JAMB UTME - Biology - 2019

Answer Details

The correct answer is: "Fusion of sperm and egg nuclei" Fertilization is the process in which a male gamete (sperm) combines with a female gamete (egg or ovum) to form a zygote, which is the first cell of the new organism. In higher organisms, including humans, fertilization occurs when a sperm cell penetrates the outer membrane of the egg cell and fuses with the egg's nucleus, resulting in the fusion of genetic material from both the sperm and the egg. The other options listed are not examples of fertilization. - Pollen grain landing on a sticky stigma is a process called pollination, which occurs in plants. Pollen grains contain male gametes, but pollination is not the same as fertilization, as the male and female gametes do not actually combine until after the pollen tube grows down into the ovule and the sperm cells are released to fuse with the egg. - Ejaculation of the egg and pollen grain is not a biological process that occurs in any known organism. - Ejaculation of sperm into the female body is the first step in the process of fertilization, but it is not fertilization itself. The sperm must still reach and penetrate the egg to complete the process of fertilization.

Answer Details

The possession of chloroplast in Euglena viridis enables it to carry out photosynthesis. Photosynthesis is the process by which green plants and algae use sunlight to synthesize food (glucose) from carbon dioxide and water. Chloroplasts are organelles found in the cells of green plants and algae that contain the pigment chlorophyll, which absorbs sunlight and is essential for photosynthesis. Euglena viridis is a unicellular organism that possesses chloroplasts, which enables it to harness sunlight to produce its own food through photosynthesis. Therefore, the answer is that the possession of chloroplast in Euglena viridis enables it to carry out photosynthesis.

Answer Details

Among the options listed, clay has the highest water retaining capacity. This is because clay particles are very small and have a large surface area, allowing them to attract and hold onto water molecules tightly through a process called adsorption. Additionally, the spaces between the clay particles are very small, which creates a high capillary action that further helps the clay to retain water. In contrast, sand particles are much larger and have a lower surface area, which means that water molecules are less likely to adhere to them. Sand also has larger spaces between its particles, which results in a lower capillary action and less water retention. Loam and laterite fall somewhere in between clay and sand in terms of their water retention capabilities, depending on their specific composition.

Answer Details

The structure that controls the activities of the living cell is the nucleus. The nucleus is a membrane-bound organelle that contains the genetic material (DNA) of the cell. It serves as the control center for the cell, directing all of its activities by regulating the expression of genes. The DNA in the nucleus provides the instructions for making proteins, which are the building blocks of the cell and carry out various functions in the body. The nucleus also plays a critical role in cell division, which is the process by which new cells are formed. During cell division, the DNA in the nucleus is replicated and then distributed to the daughter cells, ensuring that they each receive a complete set of genetic material. In summary, the nucleus is responsible for regulating gene expression and directing all of the activities of the cell. It is the structure that controls the fundamental processes of life, making it a vital organelle in all living organisms.

Answer Details

Starch is the main and first product formed during photosynthesis because the simple sugar formed is partly used by the plant and excess of it is converted into starch immediately for storage and the starch is transported to other parts of the plant through the phloem vessels for storage.

Answer Details

Halophiles are organisms that thrive in high salt concentrations. The adaptations of halophile organisms to their environment are:
(a) The integrity of non-halophile macromolecules is compromised, and the flow of water out of the cell produces a Turgor effect. • (b) Moderate halophiles maintain their structures via the synthesis of compatible organic solutes. • (c) Extreme halophiles maintain their structures via equilibration of cellular and environmental salt concentrations.

Answer Details

The period of inactivity seen in some animals during long periods of heat or drought is called aestivation. Aestivation is a type of dormancy, similar to hibernation, but it occurs in response to hot or dry conditions, while hibernation occurs in response to cold or food scarcity. During aestivation, animals reduce their metabolic activity and enter a state of deep sleep to conserve energy and water until more favorable conditions return. This strategy helps them survive harsh environmental conditions and avoid dehydration, which can be deadly in hot and dry environments. Some animals that undergo aestivation include certain snails, frogs, and turtles, as well as some mammals like the marsupial mouse and the fat-tailed dwarf lemur.

