JAMB UTME - Biology - 2017

What is the primary function of cofactors?

Détails de la réponse

Most enzymes do not function optimally, or even at all, unless bound to other non-protein helper molecules called cofactors.

How does an enzyme affect the rate of a reaction?

Détails de la réponse

An enzyme is a protein that acts as a catalyst in biochemical reactions. Enzymes work by lowering the activation energy required for a reaction to occur. Activation energy is the minimum amount of energy needed to start a chemical reaction. By lowering the activation energy, enzymes make it easier for reactant molecules to form the necessary chemical bonds and undergo the reaction, leading to a faster reaction rate. This means that the correct answer is: "It lowers the activation energy of the reaction, increasing the reaction rate."

The appendicular skeleton comprises of

Détails de la réponse

The appendicular skeleton includes the bones that make up the arms, legs, and the girdles (shoulder and hip) that attach them to the rest of the body. So, the correct option is "pectoral and pelvic girdles" and "forelimbs". The pectoral girdle is made up of the scapula (shoulder blade) and the clavicle (collarbone). The pelvic girdle is made up of the two hip bones. The forelimbs consist of the humerus (upper arm bone), radius and ulna (lower arm bones), and the bones of the hand (carpals, metacarpals, and phalanges). Together, the bones of the appendicular skeleton help us move around and carry out a wide range of physical activities, from running and jumping to manipulating objects with our hands.

The key event in the transition of the amphibians from water to land is the ________

Détails de la réponse

Amphibians display some interesting and changing characteristics as they metamorphose through various forms on their way to adulthood. The frog, for instance, begins life underwater as a larva with gills and becomes and air-breather with lungs as an adult.
&therefore4; in case of draught, frog can amphibians can use lungs to breathe on land

Which of the following choices correctly describes the composition of the cell membrane?

Détails de la réponse

The correct choice is "contains lipids and proteins." The cell membrane is the outermost layer of the cell that separates the internal environment of the cell from the external environment. It is composed mainly of two types of molecules: lipids and proteins. The lipids in the cell membrane are primarily phospholipids, which have a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail. These lipids are arranged in a bilayer, with the hydrophobic tails facing each other and the hydrophilic heads facing outward towards the watery environments on either side of the membrane. The proteins in the cell membrane serve a variety of functions, including transport of molecules across the membrane, cell signaling, and structural support. Some proteins span the entire membrane, while others are only present on one side. The cell membrane also contains small amounts of carbohydrates and other molecules, but lipids and proteins are the two main components.

Agglutination is the _______ of the ________

Détails de la réponse

The clumping of cells such as bacteria or red blood cells in the presence of an antibody or complement.

During blood transfusions, the antibodies react with the transfused blood group(if its of different blood group), the erythrocytes clump up and stick together causing them to agglutinate

Coloration of the eye is ______ variation

Détails de la réponse

Eye coloration is a caused by morphological variation

The biome that is characterized with large herbivores, few and scattered fire resistant trees is

Détails de la réponse

The biome that is characterized by large herbivores, few and scattered fire-resistant trees is the savanna. Savannas are grasslands with scattered trees. They are found in many parts of the world, including Africa, South America, and Australia. Large herbivores, such as zebras, elephants, and giraffes, roam the savanna and feed on the grass. The few trees that grow in the savanna are often fire-resistant, meaning they can survive fires that occur naturally in the area. The combination of grass and scattered trees makes the savanna a unique and important ecosystem.

Food chain refers to the feeding relationships between animals in a ______?

Détails de la réponse

Food chain refers to the sequence of transfers of matter and energy in the form of food from organism to organism. Food chains intertwine locally into a food web because most organisms consume more than one type of animal or plant. Plants, which convert solar energy to food by photosynthesis, are the primary food source. In a predator chain, a plant-eating animal is eaten by a flesh-eating animal. In a parasite chain, a smaller organism consumes part of a larger host and may itself be parasitized by even smaller organisms.

In a saprophytic chain, microorganisms live on dead organic matter.

In mosses the structure which performs the function of water absorption is the _________?

Détails de la réponse

In mosses, the structure that performs the function of water absorption is the rhizoids. Rhizoids are thin, hair-like structures that grow from the lower surface of the moss and penetrate into the soil or substrate. They do not have the specialized tissues that are found in true roots, such as root hairs, but they function in a similar way by absorbing water and minerals from the environment. Rhizoids also help to anchor the moss to its substrate, preventing it from being swept away by wind or water.

Use the diagram below to answer the question that follow:

The diagram represents a

Détails de la réponse

It should be Anemometer, which is used to measure the speed of wind

What organelle is the site of photosynthesis in plants?

