JAMB UTME - Biology - 2022

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Volvox is a genus of green algae containing around 20 species of freshwater algae. Thousands of cells together form colonies. There are around 500 to 60,000 cells in each colony of volvox. Leeuwenhoek was the first scientist to observe them in 1700. Volvox is widely studied to understand the process of morphogenesis.

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During mitosis, the stage at which chromosomes line up around the equator is metaphase. Metaphase is the stage in the cell cycle when the chromosomes condense and become visible. They then line up along the equator, or the center of the cell, in preparation for separation and distribution to the two daughter cells. This is a critical stage in the process of cell division and ensures that each daughter cell receives a complete set of chromosomes.

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Genetic crossing over occurs during meiosis, which is a type of cell division that produces cells called gametes that are used for sexual reproduction. During meiosis, homologous chromosomes (chromosomes that carry similar genes) pair up and exchange genetic material, resulting in the shuffling of genetic information and creating genetic diversity. This process of exchanging genetic material between homologous chromosomes is called genetic crossing over. The end result of crossing over is the production of genetically unique offspring that have a combination of traits from both parents.

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The body of a snail is divided into a head, visceral mass, and foot.

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The internal structure of a leaf with larger air spaces is the spongy mesophyll. The mesophyll is the main tissue inside the leaf, and it is divided into two main layers: the palisade mesophyll and the spongy mesophyll. The palisade mesophyll is located near the upper surface of the leaf and has tightly packed cells that are responsible for carrying out photosynthesis. The spongy mesophyll is located near the lower surface of the leaf and has loosely packed cells with larger air spaces between them. The larger air spaces in the spongy mesophyll allow for the exchange of gases such as carbon dioxide and oxygen between the leaf and the air. This is important for the process of photosynthesis, where the plant uses energy from sunlight to convert carbon dioxide and water into glucose and oxygen. The oxygen produced during photosynthesis is released into the air through the stomata, which are small pores found on the surface of the leaf.

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Petaloid sepals serve the function of attracting pollinators to a flower. In many plants, the sepals look similar to petals and are brightly colored to catch the attention of insects, birds, bats or other animals. These animals are attracted to the flower for the nectar or pollen that it provides, and in the process, they help to pollinate the flower, which is essential for the plant to produce seeds and reproduce. So, the petaloid sepals help the flower to attract pollinators and ensure its survival.

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The structure that joins the two strands of a chromosome together is the centromere.

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The system of classification in which there are seven hierarchies from kingdom to species was introduced by Carolus Linneus. He was a Swedish botanist and zoologist who is known as the "father of modern taxonomy." He developed a system of classification that organized all living things into groups based on their physical characteristics. This system has seven levels, starting with the kingdom and ending with the species. Linneus's system is still widely used today and forms the basis for our modern understanding of the classification of living things. In a simple and comprehensive way, Carolus Linneus introduced the system of classification that organizes living things into seven groups based on their physical characteristics.

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The movement of sugars from the leaf to other parts of the plant is called translocation. Plants make food through photosynthesis, which occurs in the leaves. The sugar produced in the leaves is used by the plant as energy, but it also needs to be transported to other parts of the plant, such as the roots, stems, and flowers. This movement of sugar is called translocation. Translocation occurs through the plant's transport system, which includes tiny tubes called xylem and phloem. The xylem transports water and minerals from the roots to the leaves, while the phloem transports sugars and other organic compounds from the leaves to other parts of the plant. This helps ensure that all parts of the plant have the necessary resources to grow and thrive.

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Erythrocyte.

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Succession that occurs on an abandoned farm land is referred to as secondary succession. Secondary succession is the process of change and development of plant and animal communities that occurs after a disturbance, such as a fire, flood, or human activity, has removed or altered the existing community. In the case of an abandoned farm land, the removal of crops, trees, and other vegetation, as well as the disturbance of the soil, creates an opportunity for new species to colonize the area and establish new communities. Over time, the community changes and evolves, eventually reaching a stable state known as the climax community. Primary succession, on the other hand, occurs in areas where there was previously no vegetation, such as newly formed volcanic islands or areas that have been covered by glaciers. In these areas, the first organisms to colonize the area are typically lichens, mosses, and other small plants that can tolerate the harsh conditions. As the community becomes more established, larger plants and animals move in, leading to the development of a more complex and diverse community. Tertiary succession is a less common type of succession that occurs on previously disturbed sites that have been abandoned for a longer period of time, such as old fields or abandoned industrial sites. In these cases, the community has already undergone secondary succession, but further changes and evolution may occur due to changes in the environment or the introduction of new species.

