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jamb biology questions and answers 2024
Ace your jamb biology exam! You need to practice jamb biology past questions with their respective answers because they are essential for your preparation. Past questions assist in revealing the information about exam format together with typical questions and required answer methods. The PDF download of jamb biology past questions is available here together with expert advice for better exam preparation.
jamb biology questions and answers |Question12: Answer:
Question: A tapeworm has no alimentary canal because (A) it is autotrophic (B) it does not feed (C) it absorbs digested food (D) it has no enzymes
Answer:
Topic: Parasitology / Animal Adaptations / Digestive System (Variations)
Explanation: A tapeworm is a parasite that lives inside the intestines of another animal (the host). The host does all the work of digesting food. The tapeworm simply lives bathed in this already digested food. Therefore, it doesn’t need its own mouth, stomach, or intestine (alimentary canal). It can just absorb the digested nutrients directly through its body surface. It’s not autotrophic (making its own food), it definitely feeds (on the host’s digested food), and while it doesn’t need digestive enzymes, the reason it lacks the canal is its absorption strategy.
- Correct Answer: (C) it absorbs digested food
jamb biology questions and answers |Question13:
Question: External ears of mammals consist of (A) pinna and tympanum (B) pinna only (C) pinna and auditory meatus (D) meatus only
Topic: Sensory Organs / Mammalian Anatomy / The Ear
Explanation: The external ear is the part you can see and the tube leading inwards. The fleshy, visible part that collects sound waves is the pinna (or auricle). This leads into the ear canal, called the external auditory meatus. The tympanum (eardrum) is at the end of the auditory meatus and marks the beginning of the middle ear. So, the external ear includes both the pinna and the auditory meatus.
Correct Answer: (C) pinna and auditory meatus
jamb biology questions and answers |Question14:
Question: Jointed skeleton is absent in (A) spider (B) snail (C) spider (D) millipede (Note: Option A and C are identical)
Topic: Skeletal Systems / Invertebrate Zoology / Classification
Explanation: A jointed skeleton, specifically a jointed exoskeleton (a hard outer covering with flexible joints), is characteristic of arthropods. Spiders and millipedes are both arthropods, so they do have jointed skeletons (legs, body segments). A snail is a mollusc. It has a shell (an exoskeleton), but it’s a single piece, not jointed in the way an arthropod’s is. Its movement relies more on muscular contractions and hydrostatic pressure, not jointed limbs attached to the skeleton. (Ignoring the duplicate option A/C).
Correct Answer: (B) snail
jamb biology questions and answers |Question15:
Question: What is the genotype of a child from a man with normal haemoglobin (AA) and a woman who has sickle-cell haemoglobin (SS)? (A) AA (B) SS (C) AS (D) O
Topic: Genetics / Inheritance Patterns / Human Genetics
Explanation: Genotype refers to the combination of alleles (gene versions) an individual has. The man has normal haemoglobin, genotype AA. He can only pass on the ‘A’ allele in his sperm. The woman has sickle-cell haemoglobin, genotype SS. She can only pass on the ‘S’ allele in her eggs. When sperm (A) fertilizes egg (S), the child’s genotype must be AS. This genotype results in sickle-cell trait (usually less severe than sickle-cell anaemia, SS). ‘O’ refers to blood groups, not haemoglobin type here.
Correct Answer: (C) AS
jamb biology questions and answers |Question16:
Question: Fehling’s solution will readily change colour from blue to a reddish colour when it is (A) mixed with sugar solution in the cold (B) warmed by itself (C) mixed with a reducing sugar in the cold (D) warmed with a solution of reducing sugar
Topic: Biochemistry / Food Tests / Carbohydrates
Explanation: Fehling’s solution (or Benedict’s solution, which is similar and more common in schools) is used to test for the presence of reducing sugars (like glucose, fructose, lactose). The test requires two conditions: the presence of a reducing sugar AND heat. When you warm Fehling’s solution (which is blue) with a reducing sugar, a chemical reaction occurs, and the colour changes through green, yellow, orange to a brick-red precipitate. It won’t change colour if warmed alone, or if mixed with the sugar in the cold, or if the sugar is non-reducing (like sucrose).
