JAMB UTME - Biology - 2018
Question 1 Report
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Use the diagram shown to answer the question. After an hour, the level of water in the thistle funnel will
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Question 2 Report
A man who is heterozygous for the disease haemophilia marries a woman who is double recessive for haemophilia. What percentage of their offspring would have the disease?
Answer Details
Haemophilia is an X-linked recessive genetic disorder. This means that the gene responsible for haemophilia is located on the X chromosome, and individuals with two copies of the defective gene (one inherited from each parent) will have the disease.
The man in this scenario is heterozygous, meaning he has one normal X chromosome and one X chromosome with the defective gene. The woman is double recessive, meaning she has two copies of the defective gene.
When the man and woman have offspring, each child will inherit one of their father's X chromosomes and one of their mother's X chromosomes.
The possible combinations of X chromosomes the children could inherit are:
- Normal X chromosome from the father and normal X chromosome from the mother
- Normal X chromosome from the father and defective X chromosome from the mother
- Defective X chromosome from the father and normal X chromosome from the mother
- Defective X chromosome from the father and defective X chromosome from the mother
Of these possible combinations, only the last one (defective X chromosome from both parents) will result in the child having haemophilia.
The probability of a child inheriting a defective X chromosome from the father is 50%, since the father is heterozygous. The probability of a child inheriting a defective X chromosome from the mother is 100%, since the mother is double recessive.
Therefore, the probability of a child inheriting a defective X chromosome from both parents and having haemophilia is 50% x 100% = 50%.
So the correct answer is: 50% of their offspring would have the disease.
Question 3 Report
Which of the following cycles involves the process of precipitation and transpiration?
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The cycle that involves the process of precipitation and transpiration is the water cycle.
The water cycle is the process by which water circulates through the Earth's environment. It starts with the evaporation of water from bodies of water, such as oceans, lakes, and rivers, as well as from the soil and plants through a process called transpiration. This water vapor then rises into the atmosphere, where it cools and condenses into clouds. When these clouds become heavy enough, the water falls back to Earth as precipitation, which can take the form of rain, snow, sleet, or hail.
Once the precipitation falls to the ground, it can either be absorbed by the soil and become groundwater or run off into bodies of water. From there, the cycle starts again.
In summary, the water cycle involves the process of precipitation, which is the falling of water from the atmosphere to the Earth's surface, as well as the process of transpiration, which is the release of water vapor from plants. This cycle is essential for providing fresh water to living things and maintaining the Earth's environment.
Question 4 Report
Study the diagram of a food chain shown and use it to answer the question.
P ---> Q ---> R ---> S ---> T
The organism designated P in the food chain above is normally sustained by energy from
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The organism designated P in the food chain is normally sustained by energy from the sun. This is because P is likely at the bottom of the food chain, which means it is a primary producer. Primary producers, such as green plants, use energy from the sun to produce their own food through photosynthesis. This food is then consumed by the next organism in the food chain, which is Q. The energy then passes from one organism to the next, all the way up the food chain to the top predator.
Therefore, in this food chain, P is likely a green plant or another type of primary producer that uses energy from the sun to produce its own food, making sunlight the source of energy for P.
Question 5 Report
At which stage in this cycle can a man be infected?
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In the animal's intestine, the oncospheres hatch, invade the intestinal wall, and migrate to the striated muscles, where they develop into cysticerci. A cysticercus can survive for several years in the animal. Humans become infected by ingesting raw or undercooked infected meat.
Question 6 Report
The function of pith in plant is
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Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant. In eudicots, pith is located in the center of the stem. In monocots, it extends also into flowering stems and roots.
Question 7 Report
The immediate product of meiosis in flowering plants is the
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Pollen grains form in the two pollen sacs located in the anther. Each pollen sac contains specialized chambers in which the microspore mother cells are enclosed and protected. The microspore mother cells undergo meiosis to form four haploid microspores. Subsequently, mitotic divisions form four pollen grains. Inside each pollen grain is a generative cell; this cell will later divide to produce two sperm cells. Pollen grain shapes are specialized for specific flower species.
