WAEC SSCE - Biology - 2014

In which of the following yam tissues will osmosis occur?

Détails de la réponse

Osmosis is the movement of water molecules from an area of higher concentration to an area of lower concentration through a semi-permeable membrane. In the context of yam tissues, osmosis will occur in those tissues that are separated from their environment by a semi-permeable membrane. Out of the given options, the tissues that are most likely to undergo osmosis are the raw and peeled yam tissues. This is because the raw yam tissues have intact cell membranes which act as semi-permeable membranes, allowing the movement of water molecules in and out of the cells through osmosis. Additionally, peeling the yam removes the waxy cuticle layer which further enhances the permeability of the cell membrane to water molecules. On the other hand, boiling and roasting alter the cell structure of the yam tissues, making them less likely to undergo osmosis. Boiling and roasting cause the cell walls to rupture and lose their semi-permeable nature, which makes it difficult for water molecules to move in and out of the cells through osmosis. In summary, osmosis is most likely to occur in the raw and peeled yam tissues, as they have intact cell membranes that act as semi-permeable membranes. The boiled and unpeeled yam tissues may also undergo osmosis, but to a lesser extent due to the alteration of the cell walls caused by boiling. The roasted and peeled yam tissues are the least likely to undergo osmosis due to the complete alteration of the cell structure caused by roasting.

In a Biuret test , some protein was mixed with sodium hydroxide solution. Which of the following chemicals should be added to the mixture for a positive result?

Détails de la réponse

To conduct a Biuret test, after adding sodium hydroxide to the protein solution, copper sulphate should be added to the mixture for a positive result. This is because the Biuret test is a colorimetric test used to detect peptide bonds in proteins. When copper (II) ions react with peptide bonds in an alkaline solution, a complex is formed that results in a violet or purple color. Therefore, the presence of copper sulphate in the protein-sodium hydroxide mixture is necessary for the test to detect the presence of protein.

Which of the following statements about the circulation of water in nature is not correct? Water

Détails de la réponse

The statement that is not correct about the circulation of water in nature is "removed from ocean is permanently lost". This is incorrect because water removed from the ocean through evaporation is not permanently lost, but rather it goes through the water cycle, which is the continuous movement of water on, above, and below the surface of the Earth. The water cycle involves the evaporation of water from oceans, lakes, and rivers, which then forms clouds in the atmosphere. These clouds then release water in the form of precipitation (rain, snow, sleet, or hail) which falls on the land surface and replenishes rivers, lakes, and groundwater. Therefore, the water that evaporates from the ocean is not permanently lost but rather becomes part of the Earth's water cycle.

Which of the following is a living organism?

Détails de la réponse

Yeast is a living organism. Yeast is a type of fungus that belongs to the Kingdom Fungi. It is a unicellular organism, meaning it is made up of a single cell, and it can reproduce asexually by budding. Yeast is commonly used in baking and brewing because it can convert sugar into alcohol and carbon dioxide through a process called fermentation. In addition to being used in food production, yeast is also used in scientific research as a model organism to study genetics and cell biology.

The following habitats can be found in West Africa except

Détails de la réponse

The correct option is "temperate grassland". West Africa is known for its diverse ecological zones, which include mangrove swamps, Sahel savanna, and savanna grassland. However, temperate grasslands are not found in West Africa. Temperate grasslands are typically located in regions with a continental climate and moderate rainfall, such as the Great Plains in North America, the Pampas in South America, and the steppes of Eurasia. They are characterized by vast expanses of grasses and few trees, with hot summers and cold winters. In contrast, West Africa is located near the equator and has a tropical climate, with high temperatures and distinct wet and dry seasons.

Which of the following statements about chromosomes is correct?

Détails de la réponse

The correct statement about chromosomes is that the chromosome number present in a species is constant. Chromosomes are thread-like structures found in the nucleus of a cell and carry genetic information in the form of DNA. Each species has a specific number of chromosomes, and this number is constant within the species. For example, humans have 46 chromosomes, dogs have 78 chromosomes, and cats have 38 chromosomes. Chromosomes vary in size, shape, and arrangement, and they are not neatly arranged in the cytoplasm. The outer membrane of the nucleus bears nuclear pores, which allow molecules such as RNA to move in and out of the nucleus, but not ribosomes. The ability to bear ribosomes is a characteristic of the rough endoplasmic reticulum, which is an organelle involved in protein synthesis.

