Chamberlain University
A N AT O M Y A N D P H Y S I O L O G Y I W I T H L A B
BIOS 251 Lab Practicum
Comprehensive Exam Review
100 Questions with Verified Answers and Comprehensive Rationales
All Laboratory Units Covered | 2026/2027 Curriculum Update
COURSE BIOS 251
TOTAL QUESTIONS 100 Multiple Choice
SECTIONS 8 Laboratory Content Areas
ACADEMIC YEAR 2026 - 2027
Latest 2026/2027 Update | Chamberlain University Curriculum Standards
,BIOS 251 Anatomy and Physiology I Lab Practicum | Chamberlain University | 2026/2027
Section 1: Microscopy and Laboratory Safety (Q1-Q12)
Q1: A student is using a compound light microscope and wants to achieve a total magnification of 400x. Which
combination of eyepiece and objective lenses will achieve this?
A. Eyepiece 10x and scanning objective 4x
B. Eyepiece 10x and low-power objective 10x
C. Eyepiece 10x and high-power objective 40x [CORRECT]
D. Eyepiece 10x and oil-immersion objective 100x
Correct Answer: C
Rationale: Total magnification is calculated by multiplying the eyepiece lens magnification by the objective lens magnification.
The eyepiece is always 10x in standard compound microscopes, so 10x multiplied by the high-power objective 40x equals 400x.
Scanning (4x) gives 40x, low-power (10x) gives 100x, and oil-immersion (100x) gives 1000x. Chamberlain BIOS 251 emphasizes
that students must memorize the formula Total Mag = Eyepiece x Objective.
Q2: Which microscope part focuses light from the illuminator onto the specimen and is located directly below the
stage?
A. Eyepiece (ocular lens)
B. Rotating nosepiece (revolving turret)
C. Condenser [CORRECT]
D. Iris diaphragm
Correct Answer: C
Rationale: The condenser is a lens system located below the stage that focuses light from the illuminator onto the specimen,
improving resolution and contrast. The eyepiece is at the top of the microscope. The rotating nosepiece holds the objective lenses.
The iris diaphragm is within or below the condenser and controls the amount of light entering the lens system. Chamberlain BIOS
251 lab practical tests the ability to identify the condenser and distinguish it from the iris diaphragm.
Q3: A student is carrying a compound light microscope from one lab bench to another. Which is the correct
technique?
A. Carry the microscope by the eyepiece with one hand
B. Carry with one hand on the arm and one hand supporting the base [CORRECT]
C. Carry by the stage with both hands
D. Hold the microscope by the power cord near the base
Correct Answer: B
Rationale: The correct technique for carrying a compound light microscope is to use two hands: one hand gripping the arm for
support and the other hand supporting the base. This prevents damage from dropping and ensures stability. Carrying by the
eyepiece can misalign optics. Carrying by the stage risks damaging the stage mechanism. The power cord should never be used as
a handle. Chamberlain BIOS 251 laboratory safety protocols mandate the two-hand carry technique.
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,BIOS 251 Anatomy and Physiology I Lab Practicum | Chamberlain University | 2026/2027
Q4: What is the function of the iris diaphragm on a compound light microscope?
A. Holds the objective lenses and allows rotation to change magnification
B. Controls the amount of light entering the lens system to adjust contrast and resolution
[CORRECT]
C. Provides magnification of 10x for initial viewing of the specimen
D. Allows precise movement of the slide along the X and Y axes
Correct Answer: B
Rationale: The iris diaphragm (also called the condenser iris) controls the amount of light passing through the condenser and onto
the specimen. Adjusting it changes the contrast and resolution of the image. Opening it allows more light (lower contrast), while
closing it reduces light (higher contrast). The rotating nosepiece holds objectives, the eyepiece provides 10x magnification, and the
mechanical stage controls slide movement. Chamberlain BIOS 251 emphasizes understanding the iris diaphragm for optimizing
image quality.
Q5: When switching from the low-power (10x) objective to the high-power (40x) objective, the image remains
nearly in focus and only requires a minor adjustment with the fine focus knob. This property of the microscope is
called:
A. Resolution
B. Parfocality [CORRECT]
C. Depth of field
D. Field of view
Correct Answer: B
Rationale: Parfocality means that when the microscope is focused with one objective lens, switching to another objective lens will
keep the specimen approximately in focus, requiring only minor fine focus adjustment. This is a built-in property of quality
microscopes. Resolution is the ability to distinguish two close objects. Depth of field is the thickness of the specimen in focus. Field
of view is the diameter of the visible area. Chamberlain BIOS 251 stresses parfocality as a key microscope concept.
