UPCAT Biology Reviewer 2026
12 Biology practice questions for the University of the Philippines College Admission Test, each with the correct answer and an explanation of why it's right.
Biology Practice Questions with Answers
- 1medium
The diagram shows a four-generation pedigree of a family with a sex-linked disease. What can be assumed about the nature of the gene causing the disease? [pedigree diagram]
- A.X-linked and dominant
- B.Limited to females only
- C.Y-linked and recessive
- D.X-linked and recessive
Show answer & explanation
Answer: D. X-linked and recessive
Sex-linked recessive conditions are more common in males (who have only one X chromosome). The pedigree pattern of carriers and affected individuals is consistent with X-linked recessive inheritance.
- 2medium
Pig, chicken, snake, frog, milkfish ______. What comes next?
- A.rat
- B.shark
- C.whale
- D.worm
Show answer & explanation
Answer: B. shark
Pig=Mammalia, Chicken=Aves, Snake=Reptilia, Frog=Amphibia, Milkfish=Actinopterygii. The missing class is Chondrichthyes → shark.
- 3medium
Pigeon:beak; elephant:trunk; snake:mouth; Man: ______
- A.lips
- B.mouth
- C.hands
- D.teeth
Show answer & explanation
Answer: C. hands
The analogy pairs animals with body parts used to obtain food. Man uses hands to eat.
- 4medium
Sydney picked 3 guavas — two had worms near seeds but only one had a hole. What could be said about the presence of worms?
- A.Only one guava was infected first then a worm transferred to the other.
- B.Two guavas were infected from the beginning.
- C.The two guavas were infected while still a flower; the one with a hole was infected as a fruit.
- D.It is normal to find worms in guavas because they are filled with seeds.
Show answer & explanation
Answer: C. The two guavas were infected while still a flower; the one with a hole was infected as a fruit.
Worms can enter fruit before the skin hardens (while still a flower). A guava infected as a flower would have no hole; one infected as fruit would have an entry hole.
- 5medium
Which does NOT belong to the group? [Squid, Dugong, Tunicates, Eel | Sea star, Whale, Fish, Sting ray]
- A.Tunicates
- B.Squid
- C.Sea star
- D.Fish
Show answer & explanation
Answer: A. Tunicates
Tunicates (urochordates) are sessile filter feeders and are taxonomically distinct from the other common marine animals. They belong to a separate phylum (Urochordata) compared to the vertebrates and molluscs listed.
- 6medium
Some inherited disorders have symptoms of difficulty breathing and, in males, infertility. What is the molecular basis of this disorder?
- A.Defective enzyme in the mitochondria
- B.Defective actin molecules in cellular microfilaments
- C.Defective molecules in cilia and flagella
- D.Abnormal hydrolytic enzymes in the lysosomes
Show answer & explanation
Answer: C. Defective molecules in cilia and flagella
Primary Ciliary Dyskinesia (Kartagener syndrome) is caused by defective dynein proteins in cilia and flagella, causing impaired mucus clearance (breathing difficulties) and immotile sperm (infertility).
- 7medium
Cassie has no history of haemophilia but her father is an albino. John has haemophilia and his mother is an albino. What is the probability that Cassie and John will have an albino son with haemophilia?
- A.75%
- B.50%
- C.25%
- D.0%
Show answer & explanation
Answer: D. 0%
Cassie has no family history of haemophilia. Since she cannot be a carrier, probability of haemophilic child is 0%.
- 8medium
Lactose intolerance: people without lactase get LBM after consuming dairy. Which BEST explains this?
- A.Lactose irritates the lining of the intestines causing LBM.
- B.Loose bowel movement is a way to get rid of a nutrient the body cannot process.
- C.Lactose is processed by bacteria in the intestines which facilitates their growth, causing LBM.
- D.If undigested, Lactose can form hydrogen bonds with water in the intestines which leads to watery stool.
Show answer & explanation
Answer: D. If undigested, Lactose can form hydrogen bonds with water in the intestines which leads to watery stool.
Undigested lactose is osmotically active — it draws water into the intestine through hydrogen bonding and osmosis, resulting in watery stool (osmotic diarrhea).
- 9medium
In Binomial Nomenclature, the first word represents a ______ classification.
- A.Species
- B.Genus
- C.Kingdom
- D.Domain
Show answer & explanation
Answer: B. Genus
In binomial nomenclature, the first word is the Genus (broader), and the second word is the species (specific). E.g., Homo sapiens — Homo is genus.
- 10medium
In Binomial Nomenclature, the second word represents:
- A.Species
- B.Genus
- C.Kingdom
- D.Domain
Show answer & explanation
Answer: A. Species
The second word in binomial nomenclature is the species epithet, which identifies the specific organism within its genus.
- 11medium
What is the broadest level of classification in the taxonomy of living things?
- A.Kingdom
- B.Domain
- C.Order
- D.Class
Show answer & explanation
Answer: B. Domain
Domain is the broadest/highest taxonomic rank in the modern classification system (above Kingdom). The three domains are Bacteria, Archaea, and Eukarya.
- 12medium
Which of the following kingdoms is NOT a eukaryote?
- A.Kingdom Fungi
- B.Kingdom Plantae
- C.Kingdom Monera
- D.Kingdom Animalia
Show answer & explanation
Answer: C. Kingdom Monera
Kingdom Monera consists of prokaryotes (bacteria and archaea) — they lack a true nucleus and membrane-bound organelles. All other kingdoms (Fungi, Plantae, Animalia) are eukaryotes.
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