The amount of starch in a germinating seed decreases because the starch is used up

Détails de la réponse

During germination, the embryo in a seed grows into a new plant. In order for the embryo to grow, it needs energy and building materials. The energy is obtained through respiration, which breaks down stored food molecules such as starch into smaller molecules that can be used by the plant. Therefore, the starch in the seed is used up as a source of energy for respiration and for building new cells as the plant grows. This is why the amount of starch in a germinating seed decreases. The other options, building cellulose cell wall, developing meristematic tissues, and producing enzymes, may require energy and building materials, but do not directly lead to the breakdown of starch.

Which of the following substances constitute domestic waste?
I Fertilizer II. Insecticides III. Sewage IV. Crude oil
V. Sulphur dioxide

Détails de la réponse

Lamarck's theory of evolution is based on the fact that

Détails de la réponse

Lamarck's theory of evolution is based on the idea that organisms can acquire new traits during their lifetime through use or disuse of certain body parts, and that these acquired traits can be passed down to their offspring. In other words, Lamarck believed that an organism can change its characteristics over time, and those changes can be inherited by its offspring. This is known as the theory of inheritance of acquired characteristics. However, this theory has been largely discredited by modern science, as it is now understood that genetic information is only passed down through DNA, and not through changes that occur during an organism's lifetime.

Which of the following organisms is not a social insect?

Détails de la réponse

Grasshoppers are not social insects. Social insects are those that live in highly organized colonies or communities where there are divisions of labor, communication, and cooperation among individuals. Examples of social insects include termites, ants, and bees. Grasshoppers, on the other hand, are solitary insects that do not live in colonies or exhibit social behavior.

The inability to maintain proper balance of the body in humans may be due to a defect in the

Détails de la réponse

The inability to maintain proper balance of the body in humans may be due to a defect in the Semi-circular canals. The Semi-circular canals are three fluid-filled tubes located in the inner ear that are responsible for maintaining balance and detecting head movements. When the head moves, the fluid in the canals moves, which sends signals to the brain to help the body maintain its balance. If there is a defect in the semi-circular canals, it can affect the normal functioning of the balance system and cause balance problems such as vertigo, dizziness, and unsteadiness.

l. Fertilizer II. Insecticides III. Sewage IV. Crude oil V. Sulphur dioxide. The atmosphere can polluted by

Détails de la réponse

The legs of an accident victim with a fractured vertebral column and injured spinal cord could not be raised because

Détails de la réponse

Which of the following cell inclusions can destroy other cell organelles?

Détails de la réponse

Lysosome is the cell inclusion that can destroy other cell organelles. Lysosomes are membrane-bound organelles that contain enzymes capable of breaking down biomolecules. They function as the cell's digestive system, breaking down worn-out organelles, cell debris, and foreign substances that have been ingested by the cell. In the process of autophagy, lysosomes also degrade and recycle old or damaged cell components. Therefore, lysosomes have the ability to destroy other cell organelles.

The difference between a community and population is

Détails de la réponse

The correct answer is: a community is made up of populations of living organisms while a population is made up of organisms of the same species. A population refers to a group of individuals of the same species living in a particular area at a particular time, while a community refers to all the populations of different species living in a particular area at a particular time. For example, a population can refer to all the lions in a particular game reserve, while the community would include all the different species of organisms living in the same game reserve, such as lions, zebras, giraffes, and many others. Therefore, the main difference between a community and a population is that a community includes different populations of different species, while a population includes individuals of the same species.

A small stem from a hibiscus plant was placed in a nutrieent medium, and it developed into a new plant. The new plant was reproduced

Détails de la réponse

The new plant reproduced asexually with the same genotype as the parent plant. This process is called vegetative propagation, where a new plant is produced from a vegetative part of the parent plant (in this case, a stem) without the involvement of gametes or fertilization. The new plant is essentially a clone of the parent plant and has the same genetic makeup.