Question 8 Report
The energy released by 1 gram of glucose is
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The energy released by 1 gram of glucose is about 4 kcal. To put it simply, when our bodies break down glucose, a type of sugar that is a source of energy, it releases energy that we can use. This energy is measured in units of calories, and 1 kilocalorie (kcal) is equivalent to 1,000 calories. So, when 1 gram of glucose is broken down, it releases approximately 4 kcal of energy.
Question 9 Report
Examples of animals with mammary glands include the following except
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A mammary gland is an exocrine gland in mammals that produces milk to feed young offspring. Mammals get their name from the Latin word mamma, "breast". Hens do not have mammary glands.
Question 10 Report
Which of the following processes removes carbon from the atmosphere?
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The process that removes carbon from the atmosphere is "photosynthesis".
Photosynthesis is the process by which green plants and other organisms use sunlight to synthesize foods with the help of carbon dioxide and water. During photosynthesis, carbon dioxide (CO2) is taken in from the atmosphere and used to produce glucose, a type of sugar that serves as food for the plant. In this process, the carbon from CO2 is converted into organic carbon compounds, which are then used to build the plant's structure and stored in the plant's tissues. This means that photosynthesis helps to remove carbon from the atmosphere and store it in the biomass of plants.
In contrast, processes such as putrefaction, volcanic eruption, and burning of fuels release carbon into the atmosphere, contributing to the increase of atmospheric carbon dioxide levels and, in turn, to climate change.
Question 11 Report
Maltose is combination of glucose and
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Maltose is a disaccharide, which means it is made up of two simple sugar molecules. Specifically, maltose is made up of two glucose molecules that are joined together by a type of bond called a glycosidic bond.
Glucose is a monosaccharide, which means it is a simple sugar that cannot be broken down into any simpler sugars. Maltose is formed when two glucose molecules are linked together by a glycosidic bond. This bond is formed by the removal of a molecule of water between the two glucose molecules. The resulting molecule of maltose is therefore a combination of two glucose molecules.
Sucrose, on the other hand, is a different type of disaccharide that is made up of one glucose molecule and one fructose molecule, while galactose is a monosaccharide that can combine with glucose to form lactose, a disaccharide found in milk.
So to summarize, maltose is a disaccharide made up of two glucose molecules that are linked together by a glycosidic bond. It is not made up of fructose, sucrose, or galactose.
Question 12 Report
Man can contact tapeworm through
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Yes, a person can come into contact with tapeworms by ingesting uncooked or undercooked meat that contains tapeworm larvae. Tapeworms can infect animals such as cows, pigs, and fish, and when humans eat infected meat, they can get infected too. This is why it's important to cook meat thoroughly and to wash fruits and vegetables before eating them. Contact with tapeworms cannot occur through breathing or simple physical contact with an infected person or animal.
Question 13 Report
A seed of a flowering plant can best be described as
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A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth with in the motherplant.
Question 14 Report
An example of a radially symmetrical organisms is
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An example of a radially symmetrical organism is Hydra. Radial symmetry means that an organism has a circular shape and its body parts are arranged around a central axis, like the spokes on a wheel. Hydra is a small, freshwater animal that has a cylindrical body and tentacles that radiate out from its central axis. This type of symmetry allows Hydra to detect and capture prey from all directions. Planaria are also radially symmetrical flatworms, while tapeworms and roundworms are examples of organisms with bilateral symmetry, meaning that they have a distinct front and back and a left and right side.
Question 15 Report
The reason why the flow of blood through the capillaries is very slow is
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The rate, or velocity, of blood flow varies inversely with the total cross-sectional area of the blood vessels. As the total cross-sectional area of the vessels increases, the velocity of flow decreases. Blood flow is slowest in the capillaries, which allows time for exchange of gases and nutrients. Flow is slowest in the capillaries because of their larger cross-sectional area and narrow diameter.
