BIO 181
BIO 181 LAB MIDTERM EXAM QUESTIONS
AND ANSWERS GRADED A+ 2025
Hypothesis - Correct Ans-•A tentative explanation that can be tested scientifically
•Once proven by rigorous scientific investigation, hypothesis becomes a theory or a law
dependent variable - Correct Ans-what is measured or counted as a response
independant variable - Correct Ans-what is manipulated or changed in the experiment
control group - Correct Ans-independent variable is omitted or set at a standard
experimental group - Correct Ans-•independent variable is manipulated
why is it important to formulate a hypothesis? - Correct Ans-scientists circle closer and
closer to their best estimation of the laws governing nature.
scientific method steps - Correct Ans-1. Observation: a piece of the natural world
2. Question: What? Why? How?
3. Hypothesis: Testable, Reproducible & Falsifiable (STATEMENT!! because)
4. Prediction: "If - Then" reasoning
5. Experimental & Observational Tests: Analyze results
6. Conclusion: What do the results mean?
what types of statements can be supported or rejected using the scientific method -
Correct Ans-
difference between hypothesis and theory - Correct Ans-When one person thinks of an
idea, it is a hypothesis. When the entire scientific community agrees on an idea, it is a
theory.
Know the difference between hypothesis-based science and observation-based science
- Correct Ans-observation based science is about describing nature, whereas
hypothesis-driven science tries to explain nature
Alka Setzer Lab procedure - Correct Ans-1. Once Alka Seltzer interacts with water it
releases carbon dioxide causing it to dissolve.
2. Dissolve half a tablet of Alka-Seltzer in cold, hot, and room temperature water
Alka Seltzer Lab variables - Correct Ans--Dependent variable: Time (seconds)
-Independent variable: Water Temperature (Celsius)
-Controls: Room temperature water and the half tab of Alka-Seltzer.
1|Page
, BIO 181
Alka Seltzer Hypothesis - Correct Ans-As the water temperature increases, the time it
takes to dissolve a half tab of Alka-Seltzer will decrease because heat breaks down
substances faster than any other temperature.
Alka Seltzer Bar Graph - Correct Ans-Y axis: Time
X axis: temperature
Which temperature caused the Alka-Seltzer to dissolve quickest? - Correct Ans-Hot
water
What is the relationship between temperature and speed at which Alka-Seltzer
dissolves? - Correct Ans-The relationship between temperature and speed is the higher
the temperature, the less time it takes for Alka-Seltzer to dissolve.
Microscopy and Cell Staining Lab; how to calculate total magnification - Correct Ans-1.
Line up the edge of the ruler with the left edge of the FOV
2. Count the number of marks seen in the FOV. Mark is a mm.
3. Using Equation Diameter of high(er)power=Diameter (low power) × Magnification
(low power divided by Magnification at high(er)power, estimate the FOV with the 10X
lens.
4. Calculate the diameter of the FOV for each magnification.
5. Divide the diameter of each magnification by 2—this is the radius of the FOV.
6. Calculate the area of each magnification using A=𝛑r^2
How to Estimate the Size of an Object Under a Microscope - Correct Ans-1. Focus on
the object at a certain magnification, and note the diameter of the FOV at that
magnification.
2. Determine (guesstimate) the percent of the diameter of the FOV occupied by the
object (image).
3. Determine the object size using Equation: Object size = % Occupied by object in the
FOV x Diameter of the FOV
Know all parts and functions of a microscope - Correct Ans-quiz on lab website
Know why oil immersion is used only in 100X objective lens (oil immersion lens) -
Correct Ans-Oil distorts images seen with dry lenses
Arm - Correct Ans-The part of a microscope that connects the body to the base.
Body - Correct Ans-The bottom of the microscope.
Coarse Focus Adjustment Knob - Correct Ans-The large knob of a compound
microscope used to bring the specimen into an approximate focus.
Field of View (FOV) - Correct Ans-The area seen through the oculars of a microscope.