Q6: A student needs to clean the objective lens of a microscope. Which material should the student use?
A. Kimwipes or paper towels
B. A cotton swab with water
C. Lens paper designed for optical cleaning [CORRECT]
D. A laboratory tissue with alcohol
Correct Answer: C
Rationale: Only lens paper should be used to clean microscope lenses because it is specifically designed to be soft and lint-free,
preventing scratches on the delicate optical coatings. Kimwipes, paper towels, and laboratory tissues are too abrasive and can
scratch the lens surface. Cotton swabs can leave fibers behind. Chamberlain BIOS 251 laboratory safety protocols explicitly
require lens paper for all optical cleaning.
Q7: When preparing a wet mount slide, what is the purpose of the cover slip?
A. To increase the magnification of the specimen
B. To protect the objective lens and flatten the specimen for better viewing [CORRECT]
C. To stain the specimen for contrast enhancement
D. To hold the slide securely on the mechanical stage
Correct Answer: B
Rationale: The cover slip serves two main purposes: it protects the objective lens from direct contact with the wet specimen (which
could damage the lens), and it flattens the specimen into a single optical plane for clearer viewing. Stage clips or a mechanical
stage hold the slide in position. Stains are applied separately for contrast. Magnification is determined by the lens system, not the
cover slip. Chamberlain BIOS 251 lab protocol requires proper cover slip placement on all wet mounts.
Page 2
, BIOS 251 Anatomy and Physiology I Lab Practicum | Chamberlain University | 2026/2027
Q8: A student uses the oil-immersion objective (100x) to view a bacterial specimen. What is the primary purpose
of the immersion oil?
A. To stain the specimen for better contrast
B. To reduce light refraction and increase resolution by matching the refractive index of glass
[CORRECT]
C. To lubricate the mechanical stage for smoother movement
D. To cool the specimen and prevent heat damage from the light source
Correct Answer: B
Rationale: Immersion oil is placed between the 100x objective lens and the cover slip to reduce light refraction (light bending) at
the air-glass interface. Oil has approximately the same refractive index as glass, so light passes straight through without
scattering, which increases the numerical aperture and resolution of the lens system. This allows finer detail to be resolved. It has
nothing to do with staining, lubrication, or cooling. Chamberlain BIOS 251 teaches that oil immersion is essential for maximum
resolution at 1000x.
Q9: As a student increases magnification from 40x to 400x, what happens to the field of view and depth of field?
A. Both the field of view and depth of field increase
B. The field of view decreases but the depth of field increases
C. The field of view increases but the depth of field decreases
D. Both the field of view and depth of field decrease [CORRECT]
Correct Answer: D
Rationale: Both the field of view (the diameter of the visible area) and the depth of field (the thickness of the specimen in focus)
are inversely proportional to magnification. As magnification increases, you see a smaller area of the specimen (field of view
decreases) and a thinner slice remains in focus (depth of field decreases). This is why focusing becomes more critical at higher
magnifications. Chamberlain BIOS 251 emphasizes understanding these inverse relationships for practical microscopy.
Q10: Which laboratory safety protocol is mandatory when handling preserved biological specimens in the
anatomy lab?
A. Wearing a lab coat is sufficient; gloves are optional for preserved specimens
B. Wear gloves, disinfect surfaces after use, and dispose of biological waste in designated containers
[CORRECT]
C. Specimens can be handled without protection if they have been preserved for more than 30 days
D. Only wear safety goggles; gloves are only required for fresh (unpreserved) specimens
Correct Answer: B
Rationale: When handling preserved biological specimens, students must wear gloves to protect against exposure to preservative
chemicals (such as formaldehyde), disinfect work surfaces after the lab, and dispose of all biological waste in designated
biohazard containers. Safety goggles and lab coats are also typically required. Even preserved specimens require standard
precautions because preservatives can be irritants or toxic. Chamberlain BIOS 251 lab safety rules mandate full PPE for all
specimen handling.
