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100+ Free CLEP Biology Practice Questions

Pass your CLEP Biology (College-Level Examination Program) exam on the first try — instant access, no signup required.

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Active transport of ions across a cell membrane differs from passive diffusion because active transport requires which of the following?

A
B
C
D
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Key Facts: CLEP Biology Exam

115

approximate number of multiple-choice questions, some unscored pretest items

College Board

90 minutes

time limit for the computer-based exam

College Board

20-80

score scale, with 50 the ACE credit-granting score

College Board / ACE

6

semester hours of credit recommended for a score of 50 or higher

ACE

33% / 34% / 33%

weighting of molecular-cellular, organismal, and population biology

College Board

$97

exam fee plus a test-center administration fee

College Board

The CLEP Biology exam has about 115 multiple-choice questions to answer in 90 minutes, covering a full year of introductory college general biology. The content is split roughly evenly across Molecular and Cellular Biology (33%), Organismal Biology (34%), and Population Biology (33%). It is computer-based and scored on a 20-80 scale, with 50 the ACE-recommended credit-granting score (worth up to 6 semester hours). Registration costs $97 plus a test-center administration fee (source: College Board, clep.collegeboard.org).

Sample CLEP Biology Practice Questions

Try these sample questions to test your CLEP Biology exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which four elements make up roughly 96 percent of the mass of most living organisms?
A.Carbon, hydrogen, oxygen, and nitrogen
B.Sodium, potassium, calcium, and chlorine
C.Iron, magnesium, sulfur, and phosphorus
D.Helium, neon, argon, and silicon
Explanation: Carbon, hydrogen, oxygen, and nitrogen account for about 96 percent of living matter by mass. These elements form the backbone of the four major classes of biological macromolecules. Carbon's ability to form four covalent bonds makes the diversity of organic molecules possible.
2Which property of water is most directly responsible for its ability to moderate temperature changes in organisms and environments?
A.Its low surface tension
B.Its high specific heat
C.Its nonpolar covalent bonds
D.Its inability to form hydrogen bonds
Explanation: Water has a high specific heat because hydrogen bonds must absorb or release substantial energy before the temperature changes. This allows water to absorb large amounts of heat with only small temperature change, moderating climate and stabilizing internal body temperature. The same hydrogen bonding underlies water's high heat of vaporization.
3The monomers that link together to form proteins are best described as which of the following?
A.Monosaccharides
B.Nucleotides
C.Amino acids
D.Fatty acids
Explanation: Proteins are polymers of amino acids joined by peptide bonds formed through dehydration synthesis. There are 20 standard amino acids, and their sequence determines a protein's folding and function. Each amino acid has an amino group, a carboxyl group, and a distinctive side chain.
4Which organelle is the primary site of aerobic cellular respiration and ATP production in eukaryotic cells?
A.Chloroplast
B.Lysosome
C.Golgi apparatus
D.Mitochondrion
Explanation: The mitochondrion is the site of the Krebs cycle and oxidative phosphorylation, producing the bulk of a cell's ATP through aerobic respiration. Its inner membrane folds, called cristae, house the electron transport chain. Mitochondria contain their own DNA, supporting the endosymbiotic theory.
5A key structural feature that distinguishes prokaryotic cells from eukaryotic cells is that prokaryotes lack which of the following?
A.A membrane-bound nucleus
B.Ribosomes
C.A plasma membrane
D.Cytoplasm
Explanation: Prokaryotic cells lack a membrane-bound nucleus; their genetic material is concentrated in a nucleoid region but not enclosed by a membrane. They also lack other membrane-bound organelles such as mitochondria. Eukaryotic cells, by contrast, compartmentalize DNA within a true nucleus.
6According to the fluid mosaic model, the plasma membrane is best described as which of the following?
A.A rigid wall of cellulose fibers
B.A phospholipid bilayer with embedded proteins that can move laterally
C.A solid sheet of protein with no lipids
D.A single layer of cholesterol molecules
Explanation: The fluid mosaic model describes the membrane as a phospholipid bilayer in which proteins are embedded and can drift laterally. The hydrophilic phosphate heads face the aqueous environments while the hydrophobic tails face inward. This arrangement gives the membrane both fluidity and selective permeability.
7Enzymes increase the rate of biochemical reactions primarily by doing which of the following?
A.Increasing the activation energy required
B.Changing the overall free-energy change of the reaction
C.Lowering the activation energy of the reaction
D.Permanently binding to and being consumed by the substrate
Explanation: Enzymes are biological catalysts that lower the activation energy needed for a reaction to proceed, speeding up the reaction without being consumed. They achieve this by stabilizing the transition state at the active site. Enzymes do not alter the net free-energy change (delta G) of a reaction.
8In competitive enzyme inhibition, the inhibitor reduces enzyme activity by which mechanism?
A.Increasing the substrate concentration
B.Binding to a site away from the active site and changing enzyme shape
C.Permanently denaturing the enzyme with heat
D.Binding to the active site and blocking substrate access
Explanation: A competitive inhibitor resembles the substrate and binds directly to the active site, preventing substrate binding. Its effect can be overcome by increasing substrate concentration, which outcompetes the inhibitor. This contrasts with noncompetitive inhibition, which acts at an allosteric site.
9During glycolysis, a single molecule of glucose is broken down into two molecules of which compound?
A.Pyruvate
B.Lactic acid
C.Acetyl-CoA
D.Carbon dioxide
Explanation: Glycolysis splits one six-carbon glucose molecule into two three-carbon pyruvate molecules in the cytoplasm. The process yields a net of 2 ATP and 2 NADH. Pyruvate then enters the mitochondrion for the Krebs cycle under aerobic conditions.
10In aerobic respiration, what serves as the final electron acceptor at the end of the electron transport chain?
A.Carbon dioxide
B.Oxygen
C.Water
D.Glucose
Explanation: Oxygen is the final electron acceptor in the electron transport chain of aerobic respiration. It accepts electrons and combines with hydrogen ions to form water. Without oxygen, the chain backs up and aerobic ATP production halts.

