CLEP Biology Exam Prep 2026 practice questions and answers. Tap an option to test yourself — you'll see the correct answer and a plain-English explanation for every question. Free, no login.
Q11Evaluate the table below to identify which factors contribute to increased biodiversity within an ecosystem. Factor Description Effect on Biodiversity Natural selection Adaptive traits become more prevalent Neutral Gene flow Movement of genes between populations Increase Overharvesting Excessive removal of species Decrease Mutation Random changes in DNA Increase
✓ Correct answer: B. Gene flow and mutation
Gene flow and mutation both introduce new genetic variations, increasing biodiversity. Natural selection does not inherently increase biodiversity, as it often selects for specific traits, potentially reducing variation. Overharvesting decreases biodiversity by removing significant numbers of individuals from a population.
Q12The marine biome is characterized by an abundance of which animals?
✓ Correct answer: E. Fish and marine mammals
Answer: Fish and marine mammals The marine biome, encompassing oceans and seas, is home to abundant fish and marine mammals due to its vast water resources and ecosystem diversity. Large herbivores typically inhabit savannah and grassland biomes, reptiles thrive in deserts and rainforests, insects can be found in most terrestrial biomes.
Q13Which component of the cell contains the enzymes needed for the Calvin cycle? Cell Component Function Chloroplast stroma Site of Calvin cycle Thylakoid membrane Site of light-dependent reactions Cytosol Site of glycolysis Nucleus Stores genetic material Mitochondrial matrix Site of Krebs cycle
✓ Correct answer: A. Chloroplast stroma
Answer: Chloroplast stroma The Calvin cycle occurs in the chloroplast stroma, where it utilizes ATP and NADPH generated by the light-dependent reactions in the thylakoid membrane.
Q14What is the main structural difference between the plasma membrane of an animal cell and the cell wall of a fungal cell?
✓ Correct answer: E. Animal cell membranes are lipid bilayers without structural rigidity; fungal cell walls are strong due to chitin.
Answer: Animal cell membranes are lipid bilayers without structural rigidity; fungal cell walls are strong due to chitin. The plasma membrane of animal cells is composed of a fluid lipid bilayer that provides flexibility and is not inherently rigid. In contrast, fungal cell walls are structured with chitin, which is tough and provides the structural rigidity needed for protection and support.
Q15During glycolysis, what occurs to glucose at the start of the pathway?
✓ Correct answer: B. It is converted into two molecules of pyruvate
During glycolysis, glucose is broken down through a series of reactions into two molecules of pyruvate. This process generates a small amount of ATP and NADH. The pyruvate may then enter the mitochondria for further processing in the citric acid cycle if oxygen is present or be converted to lactate or ethanol if it is not.
Q16During the process of transcription, which statement correctly describes the relationship between the primary molecular components involved?
✓ Correct answer: A. DNA serves as a template to synthesize a complementary RNA sequence, where the RNA polymerase initiates and elongates the RNA chain.
Answer: DNA serves as a template to synthesize a complementary RNA sequence, where the RNA polymerase initiates and elongates the RNA chain. Transcription is the process in which a segment of DNA is used as a template to generate a complementary RNA strand. The enzyme RNA polymerase binds to a specific section of DNA and facilitates the unwinding of the DNA double helix, reading the DNA sequence to synthesize a corresponding RNA sequence. This process is fundamental for conveying genetic information from the DNA to be eventually translated into proteins.
Q17Which of the following best describes the concept of enzymatic specificity?
✓ Correct answer: B. Enzymes catalyzing reactions only with specific substrates due to their active site's shape
Answer: Enzymes catalyzing reactions only with specific substrates due to their active site's shape Enzymatic specificity refers to the ability of an enzyme to choose exact substrate molecules to catalyze a chemical reaction. This specificity is explained by the lock-and-key model, where the enzyme's active site binds only to specific substrates.
Q18What is the primary role of codons found in mRNA during protein synthesis?
✓ Correct answer: A. To specify the sequence of amino acids in a protein
Answer: To specify the sequence of amino acids in a protein mRNA consists of codons, which are sequences of three nucleotides that correspond to specific amino acids or stop signals during translation. The sequence of codons in mRNA determines the order of amino acids in a polypeptide chain, forming the primary structure of proteins.
Q19Where would you expect to find cilia on a cell?
✓ Correct answer: B. Cell membrane exterior
Answer: Cell membrane exterior Cilia are hair-like extensions on the cell surface that help in movement and are involved in clearing particles from places like the respiratory tract.
Q20Identify which of the following conditions can lead to a permanent change in the DNA sequence of a bacterial cell. i. High levels of UV radiation ii. Mutagenic chemicals interacting with the DNA iii. Normal bacterial cell division iv. Oxidative stress within the cell
✓ Correct answer: D. i, ii, and iv
Answer: i, ii, and iv Permanent mutations in bacterial DNA can be induced by UV radiation, mutagenic chemicals, or oxidative stress. While normal bacterial cell division can introduce errors, it does not typically result in permanent mutations unless other factors are present.
Use the free CLEP Biology Exam Prep 2026 sample, download the PDF, then unlock web-based timed mock exams for a full exam rehearsal.
Theory