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The dark stage of photosynthesis is associated with "Assimilation of Carbon(IV)oxide". Photosynthesis can be divided into two stages: light-dependent reactions and light-independent reactions. The light-dependent reactions occur in the thylakoid membranes of the chloroplasts and require light energy to produce ATP and NADPH, which are energy-rich molecules. The light-independent reactions, also known as the dark reactions, occur in the stroma of the chloroplasts and use the energy from the ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose. This process is called "Assimilation of Carbon(IV)oxide". "Photophosphorylation" refers to the process of producing ATP in the light-dependent reactions, while "Photolysis" refers to the splitting of water molecules into oxygen and hydrogen ions during the light-dependent reactions. "Excitation of chlorophyll" refers to the process of capturing light energy by chlorophyll molecules in the light-dependent reactions.

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The waste product of insects is typically excreted in the form of uric acid. Unlike other insects and mammals, insects do not have a separate organ for the elimination of liquid waste, like a bladder. Instead, they excrete nitrogenous waste in the form of uric acid, which is a solid substance. This solid form of waste helps to conserve water, as insects can lose a significant amount of water through evaporation. The uric acid is excreted through specialized structures called Malpighian tubules, which are found in the insect's abdomen. The uric acid is then passed out of the body through the anus.

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An adaptation for defense in animals is spines in porcupine fish. Porcupine fish have spines on their bodies that can be raised when they feel threatened. The spines act as a defense mechanism to deter predators from attacking the fish. When the spines are raised, they make the fish look larger and more intimidating, and the spines can also cause injury to the predator if it tries to bite the fish. Croaking of a male toad is a type of communication that is used to attract mates or defend territory, but it is not an adaptation for defense. Basking in lizards is a behavior that helps the lizards regulate their body temperature, but it is not an adaptation for defense. Huddling together of penguins is a behavior that helps the penguins stay warm in cold environments, but it is not an adaptation for defense.

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In simple organisms, such as cnidarians and flatworms, every cell in the body is close to the external environment. Their cells are kept moist and gases diffuse quickly via direct diffusion. Flatworms are small, literally flat worms, which “breathe” through diffusion across the outer membrane. Annelids have a closed circulatory system; the blood is entirely contained in vessels. Annelids have no lungs, although many species have simple gills.

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One of the functions of water in seed germination is to activate the enzymes. When a seed is planted in soil, it needs water to start growing. The water activates certain enzymes in the seed that help it to begin the process of germination. Enzymes are like tiny helpers that carry out specific tasks in the seed. Some enzymes break down stored food in the seed, while others help to soften the seed coat so that the plant can emerge. By activating the enzymes, the water helps to kick-start the process of growth and development in the seed, making it possible for it to sprout and eventually become a mature plant.

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The growth of mucor on a piece of bread is saprophytism. Saprophytes are organisms that obtain their nutrients from dead organic matter, such as bread in this case. Mucor is a type of fungus that is known to grow on organic matter in a saprophytic manner.

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An aggregate fruit is the type of fruit that is formed from a single flower having several free carpels.

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The conversion of atmospheric carbon into chemical bond energy occurs during the process of photosynthesis.

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The feeding relationship that exists between a tick and a cow is parasitism.

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AB positive blood type is known as the “universal recipient” because AB positive patients can receive red blood cells from all blood types.

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The development of big muscles by a wrestler is an example of acquired characteristics. Acquired characteristics refer to changes that an organism acquires during its lifetime as a result of its experiences and environment. For example, a wrestler may develop big muscles through regular exercise and weightlifting. These changes are not passed on to the next generation and are not part of the organism's genetic material.

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The correct answer is: red blood cells, white blood cells, plasma and platelets. Blood is a complex fluid that is made up of different components, each with a specific function.