Détails de la réponse

The organelle that is the site of photosynthesis in plants is called the chloroplast. Chloroplasts are tiny structures that are found in the cells of green plants and algae. They contain a green pigment called chlorophyll, which is responsible for capturing light energy from the sun. This energy is then used to convert carbon dioxide and water into glucose, a type of sugar that plants use as food. During photosynthesis, the chloroplasts use a series of chemical reactions to produce glucose and oxygen as byproducts. This process is crucial for the survival of plants, as it provides them with the energy they need to grow and reproduce. Without chloroplasts, plants would not be able to carry out photosynthesis and would eventually die. This is why chloroplasts are considered one of the most important organelles in plant cells.

Gregor Mendel is regarded as the father of ______

Détails de la réponse

Gregor Mendel is regarded as the father of genetics. Mendel was a monk who conducted experiments with pea plants in the mid-19th century. He discovered that certain traits, such as the color of a pea or the height of a plant, are determined by "factors" that are passed down from parent to offspring. These factors are now known as genes, which are made up of DNA and serve as the basic units of heredity. Mendel's experiments and observations led him to formulate the laws of inheritance, which describe how genes are passed down from generation to generation. His work laid the foundation for modern genetics and helped establish the idea that traits are determined by specific genes. Mendel's discoveries had a profound impact on the scientific community and are now recognized as one of the most important breakthroughs in the history of biology. As a result, he is commonly referred to as the father of genetics.

The product after the union of the male and female gamete in animals is called

Détails de la réponse

The product after the union of the male and female gamete in animals is called a zygote. A gamete is a specialized reproductive cell, either a sperm in males or an egg in females, that contains half the number of chromosomes as a regular body cell. When a sperm and an egg join together during fertilization, they form a single cell called a zygote, which has the full number of chromosomes and contains all the genetic information necessary to form a new organism. The zygote then divides and grows into an embryo, which will eventually develop into a mature animal.

Size, colour and fingerprints are examples of ______

Détails de la réponse

Size, color, and fingerprints are examples of morphological variation. Morphological variation refers to differences in the physical appearance or structure of individuals within a species. This type of variation can be caused by genetic factors, environmental factors, or a combination of both. In the case of size, genetic factors can determine an individual's height or weight, while environmental factors such as nutrition can also play a role. Color variations can also be influenced by genetics as well as environmental factors such as diet or exposure to sunlight. Fingerprints, on the other hand, are determined by genetic factors and do not change throughout an individual's lifetime. Overall, morphological variation can be used to distinguish individuals within a species, and in some cases, can provide information about an individual's genetic makeup or environmental history.

Détails de la réponse

An example of an organism that exists as a colony is Volvox. Volvox is a green alga that forms spherical colonies made up of hundreds to thousands of individual cells. The cells work together to perform functions such as movement and reproduction, giving the appearance of a single organism. However, each cell is still capable of functioning independently. This is an example of colonial organization, where individuals come together to form a larger entity that acts as a single organism.

Use the diagram to answer the question that follows.

The dentition is found in

Détails de la réponse

Which of the following is an example of active transport?

Détails de la réponse

Although sodium ions are small, their charge prevents them from moving across the cell membrane through simple diffusion. They must be transported using active transport.

The level of organization of Amoeba and Euglena cell is ________?

Détails de la réponse

The level of organization of Amoeba and Euglena cells is "cell." Both Amoeba and Euglena are single-celled organisms, meaning that they are made up of only one cell. This single cell contains all the necessary structures and functions needed to carry out the organism's life processes, such as obtaining nutrients, reproducing, and responding to the environment. Therefore, the level of organization for Amoeba and Euglena cells is at the cellular level. They do not have specialized organs or tissues, nor do they have complex systems of organs working together to carry out specific functions, which are characteristics of higher levels of organization found in more complex organisms.

Carbon (iv) oxide is added to the atmosphere when ________?

Détails de la réponse

Plant build of of organic compounds such as oil, coal and gas is a great source of emission of carbon dioxide into the atmosphere
Human activities such as the burning of oil, coal and gas, as well as deforestation are the primary cause of the increased carbon dioxide concentrations in the atmosphere.
Other source such has respiration by animals, thunderstorm release carbon dioxide in smaller quantities compare to 87% of carbon dioxide emission from plants build-up organic compounds through human activities

The common thing in plant and animal cell is

Détails de la réponse

The common thing that both plant and animal cells have is the nucleus. The nucleus is a membrane-bound organelle that contains the genetic material of the cell, in the form of DNA. It is often called the "control center" of the cell because it regulates all of the cell's activities. Both plant and animal cells have a nucleus, although there are some differences between the two. For example, plant cells have a cell wall and chloroplasts, which animal cells do not have. Animal cells, on the other hand, have centrioles, which plant cells do not have. In summary, while there are many differences between plant and animal cells, the one thing they have in common is the nucleus.