Which of the following organisms is the most specialized ?

Détails de la réponse

Rhizopus is the most specialized organism among the given options. Rhizopus is a fungus that belongs to the class Zygomycetes, and it is characterized by the formation of a specific structure called a zygospore during sexual reproduction. Rhizopus is also known for its ability to grow and spread rapidly on organic materials, and it is commonly found on bread, fruits, and other decaying plant matter. In contrast, paramecium, amoeba, and spirogyra are all unicellular organisms that lack specialized tissues and organs, making them less specialized than Rhizopus.

The following organisms are consumers except

Détails de la réponse

The F1 generation of a cross between a red cock and white hen were all red because the gene for the

Détails de la réponse

In genetics, the physical appearance or trait expressed by an organism is determined by the alleles it inherits from its parents. Alleles are different versions of the same gene, and they can be either dominant or recessive. In this case, the F1 generation (first filial generation) of a cross between a red cock and white hen were all red, which means that they inherited the red allele from the red cock parent. The gene for the red color is dominant over the gene for white color, which is recessive. Therefore, in the F1 generation, all the offspring expressed the dominant allele for red color and not the recessive allele for white color, which did not segregate. Thus, the correct option is "red color was dominant".

In the diagram, the part labelled II is the

Détails de la réponse

The part labelled II in the diagram is the contractile vacuole. A contractile vacuole is an organelle found in certain unicellular organisms that helps to regulate water content within the cell. It works by actively pumping excess water out of the cell, which helps to prevent the cell from bursting due to osmotic pressure. The contractile vacuole is easily identified in the diagram due to its spherical shape and proximity to the cell membrane.

In dihybrid inheritance, Mendel considered

Détails de la réponse

In dihybrid inheritance, Mendel considered two pairs of contrasting characters. This means that he studied how two different traits, each with two different variations, are inherited together. For example, he studied pea plants that had different colors for their seeds (yellow or green) and different shapes for their pods (inflated or constricted). By studying how these traits were passed down from generation to generation, Mendel was able to develop his laws of inheritance, which are still used today to understand how traits are passed down from parents to their offspring.

Differences in characteristics that exist among individuals of the same species is referred to as

Détails de la réponse

Differences in characteristics that exist among individuals of the same species is referred to as variation. This means that individuals of the same species can have different traits or features, such as height, weight, color, or behavior. Variation can be influenced by genetic factors, environmental factors, or a combination of both. The presence of variation is important for the process of natural selection, which allows individuals with advantageous traits to survive and reproduce, while individuals with less advantageous traits are less likely to survive and pass on their genes to the next generation.

Active transport can be defined as the movement of

Détails de la réponse

Older parts of plant roots do not normally absorb water because

Détails de la réponse

Older parts of plant roots do not normally absorb water because they lack root hairs. Root hairs are tiny protrusions from the epidermal cells of the root that increase the surface area for water and mineral absorption. As roots get older, the root hairs wear out and do not regenerate, leading to reduced surface area and a decrease in the plant's ability to absorb water and minerals. However, the xylem, which transports water and minerals, is present in the entire length of the root, including the older parts.

In the diagram, the young proglottid is represented by

Détails de la réponse

The following events occur during mitosis in a cell:
I. Chromatids separate;
II. Chromosomes become visible;
III. Chromosomes align at the equator
IV. Cytoplasm divides (Cytokinesis):
The correct sequence of the events is

Détails de la réponse

The correct sequence of events during mitosis is: II. Chromosomes become visible; III. Chromosomes align at the equator; I. Chromatids separate; IV. Cytoplasm divides (Cytokinesis). This means that first, the chromosomes become visible, then they align at the equator, then the chromatids separate, and finally, the cytoplasm divides to form two daughter cells.

Which of the following natural resources is non-renewable?

