BYU MMBIO 221 EXAM 1 ROBISON
QUESTIONS AND ANSWERS GRADED A+
2025/2026
Obligate halophiles - ANS High osmotic pressure aka lots of salt like the great salt lake
Confocal Microscope - ANS 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? - ANS No some require staining to see on fluorescent
microscopes
Fluorescent Microscopes - ANS 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
1 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
,Two types of Phase Microscopes - ANS Phase-Contrast Microscope
Differential Interference Contrast (DIC) Microscope
Phase Microscopes - ANS 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 - ANS - 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? - ANS magnification of objective lens X magnification of ocular
lens
Oil immersion lens - ANS increases resolution because light does not refract
2 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
, compound bright field microscope - ANS - 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
-Most have condenser lens to direct light through specimen
simple bright field microscope - ANS -Contains a single magnifying lens
-Similar to magnifying glass
-Leeuwenhoek used simple microscope to observe microorganisms
Bright-Field Microscopes:
two types - ANS Simple
Compound
Bright-Field Microscopes are most frequently used on what specimens? - ANS Stained
specimens
Light Microscopy types - ANS 1. Bright-field microscopes
2. Dark-field microscopes
3. Phase microscopes
4. Fluorescent microscopes
Confocal microscope
3 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
QUESTIONS AND ANSWERS GRADED A+
2025/2026
Obligate halophiles - ANS High osmotic pressure aka lots of salt like the great salt lake
Confocal Microscope - ANS 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? - ANS No some require staining to see on fluorescent
microscopes
Fluorescent Microscopes - ANS 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
1 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
,Two types of Phase Microscopes - ANS Phase-Contrast Microscope
Differential Interference Contrast (DIC) Microscope
Phase Microscopes - ANS 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 - ANS - 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? - ANS magnification of objective lens X magnification of ocular
lens
Oil immersion lens - ANS increases resolution because light does not refract
2 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
, compound bright field microscope - ANS - 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
-Most have condenser lens to direct light through specimen
simple bright field microscope - ANS -Contains a single magnifying lens
-Similar to magnifying glass
-Leeuwenhoek used simple microscope to observe microorganisms
Bright-Field Microscopes:
two types - ANS Simple
Compound
Bright-Field Microscopes are most frequently used on what specimens? - ANS Stained
specimens
Light Microscopy types - ANS 1. Bright-field microscopes
2. Dark-field microscopes
3. Phase microscopes
4. Fluorescent microscopes
Confocal microscope
3 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
