All Practice Exams
100+ Free Andalusia PAU Biology Practice Questions
Andalusia PAU Biology (Biología 2º Bachillerato) practice questions are available now; exam metadata is being verified.
✓ No registration✓ No credit card✓ No hidden fees✓ Start practicing immediately
High (~85-95% PAU overall pass rate in Andalusia) Pass Rate
100+ Questions
100% Free
Loading practice questions...
Same family resources
Explore More Spain Andalusia PAU (Prueba de Acceso a la Universidad)
Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.
2026 Statistics
Key Facts: Andalusia PAU Biology Exam
90 min
Exam Time Limit
Distrito Único Andaluz
0–10
Grading Scale
Junta de Andalucía
4.0
Min. Access Phase Score
Comisión Interuniversitaria
EUR 58.70
Base Registration Fee
Junta de Andalucía
5 Blocks
Curriculum Content Areas
2º Bachillerato Biology Syllabus
The Andalusia PAU Biology exam (Biología) is administered by the Distrito Único Andaluz and Comisión Interuniversitaria de Andalucía for students completing 2nd Bachillerato. The exam lasts 90 minutes and is graded on a 0–10 scale (minimum 4.0 required in the Access Phase). Note that local questions on this platform are an English-language MCQ study adaptation created to help students master the underlying 2nd Bachillerato curriculum.
Sample Andalusia PAU Biology Practice Questions
Try these sample questions to test your Andalusia PAU Biology exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1Which physical property of water allows it to absorb or release large amounts of heat energy with minimal change in its own temperature?
A.High specific heat capacity
B.High surface tension
C.Low heat of vaporization
D.Maximum density at 0 °C
Explanation: Water has a high specific heat capacity because a significant amount of heat energy is required to break the extensive hydrogen-bonding network between water molecules before kinetic energy can increase. This buffers organisms and aquatic environments against rapid temperature fluctuations. Other options describe surface tension, latent heat of vaporization, or density anomalies.
2When a plant cell is placed in a hypertonic solution, water leaves the vacuole and cytoplasm, causing the plasma membrane to pull away from the rigid cell wall. What is this phenomenon called?
A.Plasmolysis
B.Turgor
C.Hemolysis
D.Crenation
Explanation: Plasmolysis occurs when plant cells lose water in a hypertonic environment, causing the protoplast to shrink away from the rigid cell wall. Turgor refers to the outward pressure against the cell wall in a hypotonic medium. Hemolysis and crenation apply to animal cells (specifically red blood cells).
3Which of the following monosaccharides is classified as a ketohexose?
A.D-Fructose
B.D-Glucose
C.D-Galactose
D.D-Ribose
Explanation: D-Fructose is a ketohexose because it contains six carbon atoms and a ketone functional group at carbon-2. D-Glucose and D-Galactose are aldohexoses, while D-Ribose is an aldopentose.
4What type of chemical reaction links two monosaccharides together to form a disaccharide, releasing a molecule of water?
A.Condensation (dehydration synthesis)
B.Hydrolysis
C.Oxidative decarboxylation
D.Phosphorylation
Explanation: Condensation or dehydration synthesis involves the covalent coupling of two hydroxyl groups from monosaccharides to form an O-glycosidic bond, releasing one molecule of water. Hydrolysis is the reverse cleavage reaction requiring water.
5Why do unsaturated fatty acids with cis double bonds generally have lower melting points than saturated fatty acids of equivalent chain length?
A.Cis double bonds introduce kinks that prevent tight molecular packing
B.Unsaturated fatty acids form stronger ester bonds with glycerol
C.Saturated fatty acids contain fewer hydrocarbon hydrogen atoms
D.Cis double bonds increase non-polar van der Waals interactions
Explanation: Cis double bonds create rigid bends (kinks) in the hydrocarbon tail of fatty acids. These kinks interfere with close, crystalline molecular packing, weakening intermolecular van der Waals forces and lowering the melting point.
6A peptide bond forms between which two functional groups of adjacent amino acids?
A.The carboxyl group of one amino acid and the amino group of another
B.The hydroxyl group of one amino acid and the phosphate group of another
C.The R-group side chains of two cysteine residues
D.The carbonyl oxygen and the alpha-carbon atom
Explanation: A peptide bond is a covalent amide linkage (-CO-NH-) formed by a condensation reaction between the alpha-carboxyl group of one amino acid and the alpha-amino group of the next amino acid.
7What structural feature of a protein remains intact when it undergoes reversible denaturation caused by mild heat or pH changes?
A.Primary structure
B.Secondary structure
C.Tertiary structure
D.Quaternary structure
Explanation: Denaturation disrupts non-covalent interactions (hydrogen bonds, ionic bonds, hydrophobic interactions) and disulfide bridges, altering secondary, tertiary, and quaternary structures. The primary structure (covalent peptide backbone) remains intact.
8According to Chargaff's rules for double-stranded DNA, which relationship between nitrogenous bases is always true?
A.A + G = T + C
B.A + T = G + C
C.A / G = 1.0
D.A + C = 100%
Explanation: Chargaff's rules state that in double-stranded DNA, Adenine equals Thymine (A = T) and Guanine equals Cytosine (G = C). Therefore, the sum of purines (A + G) equals the sum of pyrimidines (T + C).
9Why is water an excellent solvent for polar molecules and ionic salts?
A.Water molecules form hydration shells around charged ions due to dipoles
B.Water molecules form non-polar hydrophobic interactions with solutes
C.Water has a low dielectric constant that stabilizes ionic bonds
D.Water reacts chemically with solutes to form covalent hydrates
Explanation: Water is a polar molecule with a partial negative charge on oxygen and partial positive charges on hydrogen. It surrounds cations with oxygen atoms and anions with hydrogen atoms, forming hydration shells that screen electrostatic charges and dissolve polar/ionic substances.
10In human blood plasma, which buffer system plays the primary role in maintaining physiological pH around 7.4?
A.Carbonic acid / bicarbonate buffer system
B.Acetic acid / acetate buffer system
C.Ammonia / ammonium buffer system
D.Lactic acid / lactate buffer system
Explanation: The carbonic acid / bicarbonate system (H2CO3 / HCO3-) is the principal extracellular buffer in human blood. It regulates pH by equilibrating dissolved CO2 gas in lungs with bicarbonate ions excreted by kidneys.
About the Andalusia PAU Biology Practice Questions
Verified exam format metadata for Andalusia PAU Biology (Biología 2º Bachillerato) is pending. The practice questions above remain available while official exam length, timing, passing score, fee, and administrator details are reviewed.