BIOLOGY 101 PRACTICE EXAM
QUESTIONS 2026 100 Questions &
Answers with Detailed Explanations
EXAM INFORMATION
Institution: Various U.S. colleges and universities – Introductory Biology Courses
Subject: Biology 101 – General Biology / Principles of Biology
Reference Materials: Campbell Biology, 12th Edition; OpenStax Biology, 2nd Edition
Number of Questions: 100 Multiple Choice Questions
Answer Format: Correct answer indicated with detailed rationale
Exam Year: 2026/2027 Updated Standards
EXAM TOPICS COVERED
- The Science of Biology & Scientific Method
- Chemical Foundations of Life (Atoms, Bonds, Water, pH)
- Biological Macromolecules (Carbohydrates, Lipids, Proteins, Nucleic Acids)
- Cell Structure & Function (Prokaryotic vs. Eukaryotic, Organelles)
- Membrane Structure & Transport
- Metabolism & Enzymes
- Cellular Respiration & Fermentation
- Photosynthesis
- Cell Division (Mitosis & Meiosis)
- Genetics & Heredity (Mendelian Genetics)
- Molecular Biology (DNA Structure, Replication, Transcription, Translation)
- Gene Regulation & Biotechnology
- Evolution & Natural Selection
- Ecology & Ecosystems
,SECTION 1: THE SCIENCE OF BIOLOGY (Questions 1–10)
QUESTION 1
What is the basic unit of life?
A) Atom
B) Molecule
C) Cell
D) Tissue
Answer: C) Cell
Rationale: The cell is the fundamental structural and functional unit of all living organisms. It is
the simplest structure that exhibits the characteristics of life, including metabolism, growth,
reproduction, and response to stimuli. Atoms and molecules are non-living components, and
tissues are collections of cells.
QUESTION 2
What is the process by which organisms maintain a stable internal environment?
A) Metabolism
B) Homeostasis
C) Reproduction
D) Adaptation
Answer: B) Homeostasis
Rationale: Homeostasis is the ability of living organisms to maintain a stable internal
environment despite changes in the external environment. This is essential for survival and is a
defining characteristic of all living things.
QUESTION 3
In an experiment, the group that receives the treatment being tested is called the:
A) Control group
B) Experimental group
C) Variable group
D) Constant group
,Answer: B) Experimental group
Rationale: The experimental group is exposed to the independent variable or treatment being
tested. The control group is not exposed to the treatment and serves as a baseline for
comparison. This design allows researchers to determine whether the treatment had an effect.
QUESTION 4
What is the correct order of the scientific method?
A) Hypothesis → Observation → Experiment → Conclusion
B) Observation → Hypothesis → Experiment → Conclusion
C) Experiment → Observation → Hypothesis → Conclusion
D) Conclusion → Hypothesis → Experiment → Observation
Answer: B) Observation → Hypothesis → Experiment → Conclusion
Rationale: The scientific method follows a logical sequence: make observations, formulate a
testable hypothesis, design and conduct experiments to test the hypothesis, and draw
conclusions based on the results. This systematic approach helps ensure objective and reliable
findings.
QUESTION 5
What is the variable that is manipulated by the researcher in an experiment?
A) Dependent variable
B) Independent variable
C) Control variable
D) Constant variable
Answer: B) Independent variable
Rationale: The independent variable is the factor that the researcher deliberately changes or
manipulates in an experiment. The dependent variable is measured to see if it is affected by
changes in the independent variable.
QUESTION 6
Which of the following is NOT a characteristic of all living organisms?
, A) Made of cells
B) Respond to stimuli
C) Can photosynthesize
D) Reproduce
Answer: C) Can photosynthesize
Rationale: Not all living organisms can photosynthesize—only plants, algae, and some bacteria
perform photosynthesis. Animals, fungi, and many other organisms obtain energy through other
means. All living things are made of cells, respond to stimuli, and reproduce.
QUESTION 7
The level of biological organization that includes all populations of different species living in a
particular area is called a:
A) Population
B) Community
C) Ecosystem
D) Biosphere
Answer: B) Community
Rationale: A community consists of all the populations of different species that live and interact
in a specific area. An ecosystem includes both the community and the abiotic (non-living)
factors in the environment.
QUESTION 8
In a controlled experiment, what is the purpose of a control group?
A) To test multiple variables simultaneously
B) To provide a baseline for comparison
C) To ensure the experiment is complex
D) To eliminate the need for repetition
Answer: B) To provide a baseline for comparison
Rationale: The control group provides a standard against which the experimental results can be
compared. It helps ensure that any observed effects are due to the independent variable being
tested rather than other factors.
