POST UTME CHRISTOPHER UNIVERSITY 2018 Biology | Objective

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Question 1
The xylem is responsible for transporting water and minerals from the roots to the leaves of a plant. What is the primary mechanism by which water is transported through the xylem?
A. Transpiration pull
B. Root pressure
C. Capillary action
D. Osmosis
Question 2
A patient with a rare genetic disorder has a mutation in the HBB gene, which codes for the \beta-globin subunit of hemoglobin. The mutation results in a substitution of glutamic acid for valine at position 6 of the \beta-globin protein. Which of the following is the most likely effect of this mutation on the structure and function of hemoglobin?
A. The mutation will result in a decrease in the affinity of hemoglobin for oxygen.
B. The mutation will result in a decrease in the cooperativity of hemoglobin.
C. The mutation will result in a decrease in the stability of hemoglobin.
D. The mutation will result in a decrease in the ability of hemoglobin to bind to 2,3-bisphosphoglycerate.
Question 3
In a population of 1000 individuals, the frequency of the recessive allele 'a' is 0.2. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the dominant allele 'A'?
A. 0.8
B. 0.6
C. 0.4
D. 0.2
Question 4
A diagram of a human eye is shown below. Identify the part labeled 'Y'.
A. A
B. B
C. C
D. D
Question 5
A bio\logist is studying the population dynamics of a species of rabbit. The population grows \logistically according to the equation dP/dt = rP\( 1 - P/K \), where P is the population size, r is the intrinsic growth rate, and K is the carrying capacity. If the initial population size is 100, the intrinsic growth rate is 0.2, and the carrying capacity is 1000, what is the population size after 5 years?
A. 500
B. 600
C. 700
D. 800
Question 6
The diagram below shows a cross-section of a plant root. What is the function of the structure labeled 'A'?
A. To absorb water and minerals
B. To store starch
C. To produce hormones
D. To support the root
Question 7
A researcher is studying the effect of pH on the growth of a microorganism. The growth rate is measured in terms of the specific growth rate (μ) in the equation dN/dt = μN. If the growth rate is 0.5 h^-1 at pH 7 and 0.2 h^-1 at pH 5, what is the value of the Hill coefficient (n) in the equation μ = μmax * \( H^\( -n \ \))?
A. 2
B. 3
C. 4
D. 5
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 'AA'?
A. 0.36
B. 0.64
C. 0.72
D. 0.84
Question 9
A 2.5 cm long root hair cell is placed in a solution with a concentration of 0.1 M KCl. If the cell membrane is selectively permeable to K+ ions, what is the concentration of K+ ions inside the cell after 10 minutes?
A. 0.05 M
B. 0.1 M
C. 0.15 M
D. 0.2 M
Question 10
A 0.5 M solution of NaOH is mixed with a 0.5 M solution of HCl. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 11
A cell is in the M phase of the cell cycle. If the cell is to divide in 1 hour, what is the rate of mitosis (r) in the equation N(t) = N0 * e^(rt)?
A. 0.1
B. 0.5
C. 1.0
D. 2.0
Question 12
The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain cons\tant from generation to generation in the absence of other evolutionary influences. Which of the following is a necessary condition for the Hardy-Weinberg principle to hold?
A. Random mating
B. Genetic drift
C. Mutation
D. Gene flow
Question 13
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 'AA'?
A. 0.64
B. 0.36
C. 0.16
D. 0.04
Question 14
A 2.5 kg block is attached to a horizontal, massless spring with a force cons\tant of 100 N/m. The block is displaced by 0.2 m from its equilibrium position and released from rest. What is the maximum speed of the block?
A. 0.5 m/s
B. 1.0 m/s
C. 1.5 m/s
D. 2.0 m/s
Question 15
A patient is diagnosed with a rare genetic disorder that affects the production of melanin. The patient's skin is pale and they have a high risk of skin cancer. Which of the following is the most likely cause of the patient's condition?
A. A mutation in the TYR gene, which codes for the enzyme tyro\sinase.
B. A mutation in the SLC24A4 gene, which codes for the protein SLC24A4.
C. A mutation in the MC1R gene, which codes for the protein MC1R.
D. A mutation in the OCA2 gene, which codes for the protein OCA2.

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