BIOD 171 MODULE 3 (2025) Actual Exam
Questions and Answers A+ Graded
A .nanometer .is .defined .as: .- .CORRECT .ANSWER-10 .-9 .or .one-billionth .of .a
.meter
True .or .False: .A .nanometer .is .longer .than .a .micrometer .- .CORRECT .ANSWER-
False
A .nanometer .is .1000x .smaller .than .a .micrometer
Resolution .and .contrast .are .two .critical .factors .that .influence .your .ability .to
.see .an .object. .Explain .each. .- .CORRECT .ANSWER-Resolution .refers .to .the
.distance .between .two .objects .at .which .the .objects .can .still .be .seen .as
.separate. .Poor .or .low .resolution .means .two .or .more .objects .may .appear .as
.one.
Contrast .on .the .other .hand .is .the .difference .in .light .absorbance .between .two
.objects. .Poor .contrast .gives .a .high .background .and .makes .the .visualization .of
.multiple .objects .difficult. .For .instance, .trying .to .identify .2 .dark .colored .objects
.at
night .(low .light .= .low .contrast) .versus .the .same .2 .objects .in .the .middle .of
a .sunny .afternoon .(bright .light .against .2 .dark .objects .= .high .contrast).
Assuming .a .fixed .ocular, .identify .the .part .of .the .microscope .you .would .adjust
.to .enhance .the .magnification .of .a .sample. .- .CORRECT .ANSWER-Objective
Only .the .oculars .(eyepiece) .and .the .objectives .contribute .to .the .magnification
.of .the .sample. .Since .the .eyepiece
is .fixed, .only .the .objectives .could .be .altered.
, Assuming .a .constant .(non-adjustable) .light .source .power, .identify .the .part .of
.the .microscope .you .would .adjust .to .limit .the .amount .of .light .entering .the
.microscope. .- .CORRECT .ANSWER-Iris .diaphragm
What .is .the .total .magnification .on .(relative .to .your .eye) .of .a .sample .imaged
.with .a .60x .objective .and .a .10x .eyepiece? .Show .your .math. .- .CORRECT
.ANSWER-60x .objective .x .10x .ocular .= .600x .magnification
True .or .False: .Staining .is .often .required .to .image .a .cell .that .is .adherent .and
.flat .(thin). .- .CORRECT .ANSWER-True
Adherent, .flat .and .unstained .cells .are .almost .invisible .due .to .the .limits .on .both
resolution .and .contrast. .Therefore, .cell .staining .is .often .required .to .adequately
.image
the .sample.
True .or .False: .A .cell .that .is .adherent, .flat .(thin), .and .unstained .is .easily
.identified .using .bright .field .microscopy .- .CORRECT .ANSWER-False: .Adherent,
.flat .cells .are .almost .invisible .due .to .the .limits .on .both .resolution .and .contrast
Which .of .the .following .could .be .seen .clearly .by .the .unaided .eye? .Select .all .that
.apply.
A. .Bacteria .with .diameter .of .24 .μm
B. .Protozoa .with .diameter .of .150 .μm
C. .Virus .with .a .diameter .of .0.2 .μm
D. .Skin .cell .with .diameter .of .1500 .μm .- .CORRECT .ANSWER-B. .Protozoa .with
.diameter .of .150 .μm
D. .Skin .cell .with .diameter .of .1500 .μm
The .unaided .eye .can, .on .average, .clearly .resolve .objects .> .100 .μm
2. .Which .of .the .following .could .NOT .be .seen .clearly .by .the .unaided .eye? .Select
.all .that .apply.
A. .Bacteria .with .diameter .of .24 .μm
B. .Protozoa .with .diameter .of .150 .μm
C. .Virus .with .a .diameter .of .0.2 .μm
D. .Skin .cell .with .diameter .of .1500 .μm .- .CORRECT .ANSWER-A. .Bacteria .with
.diameter .of .24 .μm
Questions and Answers A+ Graded
A .nanometer .is .defined .as: .- .CORRECT .ANSWER-10 .-9 .or .one-billionth .of .a
.meter
True .or .False: .A .nanometer .is .longer .than .a .micrometer .- .CORRECT .ANSWER-
False
A .nanometer .is .1000x .smaller .than .a .micrometer
Resolution .and .contrast .are .two .critical .factors .that .influence .your .ability .to
.see .an .object. .Explain .each. .- .CORRECT .ANSWER-Resolution .refers .to .the
.distance .between .two .objects .at .which .the .objects .can .still .be .seen .as
.separate. .Poor .or .low .resolution .means .two .or .more .objects .may .appear .as
.one.
Contrast .on .the .other .hand .is .the .difference .in .light .absorbance .between .two
.objects. .Poor .contrast .gives .a .high .background .and .makes .the .visualization .of
.multiple .objects .difficult. .For .instance, .trying .to .identify .2 .dark .colored .objects
.at
night .(low .light .= .low .contrast) .versus .the .same .2 .objects .in .the .middle .of
a .sunny .afternoon .(bright .light .against .2 .dark .objects .= .high .contrast).
Assuming .a .fixed .ocular, .identify .the .part .of .the .microscope .you .would .adjust
.to .enhance .the .magnification .of .a .sample. .- .CORRECT .ANSWER-Objective
Only .the .oculars .(eyepiece) .and .the .objectives .contribute .to .the .magnification
.of .the .sample. .Since .the .eyepiece
is .fixed, .only .the .objectives .could .be .altered.
, Assuming .a .constant .(non-adjustable) .light .source .power, .identify .the .part .of
.the .microscope .you .would .adjust .to .limit .the .amount .of .light .entering .the
.microscope. .- .CORRECT .ANSWER-Iris .diaphragm
What .is .the .total .magnification .on .(relative .to .your .eye) .of .a .sample .imaged
.with .a .60x .objective .and .a .10x .eyepiece? .Show .your .math. .- .CORRECT
.ANSWER-60x .objective .x .10x .ocular .= .600x .magnification
True .or .False: .Staining .is .often .required .to .image .a .cell .that .is .adherent .and
.flat .(thin). .- .CORRECT .ANSWER-True
Adherent, .flat .and .unstained .cells .are .almost .invisible .due .to .the .limits .on .both
resolution .and .contrast. .Therefore, .cell .staining .is .often .required .to .adequately
.image
the .sample.
True .or .False: .A .cell .that .is .adherent, .flat .(thin), .and .unstained .is .easily
.identified .using .bright .field .microscopy .- .CORRECT .ANSWER-False: .Adherent,
.flat .cells .are .almost .invisible .due .to .the .limits .on .both .resolution .and .contrast
Which .of .the .following .could .be .seen .clearly .by .the .unaided .eye? .Select .all .that
.apply.
A. .Bacteria .with .diameter .of .24 .μm
B. .Protozoa .with .diameter .of .150 .μm
C. .Virus .with .a .diameter .of .0.2 .μm
D. .Skin .cell .with .diameter .of .1500 .μm .- .CORRECT .ANSWER-B. .Protozoa .with
.diameter .of .150 .μm
D. .Skin .cell .with .diameter .of .1500 .μm
The .unaided .eye .can, .on .average, .clearly .resolve .objects .> .100 .μm
2. .Which .of .the .following .could .NOT .be .seen .clearly .by .the .unaided .eye? .Select
.all .that .apply.
A. .Bacteria .with .diameter .of .24 .μm
B. .Protozoa .with .diameter .of .150 .μm
C. .Virus .with .a .diameter .of .0.2 .μm
D. .Skin .cell .with .diameter .of .1500 .μm .- .CORRECT .ANSWER-A. .Bacteria .with
.diameter .of .24 .μm
