POST UTME SUMMIT UNIVERSITY 2025 Biology | Objective

Practice these randomly selected questions to test your readiness.

Question 1
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%
B. 50%
C. 60%
D. 70%
Question 2
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?
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.
Question 3
A population of bacteria is growing exponentially. If the initial population is 100 cells and the population doubles every 2 hours, what will be the population after 6 hours?
A. 1000
B. 2000
C. 4000
D. 8000
Question 4
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.
A. 180
B. 200
C. 220
D. 240
Question 5
The process of cellular respiration in plants involves the breakdown of glu\cose to produce ATP, NADH, and FADH2. Which of the following is the correct sequence of events in the electron transport chain?
A. NADH → FADH2 → ATP
B. FADH2 → NADH → ATP
C. ATP → NADH → FADH2
D. NADH → ATP → FADH2
Question 6
The following diagram shows a cross-section of a plant root. What is the primary function of the tissue labeled 'A'?
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.
Question 7
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.
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.
Question 8
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?
A. 0.16
B. 0.36
C. 0.64
D. 0.84
Question 9
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
C. 0.15 M
D. 0.2 M
Question 10
A diagram of the human respiratory system is shown below. Identify the structure labeled 'A' in the diagram.
A. Trachea
B. Lungs
C. Diaphragm
D. Bronchi
Question 11
The diagram below shows the structure of a mitochondrion.
A. The mitochondrial membrane is the outermost layer of the mitochondrion.
B. The mitochondrial matrix is the region where cellular respiration occurs.
C. The cristae are the infoldings of the mitochondrial membrane.
D. The porin is the channel that allows molecules to pass through the mitochondrial membrane.
Question 12
A plant cell has a vacuole that contains 0.5 M sucrose. If the cell membrane is permeable to sucrose, what will be the concentration of sucrose in the cytosol after 1 hour?
A. 0.5 M
B. 0.25 M
C. 1.0 M
D. 1.5 M
Question 13
The diagram below shows a cross-section of the human kidney. Identify the structure labeled 'X' in the diagram.
A. Renal cortex
B. Renal medulla
C. Renal pelvis
D. Ureter
Question 14
In the context of osmoregulation, what is the primary function of the hypothalamus in regulating thirst?
A. To regulate pH levels in the blood
B. To maintain the balance of electrolytes in the body
C. To regulate thirst and hunger
D. To regulate blood pressure
Question 15
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
C. 1.0 M
D. 1.2 M

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