POST UTME AFE BABALOLA UNIVERSITY 2023 Biology | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A researcher is studying the effect of pH on the activity of an enzyme. The enzyme is most active at a pH of 7.0, and its activity decreases as the pH deviates from this value. Which of the following terms best describes the relationship between pH and enzyme activity?
A. Optimum pH
B. pH range
C. pH tolerance
D. pH sensitivity
Question 2
A plant with the genotype AaBb is crossed with a plant with the genotype aaBb. What is the probability that the offspring will have the genotype AaBb?
A. 0.5
B. 0.75
C. 0.9
D. 0.95
Question 3
In a human body, the process of cellular respiration occurs in three main stages: glycolysis, the citric acid cycle, and oxidative phosphorylation. What is the primary function of the citric acid cycle in this process?
A. To generate ATP through substrate-level phosphorylation
B. To produce NADH and FADH2
C. To pump protons across the mitochondrial membrane
D. To reduce oxygen to water
Question 4
In a eukaryotic cell, the process of mitosis is initiated by the breakdown of the nuclear envelope, which is triggered by the activation of the protein kinase Cdk1. What is the primary function of Cdk1 in this process?
A. To phosphorylate and activate the nuclear lamina
B. To bind to and inhibit the anaphase-promoting complex
C. To regulate the spindle checkpoint
D. To control the condensation of chromatin
Question 5
A bio\logist is studying the structure of a plant cell. The cell has a large central vacuole, a small nucleus, and a cell wall. Which of the following organelles is responsible for the synthesis of proteins in the cell?
A. Ribosomes
B. Mitochondria
C. Endoplasmic reticulum
D. Golgi apparatus
Question 6
A researcher is studying the effects of light intensity on the rate of photosynthesis in a plant. Which of the following graphs best represents the relationship between light intensity and photosynthetic rate?
A. \( y = \frac{1}{x} \)
B. \( y = x^2 \)
C. \( y = 2x^2 - 3x - 4 \)
D. \( y = -2x^2 + 3x + 4 \)
Question 7
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. Large population size
C. No mutation
D. No gene flow
Question 8
A researcher is studying the effects of light intensity on the rate of photosynthesis in a plant. Which of the following graphs best represents the relationship between light intensity and photosynthetic rate?
A. \( y = \frac{1}{x} \)
B. \( y = x^2 \)
C. \( y = 2x^2 - 3x - 4 \)
D. \( y = -2x^2 + 3x + 4 \)
Question 9
In a eukaryotic cell, the process of mitosis is initiated by the breakdown of the nuclear envelope, which is triggered by the activation of the protein kinase Cdk1. What is the primary function of the nuclear lamina in this process?
A. To phosphorylate and activate the nuclear lamina
B. To bind to and inhibit the anaphase-promoting complex
C. To regulate the separation of sister chromatids
D. To control the condensation of chromatin
Question 10
The xylem is a type of vascular tissue found in plants that is responsible for transporting water and minerals from the roots to the leaves. Which of the following is a key component of the xylem?
A. Tracheids
B. Vessel elements
C. Fibers
D. Parenchyma cells
Question 11
A diagram of the xylem tissue in a plant stem is shown below. What is the primary function of the xylem vessels in this tissue?
A. To transport water and minerals from the roots to the leaves
B. To store water and nutrients in the stem
C. To provide structural support to the stem
D. To regulate the opening and clo\sing of stomata
Question 12
A study on the population dynamics of the African elephant (Loxodonta africana) in a savanna e\cosystem revealed a significant decline in population size over a 20-year period. The decline was attributed to habitat loss and fragmentation, human-wildlife conflict, and poaching. Which of the following eco\logical concepts best explains the observed decline in population size?
A. Source-\sink dynamics
B. Metapopulation dynamics
C. Population regulation
D. Community eco\logy
Question 13
A researcher is studying the evolution of the peppered moth (Biston betularia) in England. The moth has two distinct color morphs: a light-colored morph and a dark-colored morph. The light-colored morph is dominant, while the dark-colored morph is recessive. Which of the following genetic principles explains the observed variation in the moth population?
A. Incomplete dominance
B. Codominance
C. Incomplete penetrance
D. Epistasis
Question 14
A diagram of the digestive system in a human is shown below. What is the primary function of the pancreas in this system?
A. To produce digestive enzymes that break down proteins
B. To produce digestive enzymes that break down carbohydrates
C. To produce digestive enzymes that break down fats
D. To absorb nutrients from the small intestine
Question 15
In a human cell, the process of cellular respiration occurs in three main stages: glycolysis, the citric acid cycle, and oxidative phosphorylation. What is the primary function of the electron transport chain in oxidative phosphorylation?
A. To generate ATP through substrate-level phosphorylation
B. To produce NADH and FADH2
C. To pump protons across the mitochondrial membrane
D. To reduce oxygen to water

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