BIO 225 Lab Test 1 – Practice Questions, Study Guide & Exam Review
2026
Ocular lenses - ANS ✔✔Eyepiece lenses located at at the top of the microscope
10x - ANS ✔✔Magnification level of each ocular lens
Objective lenses - ANS ✔✔Lenses located above the stage, mounted on the revolving nosepiece
Mechanical stage - ANS ✔✔Movable part of the microscope that acts as a platform on which to
mount slides
Scanning objective - ANS ✔✔Shortest, red-striped lens that carries the lowest magnification
4x (5x) - ANS ✔✔Magnification level of scanning objective
Low power objective - ANS ✔✔Yellow-striped lens that is the second shortest on the
microscope
10x - ANS ✔✔Magnification level of low power objective
Yellow - ANS ✔✔Color of low power objective
Red - ANS ✔✔Color of scanning objective
High power or Hi-dry objective - ANS ✔✔Second-longest objective lens that has a blue-stripe
, 40x - ANS ✔✔Magnification level of hi-dry lens
Blue - ANS ✔✔Color of hi-dry lens
Oil immersion objective - ANS ✔✔Longest objective lens
White - ANS ✔✔Color of longest objective lens
100x - ANS ✔✔Magnification level of longest objective lens
Immersion oil - ANS ✔✔Used to remove refraction when viewing items under the microscope
at 100x magnification
Condenser - ANS ✔✔Third lens system that focuses light rays from the illuminator onto the
specimen from below
Iris diaphragm - ANS ✔✔Microscope part that is adjusted to control the width of the cone of
light that gets focused onto the specimen
Illuminator - ANS ✔✔The light source at the base of the microscope
Base - ANS ✔✔Lower foundation of the microscope
Arm - ANS ✔✔Structure that supports the top section of the microscope
Slide assembly holder - ANS ✔✔Mechanism for holding microscope slides in place that includes
metal brackets and two knobs used to move slide side to side and up and down
2026
Ocular lenses - ANS ✔✔Eyepiece lenses located at at the top of the microscope
10x - ANS ✔✔Magnification level of each ocular lens
Objective lenses - ANS ✔✔Lenses located above the stage, mounted on the revolving nosepiece
Mechanical stage - ANS ✔✔Movable part of the microscope that acts as a platform on which to
mount slides
Scanning objective - ANS ✔✔Shortest, red-striped lens that carries the lowest magnification
4x (5x) - ANS ✔✔Magnification level of scanning objective
Low power objective - ANS ✔✔Yellow-striped lens that is the second shortest on the
microscope
10x - ANS ✔✔Magnification level of low power objective
Yellow - ANS ✔✔Color of low power objective
Red - ANS ✔✔Color of scanning objective
High power or Hi-dry objective - ANS ✔✔Second-longest objective lens that has a blue-stripe
, 40x - ANS ✔✔Magnification level of hi-dry lens
Blue - ANS ✔✔Color of hi-dry lens
Oil immersion objective - ANS ✔✔Longest objective lens
White - ANS ✔✔Color of longest objective lens
100x - ANS ✔✔Magnification level of longest objective lens
Immersion oil - ANS ✔✔Used to remove refraction when viewing items under the microscope
at 100x magnification
Condenser - ANS ✔✔Third lens system that focuses light rays from the illuminator onto the
specimen from below
Iris diaphragm - ANS ✔✔Microscope part that is adjusted to control the width of the cone of
light that gets focused onto the specimen
Illuminator - ANS ✔✔The light source at the base of the microscope
Base - ANS ✔✔Lower foundation of the microscope
Arm - ANS ✔✔Structure that supports the top section of the microscope
Slide assembly holder - ANS ✔✔Mechanism for holding microscope slides in place that includes
metal brackets and two knobs used to move slide side to side and up and down