JAMB Biology 2008
Questions & Answers

Nitrogen (IV) oxide reacts with water vapor in the atmosphere to form nitric acid, a key component of acid rain, lowering the pH of precipitation.

Paramecium, a ciliate protozoan, resorts to conjugation under stress, exchanging genetic material between two individuals to enhance genetic diversity.

Fingerprints exhibit unique patterns such as whorls, arches, loops, and compounds, serving as individual identifiers due to their distinct variations.

Sex determination depends on the sperm’s contribution (X or Y). The consistent production of female children suggests the man’s sperm predominantly carried the X chromosome, influenced by the woman’s constant X contribution.

Interferon, a protein produced by host cells, inhibits viral replication by enhancing immune responses, serving as a natural antiviral agent.

Outbreeding increases genetic diversity through crossbreeding, enhancing disease resistance by introducing varied immune-related genes.

Blood group AB individuals, as universal recipients, can receive blood from all groups (A, B, AB, O) due to the absence of antibodies against A, B, or O antigens.

The streamlined shape of fishes reduces water resistance, enabling efficient movement through aquatic environments.

Lizards, as poikilothermic organisms, have body temperatures that vary with environmental conditions, relying on external heat sources.

Charles Darwin proposed the struggle for existence as a core concept in his theory of natural selection, driving evolutionary adaptation.

Adaptive radiation in insect mouthparts demonstrates diverse structural adaptations for varied feeding habits, reflecting evolutionary divergence.

The appendix, a small pouch in the digestive tract, is a vestigial structure in humans, with no significant function in modern digestion.

Abscission is the process by which plants shed leaves to conserve water and energy during harsh environmental conditions, such as drought.

Earthworms are hermaphrodites, possessing both male and female reproductive organs, allowing mutual sperm exchange during reproduction.

Rhizopus, a fungus, exhibits saprophytic nutrition, obtaining nutrients by decomposing dead organic matter in its environment.

Insects respire through a tracheal system, a network of tubes that delivers oxygen directly to tissues, with air entering via spiracles.

Mushrooms, as fungi, are saprophytic, feeding on dead organic matter by secreting enzymes to break it down for absorption.

Producers, such as plants, capture solar energy through photosynthesis, forming the base of the food chain and providing energy to other organisms.

Dicotyledonous plants are characterized by net-like leaf venation, where veins form a branched network, unlike the parallel venation of monocots.

During photosynthesis, plants produce oxygen as a byproduct, released through stomata as they convert carbon dioxide and water into glucose.

Mycorrhizal fungi and plant roots share a mutualistic relationship, where fungi enhance nutrient uptake for the plant, and the plant provides sugars to the fungi.

Estrogen, produced by the ovaries, drives the development of female secondary sexual characteristics, such as breast growth and hip widening.

The nasal cavity warms, moistens, and filters incoming air through mucus and cilia, preparing it for the lungs.

Using the Hardy-Weinberg equilibrium, if the dominant allele frequency (p) is 0.7, the recessive allele frequency (q) is 1 - 0.7 = 0.3. The recessive phenotype (dd) frequency is q² = 0.3² = 0.09.

Nitrogen fixation in leguminous plants, facilitated by symbiotic bacteria, requires adequate oxygen in root nodules to support energy production for the process.

Venus flytraps are primarily autotrophic via photosynthesis but exhibit heterotrophic nutrition when capturing and digesting insects to supplement nutrients.

A typical virus consists of genetic material (DNA or RNA) enclosed in a protein coat called a capsid, lacking organelles like a nucleus or chloroplasts.

Vultures are scavengers, primarily feeding on carrion, the remains of dead animals, contributing to ecosystem cleanup.

Earthworms decompose leaf litter by breaking it down and mixing it with soil, facilitating nutrient recycling in forest ecosystems.

Mammals are distinguished by mammary glands, which produce milk to nourish their young, a unique feature among vertebrates.

Barnacles benefit by attaching to a whale for transport and feeding opportunities, while the whale remains unaffected, exemplifying commensalism.

Geotropism, or gravitropism, describes the growth of plant roots downward in response to gravity, ensuring anchorage and nutrient access.

Testosterone, secreted by the testes, regulates male reproductive functions, including sperm production and secondary sexual characteristics.

Tapeworms are parasitic, residing in the human intestine, absorbing nutrients and causing harm to the host.

Earthworms are detritivores, feeding on decaying organic matter like dead leaves, contributing to decomposition in ecosystems.

Gills enable fish to extract dissolved oxygen from water, a critical adaptation for respiration in aquatic environments.

Chlorophyll, a pigment in chloroplasts, absorbs light energy, primarily in the blue and red wavelengths, to drive photosynthesis.

Herbivores have long intestines to facilitate the breakdown of tough plant material, allowing ample time for nutrient extraction.

Antidiuretic hormone (ADH), secreted by the pituitary gland, regulates water reabsorption in the kidneys, maintaining the body’s water balance.

Lichens, as pioneer species, are the first to colonize barren areas during ecological succession, breaking down rock and forming soil to support other organisms.