Correct Answer: (D) warmed with a solution of reducing sugar
jamb biology questions and answers |Question17:
Question: The axial skeleton of a mammal does not include the bones of the (A) skull (B) tail (C) limbs (D) back
Topic: Skeletal System / Mammalian Anatomy
Explanation: The skeleton is divided into two main parts:
Axial Skeleton: Forms the central axis of the body – includes the skull, the vertebral column (backbone, including the tail vertebrae), and the rib cage.
Appendicular Skeleton: Consists of the bones of the limbs (arms and legs) and the girdles (shoulder and pelvic) that attach the limbs to the axial skeleton.
Therefore, the limbs are part of the appendicular skeleton, not the axial skeleton.
Correct Answer: (C) limbs
jamb biology questions and answers |Question18:
Question: Which of the following elements is essential for the formation of haemoglobin? (A) sodium (B) Iron (C) calcium (D) potassium
Topic: Biochemistry / Blood / Respiration / Nutrition (Minerals)
Explanation: Haemoglobin is the protein found in red blood cells that is responsible for carrying oxygen around the body. The ‘haem’ part of haemoglobin is a special molecule that contains an atom of Iron (Fe) right at its center. It is this iron atom that actually binds to the oxygen molecule. Without sufficient iron, the body cannot make enough functional haemoglobin, leading to iron-deficiency anaemia. Sodium and potassium are important for nerves and fluid balance, calcium for bones and muscles.
Correct Answer: (B) Iron
jamb biology questions and answers |Question19:
Question: Which of the following is an example of discontinuous variation? (A) skin (B) colouration (C) left-handedness (D) height (D) weight (Note: Two options labelled (D))
Topic: Genetics / Variation / Evolution
Explanation: Variation refers to the differences between individuals.
Continuous variation: Shows a smooth range of intermediate types (e.g., height, weight, skin colouration intensity – people aren’t just ‘tall’ or ‘short’, there’s a whole range).
Discontinuous variation: Falls into distinct, separate categories with no intermediates (e.g., human blood groups – A, B, AB, or O; or left-handedness vs. right-handedness – while some people are ambidextrous, it’s generally considered distinct categories).
Height and weight clearly show continuous variation. Skin colouration also shows a wide continuous range. Left-handedness fits the definition of discontinuous variation best among these options.
Correct Answer: (C) left-handedness
Question 20:
Most cells in higher animals retain their power of division except (A) germ cells (B) nerve cells (C) erythrocytes (D) leucocytes
Topic: Cell Biology / Tissues / Nervous System
Explanation: Many cells in your body divide to replace old ones or for growth (like skin cells, gut lining cells). Germ cells divide to make sperm or eggs. Leucocytes (white blood cells) can divide, especially during an immune response. Mature erythrocytes (red blood cells) lose their nucleus and cannot divide. However, the question asks about cells retaining the power, implying most do, but some specialized ones lose it. Nerve cells (neurons) become highly specialized after development and, in most cases, lose the ability to divide (they are post-mitotic). While red blood cells don’t divide, they are constantly replaced by dividing precursor cells in the bone marrow. Neurons, once mature, generally don’t get replaced if damaged.
Correct Answer: (B) nerve cells
Question 21:
A severe deficiency of thyroxine results in (A) diabetes mellitus (B) sexual underdevelopment (C) cretinism (D) gigantism
Topic: Endocrine System / Hormones / Human Health
Explanation: Thyroxine is a hormone produced by the thyroid gland, essential for regulating metabolism and normal growth and development. A severe deficiency of thyroxine, especially during infancy and childhood, leads to a condition called cretinism, characterized by stunted physical growth and impaired mental development. Diabetes mellitus is related to insulin and blood sugar. Sexual underdevelopment is usually related to sex hormones. Gigantism is caused by an excess of growth hormone.
Correct Answer: (C) cretinism
Question 22:
The division thallophyta comprises (A) ferns and mosses (B) algae and fungi (C) mosses and liverworts (D) fungi and ferns
Topic: Classification / Plant Kingdom / Algae / Fungi
Explanation: Thallophyta is an older biological classification grouping together organisms with a simple body structure called a thallus – meaning they lack distinct roots, stems, and leaves. This group traditionally included algae and fungi. Modern classification separates Fungi into its own kingdom and places Algae within the Protists or Plants, but historically, they were grouped as Thallophytes due to their simple structure. Ferns are Pteridophytes, mosses and liverworts are Bryophytes.