Détails de la réponse

Coal is a non-renewable natural resource. This means that once it is extracted from the earth and used, it cannot be replenished or replaced within a human lifespan. Coal takes millions of years to form, and therefore it is not considered a sustainable resource. In contrast, resources such as water and air are renewable, as they can be replenished naturally over time. Forests can be renewable if they are managed sustainably, but if they are over-harvested or destroyed, it can take many years for them to regrow and function as they did before.

An inferior ovary of a flower is situated

Détails de la réponse

An inferior ovary of a flower is situated below the floral parts. In a flower, the ovary is the structure that contains the ovules and later develops into a fruit. If the ovary is inferior, it means that it is located beneath the attachment point of the other floral parts such as the petals, sepals, and stamens. The inferior ovary is often surrounded by a floral tube formed by the fusion of the sepals, petals, and stamens. This is in contrast to a superior ovary, which is located above the attachment point of the other floral parts.

Which of the following conditions in flowering plants enhance self-pollination?

Détails de la réponse

Among the options provided, the condition that enhances self-pollination in flowering plants is cleistogamy. Cleistogamous flowers are self-fertile and never open, meaning the anthers and stigma are in close proximity to facilitate self-pollination. This adaptation is useful in ensuring successful reproduction even when pollinators are scarce or absent. Heterostyly, protandry, and protogyny are mechanisms that promote cross-pollination. Heterostyly involves the presence of flowers with different style and stamen lengths, which promotes cross-pollination between different plants. Protandry is the condition where the anthers mature before the stigma, while protogyny is the opposite condition where the stigma matures before the anthers. Both conditions promote cross-pollination as they encourage the plant to receive pollen from a different plant or source.

Which of the following statements about asexual reproduction is correct? It

Détails de la réponse

The correct statement about asexual reproduction is that it always involves one parent and the offspring is genetically identical to the parent. In asexual reproduction, a single parent organism produces offspring that are genetically identical to itself, without the involvement of gametes or the fusion of nuclei. This type of reproduction is common in simple organisms like bacteria, protists, and some plants. The offspring produced through asexual reproduction have the same DNA as the parent organism, which means they are genetically identical. This process helps to maintain the characteristics of a particular species over time.

Which of the following diseases can be inherited?

Détails de la réponse

Out of the options given, sickle cell anemia is the disease that can be inherited. Sickle cell anemia is an inherited genetic disorder that affects the red blood cells. It is caused by a mutation in the HBB gene that provides instructions for making a protein called hemoglobin, which carries oxygen in the blood. In sickle cell anemia, the mutation leads to the production of abnormal hemoglobin, which causes the red blood cells to become rigid, sticky and sickle-shaped. These cells can block small blood vessels, leading to pain, organ damage, and other complications. Sickle cell anemia is an example of an inherited disease, meaning it is passed down from parent to child through their genes.

Characteristics that exhibit continuous variation are generally controlled by

Détails de la réponse

Characteristics that exhibit continuous variation are generally controlled by multiple genes. Continuous variation refers to traits that can vary along a continuous range, such as height or weight. These traits are not controlled by a single gene, but rather by the combined effects of multiple genes, often with additive effects. This is why the distribution of traits in a population tends to follow a bell-shaped curve, with most individuals clustering around the average and fewer individuals at the extremes.

In the diagram, the part responsible for photosynthesis is labelled

Détails de la réponse

The purpose of treating poor soil with lime is to increase the quantity of

Détails de la réponse

Which of the following statement is not a reason for banning bush burning? It

Détails de la réponse

The correct answer is "allows for quick regrowth of grasses". This statement does not provide a reason for banning bush burning. In fact, it suggests that bush burning could be beneficial for the regrowth of grasses. However, the other options provide reasons for banning bush burning, such as killing soil microorganisms, leaving the soil bare of vegetation, and burning off organic soil nutrients.