Answer Details

Turbidity is not typically considered a factor in a terrestrial habitat. A terrestrial habitat is a place where land-dwelling organisms, such as plants and animals, live and interact with their environment. Temperature, sunlight, and humidity are all important factors in determining the characteristics of a terrestrial habitat and the organisms that live there. Temperature affects the rate of biochemical reactions in organisms, while sunlight provides energy for photosynthesis in plants and affects the behavior of many animals. Humidity, or the amount of moisture in the air, can affect the water balance of plants and animals. On the other hand, turbidity refers to the cloudiness or haziness of a fluid, such as water, due to the presence of suspended particles. Turbidity is typically associated with aquatic habitats, where it can affect the penetration of light and the availability of nutrients for aquatic plants and animals. In a terrestrial habitat, there is generally no water for particles to be suspended in, so turbidity is not usually a significant factor.

Answer Details

A nitrifying bacterium is a type of bacterium that is capable of converting nitrogen compounds from one form to another. Out of the options you provided, the correct nitrifying bacterium is Nitrobacter. Nitrobacter is a genus of bacteria that oxidizes nitrite (NO2-) to nitrate (NO3-). This process is called nitrification and is an important part of the nitrogen cycle in the environment.

Answer Details

The sum total of adaptive changes from pre-existing forms that have taken place over a long time resulting in diversity of forms, structures, and functions among organisms is referred to as Evolution. This process of organic evolution involves changes in the genetic makeup of populations of organisms over time, resulting in new species that are better adapted to their environment. These changes occur due to natural selection, genetic drift, mutation, and gene flow, and can lead to the development of diverse forms, structures, and functions among organisms. , Specification, is not a term used in evolutionary biology. Inorganic Evolution, is not a recognized term in biology, as evolution only applies to living organisms. Evolution, is the correct answer, but to be more specific, the full term is Organic Evolution. Organic Evolution, is also a correct answer that specifically refers to the evolution of living organisms.

Answer Details

It is found in moist environment because of its adaptive features.

Answer Details

Tadpole's ability to swim and adapt to an aquatic habitat is due to the presence of its tail.

Answer Details

The irregular and amoeboid-shaped blood corpuscles are called "Leucocytes," which are also known as white blood cells. Leucocytes are an essential part of our immune system, and their main function is to protect the body against infections, diseases, and foreign invaders. Unlike erythrocytes (red blood cells) and thrombocytes (platelets), which have a uniform, round shape, leucocytes are irregular and amoeboid in shape, allowing them to move freely throughout the body and easily pass through the walls of blood vessels to reach the site of infection or injury. Leucocytes are classified into two main types: granulocytes and agranulocytes, based on the presence or absence of granules in their cytoplasm. Granulocytes have granules in their cytoplasm and include neutrophils, eosinophils, and basophils, while agranulocytes lack granules and include lymphocytes and monocytes. Overall, leucocytes play a critical role in our immune system and help keep us healthy by identifying and fighting off pathogens and foreign invaders.

Answer Details

Discontinuous variation is the differences of variations in behaviour by which organisms can be grouped into 2 or more classes within a population without any intermediates among them e.g Behaviour, ability to roll tongue.

Answer Details

Good quality food is essential for the proper functioning of the human body. It provides us with the nutrients that we need to stay healthy and strong. However, it is important to note that good quality food cannot provide resistance against malaria. Malaria is a disease that is caused by a parasite that is transmitted through the bite of an infected mosquito. While good nutrition can help support a healthy immune system, it cannot provide specific resistance against malaria. The other functions listed are all important roles that good quality food can perform in the human body. 1. Supplying energy: Food provides us with the energy we need to carry out daily activities, from walking and talking to more strenuous activities like exercising or playing sports. 2. Maintaining health: Eating a balanced diet that includes a variety of nutrient-rich foods helps to maintain good health. Nutrients like vitamins, minerals, and antioxidants are important for proper bodily function and can help prevent chronic diseases. 3. Sustaining growth: Children and teenagers require a balanced diet to support their growth and development. A diet rich in nutrients like protein, calcium, and iron is essential for building strong bones, muscles, and other tissues. In summary, good quality food is important for supplying energy, maintaining health, and sustaining growth. However, it cannot provide specific resistance against malaria or other infectious diseases.