Correct Answer: (B) algae and fungi
Question 23:
For an animal to have diastema, it must lack (A) incisors (B) molars (C) canines (D) premolars
Topic: Mammalian Anatomy / Digestive System (Dentition) / Adaptations
Explanation: A diastema is a gap between teeth. In mammals, it most commonly refers to the space found in many herbivores (like rodents, rabbits, horses, deer) between the front teeth (incisors) and the cheek teeth (premolars and molars). This gap exists because these animals often have reduced or completely absent canine teeth. The canines would normally sit in that position. This gap is useful for manipulating food.
Correct Answer: (C) canines
Question 24:
Parenchyma cells serve as supporting tissue when they (A) contain crystals (B) become turgid (C) become flaccid (D) lose chloroplasts
Topic: Plant Anatomy & Physiology / Plant Tissues / Water Relations
Explanation: Parenchyma cells are common, relatively unspecialized plant cells involved in photosynthesis, storage, and secretion. They have thin walls. In non-woody parts of plants (like leaves and young stems), these cells provide support when they are full of water. When a plant cell absorbs water, the internal pressure (turgor pressure) pushes the cell membrane against the cell wall, making the cell firm or turgid. Millions of turgid parenchyma cells pressing against each other provide hydrostatic support, keeping the plant part firm. If the cells lose water and become flaccid, the plant wilts.
Correct Answer: (B) become turgid
Question 25:
The mineral nutrient that easily gets leached out of the soil is (A) phosphorus (B) nitrate (C) calcium (D) magnesium
Topic: Ecology / Soil Science / Plant Nutrition / Biogeochemical Cycles (Nitrogen Cycle)
Explanation: Leaching is the process where water moving through the soil dissolves nutrients and carries them downwards, potentially out of reach of plant roots. Soil particles typically have negative charges. Positively charged ions (cations) like calcium (Ca2+) and magnesium (Mg2+) are held reasonably well by the soil. Phosphorus (often as phosphate, PO4 3-) tends to bind tightly to soil particles. Nitrate (NO3-), however, is negatively charged. Because like charges repel, nitrate ions are not held well by the negatively charged soil particles and are very soluble in water, making them easily leached out by rainfall or irrigation.
Correct Answer: (B) nitrate
Question 26:
Hydra removes undigested food by (A) passing it through the mouth (B) passing it through the anus (C) passing it through the body surface (D) passing it through its contractile vacuole
Topic: Invertebrate Zoology / Animal Physiology / Digestive Systems (Variations)
Explanation: Hydra has a very simple body plan – basically a sac with tentacles around an opening. This single opening serves as both the mouth (for taking food in) and the anus (for expelling undigested waste). It has a gastrovascular cavity where digestion occurs, but no separate exit. Waste materials are simply ejected back out through the mouth. Contractile vacuoles are mainly for water balance (osmoregulation) in freshwater protozoa.
Correct Answer: (A) passing it through the mouth
Question 27:
A feature which adapts birds to flight is the possession of (A) scales (B) legs (C) light bones (D) pointed beaks
Topic: Animal Adaptations / Vertebrate Zoology (Birds) / Skeletal System
Explanation: Birds have many adaptations for flight, including feathers, wings, powerful flight muscles, and an efficient respiratory system. A crucial adaptation is reducing weight. Bird bones are often thin-walled and hollow, or contain internal struts (pneumatized bones), making them very light but still strong. Scales are found on their legs (a remnant of reptilian ancestry). Legs are for perching/walking. Beak shape relates to diet, not directly to flight mechanics.
Correct Answer: (C) light bones
Question 28:
The gill rakers of fishes take part in (A) feeding (B) cellular respiration (C) swimming (D) diffusion
Topic: Vertebrate Zoology (Fish) / Respiratory System / Feeding Mechanisms
Explanation: Gills are used for breathing (gas exchange via diffusion across gill filaments). However, attached to the inner edge of the gill arches (the bony or cartilaginous supports for the gills) are projections called gill rakers. These act like a sieve or strainer. As water flows over the gills, the gill rakers prevent food particles (like plankton or debris) from escaping the mouth or clogging the delicate gill filaments. They help channel food towards the oesophagus. So, they are primarily involved in feeding.
