MMBIO 221 EXAM 3 CERTIFICATION
EVALUATION 2026 FULL QUESTIONS AND
CORRECT ANSWERS
◉ Confocal Microscope.
Answer: Also uses fluorescent dyes
Use UV lasers to illuminate fluorescent chemicals in a single plane
that is no thicker than 1.0 μm
Resolution increased by up to 40% because emitted light passes
through pinhole aperture
Computer constructs 3-D image from digitized images
◉ are all cells naturally fluorescent?.
Answer: No some require staining to see on fluorescent microscopes
◉ Fluorescent Microscopes.
Answer: Direct UV light source at specimen; fluorochromes absorb
the UV light and radiate energy back as a longer, visible wavelength
UV light increases resolution and contrast
,◉ Two types of Phase Microscopes.
Answer: Phase-Contrast Microscope
Differential Interference Contrast (DIC) Microscope
◉ Phase Microscopes.
Answer: Used to examine LIVING organisms or specimens that
would be damaged or altered by attaching them to slides or staining
them
These microscopes treat one set of light rays differently from
another set
Light rays IN PHASE produce BRIGHTER image,
while light rays OUT of PHASE produce DARKER image
Contrast is created because light waves are ½ wavelength out of
phase
◉ Dark-Field Microscopes.
, Answer: - Best for observing pale or very thin objects that are
LIVING
Only those oblique light rays scattered by specimen enter objective
lens
Specimen appears light against dark background
Increases contrast and enables observation of thin and translucent
orgs
◉ total magnification equals?.
Answer: magnification of objective lens X magnification of ocular
lens
◉ Oil immersion lens.
Answer: increases resolution because light does not refract
◉ compound bright field microscope.
Answer: - Uses a series of lenses for magnification
-Light rays pass through specimen and into objective lens (one of a
series)
-Has one or two ocular lenses
EVALUATION 2026 FULL QUESTIONS AND
CORRECT ANSWERS
◉ Confocal Microscope.
Answer: Also uses fluorescent dyes
Use UV lasers to illuminate fluorescent chemicals in a single plane
that is no thicker than 1.0 μm
Resolution increased by up to 40% because emitted light passes
through pinhole aperture
Computer constructs 3-D image from digitized images
◉ are all cells naturally fluorescent?.
Answer: No some require staining to see on fluorescent microscopes
◉ Fluorescent Microscopes.
Answer: Direct UV light source at specimen; fluorochromes absorb
the UV light and radiate energy back as a longer, visible wavelength
UV light increases resolution and contrast
,◉ Two types of Phase Microscopes.
Answer: Phase-Contrast Microscope
Differential Interference Contrast (DIC) Microscope
◉ Phase Microscopes.
Answer: Used to examine LIVING organisms or specimens that
would be damaged or altered by attaching them to slides or staining
them
These microscopes treat one set of light rays differently from
another set
Light rays IN PHASE produce BRIGHTER image,
while light rays OUT of PHASE produce DARKER image
Contrast is created because light waves are ½ wavelength out of
phase
◉ Dark-Field Microscopes.
, Answer: - Best for observing pale or very thin objects that are
LIVING
Only those oblique light rays scattered by specimen enter objective
lens
Specimen appears light against dark background
Increases contrast and enables observation of thin and translucent
orgs
◉ total magnification equals?.
Answer: magnification of objective lens X magnification of ocular
lens
◉ Oil immersion lens.
Answer: increases resolution because light does not refract
◉ compound bright field microscope.
Answer: - Uses a series of lenses for magnification
-Light rays pass through specimen and into objective lens (one of a
series)
-Has one or two ocular lenses