Question 16 Report
Evidence of evolution include the following except
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Note: Evolution is a process of gradual change that takes place over many generations, during which species of animals, plants, or insects slowly change some of their physical characteristics.
Question 17 Report
A distinguishing feature of mammals is the possession of
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One distinguishing feature of mammals is the possession of hair. Hair is a unique type of structure that grows from the skin of mammals and is made up of a protein called keratin. Hair serves many important functions in mammals, such as keeping the body warm, protecting the skin from damage, and providing sensory information. Hair can also be used for social communication, such as when a cat raises its fur to make itself look bigger and more intimidating. While other animals like reptiles may have scales, and birds may have feathers, only mammals have hair as a defining feature.
Question 18 Report
Long neck in giraffe is used to illustrate the theory of
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The giraffe's long neck is a perfect adaptation to the animal's natural habitat. Clearly the giraffe evolved this uncommon and helpful trait in order to reach those nourishing leaves. That's how natural selection works. Use and disuse' theory in human life advocate the idea that animals acquired characteristics after using certain physical traits constantly.
Question 19 Report
The part of the ear which contains nerve cells sensitive to sound vibrations is the
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The part of the ear which contains nerve cells sensitive to sound vibrations is the cochlea.
The cochlea is a small, spiral-shaped structure in the inner ear. It is responsible for translating sound waves into electrical signals that can be interpreted by the brain. The cochlea contains tiny hair cells that are responsible for detecting sound vibrations. These hair cells are arranged along the length of the cochlea and are stimulated by different frequencies of sound.
When sound waves enter the ear, they cause the eardrum to vibrate. These vibrations are then transmitted to the three small bones in the middle ear, including the malleus. The malleus transmits the vibrations to the inner ear, where they are picked up by the hair cells in the cochlea. The hair cells then convert the vibrations into electrical signals that are transmitted to the brain via the auditory nerve, allowing us to hear and interpret sounds.
In summary, the cochlea is the part of the ear that contains nerve cells sensitive to sound vibrations. The hair cells within the cochlea are responsible for detecting sound waves and translating them into electrical signals that can be interpreted by the brain.
Question 20 Report
Examples of micronutrients include the following except
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The essential elements can be divided into macronutrients and micronutrients. Nutrients that plants require in larger amounts are called macronutrients. About half of the essential elements are considered macronutrients: carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.
Question 21 Report
What is the critical limiting factor for plants below the photic zone in an aquatic ecosystem?
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Primary production in the photic zone is influenced by three major factors—nutrients and light, which are essential for photosynthesis, and grazing pressure, the rate at which the plants are eaten by herbivores.
Question 22 Report
The vitamin which is important in the formation of the retina pigment is
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The vitamin that is important in the formation of the retina pigment is Vitamin A.
The retina is a part of the eye that contains cells called rods and cones which help us to see. Vitamin A is important for the normal functioning of these cells, especially the rods, which are responsible for vision in low light conditions.
The retina pigment, also known as rhodopsin, is a protein found in the rods of the retina. It helps to absorb light and convert it into electrical signals that the brain can interpret as vision. Vitamin A plays a crucial role in the formation of this pigment, and a deficiency of this vitamin can lead to a condition called night blindness, where a person has difficulty seeing in low light conditions.
In summary, Vitamin A is essential for the normal functioning of the cells in the retina, especially the rods, and is important for the formation of the retina pigment, which is necessary for vision in low light conditions.
Question 23 Report
Total salt content in blood is about
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The total salt content in blood is about 0.85 to 0.9%. Salt, which is also known as sodium chloride, is an essential mineral that is necessary for many bodily functions such as maintaining fluid balance, transmitting nerve impulses, and contracting muscles. However, too much salt in the blood can lead to health problems like high blood pressure, so it's important to maintain a proper balance. The normal range for salt content in the blood is typically around 0.9%, which is equivalent to 9 grams of salt per liter of blood.