Page 3
A N AT O M Y A N D P H Y S I O L O G Y I W I T H L A B
BIOS 251 Lab Practicum
Comprehensive Exam Review
100 Questions with Verified Answers and Comprehensive Rationales
All Laboratory Units Covered | 2026/2027 Curriculum Update
COURSE BIOS 251
TOTAL QUESTIONS 100 Multiple Choice
SECTIONS 8 Laboratory Content Areas
ACADEMIC YEAR 2026 - 2027
Latest 2026/2027 Update | Chamberlain University Curriculum Standards
,BIOS 251 Anatomy and Physiology I Lab Practicum | Chamberlain University | 2026/2027
Section 1: Microscopy and Laboratory Safety (Q1-Q12)
Q1: A student is using a compound light microscope and wants to achieve a total magnification of 400x. Which
combination of eyepiece and objective lenses will achieve this?
A. Eyepiece 10x and scanning objective 4x
B. Eyepiece 10x and low-power objective 10x
C. Eyepiece 10x and high-power objective 40x [CORRECT]
D. Eyepiece 10x and oil-immersion objective 100x
Correct Answer: C
Rationale: Total magnification is calculated by multiplying the eyepiece lens magnification by the objective lens magnification.
The eyepiece is always 10x in standard compound microscopes, so 10x multiplied by the high-power objective 40x equals 400x.
Scanning (4x) gives 40x, low-power (10x) gives 100x, and oil-immersion (100x) gives 1000x. Chamberlain BIOS 251 emphasizes
that students must memorize the formula Total Mag = Eyepiece x Objective.
Q2: Which microscope part focuses light from the illuminator onto the specimen and is located directly below the
stage?
A. Eyepiece (ocular lens)
B. Rotating nosepiece (revolving turret)
C. Condenser [CORRECT]
D. Iris diaphragm
Correct Answer: C
Rationale: The condenser is a lens system located below the stage that focuses light from the illuminator onto the specimen,
improving resolution and contrast. The eyepiece is at the top of the microscope. The rotating nosepiece holds the objective lenses.
The iris diaphragm is within or below the condenser and controls the amount of light entering the lens system. Chamberlain BIOS
251 lab practical tests the ability to identify the condenser and distinguish it from the iris diaphragm.
Q3: A student is carrying a compound light microscope from one lab bench to another. Which is the correct
technique?
A. Carry the microscope by the eyepiece with one hand
B. Carry with one hand on the arm and one hand supporting the base [CORRECT]
C. Carry by the stage with both hands
D. Hold the microscope by the power cord near the base
Correct Answer: B
Rationale: The correct technique for carrying a compound light microscope is to use two hands: one hand gripping the arm for
support and the other hand supporting the base. This prevents damage from dropping and ensures stability. Carrying by the
eyepiece can misalign optics. Carrying by the stage risks damaging the stage mechanism. The power cord should never be used as
a handle. Chamberlain BIOS 251 laboratory safety protocols mandate the two-hand carry technique.
Page 1
,BIOS 251 Anatomy and Physiology I Lab Practicum | Chamberlain University | 2026/2027
Q4: What is the function of the iris diaphragm on a compound light microscope?
A. Holds the objective lenses and allows rotation to change magnification
B. Controls the amount of light entering the lens system to adjust contrast and resolution
[CORRECT]
C. Provides magnification of 10x for initial viewing of the specimen
D. Allows precise movement of the slide along the X and Y axes
Correct Answer: B
Rationale: The iris diaphragm (also called the condenser iris) controls the amount of light passing through the condenser and onto
the specimen. Adjusting it changes the contrast and resolution of the image. Opening it allows more light (lower contrast), while
closing it reduces light (higher contrast). The rotating nosepiece holds objectives, the eyepiece provides 10x magnification, and the
mechanical stage controls slide movement. Chamberlain BIOS 251 emphasizes understanding the iris diaphragm for optimizing
image quality.
Q5: When switching from the low-power (10x) objective to the high-power (40x) objective, the image remains
nearly in focus and only requires a minor adjustment with the fine focus knob. This property of the microscope is
called:
A. Resolution
B. Parfocality [CORRECT]
C. Depth of field
D. Field of view
Correct Answer: B
Rationale: Parfocality means that when the microscope is focused with one objective lens, switching to another objective lens will
keep the specimen approximately in focus, requiring only minor fine focus adjustment. This is a built-in property of quality
microscopes. Resolution is the ability to distinguish two close objects. Depth of field is the thickness of the specimen in focus. Field
of view is the diameter of the visible area. Chamberlain BIOS 251 stresses parfocality as a key microscope concept.