Answer Details

A population is best described as a group of individuals of the same species that live together in the same area and can potentially interact with each other. For example, a population of deer living in a forest would consist of all the individual deer of the same species that live in that forest and are able to mate with each other. This definition excludes which includes plants and animals of different species living together, and which includes different species of wild animals. includes only a specific subset of organisms, and is not a comprehensive definition of a population.

Answer Details

The theory of natural selection stated by Charles Darwin is not "Characteristics acquired through use or disuse are transmitted to offspring". This idea is sometimes referred to as "Lamarkism," and it was popular before Darwin's theory of natural selection became widely accepted. The theory of natural selection states that variations that are beneficial for survival and reproduction are more likely to be passed on to the next generation, while variations that are harmful are less likely to be passed on. However, the theory does not suggest that the use or disuse of a particular trait can directly cause it to be transmitted to offspring. Instead, the transmission of traits is determined by the genetic information that is passed from parents to offspring.

Answer Details

Mutation is the change in the genetic make up of an organism, which results in a new inheritable characteristic. Simply put, a mutation is a change in an organism's DNA that can be passed down to future generations. Mutations can happen naturally or can be caused by environmental factors such as exposure to radiation or chemicals. These changes can result in a variety of effects, from a simple alteration in an organism's appearance to a serious medical condition.

Answer Details

The components of glomerular filtrate are water, electrolytes (such as salts), small organic molecules (such as glucose and amino acids), and waste products (such as urea). Glomerular filtrate is formed in the kidneys and is the fluid that is filtered from the blood in the glomerulus, a network of tiny blood vessels in the kidney. The filtrate contains all the components of blood except for plasma proteins and red and white blood cells. In other words, glomerular filtrate is the fluid that is filtered from the blood and contains all the components of the blood except for large proteins and cells. It is an important step in the process of urine formation, as the filtrate travels through the renal tubules, where it is further modified and waste products are removed to form urine.

Answer Details

Albinism is an expression of a trait controlled by recessive genes. Albinism is a genetic condition that results in a lack of melanin, a pigment that provides color to the skin, hair, and eyes. The condition is caused by mutations in genes that produce or distribute melanin. In order for an individual to have albinism, they must inherit two copies of the mutated gene, one from each parent. If an individual inherits one normal gene and one mutated gene, they will not have albinism, but they will be a carrier of the condition and can pass it on to their offspring. This is why albinism is considered a recessive trait, meaning it is only expressed when two copies of the mutated gene are present. So, in summary, albinism is an expression of a trait controlled by recessive genes, meaning that it is caused by mutations in genes that produce or distribute melanin, and it is only expressed when two copies of the mutated gene are present.

Answer Details

Southern Guinea Savanna is the largest of all biotic community in Nigeria found in Oyo, Osun, Ekiti Status etc.

Answer Details

Lymph is a fluid that circulates through the lymphatic system, which is part of the immune system. Its main function is to help defend the body against harmful substances, such as viruses and bacteria, by removing waste and debris from tissues and transporting it to the bloodstream for elimination. This makes option "Body defense" the correct answer.

Answer Details

Thunderstorms can be beneficial to plants because they add nitrogen to the soil. Lightning is an electrical discharge that can break apart nitrogen molecules in the air, and the resulting nitrogen compounds can fall to the ground in rainwater. Plants need nitrogen to grow, and thunderstorms can provide a natural source of this essential nutrient. However, it's important to note that while thunderstorms can bring benefits, they can also bring harm in the form of lightning strikes and flooding, so it's important to take necessary precautions to protect yourself and your property during severe weather.

Answer Details

The effect of using artificial pollination in plant breeding is "Improvement of the variety of crops". Artificial pollination is the process of manually transferring pollen from one flower to another to fertilize it, with the goal of producing hybrid plants with desirable traits. This allows plant breeders to combine traits from two different plants to create a new variety with improved qualities such as increased yield, disease resistance, and improved flavor. By using artificial pollination, plant breeders can control the genetics of the resulting offspring, leading to the creation of new crop varieties with improved traits. This can help to increase food production and improve the quality of crops, making them more resilient and better suited for different growing conditions.

