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Part 079 – Biology Previous Year Questions

Q1. The animal which uses sounds as its ‘eyes’ is
(a) Dog (b) Cat
(c) Snake (d) Bat
Ans: (d) Bat echolocation is a perceptual system where ultrasonic sounds are emitted specifically to produce echoes. By comparing the outgoing pulse with the returning echoes, the brain and auditory nervous system can produce detailed images of the bat’s surroundings. This allows bats to detect, localize and even classify their prey in complete darkness. At 130 decibels in intensity, bat calls are some of the most intense, airborne animal sounds.

Q2. Pregnant women usually become deficient in

(a) Sodium and Calcium
(b) Iron and Sodium
(c) Calcium and Iron
(d) Magnesium and Iron
Ans: (c) When a woman becomes pregnant her body undergoes many physiological changes. Her hormone levels change not only to support the pregnancy but also to help redirect nutrients to support the nutritional demands of the developing baby. During pregnancy, a woman’s blood volume increases 35 percent to 40 percent. Red blood cells contain the protein hemoglobin, which requires the mineral iron. Hemoglobin carries the oxygen to the cells throughout the mother and baby, making iron an important nutrient. Because the plasma volume increases by up to 50 percent but the red blood cells mass increases by only 15 percent to 20 percent, the risk of developing iron-deficiency anemia increases during pregnancy. Calcium needs increase during pregnancy to support the growth and development of the baby’s bones and teeth. Fai l ing to consume the recommended 1,200 mg of calcium per day can cause body to pull calcium from the pregnant woman’s bones to use for the baby. This increases the risk of developing osteoporosis, a disease characterized by porous, brittle bones

Q3. Which components of light are absorbed by chlorophyll ?

(a) Violet and red
(b) Indigo and orange
(c) Blue and red
(d) Violet and yellow
Ans: (a) Chlorophyll is a green pigment found in cyanobacteria and the chloroplasts of algae and plants. Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to absorb energy from light. Chlorophyll absorbs light most strongly in the blue portion of the electromagnetic spectrum, followed by the red portion. However, it is a poor absorber of green and near-green portions of the spectrum, hence the green color of chlorophyll-containing tissues.

Q4. Ginger is a stem and not a root because

(a) It stores food material
(b) It grows horizontally in the soil
(c) It has nodes and internodes
(d) It lacks chlorophyll
Ans: (c) Ginger is a modified stem. A rhizome to be exact. A rhizome is a thick horizontally growing stem which usually stores food material. It has nodes and internodes, scale leaves, axillary buds, adventitous roots and a terminal bud. Scale leaves enclosing the axillary buds are seen arising from the nodal points of the stem. Some of the axillary buds develop into branches which grow upwards into the air and then produce normal green foliage leaves. Usually the growing points of the rhizome continue to remain underground causing an elongation of the rhizome. Roots develop from the lower surface of the rhizome. Eg. Ginger, Turmeric.

Q5. Eyes of potato are useful for

(a) Nutrition
(b) Respiration
(c) Reproduction
(d) Vegetative propagation
Ans: (d) Any potato variety can be propagated vegetatively by planting tubers, pieces of tubers, cut to include at least one or two eyes, or also by cuttings, a practice used in greenhouses for the production of healthy seed tubers. Some commercial potato varieties do not produce seeds at all (they bear imperfect flowers) and are propagated only from tuber pieces.

Q6. Taenia solium (Tape worm) lives as a parasite in

(a) Pig
(b) Abdomen of man/woman
(c) Intestine of man/woman
(d) Liver of man/woman
Ans: (c) Tapeworms are flat segmented worms that live in the intestines of some animals. Animals can become infected with these parasites when grazing in pastures or drinking contaminated water. Eating undercooked meat from infected animals is the main cause of tapeworm infection in humans. The adult tapeworm is usually a whopping 15 to 30 feet long (4.5 to 9 meters) and lives in the small intestine. An infected person usually has only one or two worms. The tapeworms use their head, called the scolex, to attach themselves to the intestinal wall.