The appendicular skeleton is made up of the

Détails de la réponse

The appendicular skeleton is made up of the girdles and limbs. This means it includes the bones that form the pelvic girdle (the hip bones) and the shoulder girdle (the collarbone and shoulder blade) as well as the bones in the arms and legs. Basically, the appendicular skeleton is everything that is attached to the central part of the skeleton (the axial skeleton) and helps us move our limbs and make our movements more flexible and agile.

The host of Taenia Solium is _________

Détails de la réponse

The host of Taenia solium, also known as the pork tapeworm, is the pig. Taenia solium is a type of tapeworm that can live in the intestines of humans and pigs. Pigs become infected with the tapeworm when they ingest the eggs of the parasite, which can be present in contaminated food or water. Once inside the pig's digestive system, the tapeworm larvae hatch and penetrate the intestinal wall, then migrate to the pig's muscles and form cysts, which can be seen as small white spots in the meat. If a person eats undercooked pork that contains cysts of Taenia solium, they can become infected with the tapeworm. Once inside the human digestive system, the tapeworm can grow up to several meters long and attach itself to the intestinal wall, where it feeds on nutrients from the host's food. Therefore, it is essential to cook pork thoroughly and practice good hygiene to prevent infection with Taenia solium.

The most efficient respiratory structure used by free living protozoan is ________

Détails de la réponse

The most efficient respiratory structure used by free-living protozoa is the body surface. Protozoa are single-celled organisms that are found in a variety of habitats, including freshwater, marine environments, and soil. They need to take in oxygen in order to survive, just like multicellular organisms. The body surface of a protozoan is covered in tiny, hair-like projections called cilia, which create a current of water over the surface of the cell. This current helps to bring oxygen-rich water into contact with the protozoan's body, allowing it to diffuse across the cell membrane and into the cell where it can be used for respiration. This method of respiration is efficient because it takes advantage of the large surface area of the protozoan's body, which allows for a large amount of oxygen to be absorbed. Additionally, the constant movement of the cilia helps to maintain a constant flow of oxygen-rich water over the surface of the cell, ensuring that the protozoan has a continuous supply of oxygen.

Insects that goes through adult stage without becoming pupa are except ________

Détails de la réponse

The first stage of incomplete metamorphosis is the egg. During this time, the insect will hatch into a form called a nymph.

The nymph is basically a small version of the adult insect.

Use the diagram to answer the question that follows:

The structure is adapted for

Détails de la réponse

The possession of scales, laying of eggs with shells and bony structure of the head are characteristics shared by

Détails de la réponse

The possession of scales, laying of eggs with shells, and bony structure of the head are characteristics shared by birds and reptiles. Scales are small, hard, and flattened structures that cover the skin of animals. Both birds and reptiles have scales, although they are modified differently in each group. For example, the scales of birds are found on their legs and feet, and they are made of keratin, which is the same material that makes up our hair and nails. In contrast, the scales of reptiles cover their entire body and are made of a variety of materials, including keratin and bone. Both birds and reptiles lay eggs with shells, which protect the developing embryo and provide a source of nutrients. The shells of bird eggs are hard and calcified, while those of reptile eggs can be hard or leathery, depending on the species. Finally, both birds and reptiles have a bony structure in their head called the skull. The skull protects the brain and provides a surface for muscle attachment. The skulls of birds and reptiles are both specialized for their respective lifestyles, with features such as a beak in birds and a long snout in many reptiles. So, in summary, the possession of scales, laying of eggs with shells, and bony structure of the head are characteristics shared by birds and reptiles.

The flame cells are used for excretion in

Détails de la réponse

A flame cell is a specialized excretory cell found in the simplest freshwater invertebrates, including flatworms (fluke, planaria)

Flame cells function like a kidney, removing waste materials.
Excretion of ammonia waste through the body wall, and is not associated with any specific organs

Red blood cells are also known as _________?

Détails de la réponse

Red blood cells are also known as erythrocytes. Erythrocytes are cells in the blood that are responsible for carrying oxygen from the lungs to the rest of the body, and for carrying carbon dioxide from the body to the lungs to be expelled. They are shaped like disks and have a flexible structure, allowing them to move easily through the narrowest blood vessels. They also contain a protein called hemoglobin, which binds to oxygen and gives red blood cells their characteristic red color.

The host of liver flake are ______?

