Practice post utme summit university biology 2025 Past Questions

Question 1

In a population of Drosophila melanogaster, the frequency of the recessive allele 'a' is 0.2. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the homozygous dominant genotype?

Correct A. 0.16

B. 0.36

C. 0.64

D. 0.84

Correct Answer: A

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Question 2

A 2.5 L flask contains 0.5 M NaOH. If 25 mL of 1.5 M HCl is slowly added to the flask, what is the concentration of the resulting solution?

A. 0.6 M

B. 0.8 M

Correct C. 1.0 M

D. 1.2 M

Correct Answer: C

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Question 3

A diagram of the human respiratory system is shown below.

A. The trachea is a tube that carries air from the nose and mouth to the lungs.

B. The diaphragm is a muscle that separates the chest cavity from the abdominal cavity.

Correct C. The lungs are organs that exchange oxygen and carbon dioxide through the process of respiration.

D. The trachea is a muscle that separates the chest cavity from the abdominal cavity.

Correct Answer: C

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Question 4

A 50 mL sample of a solution containing 0.1 M NaOH is slowly added to a 100 mL sample of a solution containing 0.2 M HCl. What is the concentration of the resulting solution?

A. 0.05 M

B. 0.1 M

Correct C. 0.15 M

D. 0.2 M

Correct Answer: C

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Question 5

A diagram of the human excretory system is shown below.

A. The kidneys are organs that filter waste and excess fluids from the blood.

B. The ureters are tubes that carry urine from the kidneys to the bladder.

Correct C. The bladder is an organ that stores urine until it is eliminated from the body.

D. The kidneys are organs that store urine until it is eliminated from the body.

Correct Answer: C

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Question 6

In a population of Drosophila melanogaster, the frequency of the recessive allele 'a' is 0.2. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the homozygous recessive genotype 'aa'?

Correct A. 0.04

B. 0.08

C. 0.16

D. 0.32

Correct Answer: A

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Question 7

A plant cell has a vacuole that contains 0.5 M sucrose. If the cell membrane is permeable to sucrose, what is the concentration of sucrose in the cytosol after 1 hour?

Correct A. 0.25

B. 0.5

C. 0.75

D. 1.0

Correct Answer: A

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Question 8

A neuron has a resting potential of -70 mV. If the neuron is depolarized by 20 mV, what is the new membrane potential?

Correct A. -50

B. -60

C. -70

D. -80

Correct Answer: A

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Question 9

A xylem vessel has a diameter of 100 μm. If the vessel is filled with water at a pressure of 1 atm, what is the force exerted on the vessel wall?

Correct A. 0.01

B. 0.1

C. 1.0

D. 10.0

Correct Answer: A

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Question 10

A mitochondrion has a membrane potential of -180 mV. If the mitochondrion is in a solution with a pH of 7.0, what is the concentration of protons in the solution?

Correct A. 10^{-7}

B. 10^{-6}

C. 10^{-5}

D. 10^{-4}

Correct Answer: A

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Question 11

In a population of Drosophila melanogaster, the frequency of the recessive allele 'a' is 0.2. If the population size is 1000, calculate the number of individuals that are homozygous recessive.

Correct A. 180

B. 200

C. 220

D. 240

Correct Answer: A

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Question 12

A 2.5 L flask contains 0.5 M NaOH. If 25 mL of 1.5 M HCl is slowly added to the flask, calculate the pH of the resulting solution.

A. 0.5

B. 1.0

Correct C. 1.5

D. 2.0

Correct Answer: C

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Question 13

A diagram shows a plant with a root system that consists of a taproot and a fibrous root system. Which of the following is a characteristic of the taproot?

Correct A. It is a \single, thick root that grows straight down into the soil.

B. It is a system of roots that grows out from the base of the plant.

C. It is a root that grows out from the stem of the plant.

D. It is a root that grows up towards the light.

Correct Answer: A

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Question 14

A population of rabbits is growing according to the \logistic growth model. If the initial population size is 100 and the carrying capacity is 1000, calculate the population size after 5 years.

A. 500

B. 600

C. 700

Correct D. 800

Correct Answer: D

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Question 15

A diagram shows a cell with a nucleus and a mitochondria. Which of the following is a function of the mitochondria?

A. It is the site of protein synthesis.

B. It is the site of cell division.

Correct C. It is the site of cellular respiration.

D. It is the site of cell signaling.

Correct Answer: C

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Question 16

In a population of Drosophila melanogaster, the frequency of the recessive allele 'b' is 0.2. If the population size is 1000, calculate the number of individuals that are homozygous recessive.

Correct A. 180

B. 200

C. 220

D. 250

Correct Answer: A

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Question 17

A 2.5 L flask contains 0.5 M HCl. Calculate the number of moles of HCl in the flask.

Correct A. 1.25

B. 1.5

C. 1.75

D. 2.0

Correct Answer: A

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Question 18

A cell has a membrane potential of -70 mV. If the cell is stimulated to fire, the membrane potential changes to -40 mV. Calculate the percentage change in membrane potential.

A. 40%

Correct B. 50%

C. 60%

D. 70%

Correct Answer: B

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Question 19

A 50-year-old man has a family history of breast cancer. His mother and sister both had breast cancer. What is the probability that he will develop breast cancer?

A. 10%

B. 20%

C. 30%

Correct D. 40%

Correct Answer: D

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Question 20

A 10% solution of glu\cose is prepared by dissolving 10 g of glu\cose in 90 g of water. Calculate the molarity of the solution.

Correct A. 0.1 M

B. 0.2 M

C. 0.3 M

D. 0.4 M

Correct Answer: A

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Question 21

The process of cellular respiration in plants involves the breakdown of glu\cose to produce ATP, NADH, and FADH2. Which of the following statements is FALSE regarding the electron transport chain?

A. The electron transport chain occurs in the mitochondria.

B. The electron transport chain generates a proton gradient across the mitochondrial membrane.

C. The electron transport chain produces ATP by harnes\sing the energy from the proton gradient.

Correct D. The electron transport chain is the primary site of ATP production in cellular respiration.

Correct Answer: D

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Question 22

In the context of osmoregulation, what is the primary function of the kidneys in the human body?

A. To regulate blood pressure through the renin-angioten\sin-aldosterone system.

Correct B. To maintain electrolyte balance by reabsorbing or excreting ions.

C. To regulate blood pH by adjusting the concentration of hydrogen ions.

D. To control the concentration of glu\cose in the blood.

Correct Answer: B

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Question 23

The following diagram shows a cross-section of a plant root. What is the primary function of the tissue labeled 'A'?

Correct A. To absorb water and minerals from the soil.

B. To store starch and other nutrients.

C. To produce hormones that regulate plant growth.

D. To support the structure of the plant.

Correct Answer: A

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Question 24

The following graph shows the relationship between the concentration of a substrate and the rate of enzyme activity. What is the primary conclusion that can be drawn from this graph?

Correct A. The rate of enzyme activity increases as the concentration of the substrate increases.

B. The rate of enzyme activity decreases as the concentration of the substrate increases.

C. The rate of enzyme activity remains cons\tant regardless of the concentration of the substrate.

D. The rate of enzyme activity has a maximum value at a specific concentration of the substrate.

Correct Answer: A

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Question 25

The following diagram shows a cross-section of a human kidney. What is the primary function of the tissue labeled 'B'?

Correct A. To filter waste products from the blood.

B. To regulate blood pressure through the renin-angioten\sin-aldosterone system.

C. To maintain electrolyte balance by reabsorbing or excreting ions.

D. To control the concentration of glu\cose in the blood.

Correct Answer: A

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