Answer Details

The process involved during expiration in humans that is not accurate is "The thoracic cavity first increases in volume." During expiration, the diaphragm, which is a muscle located at the bottom of the thoracic cavity, relaxes and moves upwards, decreasing the volume of the thoracic cavity. At the same time, the intercostal muscles, located between the ribs, also relax, and the ribs move downward and inward, causing the chest to decrease in size. Additionally, the sternum moves outward, not inward, during expiration. These combined actions increase the pressure within the thoracic cavity, forcing air out of the lungs. Overall, expiration is a passive process that does not require the use of energy, and it is the opposite of inspiration, which is the process of taking air into the lungs.

Answer Details

The movement of blood between the heart and all other parts of the body beside the lungs is called systemic circulation. In the systemic circulation, oxygenated blood flows from the heart to the body's organs and tissues, providing them with the oxygen and nutrients they need to function properly. After the oxygen has been used up by the cells, the blood carrying carbon dioxide and other waste products is then transported back to the heart to be pumped to the lungs, where it will be oxygenated again in the pulmonary circulation. The systemic circulation is a critical part of the body's overall circulatory system, which also includes the pulmonary circulation. Together, these two systems help to ensure that every part of the body has a constant supply of oxygen and nutrients and that waste products are efficiently removed from the body.

Answer Details

The correct pair of photosynthetic organisms from the options provided are Euglena and Chlamydomonas. Both Euglena and Chlamydomonas are unicellular organisms that are capable of performing photosynthesis, which is the process of converting light energy into chemical energy. They have chloroplasts, the specialized organelles that carry out photosynthesis, and are therefore capable of producing their own food. On the other hand, Amoeba and Paramecium are heterotrophic organisms, meaning they obtain their food by consuming other organisms. Volvox is a colonial organism, which is also photosynthetic, but it is made up of many cells working together. Rhizopus is a type of fungus that obtains its nutrition through the absorption of organic material. Nostoc is a type of cyanobacteria that is capable of photosynthesis, while Plasmodium is a parasitic organism that causes malaria in humans and is not photosynthetic. So, the correct answer is "Euglena and Chlamydomonas".

Answer Details

Competition among individuals of a population increases the "Survival of the fittest". This means that individuals that are better adapted to their environment and can compete more effectively for resources are more likely to survive and reproduce, passing on their advantageous traits to their offspring. Over time, this process can lead to the evolution of a population and can result in the survival of the strongest, most fit individuals. In a simple way, it's like a race where the fastest runner wins and gets to advance to the next round. Similarly, in a population, the individuals who are best equipped to survive and thrive will be more likely to do so, while those who are not as well adapted may struggle and eventually die off.

Answer Details

The food supply will have the least effect on the rate of change of the numbers in a population. While food supply can impact the growth and survival of a population, it is less likely to cause rapid changes in population size compared to other factors such as disease, predation, and mutation. Disease, predation, and mutation can all have significant impacts on a population by affecting the survival and reproductive success of individuals, leading to changes in the overall population size. For example, a disease outbreak can reduce the number of individuals in a population, while predation can limit the growth of a population by preying on individuals. Mutations can also impact the population by changing the genetic makeup of the population and altering its ability to survive and reproduce. In conclusion, while food supply is important for maintaining a stable population, it is less likely to cause rapid changes in population size compared to other factors such as disease, predation, and mutation.

Answer Details

Dictating the formation of a protein by a gene in a chromosome is a process of transmitting hereditary characteristics

Answer Details

The study which involves the inter-relationship between groups of organisms or species of organisms living together in an area is called synecology. Synecology is a branch of ecology that examines the interactions and relationships between different species in a given ecosystem or community. It considers the biotic and abiotic factors that affect the survival and growth of populations and how they interact with one another. This study helps us to understand the complex network of relationships between different species and how they are dependent on one another for their survival. It is important for understanding the dynamics of ecosystems and how they may change over time due to human or natural factors.

Answer Details

The tapeworm possesses a thin membrane mostly because of it absorption of digested food from the intestine of the host.