About the CLEP Biology Exam

The CLEP Biology exam covers material usually taught in a one-year college introductory general biology course. It contains approximately 115 multiple-choice questions to be answered in 90 minutes (some are unscored pretest items) and is delivered by computer. The content is split about evenly across three areas: Molecular and Cellular Biology (33%), Organismal Biology (34%), and Population Biology (33%). Scores range from 20 to 80, and the ACE-recommended credit-granting score is 50, worth up to 6 semester hours.

Questions

115 scored questions

Time Limit

90 minutes

Passing Score

50 (on a 20-80 scale)

Exam Fee

$97 plus a test-center administration fee (College Board)

CLEP Biology Exam Content Outline

~33%

Molecular and Cellular Biology

Chemical composition of organisms, cells and membranes, enzymes, energy transformations, cell division, and the chemical nature of the gene.

~34%

Organismal Biology

Structure and function in plants and animals, plant and animal reproduction and development, and the principles of heredity.

~33%

Population Biology

Principles of ecology, evolution, animal behavior, and social biology including human population dynamics.

How to Pass the CLEP Biology Exam

What You Need to Know

  • Passing score: 50 (on a 20-80 scale)
  • Exam length: 115 questions
  • Time limit: 90 minutes
  • Exam fee: $97 plus a test-center administration fee

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

CLEP Biology Study Tips from Top Performers

1Split your study time roughly evenly across the three content areas — each is worth about a third of the exam.
2Master the energy pathways (glycolysis, the Krebs cycle, the electron transport chain, and photosynthesis) since they appear often and trip up many test takers.
3Practice Mendelian genetics problems — Punnett squares, dihybrid crosses, and probability — until they are automatic.
4Learn the difference between mitosis and meiosis and the chromosome number at each stage.
5Use the official CLEP study guide question types to get comfortable with the computer-based format and 90-minute pacing (about 47 seconds per question).

Frequently Asked Questions

How many questions are on the CLEP Biology exam and how long is it?

The CLEP Biology exam has approximately 115 multiple-choice questions and a 90-minute time limit. Some questions are unscored pretest items that do not affect your score.

What score do I need to pass CLEP Biology?

CLEP Biology is scored on a 20-80 scale. The American Council on Education (ACE) recommends a score of 50 as the credit-granting score, worth up to 6 semester hours, though individual colleges set their own requirements.

What topics does the CLEP Biology exam cover?

The exam covers a year of introductory college general biology in three roughly equal areas: Molecular and Cellular Biology (33%), Organismal Biology (34%), and Population Biology (33%).

How much does the CLEP Biology exam cost?

The CLEP exam fee is $97, plus an administration fee charged by the test center. Many active-duty military members and eligible students qualify for free CLEP testing through DANTES or institutional programs.

Is the CLEP Biology exam multiple choice?

Yes. CLEP Biology is entirely multiple choice and computer-delivered. There is no required essay or free-response section, unlike CLEP College Composition.

How much college credit can I earn with CLEP Biology?

The ACE recommends up to 6 semester hours of credit for a score of 50 or higher, typically satisfying an introductory general biology requirement. Confirm acceptance with your specific institution.