The following substances pass into the blood of the foetus from the mother's blood via the placenta except

Détails de la réponse

The placenta is an organ that connects the mother's blood supply to the developing foetus, allowing for the exchange of nutrients, oxygen, and waste products. Carbon dioxide and glucose are two examples of substances that pass from the mother's blood into the foetus's blood through the placenta. However, viruses do not pass from the mother's blood to the foetus's blood through the placenta. Similarly, antibodies, which are produced by the mother's immune system, can cross the placenta and provide passive immunity to the foetus against certain infections, so they also pass from the mother's blood to the foetus's blood through the placenta.

Which of the following traits is not a morphological variation in humans?

Détails de la réponse

The trait that is not a morphological variation in humans is the ability to taste PTC. PTC is a chemical substance that is either bitter or tasteless to people depending on their genetic makeup. While colour, fingerprints, and size are physical traits that can vary among individuals, the ability to taste PTC is not a visible or physical characteristic. Instead, it is determined by a person's genetic makeup, specifically a gene called TAS2R38. Therefore, the ability to taste PTC is not considered a morphological variation, but rather a genetic variation.

Which of the following processes is not a function of the mammalian skin?

Détails de la réponse

Gaseous exchange is not a function of mammalian skin. Mammalian skin is made up of multiple layers, with the outermost layer being the epidermis, which is impermeable to gases. Therefore, it cannot facilitate gaseous exchange. Instead, gaseous exchange in mammals occurs through the respiratory system, which includes the lungs and associated structures. In contrast, the other options mentioned are all functions of the mammalian skin. The skin helps regulate body temperature through processes such as sweating and blood vessel dilation/contraction. The skin also contains sensory receptors that allow for the reception of external stimuli such as touch, pressure, and temperature. Additionally, the skin can excrete waste products such as salts, water, and small amounts of urea through sweat glands.

The main reason for nuptial flight in termites is to

Détails de la réponse

Nuptial flight in termites is a behavior that involves the winged reproductive individuals leaving their parent colony to mate and start new colonies. The main reason for nuptial flight in termites is to form new colonies. During nuptial flight, male and female reproductive termites leave the parent colony and fly together in search of a suitable site for starting a new colony. Once they find a suitable site, they shed their wings and mate, after which the female starts to lay eggs and establish a new termite colony. Therefore, the main reason for nuptial flight in termites is to ensure the survival and propagation of the species through the formation of new colonies.

A meal consisting of yam and a lot of vegetables is not balanced because it does not contain

Détails de la réponse

A meal consisting of yam and a lot of vegetables is not balanced because it does not contain enough proteins. While yam and vegetables are good sources of carbohydrates, vitamins, and minerals, they lack significant amounts of protein. Proteins are essential nutrients that play a crucial role in building and repairing body tissues, enzymes, and hormones. A balanced meal should contain a variety of foods from different food groups, including carbohydrates, proteins, vitamins, and minerals, in the right proportions.

The following adaptations are associated with the flight of birds except

Détails de la réponse

Among the adaptations listed, the one that is not associated with the flight of birds is "clawed digits." Birds have evolved many adaptations to enable them to fly, including reduced body weight, streamlined shape, and powerful muscles. Reducing body weight makes it easier for birds to take off and stay in the air, while their streamlined shape reduces air resistance and allows for more efficient flight. Birds also have powerful muscles that enable them to flap their wings and generate lift. However, clawed digits are not necessary for flight and are not typically associated with this adaptation. Instead, birds have evolved specialized feet and toes that are adapted for perching, walking, and capturing prey.

A characteristic feature of plant parasites is the

Détails de la réponse

A characteristic feature of plant parasites is the development of haustoria. Haustoria are specialized organs that penetrate the host plant's tissue and allow the parasite to absorb nutrients and water from the host plant. This is a common adaptation seen in parasitic plants, such as mistletoe and dodder. Possession of holdfast, rhizoids or development of hanging roots are not necessarily associated with parasitism but may be adaptations for anchoring or absorbing nutrients in non-parasitic plants.