Détails de la réponse

Liver fluke (Fasciola hepatica) is a parasite affecting a range of livestock and other species. Final hosts in which it can develop to sexual maturity include livestock such as sheep, cattle, horses, pigs, goats, alpacas and deer. People can be infected by eating water cress growing along creeks in fluke-infested country

Erythrocytes are known as ________

Détails de la réponse

Erythrocytes are known as red blood cells. They are called red blood cells because they contain a red pigment called hemoglobin which binds to oxygen and gives blood its red color. Erythrocytes are responsible for carrying oxygen from the lungs to the body's tissues and organs, and they also help transport carbon dioxide from the tissues back to the lungs to be exhaled. Unlike white blood cells (leucocytes) and phagocytes, erythrocytes do not play a direct role in the immune system.

The difference in structure, morphological and behavior of plant and animal is called

Détails de la réponse

Variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).

Variation may be shown in physical appearance, metabolism, fertility, mode of reproduction, behaviour, learning and mental ability, and other obvious or measurable characters.

Which of the following factors can reduce the population of a community?

Détails de la réponse

Predation can reduce the population of a community. Predation refers to the act of one animal killing and eating another. When predators hunt and eat members of a particular population, it can cause a decrease in the number of individuals in that population. For example, a lion preying on a herd of zebras can reduce the number of zebras in the herd over time. When the number of individuals in a population decreases, it can also have a ripple effect on the entire ecosystem. For example, if the zebras in the above example are a primary food source for other predators, those predators may also experience a decrease in their population due to a lack of food. In conclusion, predation is a natural process that can cause a reduction in the population of a community, and it is an important factor in maintaining balance in the ecosystem.

The matured sex cell which takes part in sexual reproduction is referred to as

Détails de la réponse

The matured sex cell which takes part in sexual reproduction is referred to as a gamete. Gametes are specialized cells that are produced by the reproductive organs of an organism, such as the testes in males and the ovaries in females. In humans, the male gamete is called a sperm cell, which is produced in the testes, while the female gamete is called an egg cell or oocyte, which is produced in the ovaries. When a sperm cell and an egg cell fuse together during fertilization, they form a zygote, which is the first cell of a new organism. Therefore, gametes are important in sexual reproduction as they carry genetic information from both parents, and when they unite during fertilization, they form a new individual with a unique combination of genetic traits from both parents.

When an ovary is placed on the receptacle above the other floral parts it is referred to as

Détails de la réponse

When an ovary is placed on the receptacle above the other floral parts, it is referred to as a "superior ovary". In a flower, the ovary is the part that contains the ovules, which will develop into seeds after fertilization. The ovary is typically located at the base of the flower, below the other floral parts like the petals, sepals, and stamens. In some flowers, however, the ovary is situated on top of the receptacle, which is the part of the stem that supports the flower. This type of ovary is called a "superior ovary". It is said to be superior because it is located above the other floral parts. This arrangement of the ovary can have implications for the structure of the rest of the flower. For example, if the petals, sepals, and stamens are attached to the receptacle below the ovary, they are said to be "epigynous". If they are attached to the receptacle above the ovary, they are said to be "hypogynous". These terms refer to the relative positions of the floral parts and can be used to describe the overall structure of the flower.

Which of the following scenarios is an example of cohesion?

Détails de la réponse

Cohesion is an ability of water molecule to stick to one another due to the presence of hydrogen bonding

Nitrogen is released into the atmosphere when ________

Détails de la réponse

Nitrogen is essential to all living systems, which makes the nitrogen cycle one of Earth's most important nutrient cycles.

Atmospheric nitrogen becomes part of living organisms in two ways. The first is through bacteria in the soil that form nitrates out of nitrogen in the air. The second is through lightning. During electrical storms, large amounts of nitrogen are oxidized and united with water to produce an acid that falls to Earth in rainfall and deposits nitrates in the soil.

Use the diagram to answer the question that follows:

The part labelled I is the ________

Détails de la réponse

A bacteria that is spherically shaped is called?

Détails de la réponse

A bacteria that is spherically shaped is called a coccus. Bacteria can come in different shapes, and the shape of a bacterium is used to classify it into different groups. Coccus is a type of bacteria that is rounded or spherical in shape. Examples of coccus bacteria include Staphylococcus, which can cause skin infections, and Streptococcus, which can cause strep throat and other illnesses.

Which of the following is a characteristics of a bacteria except _______?

Détails de la réponse

The characteristic of bacteria that does not fit with the others listed is "they do not cause disease." Bacteria are unicellular microorganisms that can be seen under a microscope. They vary in size, but most range from 0.5 µm to 5 µm in diameter. Bacteria can be grouped according to their cell shape, which can be cocci (spherical), bacilli (rod-shaped), or spirilla (spiral-shaped). While some bacteria can cause disease, not all bacteria are harmful. In fact, many types of bacteria are beneficial and essential for human and environmental health. For example, some bacteria help with digestion, while others are used to break down waste materials. Therefore, it is incorrect to assume that all bacteria are disease-causing organisms.