Question 24 Report
What is the function of contractile vacuole in paramecium?
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The contractile vacuole in paramecium functions to get rid of excess water. Paramecium is a single-celled organism that lives in freshwater environments. As water enters the cell by osmosis, the contractile vacuole collects and pumps out the excess water to prevent the cell from swelling and potentially bursting. The contractile vacuole acts like a pump, contracting and releasing to expel the excess water out of the cell. This process helps maintain the proper balance of water and ions inside the cell, which is necessary for the organism's survival. Therefore, the function of the contractile vacuole in paramecium is to regulate water balance and prevent the cell from bursting due to excess water intake.
Question 25 Report
The graph below shows the results of a laboratory investigation which measured the body temperatures of a lizard and a bird under changing artificial conditions. Use it to answer the question.
Which of the statements below is valid?
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Question 26 Report
Spectacles with convex lenses correct long-sightedness by
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Spectacles with convex lenses correct long-sightedness by converging the light rays before they enter the eye.
In long-sightedness, also known as hyperopia, the eyeball is too short, which causes light to focus behind the retina instead of directly on it. This results in blurry vision, especially when looking at close objects.
Convex lenses are thicker in the middle and thinner at the edges, and they bend light rays towards each other. When a person with long-sightedness wears spectacles with convex lenses, the lenses converge the light rays before they enter the eye, which compensates for the shortness of the eyeball. This causes the light rays to focus directly on the retina, which results in clearer vision.
Therefore, by converging the light rays before they enter the eye, convex lenses correct long-sightedness.
Question 27 Report
DNA in eukaryotic cells is contained in the
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DNA in eukaryotic cells is contained in the nucleus. The nucleus is a membrane-bound structure found in eukaryotic cells that acts as the "brain" of the cell, controlling and regulating all of its functions. It is also where the cell's DNA is stored and protected, in a substance called chromatin. The DNA in the chromatin is organized into long structures called chromosomes, which are visible during cell division. In short, the nucleus is the place where the DNA of a eukaryotic cell is located and it plays a vital role in the functioning of the cell.
Question 28 Report
Blood circulation in a mammal is said to be double because
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The majority of mammals (including humans) utilize a double circulatory system. This means we have two loops in our body in which blood circulates. One is oxygenated, meaning oxygen rich, and the other is deoxygenated, which means it has little to no oxygen, but a lot of carbon dioxide.
Question 29 Report
Which of the following is a mixed gland?
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A mixed gland is a gland that is both exocrine and endocrine, for example, the pancreas. Pancreas is known as a mixed gland because it performs functions of both exocrine and endocrine glands.
Question 30 Report
The yellowish colored liquid component of blood that normally holds the blood cells in suspension is
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Blood plasma is a yellowish liquid component of blood that normally holds the blood cells in whole blood in suspension. In other words, it is the liquid part of the blood that carries cells and proteins throughout the body. It makes up about 55% of the body's total blood volume.
Question 31 Report
An accurate identification of a rapist can be carried out by conducting
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An accurate identification of a rapist can be carried out by conducting DNA analysis. DNA analysis involves collecting and analyzing a sample of DNA from a suspect, such as a hair, skin, or semen sample, and comparing it to a sample of DNA taken from the crime scene. If the DNA profiles match, it can provide strong evidence linking the suspect to the crime.
Blood group tests and behavioral tests are not reliable methods for identifying a rapist, as they do not provide a unique identifier like DNA analysis does. Additionally, RNA analysis is not typically used for the identification of rapists. DNA analysis is the most scientifically accepted and accurate method for identifying individuals in criminal investigations, including sexual assault cases.
Question 32 Report
Etiolation is causes by the influence of
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Etiolation is caused by the influence of LIGHT.