The excretory product in protozoans is

Détails de la réponse

Protozoans are single-celled organisms that carry out various life processes. Like other living things, they produce waste products, which must be excreted from their bodies to maintain the proper internal environment. The excretory product in protozoans is usually ammonia, a compound that is produced when proteins are broken down during cellular metabolism. Ammonia is highly toxic to cells and needs to be excreted quickly to avoid damaging the organism. Therefore, protozoans have specialized structures that help them get rid of excess ammonia, such as contractile vacuoles or diffusion through the cell membrane. Other excretory products such as urea, uric acid or amino acids are commonly found in more complex organisms with more advanced excretory systems.

The part of a leguminous plant where bacteria like Azotobacter can be found is

Détails de la réponse

Bacteria like Azotobacter are found in the root nodules of leguminous plants. Leguminous plants, such as beans, peas, and peanuts, have a symbiotic relationship with certain bacteria, including Azotobacter. The bacteria are able to take nitrogen gas from the air and convert it into a form of nitrogen that the plant can use for growth, in exchange for carbohydrates that the plant produces. The root nodules of the leguminous plant provide a suitable environment for the bacteria to live and carry out this process, which is important for the growth and development of the plant. Therefore, the correct option is "in the root nodules".

TEST OF PRACTICAL KNOWLEDGE QUESTION

Observe specimens A, B, C and D closely and use them to answer questions 1(a) to 1(e).

(a)(i) Specimen A Into its division and class.

(ii) State three observable features of specimen A which are characteristics of the class mentioned in 1(a)(i) above.

(b) State the relationship between specimen A and: (i) specimen B; (ii) specimen C; (iii) specimen D.

 (c)(i) From. your observations of specimens B and C, what type of plant is specimen A? (ii) Suggest the agent of pollination ot specimen B.

(iii) State two reasons for the answer in 1(c)(i) above.

(d) Classify specimen D fully according to origin and structure.

 (e) Make a drawing 8 cm 10 cm long of specimen C and label fully.

Détails de la réponse

None

TEST OF PRACTICAL KNOWLEDGE QUESTION

(a) Study specimens E and F carefully and use them to answer questions 2(a)(i) to 2(a)(ii).

(i) State the Class to which each of specimens E and F belong.

(ii) List four observable features each of specimens E and F. 

(iii) State how each of the observed features in 2(a)(i) adapt each of specimens E and F to their habitats. 

(b) Study specimen G and use it to answer questions 2(b)(i) to 2(b)(ii).

(i) Classify specimen G into its phylum and class.

(ii) State four observable features of specimen C. 

(iii) Name one habitat of specimen C.

Détails de la réponse

None

TEST OF PRACTICAL KNOWLEDGE QUESTION

Study specimens L, M and N carefully and use them to answer questions 4(a) to 4(c).

(a)(i) State the habitats of specimens L, M and N.

(ii) State the modes of nutrition of specimens L. M and N.

(iii) Explain how each of specimens Land M are adapted to their modes of feeding. 

(b)(i) Describe briefly the relationship that exists among specimens L, M and N.

(ii) State two ways in which specimen M is of economic importance.

 (iii) State one way in which specimen M can be controlled.

(c) Make a drawing 8cm - 10cm long of specimen M and label fully.

Détails de la réponse

None

(a)(i) Explain the term co-ordinance.

(ii) Calculate the number of individuals with co-dominant blood group. 

(iii) What is the total number of individuals in the table that are able to donate blood to an accident victim with blood group B?

(b) A man whose blood group is heterozygous A is married to a 
woman whose blood group is AB. With the aid of a genetic diagram, suggest the possible blood groups of their children.

A survey to determine blood groups was carried out on 250 people living in a community. The results are represented in the table below. 

Détails de la réponse

None

 (a) State five reasons why animals move from place to place.

(b) State one function each of the following structures found in plants:
(i) epidermis
(ii) phloem
(iii) sclerenchyma.

(c) Give two examples each of the following types of organisms:
(i) parasitic plants
(ii) saprophytes.

(d) State two adaptive features of plants which inhabit salt water swamp.

(e) State two factors each which result in
(i) increase
(ii) decrease, in population density.

(f) Mention four ways in which modern agricultural activities may threaten the survival of species.

(g) State three reasons why mitosis is important to living organisms

(h) State three causes of food spoilage. 
 

Détails de la réponse

None