QUESTIONS 2026 100 Questions &
Answers with Detailed Explanations
EXAM INFORMATION
Institution: Various U.S. colleges and universities – Introductory Biology Courses
Subject: Biology 101 – General Biology / Principles of Biology
Reference Materials: Campbell Biology, 12th Edition; OpenStax Biology, 2nd Edition
Number of Questions: 100 Multiple Choice Questions
Answer Format: Correct answer indicated with detailed rationale
Exam Year: 2026/2027 Updated Standards
EXAM TOPICS COVERED
- The Science of Biology & Scientific Method
- Chemical Foundations of Life (Atoms, Bonds, Water, pH)
- Biological Macromolecules (Carbohydrates, Lipids, Proteins, Nucleic Acids)
- Cell Structure & Function (Prokaryotic vs. Eukaryotic, Organelles)
- Membrane Structure & Transport
- Metabolism & Enzymes
- Cellular Respiration & Fermentation
- Photosynthesis
- Cell Division (Mitosis & Meiosis)
- Genetics & Heredity (Mendelian Genetics)
- Molecular Biology (DNA Structure, Replication, Transcription, Translation)
- Gene Regulation & Biotechnology
- Evolution & Natural Selection
- Ecology & Ecosystems
,SECTION 1: THE SCIENCE OF BIOLOGY (Questions 1–10)
QUESTION 1
What is the basic unit of life?
A) Atom
B) Molecule
C) Cell
D) Tissue
Answer: C) Cell
Rationale: The cell is the fundamental structural and functional unit of all living organisms. It is
the simplest structure that exhibits the characteristics of life, including metabolism, growth,
reproduction, and response to stimuli. Atoms and molecules are non-living components, and
tissues are collections of cells.
QUESTION 2
What is the process by which organisms maintain a stable internal environment?
A) Metabolism
B) Homeostasis
C) Reproduction
D) Adaptation
Answer: B) Homeostasis
Rationale: Homeostasis is the ability of living organisms to maintain a stable internal
environment despite changes in the external environment. This is essential for survival and is a
defining characteristic of all living things.
QUESTION 3
In an experiment, the group that receives the treatment being tested is called the:
A) Control group
B) Experimental group
C) Variable group
D) Constant group
,Answer: B) Experimental group
Rationale: The experimental group is exposed to the independent variable or treatment being
tested. The control group is not exposed to the treatment and serves as a baseline for
comparison. This design allows researchers to determine whether the treatment had an effect.
QUESTION 4
What is the correct order of the scientific method?
A) Hypothesis → Observation → Experiment → Conclusion
B) Observation → Hypothesis → Experiment → Conclusion
C) Experiment → Observation → Hypothesis → Conclusion
D) Conclusion → Hypothesis → Experiment → Observation
Answer: B) Observation → Hypothesis → Experiment → Conclusion
Rationale: The scientific method follows a logical sequence: make observations, formulate a
testable hypothesis, design and conduct experiments to test the hypothesis, and draw
conclusions based on the results. This systematic approach helps ensure objective and reliable
findings.
QUESTION 5
What is the variable that is manipulated by the researcher in an experiment?
A) Dependent variable
B) Independent variable
C) Control variable
D) Constant variable
Answer: B) Independent variable
Rationale: The independent variable is the factor that the researcher deliberately changes or
manipulates in an experiment. The dependent variable is measured to see if it is affected by
changes in the independent variable.
QUESTION 6
Which of the following is NOT a characteristic of all living organisms?
, A) Made of cells
B) Respond to stimuli
C) Can photosynthesize
D) Reproduce
Answer: C) Can photosynthesize
Rationale: Not all living organisms can photosynthesize—only plants, algae, and some bacteria
perform photosynthesis. Animals, fungi, and many other organisms obtain energy through other
means. All living things are made of cells, respond to stimuli, and reproduce.
QUESTION 7
The level of biological organization that includes all populations of different species living in a
particular area is called a:
A) Population
B) Community
C) Ecosystem
D) Biosphere
Answer: B) Community
Rationale: A community consists of all the populations of different species that live and interact
in a specific area. An ecosystem includes both the community and the abiotic (non-living)
factors in the environment.
QUESTION 8
In a controlled experiment, what is the purpose of a control group?
A) To test multiple variables simultaneously
B) To provide a baseline for comparison
C) To ensure the experiment is complex
D) To eliminate the need for repetition
Answer: B) To provide a baseline for comparison
Rationale: The control group provides a standard against which the experimental results can be
compared. It helps ensure that any observed effects are due to the independent variable being
tested rather than other factors.
