wall in
between two cell membranes? - 🧠 ANSWER ✔✔Gram Stain
Put the following steps in order to review the bacterial method of iron uptake for
the cell. - 🧠 ANSWER ✔✔1. Iron scarce in environment
2.Bacteria secretes siderophore
3. Iron-siderophore complex binds cell surface protein
4. Iron-siderophore complex enters cell via ABC transporter
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COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
PRIVACY STATEMENT. ALL RIGHTS RESERVED
Questions and Answers 100%
1
Guaranteed Success | Already Rated A+
After this Gram stain, both Gram-positive bacteria and Gram-negative bacteria are
purple. - 🧠 ANSWER ✔✔Crystal Violet
After this Gram stain step, purple Gram-positive bacteria and purple Gram-
negative bacteria remain purple. - 🧠 ANSWER ✔✔Gram's Iodine
After this Gram stain step, Gram-positive bacteria are purple and Gram-negative
bacteria are red or pink. - 🧠 ANSWER ✔✔Safranin
After this Gram stain step, Gram-positive bacteria are purple and Gram-negative
bacteria are colorless. - 🧠 ANSWER ✔✔Alcohol Decolorizer
Which microscope would be the best to use to view components within a cell? - 🧠
ANSWER ✔✔Transmission Electron Microscope
100% GUARATEED SUCCESS
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
PRIVACY STATEMENT. ALL RIGHTS RESERVED
,The most commonly used type of microscopy is called ___________ , because the
specimens produce dark images against brighter backgrounds. - 🧠 ANSWER
2
✔✔bright-field
In ______________ microscopy, however, bright images on a darker background
are produced because only light that is refracted by the specimen is captured. - 🧠
ANSWER ✔✔dark-field
The ____________ microscope uses slight differences in refractive indices and an
annular condenser to produce sharper images than simple bright-field microscopy.
- 🧠 ANSWER ✔✔phase-contrast
When polarized light is needed for imaging a ___________ microscope is used. - 🧠
ANSWER ✔✔differential interference contrast
Light at specific wavelengths is used to excite dyes in specimens that then emit
light at specific wavelengths in ____________ - 🧠 ANSWER ✔✔epifluorescence
Laser light is used in _____________, generating three-dimensional images. - 🧠
ANSWER ✔✔confocal
How does the addition of immersion oil provide better magnification than a high
power lens alone? - 🧠 ANSWER ✔✔The immersion oil has the same refractive
100% GUARATEED SUCCESS
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
PRIVACY STATEMENT. ALL RIGHTS RESERVED
, index as glass; by placing a drop of oil between the glass slide and the lens, this
eliminates two refractive surfaces.
3
Select all that are characteristics of transmission electron microscopes. - 🧠
ANSWER ✔✔-Highest practical magnification over 100,000 times.
-Uses electron beam for radiation source.
-Adjust current to magnetic lenses to change magnification.
What microscope would be the best to use to view cell surface features of a
specimen? - 🧠 ANSWER ✔✔Scanning
Which of the following stains would best determine if a bacterium has a single cell
membrane plus a very thick cell wall or if a bacterium has a very thin cell wall in
between two cell membranes? - 🧠 ANSWER ✔✔Gram Stain
Put the following steps in order to review the bacterial method of iron uptake for
the cell. - 🧠 ANSWER ✔✔1. Iron scarce in environment
2.Bacteria secretes siderophore
3. Iron-siderophore complex binds cell surface protein
4. Iron-siderophore complex enters cell via ABC transporter
100% GUARATEED SUCCESS
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
PRIVACY STATEMENT. ALL RIGHTS RESERVED