- Red blood cells (also called erythrocytes) are responsible for carrying oxygen from the lungs to the rest of the body. They have a biconcave shape that allows them to carry more oxygen and are flexible so they can move through the smallest blood vessels.

- White blood cells (also called leukocytes) are part of the body's immune system and help fight infections. There are different types of white blood cells, each with a specific function, such as identifying and destroying harmful bacteria and viruses.

- Plasma is the yellowish fluid part of blood that makes up about 55% of total blood volume. It contains water, proteins, hormones, and waste products. Plasma also helps to transport nutrients, hormones, and waste products throughout the body.

- Platelets (also called thrombocytes) are small, disc-shaped cells that play a crucial role in the formation of blood clots. When there is an injury or wound, platelets clump together to form a clot and stop bleeding.

So, red blood cells, white blood cells, plasma and platelets.

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The part of mammalian skin that excretes metabolic wastes is the sweat gland. The sweat glands are responsible for producing and secreting sweat, which is a mixture of water, salts, and other substances, including metabolic waste products. The sweat is produced in response to changes in body temperature, such as during physical activity or exposure to warm environments, and it is released onto the surface of the skin through small openings called sweat pores. From there, it evaporates and helps to regulate the body's temperature. The horny layer is the outermost layer of the skin, composed of dead skin cells that have been pushed to the surface. It acts as a protective barrier, helping to keep harmful substances out of the body. The Malpighian layer is the deepest layer of the skin, and it contains blood vessels, nerve endings, and other structures that are important for the skin's function. The sebaceous glands are small glands in the skin that produce an oily substance called sebum, which helps to moisturize the skin and protect it from environmental damage.

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The correct pathway for blood flow from the heart to the tissues of mammals is: heart-artery-arteriole-tissues. Here's a simple explanation: - The heart pumps blood into the arteries. - The arteries carry the blood away from the heart to smaller blood vessels called arterioles. - The arterioles further distribute the blood to the tissues. It's important to note that the blood carries oxygen and nutrients to the tissues, and picks up waste products from the tissues to be transported back to the heart and then to the lungs, kidneys, and other organs for elimination. This is called the circulatory system.

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An example of an arboreal animal is a squirrel. Arboreal animals are animals that live in trees and have adaptations that allow them to move and live effectively in this environment. Squirrels are a classic example of arboreal animals as they are well-known for their ability to climb trees and live in the branches. They have strong hind legs, sharp claws, and a tail that helps them balance and maneuver in the trees. Squirrels use trees for food, shelter, and protection, and their arboreal lifestyle is a critical aspect of their survival.

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Air pollutants are substances present in the air that can harm human health, wildlife, and the environment. They come from various sources including: 1. Industrial chimneys: Industries such as power plants, manufacturing facilities, and refineries release pollutants like sulfur dioxide, nitrogen oxides, and particulate matter into the air through their chimneys. 2. Vehicle exhausts: Cars, trucks, buses, and other vehicles emit pollutants like carbon monoxide, nitrogen oxides, and particulate matter into the air. 3. Burning fossil fuels: The burning of fossil fuels such as coal, oil, and natural gas releases pollutants like sulfur dioxide, nitrogen oxides, and carbon monoxide into the air. 4. Sewage: Waste from sewage treatment plants and septic systems can emit pollutants like methane and nitrogen into the air. 5. Smoke: Open burning of waste, forest fires, and other sources of smoke can emit pollutants like particulate matter and carbon monoxide into the air. It's important to note that not all sources of air pollutants are man-made. Natural sources such as volcanic eruptions, dust storms, and wildfires also contribute to air pollution.

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Camel's ability to tolerate high degree of dehydration is an adaptive feature to the desert. This means that camels are able to survive for a long period of time without water and can survive in the harsh, dry conditions of the desert. Their bodies have evolved to store large amounts of water and to conserve water efficiently, which allows them to go for long periods without drinking. This is a critical adaptation for survival in the desert, where water is often scarce.

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Southern Guinea Savanna is found in the following states in Nigeria: Kogi and Kwara. Southern Guinea Savanna is a type of vegetation found in Nigeria and other parts of West Africa. It is characterized by grasses and scattered trees, and it is different from the dense forests found in other parts of the country. The Southern Guinea Savanna region in Nigeria covers parts of Kogi and Kwara states.