Q6: A student needs to clean the objective lens of a microscope. Which material should the student use?
A. Kimwipes or paper towels
B. A cotton swab with water
C. Lens paper designed for optical cleaning [CORRECT]
D. A laboratory tissue with alcohol
Correct Answer: C
Rationale: Only lens paper should be used to clean microscope lenses because it is specifically designed to be soft and lint-free,
preventing scratches on the delicate optical coatings. Kimwipes, paper towels, and laboratory tissues are too abrasive and can
scratch the lens surface. Cotton swabs can leave fibers behind. Chamberlain BIOS 251 laboratory safety protocols explicitly
require lens paper for all optical cleaning.
Q7: When preparing a wet mount slide, what is the purpose of the cover slip?
A. To increase the magnification of the specimen
B. To protect the objective lens and flatten the specimen for better viewing [CORRECT]
C. To stain the specimen for contrast enhancement
D. To hold the slide securely on the mechanical stage
Correct Answer: B
Rationale: The cover slip serves two main purposes: it protects the objective lens from direct contact with the wet specimen (which
could damage the lens), and it flattens the specimen into a single optical plane for clearer viewing. Stage clips or a mechanical
stage hold the slide in position. Stains are applied separately for contrast. Magnification is determined by the lens system, not the
cover slip. Chamberlain BIOS 251 lab protocol requires proper cover slip placement on all wet mounts.
Page 2
, BIOS 251 Anatomy and Physiology I Lab Practicum | Chamberlain University | 2026/2027
Q8: A student uses the oil-immersion objective (100x) to view a bacterial specimen. What is the primary purpose
of the immersion oil?
A. To stain the specimen for better contrast
B. To reduce light refraction and increase resolution by matching the refractive index of glass
[CORRECT]
C. To lubricate the mechanical stage for smoother movement
D. To cool the specimen and prevent heat damage from the light source
Correct Answer: B
Rationale: Immersion oil is placed between the 100x objective lens and the cover slip to reduce light refraction (light bending) at
the air-glass interface. Oil has approximately the same refractive index as glass, so light passes straight through without
scattering, which increases the numerical aperture and resolution of the lens system. This allows finer detail to be resolved. It has
nothing to do with staining, lubrication, or cooling. Chamberlain BIOS 251 teaches that oil immersion is essential for maximum
resolution at 1000x.
Q9: As a student increases magnification from 40x to 400x, what happens to the field of view and depth of field?
A. Both the field of view and depth of field increase
B. The field of view decreases but the depth of field increases
C. The field of view increases but the depth of field decreases
D. Both the field of view and depth of field decrease [CORRECT]
Correct Answer: D
Rationale: Both the field of view (the diameter of the visible area) and the depth of field (the thickness of the specimen in focus)
are inversely proportional to magnification. As magnification increases, you see a smaller area of the specimen (field of view
decreases) and a thinner slice remains in focus (depth of field decreases). This is why focusing becomes more critical at higher
magnifications. Chamberlain BIOS 251 emphasizes understanding these inverse relationships for practical microscopy.
Q10: Which laboratory safety protocol is mandatory when handling preserved biological specimens in the
anatomy lab?
A. Wearing a lab coat is sufficient; gloves are optional for preserved specimens
B. Wear gloves, disinfect surfaces after use, and dispose of biological waste in designated containers
[CORRECT]
C. Specimens can be handled without protection if they have been preserved for more than 30 days
D. Only wear safety goggles; gloves are only required for fresh (unpreserved) specimens
Correct Answer: B
Rationale: When handling preserved biological specimens, students must wear gloves to protect against exposure to preservative
chemicals (such as formaldehyde), disinfect work surfaces after the lab, and dispose of all biological waste in designated
biohazard containers. Safety goggles and lab coats are also typically required. Even preserved specimens require standard
precautions because preservatives can be irritants or toxic. Chamberlain BIOS 251 lab safety rules mandate full PPE for all
specimen handling.
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