Answer Details

The organ that removes the largest quantity of water from the blood is the kidney. The kidney is a vital organ in the body that helps filter waste products and excess water from the blood, which are then eliminated from the body as urine. When blood enters the kidney, it passes through tiny blood vessels called capillaries. These capillaries are surrounded by small structures called nephrons, which are responsible for filtering the blood. As blood flows through the nephrons, excess water and waste products are filtered out and collected as urine. The kidneys play an important role in maintaining the body's water balance. They can adjust the amount of water that is excreted from the body depending on how much water is consumed, how much is lost through sweating, and other factors. This helps to maintain the body's fluid levels within a narrow range, which is important for proper bodily function. While the skin and lungs also play a role in removing water from the body, they are not as efficient as the kidneys. The skin eliminates water through sweat, but this process is limited by factors such as humidity and temperature. The lungs eliminate water through exhalation, but this is a small amount compared to the amount eliminated by the kidneys. Overall, the kidneys are the most important organ for removing excess water from the body, and play a critical role in maintaining proper bodily function.

Answer Details

Water passes through the root cell membrane by osmosis. Osmosis is the movement of water molecules from an area of higher concentration to an area of lower concentration across a semi-permeable membrane. In plants, water is absorbed through the root hairs of the plant and moves into the root cells. The root cell membrane is selectively permeable, meaning that it allows certain molecules to pass through while blocking others. Water molecules are small enough to pass through the membrane, but larger molecules like cell sap, carbon dioxide, and oxygen cannot pass through by osmosis. Therefore, the correct answer is water.

Answer Details

Animals are said to be gregarious when they are of the same species and move together in a group. This behavior can be seen in various animals, such as wildebeests, zebras, and birds. There are different reasons why animals may exhibit gregarious behavior. One reason is for protection from predators. Being in a group makes it more difficult for a predator to target one individual. Animals in a group can also help defend against predators by displaying protective behaviors, such as giving an alarm to alert others when danger threatens. Another reason for gregarious behavior is for mating purposes. Some animals may form groups during breeding season, where males compete for females and display their dominance. So, the correct answer is "they are of the same species moving together in a group."

Answer Details

Secreting irritating fluid is a behavioural adaptation that keep/protects preys from predators.

Answer Details

Rate of transpiration is reduced in savannah forest due to thick barks of the trees in savannah forest.

Answer Details

The plants which can survive in extremely dry places are called xerophytes. Xerophytes have special adaptations that allow them to conserve water and survive in arid or desert environments where water is scarce. These adaptations include things like thick, waxy leaves to reduce water loss through evaporation, deep root systems to reach water deep underground, and small, spiky leaves to reduce surface area and water loss. Examples of xerophytes include cacti, succulents, and some types of grasses.

Answer Details

The pair of scientists who discovered the Rhesis factor in human blood is Landsteiner and Levine. Karl Landsteiner was an Austrian biologist and physician who is best known for his discovery of the ABO blood group system. In 1940, he and his colleague Alexander S. Wiener discovered the Rh factor, which is a protein that is found on the surface of red blood cells in some individuals and can cause an immune response in others. This discovery was a significant breakthrough in the field of blood transfusion and helped to reduce the risk of transfusion reactions in patients. Levine is likely a reference to Philip Levine, an American immunologist who worked with Landsteiner and Wiener at the Rockefeller Institute for Medical Research in New York. Levine played a key role in the discovery of the Rh factor, conducting many of the experiments that helped to confirm the existence of the protein. Neither Hooke nor Darwin were involved in the discovery of the Rh factor in human blood. Robert Hooke was a 17th-century English scientist who made important contributions to the fields of microscopy, physics, and biology, while Charles Darwin was a 19th-century British naturalist who is best known for his theory of evolution by natural selection. In summary, the correct answer is Landsteiner and Levine, as they were the scientists who discovered the Rh factor in human blood.

Answer Details

The appendix is considered to be vestigial in humans but functional in other mammals. In humans, the appendix serves no known purpose and can become inflamed and cause pain (appendicitis), which often requires surgical removal. However, in other mammals such as cows and horses, the appendix serves as a fermentation chamber where beneficial bacteria can break down tough plant fibers into simpler sugars that can be easily absorbed. This process is important for their digestion and survival.