Q7. An ant can see the objects all around it due to the presence of

(a) Simple Eyes
(b) Eyes over the head
(c) Well-developed eyes
(d) Compound eyes
Ans: (d) Compound eyes are found among the arthropods and are composed of many simple facets which, depending on the details of anatomy, may give either a single pixelated image or multiple images, per eye. Each sensor has its own lens and photosensitive cell(s). Some eyes have up to 28,000 such sensors, which are arranged hexagonally, and which can give a full 360° field of vision. Compound eyes are very sensitive to motion. With each eye viewing a different thing, a fused image from all the eyes is produced in the brain, providing very different, high-resolution images.

Q8. What is the approximate time required for a heart-beat ?

(a) 0.5 second (b) 0.8 second
(c) 0.5 minute (d) 1.0 minute
Ans: (b) The heart has an increasing rhythmic activity. It pumps blood by its contraction and relaxation. The contraction of the heart is called systole and the relaxation is called diastole. The contraction and relaxation together constitute the heart beat. The heart beats at the rate of 72 beats per minute. There are 3 main events in the cardiac cycle. Auricular Systole (Atrial Systole) phase involves the contraction of the 2 auricles, pushing the blood into the respective ventricles. The atrial systole takes 0.1 second. Ventricular Systole takes about 0.3 seconds. Ventricular systole is followed by ventricular diastole. The auricles are already in diastole, so all the chambers of the heart are in diastole. A complete cardiac diastole takes only 0.4 seconds. An entire cardiac cycle is completed in 0.8 seconds.

Q9. Who discovered the Cholera-bacillus ?

(a) Louis Pasteur
(b) Ronald Ross
(c) Robert Koch
(d) Joseph Lister
Ans: (c) Robert Kach was a German physician. He became famous for isolating Bacillus anthracis (1877), the Tuberculosis bacillus (1882) and Vibrio cholerae (1883) and for his development of Koch’s postulates. He was awarded the Nobel Prize in Physiology or Medicine in 1905 for his tuberculosis findings. He is considered one of the founders of microbiology.

Q10. Which of the following animals has the longest life span ?

(a) Elephant (b) Crocodile
(c) Dog (d) Tortoise
Ans: (d) Tortoises generally have lifespans comparable with those of human beings, and some individuals are known to have lived longer than 150 years. Because of this, they symbolize longevity in some cultures, such as China. The oldest tortoise ever recorded, and one of the oldest individual animals ever recorded, was Tu’i Malila, which was presented to the Tongan royal family by the British explorer Captain Cook shortly after its birth in 1777.

Q11. Which animal produces the biggest baby ?

(a) Camel (b) Lion
(c) Elephant (d) Blue Whale
Ans: (d) Births in elephants tend to take place during the rains. Calves are born 85 cm (33 in) tall and weigh around 120 kg (260 lb). The sperm whale produces the largest baby that weighs about 1 ton at birth. The newborn can instinctively swim for the first 10 seconds with help from its mother and swim alone within 30 minutes after birth. When baby blue whales are first born, they weigh over 3,000 kg (3 tones), about the same weight as a fully grown hippopotamus. Once born, a baby blue whale takes two years to reach a weight of 26,000 kg (26 tones). No other living creature grows so quickly.

Q12. Heart attack occurs due to :

(a) Bacterial attack on the heart
(b) Stopping of heart beat
(c) Lack of blood supply to the heart itself
(d) Impairment of heart’s working due to unknown reasons
Ans: (c) A heart attack occurs if the flow of oxygen-rich blood to a section of heart muscle suddenly becomes blocked. If blood flow isn’t restored quickly, the section of heart muscle begins to die. Heart attacks most often occur as a result of coronary heart disease (CHD), also called coronary artery disease. CHD is a condition in which a waxy substance called plaque (plak) builds up inside the coronary arteries. These arteries supply oxygen-rich blood to the heart.

Q13. A person will have brown eyes, blue eyes or black eyes depending on the particular pigment present in the :

(a) Pupil (b) Cornea
(c) Iris (d) Choroid
Ans: (c) Eye color is a polygenic phenotypic character determined by 2 distinct factors: the pigmentation of the eye’s iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. In humans, the pigmentation of the iris varies from light brown to black, depending on the concentration of melanin in the iris pigment epithelium (located on the back of the iris), the melanin content within the iris stroma (located at the front of the iris), and the cellular density of the stroma. The appearance of blue, green, as well as hazel eyes results from the Rayleigh scattering of light in the stroma, a phenomenon similar to that which accounts for the blueness of the sky. Neither blue nor green pigments are ever present in the human iris or ocular fluid.