2|Page
BIO 181 LAB MIDTERM EXAM QUESTIONS
AND ANSWERS GRADED A+ 2025
Hypothesis - Correct Ans-•A tentative explanation that can be tested scientifically
•Once proven by rigorous scientific investigation, hypothesis becomes a theory or a law
dependent variable - Correct Ans-what is measured or counted as a response
independant variable - Correct Ans-what is manipulated or changed in the experiment
control group - Correct Ans-independent variable is omitted or set at a standard
experimental group - Correct Ans-•independent variable is manipulated
why is it important to formulate a hypothesis? - Correct Ans-scientists circle closer and
closer to their best estimation of the laws governing nature.
scientific method steps - Correct Ans-1. Observation: a piece of the natural world
2. Question: What? Why? How?
3. Hypothesis: Testable, Reproducible & Falsifiable (STATEMENT!! because)
4. Prediction: "If - Then" reasoning
5. Experimental & Observational Tests: Analyze results
6. Conclusion: What do the results mean?
what types of statements can be supported or rejected using the scientific method -
Correct Ans-
difference between hypothesis and theory - Correct Ans-When one person thinks of an
idea, it is a hypothesis. When the entire scientific community agrees on an idea, it is a
theory.
Know the difference between hypothesis-based science and observation-based science
- Correct Ans-observation based science is about describing nature, whereas
hypothesis-driven science tries to explain nature
Alka Setzer Lab procedure - Correct Ans-1. Once Alka Seltzer interacts with water it
releases carbon dioxide causing it to dissolve.
2. Dissolve half a tablet of Alka-Seltzer in cold, hot, and room temperature water
Alka Seltzer Lab variables - Correct Ans--Dependent variable: Time (seconds)
-Independent variable: Water Temperature (Celsius)
-Controls: Room temperature water and the half tab of Alka-Seltzer.
1|Page
, BIO 181
Alka Seltzer Hypothesis - Correct Ans-As the water temperature increases, the time it
takes to dissolve a half tab of Alka-Seltzer will decrease because heat breaks down
substances faster than any other temperature.
Alka Seltzer Bar Graph - Correct Ans-Y axis: Time
X axis: temperature
Which temperature caused the Alka-Seltzer to dissolve quickest? - Correct Ans-Hot
water
What is the relationship between temperature and speed at which Alka-Seltzer
dissolves? - Correct Ans-The relationship between temperature and speed is the higher
the temperature, the less time it takes for Alka-Seltzer to dissolve.
Microscopy and Cell Staining Lab; how to calculate total magnification - Correct Ans-1.
Line up the edge of the ruler with the left edge of the FOV
2. Count the number of marks seen in the FOV. Mark is a mm.
3. Using Equation Diameter of high(er)power=Diameter (low power) × Magnification
(low power divided by Magnification at high(er)power, estimate the FOV with the 10X
lens.
4. Calculate the diameter of the FOV for each magnification.
5. Divide the diameter of each magnification by 2—this is the radius of the FOV.
6. Calculate the area of each magnification using A=𝛑r^2
How to Estimate the Size of an Object Under a Microscope - Correct Ans-1. Focus on
the object at a certain magnification, and note the diameter of the FOV at that
magnification.
2. Determine (guesstimate) the percent of the diameter of the FOV occupied by the
object (image).
3. Determine the object size using Equation: Object size = % Occupied by object in the
FOV x Diameter of the FOV
Know all parts and functions of a microscope - Correct Ans-quiz on lab website
Know why oil immersion is used only in 100X objective lens (oil immersion lens) -
Correct Ans-Oil distorts images seen with dry lenses
Arm - Correct Ans-The part of a microscope that connects the body to the base.
Body - Correct Ans-The bottom of the microscope.
Coarse Focus Adjustment Knob - Correct Ans-The large knob of a compound
microscope used to bring the specimen into an approximate focus.
Field of View (FOV) - Correct Ans-The area seen through the oculars of a microscope.
2|Page