Etiolation refers to the physical changes that occur in a plant when it is grown in the absence of sufficient light. When a plant does not receive enough light, it elongates its stem and leaves to reach for the light source. This results in a spindly, pale appearance, as the plant allocates its resources towards vertical growth rather than producing chlorophyll and other pigments needed for photosynthesis.
Therefore, the absence of light, or insufficient light, is the primary cause of etiolation. While mineral salts, water, and carbon dioxide are all necessary for plant growth, they do not directly cause etiolation.
Question 33 Report
The damage to ozone layer is caused by
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Ozone sits in the upper atmosphere and absorbs ultraviolet radiaton, another type of solar energy that's harmful to humans, animals and plants. CFCs and halons cause chemical reactions that break down ozone molecules, reducing ozone's ultraviolet radiation-absorbing capacity. Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion.
Question 34 Report
The hormones secreted by pancreas serves to
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The production of pancreatic hormones, including insulin, somatostatin, gastrin, and glucagon, play an important role in maintaining sugar and salt balance in our bodies.
Question 35 Report
Name the blood cells in which nucleus is absent
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Like red cells, platelets (thrombocytes) have no nucleus. However, unlike red cells that originate in the marrow as nucleated cells and lose their nucleus, platelets are produced by budding off from a giant multinucleated marrow cell called a megakaryocyte.
Question 36 Report
Mineral salts can be absorbed into roots by
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In plants and animals, mineral absorption, also called mineral uptake is the way in which minerals enter the cellular material, typically following the same pathway as water. In plants, the entrance portal for mineral uptake is usually through the roots by a process of diffusion and active transport.
Question 37 Report
A plant tissue that carries water and mineral salt is
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The plant tissue that carries water and mineral salts from the roots to other parts of the plant is called xylem.
Xylem is like a pipeline that runs throughout the plant and is responsible for transporting water and dissolved nutrients from the roots to the leaves and other parts of the plant. This tissue is made up of specialized cells called tracheids and vessel elements that are arranged end to end to form long, hollow tubes. These tubes allow water to flow through them with minimal resistance, and the water is pulled up through the xylem by a process called transpiration.
In summary, xylem is the tissue responsible for carrying water and mineral salts from the roots to the rest of the plant, and it does so through a network of specialized cells that form long, hollow tubes.
Question 38 Report
A boy who is fond of swimming in a pond finds himself passing urine with traces of blood. He is likely to have contracted
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The boy who is fond of swimming in a pond and passes urine with traces of blood is likely to have contracted schistosomiasis. Schistosomiasis is a parasitic infection caused by a type of flatworm called Schistosoma that commonly inhabits freshwater snails and bodies of water such as ponds and lakes. When a person comes into contact with water contaminated with the parasite, it can penetrate the skin and enter the bloodstream, where it eventually travels to the bladder or intestines and causes inflammation and damage to the tissues. This can lead to symptoms such as blood in the urine or stool, abdominal pain, diarrhea, and anemia. If left untreated, schistosomiasis can lead to chronic health problems such as liver and kidney damage. Therefore, it is important to seek medical attention if experiencing symptoms after swimming or coming into contact with freshwater bodies in endemic areas.
Question 39 Report
Which of the following statements is true about sandy soil?
Answer Details
Sandy soils are well drained. They have low water holding capacity and are therefore drought prone. They become firm when wet (the opposite of clay), and loose when dry. Sandy soil is light and easy to dig.
Question 40 Report
Red blood cells were found to have burst open after being placed in distill for an hour. This phenomenon is known as
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The phenomenon you're referring to is called haemolysis. Haemolysis is the bursting of red blood cells when they are placed in a solution that is different from their normal environment. When red blood cells are placed in distilled water, the water moves into the cells and causes them to expand and eventually burst, resulting in haemolysis. This occurs because the concentration of solutes (e.g. salts, sugars) is higher inside the red blood cells than in the distilled water, causing water to move into the cells and causing them to burst. In simple terms, haemolysis is the bursting of red blood cells due to a change in the solution they are in.
