POST UTME UNN 2023 Biology | Objective

Are you preparing for POST UTME UNN exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2023 Biology (Objective) questions designed to simulate the real exam environment.

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Question 1
In the context of xylem transport, what is the primary function of the pit membrane?
Correct A. To regulate water flow between adjacent tracheids
B. To facilitate the transfer of minerals from the xylem sap to the surrounding tissues
C. To prevent the collapse of the xylem vessels under negative pressure
D. To allow for the exchange of gases between the xylem and the surrounding tissues

Correct Answer: A

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Question 2
A 25-year-old woman presents with primary amenorrhea and a history of recurrent miscarriages. Her karyotype is 45,X. What is the most likely cause of her condition?
Correct A. Turner syndrome
B. Klinefelter syndrome
C. Androgen insensitivity syndrome
D. Swyer syndrome

Correct Answer: A

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Question 3
A diagram of the nephron is shown below. What is the primary function of the thick asc\ending limb of the loop of Henle?
Correct A. To reabsorb water and ions from the filtrate
B. To secrete hydrogen ions into the filtrate
C. To reabsorb glu\cose and amino acids from the filtrate
D. To produce a hypertonic interstitium

Correct Answer: A

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Question 4
A 30-year-old man presents with a history of recurrent infections and a low white blood cell count. His karyotype is 47,XXY. What is the most likely cause of his condition?
Correct A. Klinefelter syndrome
B. Turner syndrome
C. Androgen insensitivity syndrome
D. Swyer syndrome

Correct Answer: A

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Question 5
A diagram of the respiratory system is shown below. What is the primary function of the diaphragm?
Correct A. To increase the volume of the thoracic cavity
B. To decrease the volume of the thoracic cavity
C. To facilitate the exchange of gases between the lungs and the atmosphere
D. To regulate the pH of the blood

Correct Answer: A

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Question 6
In a typical animal cell, the \endoplasmic reticulum (ER) is involved in the synthesis of proteins and lipids. Which of the following statements is true about the ER?
A. The ER is a type of organelle found in plant cells only.
B. The ER is responsible for the breakdown of proteins and lipids.
Correct C. The ER is involved in the synthesis of proteins and lipids.
D. The ER is a type of membrane-bound organelle found in animal cells only.

Correct Answer: C

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Question 7
A diagram of the human nervous system is shown below. Which of the following nerves is responsible for transmitting signals from the brain to the muscles?
A. The nerve labeled C.
B. The nerve labeled B.
Correct C. The nerve labeled A.
D. The nerve labeled D.

Correct Answer: C

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Question 8
The process of osmoregulation in animals involves the regulation of the concentration of solutes in the body fluids. Which of the following is a mechanism of osmoregulation?
Correct A. The excretion of excess water through the kidneys.
B. The reabsorption of excess ions in the kidneys.
C. The excretion of excess ions through the skin.
D. The reabsorption of excess water in the kidneys.

Correct Answer: A

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Question 9
A diagram of the human reproductive system is shown below. Which of the following is a function of the ovary?
A. The production of sperm.
B. The storage of sperm.
Correct C. The production of eggs.
D. The implantation of the fertilized egg.

Correct Answer: C

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Question 10
The process of mitosis in eukaryotic cells involves the division of the nucleus into two daughter nuclei. Which of the following stages of mitosis is responsible for the separation of the chromosomes?
A. Prophase.
B. Metaphase.
Correct C. Anaphase.
D. Telophase.

Correct Answer: C

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Question 11
In the process of osmoregulation, what is the primary mechanism by which the kidneys regulate the concentration of ions in the blood?
A. Hormonal regulation
B. Ion exchange with the environment
Correct C. Active transport of ions across the renal tubules
D. Passive diffusion of ions through the renal tubules

Correct Answer: C

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Question 12
The diagram below shows a cross-section of a plant root. Which of the following is the primary function of the xylem in this region?
Correct A. Transport of water and minerals from the roots to the leaves
B. Storage of nutrients and water
C. Support and structure for the plant
D. Production of hormones

Correct Answer: A

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Question 13
A patient has been diagnosed with a bacterial infection. Which of the following is the primary mechanism by which the immune system responds to this infection?
Correct A. Phagocytosis
B. Complement activation
C. Antibody production
D. Cytokine release

Correct Answer: A

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Question 14
The diagram below shows a cross-section of a human eye. Which of the following is the primary function of the lens in this region?
Correct A. Focu\sing of light on the retina
B. Production of tears
C. Regulation of pupil size
D. Detection of light intensity

Correct Answer: A

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Question 15
A patient has been diagnosed with a viral infection. Which of the following is the primary mechanism by which the immune system responds to this infection?
A. Phagocytosis
B. Complement activation
Correct C. Antibody production
D. Cytokine release

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 is in Hardy-Weinberg equilibrium, what is the frequency of the homozygous dominant genotype 'BB'?
Correct A. 0.36
B. 0.64
C. 0.72
D. 0.84

Correct Answer: A

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Question 17
A plant with the genotype 'Rr' is crossed with a plant with the genotype 'RR'. What is the probability that the offspring will have the genotype 'rr'?
A. 0.25
Correct B. 0.5
C. 0.75
D. 0.9

Correct Answer: B

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Question 18
Asexual reproduction in bacteria is an example of what type of reproduction?
A. Mitosis
B. Meiosis
Correct C. Binary Fission
D. Fragmentation

Correct Answer: C

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Question 19
The process by which plants convert light energy into chemical energy is called?
A. Respiration
Correct B. Photosynthesis
C. Transpiration
D. Osmosis

Correct Answer: B

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Question 20
The excretory system in humans is primarily responsible for what function?
A. Regulation of body temperature
Correct B. Removal of waste products
C. Production of hormones
D. Digestion of food

Correct Answer: B

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Question 21
In a population of 1000 individuals, 20% are heterozygous for a particular gene, while 80% are homozygous recessive. If 10 individuals are randomly selected, what is the probability that at least 2 of them are heterozygous?
A. 0.05
B. 0.10
Correct C. 0.20
D. 0.30

Correct Answer: C

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Question 22
A cell is placed in a solution with a pH of 4.5. If the cell membrane has a permeability coefficient of 10^-5 cm/s, what is the rate of diffusion of H+ ions across the membrane?
A. 10^-3 cm/s
B. 10^-4 cm/s
Correct C. 10^-5 cm/s
D. 10^-6 cm/s

Correct Answer: C

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Question 23
A plant has a photosynthetic rate of 10 umol CO2/s. If the concentration of CO2 in the atmosphere is 400 ppm, what is the rate of photosynthesis?
A. 4 umol CO2/s
B. 8 umol CO2/s
Correct C. 10 umol CO2/s
D. 12 umol CO2/s

Correct Answer: C

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Question 24
A population of 1000 individuals has a mean height of 170 cm. If the s\tandard deviation is 10 cm, what is the probability that a randomly selected individual has a height greater than 180 cm?
A. 0.05
B. 0.10
C. 0.20
Correct D. 0.30

Correct Answer: D

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Question 25
A cell has a membrane potential of -70 mV. If the concentration of K+ ions outside the cell is 5 mM, what is the equilibrium potential for K+?
A. -80 mV
Correct B. -70 mV
C. -60 mV
D. -50 mV

Correct Answer: B

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