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Tall trees with buttress roots and evergreen leaves are characteristic features of tropical rain forests. Tropical rain forests are found near the equator and receive a lot of rainfall throughout the year. The tall trees in these forests have buttress roots, which are large roots that grow out from the base of the tree and spread out horizontally, to support the tree and provide stability in the soil that is often soft and wet. The leaves of these trees are evergreen, meaning they remain green all year round, as there is no winter season in the tropical rain forest climate.

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The end product of the digestion of carbohydrates is glucose. Carbohydrates are a type of nutrient found in many foods, including breads, cereals, fruits, and vegetables. When we eat carbohydrates, they are broken down into smaller sugar molecules through a process called digestion. The simplest sugar molecule produced by this process is glucose, which is then absorbed into the bloodstream and used as a source of energy by the body's cells. So, glucose is the end product of the digestion of carbohydrates.

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In genetic counseling, it is preferred for a man with the HbA HbS blood type to marry a woman with the HbA HbA blood type. This is because the HbA HbS blood type, also known as sickle cell anemia, is a genetic condition where the red blood cells can take on a sickle shape, leading to reduced oxygen flow and causing various health problems. If a man with HbA HbS marries a woman with HbA HbA, there is a lower chance that their children will inherit the sickle cell anemia gene. On the other hand, if the man with HbA HbS marries a woman with HbS HbS, there is a higher chance that their children will inherit the sickle cell anemia gene and suffer from the condition. In summary, it is recommended for a man with HbA HbS to marry a woman with HbA HbA to reduce the risk of passing on the sickle cell anemia gene to their children.

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The beak structure of an organism is best adapted for the type of food it primarily consumes. For example, if the organism primarily consumes seeds and grass, its beak will likely be flat and wide, allowing it to effectively peck at the ground and pick up small seeds. If the organism primarily eats fish, its beak will likely be sharp and hooked, allowing it to efficiently kill and pick fish from the water. If the organism primarily feeds on nectar, its beak will likely be long and slender, allowing it to reach into flowers and efficiently suck the nectar. So, the type of food the organism consumes will determine the beak structure that is best adapted for its needs.

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The under secretion of thyroxine in children results in cretinism. Thyroxine is a hormone produced by the thyroid gland and is essential for normal growth and development. Inadequate production of this hormone can lead to cretinism, which is a condition characterized by stunted growth, intellectual disability, and physical deformities.

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A wind vane is an ecological instrument used to measure wind direction. It's a simple device that consists of a small weather-vane mounted on a tall pole or a roof. The wind vane is shaped like a arrow, and it's free to rotate on a vertical axis. The direction that the arrow points in is the direction from which the wind is blowing. This information can be useful for a variety of purposes, including monitoring wind patterns for weather forecasting, studying air pollution, and measuring wind speeds in wind energy applications.

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The pentadactyl plan of the fore limbs of frog, bird, horse, whale, and man is a proof of evolution. The pentadactyl plan refers to the similar skeletal structure of the forelimbs of these organisms, which consists of five digits, or fingers, arranged in a similar pattern. This similarity in structure suggests that these organisms share a common ancestor and have evolved over time from a common ancestral form. This is consistent with the theory of evolution and not with spontaneous generation, locomotion, or creation.

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The sum total of all observable features of an organism is called the phenotype. The phenotype includes physical traits, such as height, eye color, and hair texture, as well as behavioral traits, such as a person's ability to run quickly or play a musical instrument. The phenotype is influenced by both genetic and environmental factors. The genetic component of the phenotype is determined by the organism's genotype, which is the complete set of genetic information that it carries, while the environmental component is determined by the conditions in which the organism lives, such as the availability of food and water, the temperature, and the presence of other organisms. Heterozygous and homozygous are terms that describe the relationship between two copies of a gene in an organism's genotype. Heterozygous means that the two copies of the gene are different, while homozygous means that the two copies are the same. These terms are used to describe the genetic makeup of organisms and can be used to predict the likelihood of certain traits being expressed in the phenotype.