Correct Answer: (A) feeding
- Question: Epigeal germination can be found in (A) sorghum (B) maize (C) millet (D) groundnut
- Topic: Plant Reproduction / Seeds and Germination
- Explanation: Germination is how a seed sprouts. There are two main types:
- Hypogeal: The cotyledons (seed leaves) remain below ground (hypo = below, geal = earth). The epicotyl (part of stem above cotyledons) elongates. Typical of monocots like maize, sorghum, millet, wheat, and some dicots like peas.
- Epigeal: The hypocotyl (part of stem below cotyledons) elongates, pulling the cotyledons above ground (epi = above). Typical of beans, sunflower, castor oil, and groundnut (peanut), which is a dicot.
- Correct Answer: (D) groundnut
- Question: The greatest contribution to genetic studies was made by (A) Robert Hooke (B) Gregor Mendel (C) Charles Darwin (D) Thomas Morgan
- Topic: Genetics / History of Biology
- Explanation: While all listed scientists made huge contributions, Gregor Mendel is considered the “Father of Genetics.” Through his meticulous experiments with pea plants in the mid-1800s, he discovered the fundamental principles of heredity – how traits are passed from parents to offspring through discrete units (now called genes), concepts of dominance, segregation, and independent assortment. Hooke discovered cells. Darwin developed the theory of evolution by natural selection. Morgan established the chromosome theory of inheritance (linking Mendel’s factors to chromosomes). Mendel’s work was the foundation upon which modern genetics is built.
- Correct Answer: (B) Gregor Mendel
- Question: Neurons that receive stimuli from the body or internal organs are called (A) motor neurons (B) sensory neurons (C) efferent neurons (D) relay neurons
- Topic: Nervous System / Neurons
- Explanation: Neurons are nerve cells. They have different roles:
- Sensory neurons (or afferent neurons): Detect stimuli (light, sound, touch, temperature, internal changes) from sensory receptors in the body and transmit signals towards the central nervous system (brain and spinal cord).
- Motor neurons (or efferent neurons): Carry signals away from the central nervous system to effectors (muscles or glands) to cause a response.
- Relay neurons (or interneurons): Found within the central nervous system, they connect sensory neurons to motor neurons or other relay neurons.
- So, neurons receiving stimuli are sensory neurons.
- Correct Answer: (B) sensory neurons
- Question: Which of the following stores carbohydrate as glycogen? (A) spirogyra (B) Mangifera (C) Rattus (D) Chlamydomonas
- Topic: Biochemistry / Carbohydrates / Animal Physiology / Plant Physiology
- Explanation: Organisms store excess carbohydrates for later energy use. Plants (like Mangifera – mango tree) and algae (Spirogyra, Chlamydomonas) typically store carbohydrates as starch. Animals (like Rattus – rat) store carbohydrates primarily as glycogen. Glycogen is stored mainly in the liver and muscle cells.
- Correct Answer: (C) Rattus
- Question: The sex-linked defect in which very slight cut produces severe bleeding is known as (A) anaemia (B) anorexia (C) haemophilia (D) haemolysis
- Topic: Genetics / Human Genetics / Blood Disorders
- Explanation: Haemophilia is a genetic disorder, usually inherited as a sex-linked trait (linked to the X chromosome), where the blood lacks certain clotting factors. This means that even minor injuries can result in prolonged bleeding because the normal process of blood clot formation is impaired. Anaemia is a deficiency of red blood cells or haemoglobin. Anorexia is an eating disorder. Haemolysis is the breakdown of red blood cells.
- Correct Answer: (C) haemophilia
- Question: A band of connective tissue linking two bones in a joint is known as (A) tendon (B) cartilage (C) synovial membrane (D) ligament
- Topic: Skeletal System / Tissues / Joints
- Explanation: Joints are where bones meet. Several types of connective tissue are involved:
- Ligaments: Strong, fibrous bands that connect bone to bone, helping to stabilize the joint.
- Tendons: Tough cords that connect muscle to bone.
- Cartilage: Smooth, flexible tissue that covers the ends of bones in a joint, reducing friction.
- Synovial membrane: Lines the joint capsule and secretes synovial fluid for lubrication.
- The tissue linking bone to bone is a ligament.
- Correct Answer: (D) ligament
- Question: The speed of the wind can be measured with an instrument called (A) anemometer (B) hydrometer (C) wind vane (D) barometer
- Topic: Ecology / Meteorology / Scientific Instruments
- Explanation: These are all measuring instruments:
- Anemometer: Measures wind speed. Often looks like cups spinning on an axis.
- Hydrometer: Measures the density or specific gravity of liquids.
- Wind vane: Shows wind direction. Often shaped like an arrow.
- Barometer: Measures atmospheric pressure.
- Therefore, wind speed is measured by an anemometer.
- Correct Answer: (A) anemometer
- Question: The organism that has a hydrostatic skeleton is (A) tilapia (B) Hydra (C) earthworm (D) Lizard
- Topic: Skeletal Systems / Invertebrate Zoology
- Explanation: A hydrostatic skeleton is a system where support and movement are achieved by using fluid pressure within a confined body cavity. Muscles contract against this incompressible fluid, causing changes in shape and allowing movement. While Hydra uses fluid to maintain some shape, the classic example of a well-developed hydrostatic skeleton among these options is the earthworm. Its segmented body contains fluid-filled compartments (coelom), and coordinated muscle contractions against this fluid allow it to burrow and move. Tilapia (fish) and Lizard (reptile) have bony internal skeletons (endoskeletons).
- Correct Answer: (C) earthworm
- Question: Fertilization in humans usually takes place in the (A) lower part of the uterus (B) upper part of the uterus (C) lower part of the oviduct (D) upper part of the oviduct
- Topic: Human Reproduction / Fertilization
- Explanation: After ovulation, the egg travels into the oviduct (also called the fallopian tube). Sperm travel up through the uterus and into the oviducts. Fertilization, the fusion of sperm and egg, normally occurs in the upper part of the oviduct, specifically in a widened section called the ampulla, which is closer to the ovary. The fertilized egg (zygote) then begins to divide and travels down the oviduct to implant in the wall of the uterus a few days later.
- Correct Answer: (D) upper part of the oviduct
- Question: In mammalian males, the excretory and reproductive systems share the (A) ureter (B) testes (C) vas deferens (D) urethra
- Topic: Excretory System / Reproductive System / Mammalian Anatomy
- Explanation: Let’s trace the paths:
- Excretory: Kidneys produce urine -> ureters carry urine to the bladder -> urethra carries urine from the bladder out of the body.
- Reproductive (male): Testes produce sperm -> epididymis stores sperm -> vas deferens carries sperm -> ejaculatory ducts join the urethra -> semen (sperm + fluids) exits through the urethra.
- In males, the urethra is the common passageway for both urine and semen, serving both the excretory and reproductive systems. In females, the urethra (excretory) and vagina (reproductive) have separate openings.
- Correct Answer: (D) urethra
- Question: The dominant phase in the life cycle of a bryophyte is the (A) gametangium (B) sporophyte (C) gametophyte (D) prothallus
- Topic: Plant Kingdom (Bryophytes) / Plant Life Cycles / Alternation of Generations
- Explanation: Plants have a life cycle called “alternation of generations,” switching between a haploid (n) stage and a diploid (2n) stage.
- Gametophyte (n): Produces gametes (sperm and eggs).
- Sporophyte (2n): Produces spores (through meiosis).
- In Bryophytes (mosses, liverworts, hornworts), the gametophyte is the dominant generation. This is the green, leafy (or flattened) plant that you typically see. It’s photosynthetic and lives longer. The sporophyte grows out of the gametophyte and is dependent on it for nutrition, usually appearing as a stalk and capsule. Gametangia are the structures on the gametophyte that produce gametes. Prothallus is the term for the gametophyte in ferns.
- Correct Answer: (C) gametophyte
- Question: In the mammalian kidney, the Bowman’s capsule is located in the (A) ureter (B) pelvis (C) cortex (D) medulla
- Topic: Excretory System / Kidney Anatomy & Function / The Nephron
- Explanation: The kidney has distinct regions. The outer region is the cortex, the inner region is the medulla, and the central collecting area is the pelvis (which leads to the ureter tube). The functional unit of the kidney is the nephron. Each nephron starts with a filtering unit called the renal corpuscle, which consists of the glomerulus (a ball of capillaries) surrounded by the Bowman’s capsule. This entire filtering structure, along with the convoluted tubules (proximal and distal), is located in the cortex of the kidney. The loops of Henle and collecting ducts dip down into the medulla.
- Correct Answer: (C) cortex
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