Q14. Which of the following elements is obtained from the sea algae ?

(a) Argon (b) Sulphur
(c) Vanadium (d) Iodine
Ans: (d) Fusus vesiculosus is a brown seaweed and is also known as bladderwrack or red algae, according to the National Institutes of Health (NIH). Red marine algae and other seaweeds are common components of Asian diets and are often used in dietary supplements. The high iodine content in red marine algae can lead to hypothyroidism or hyperthyroidism.

Q15. Which of the following is not a component of chlorophyll ?

(a) Hydrogen (b) Magnesium
(c) Carbon (d) Calcium
Ans: (d) Chlorophyll, a photo-receptive pigment, allows plants to absorb sunlight and synthesize it into carbohydrates and oxygen. The basic formula for photosynthesis takes 6 molecules of carbon dioxide and 6 molecules of water, reacts them in the presence of chlorophyll and sunlight (a catalyst), and converts them into 1 molecule of glucose (C6H12O6) and 6 molecules of oxygen. Chlorophyll is a chlorin pigment, which is structurally similar to and produced through the same metabolic pathway as other porphyrin pigments such as heme. At the center of the chlorin ring is a magnesium ion. The molecular formula of C55H70O6N4 Mg and a structure of (2-formyl)- chlorophyll has been deduced based on NMR, optical and mass spectra.

Q16. Which of the following is the largest living bird ?

(a) Peacock (b) Ostrich
(c) Dodo (d) Turkey
Ans: (b) The ostrich is the largest and heaviest bird that is alive today. Although it cannot fly, the ostrich is also the fastest-running bird today; it can run up to about 43 mph (70 kph). It can outrun most predators, but can also kick to protect itself; another strategy against threats is to crouch close to the ground to camouflage itself. The ostrich can grow up to 9 feet (2.7 m) tall and weighs up to 345 pounds (156 kg). The ostrich also has the biggest eyeballs of any bird alive today; each eyeball is 2 inches (5 cm) across. It has a long neck that allows it to see predators from far away.

Q17. In which of the following generally hormone is not found ?

(a) Rat (b) Monkey
(c) Bacteria (d) Cat
Ans: (d) Neutering involves removing the source of the hormones that control reproduction and that determine the typical physical and behavioral characteristics that distinguish males and females. In dogs and cats, this is usually done by surgically removing the testicles in males (castration) and the ovaries in females (spaying). The primary purpose of neutering is to prevent reproduction.

Q18. The causative organism of dengue fever is

(a) Fungus (b) Bacteria
(c) Protozoa (d) Virus
Ans: (d) Dengue fever also known as breakbone fever, is an infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles. In a small proportion of cases the disease develops into the life-threatening dengue hemorrhagic fever, resulting in bleeding, low levels of blood platelets and blood plasma leakage, or into dengue shock syndrome, where dangerously low blood pressure occurs. Dengue is transmitted by several species of mosquito within the genus Aedes, principally A. aegypti.

Q19. Which of the following is considered to be the best cholesterol ?

(a) VLDL (b) LDL
(c) HDL (d) Triglycerids
Ans: (c) High-density lipoprotein (HDL) is one of the five major groups of lipoproteins, which, in order of sizes, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, which enable lipids like cholesterol and triglycerides to be transported within the waterbased bloodstream. In healthy individuals, about thirty percent of blood cholesterol is carried by HDL. About one-fourth to one-third of blood cholesterol is carried by high-density lipoprotein (HDL). HDL cholesterol is known as “good” cholesterol, because high levels of HDL seem to protect against heart attack. Low levels of HDL (less than 40 mg/dL) also increase the risk of heart disease. Medical experts think that HDL tends to carry cholesterol away from the arteries and back to the liver, where it’s passed from the body. Some experts believe that HDL removes excess cholesterol from arterial plaque, slowing its buildup.

Q20. Thalassemia is a hereditary disease.
It affects

(a) Blood (b) Spleen
(c) Lungs (d) Heart
Ans: (a) Thalassemia are forms of inherited autosomal recessive blood disorders that originated in the Mediterranean region. In thalassemia, the disease is caused by the weakening and destruction of red blood cells. Whilst possessing the ability to cause significant complications, including anaemia, iron overload, bone deformities and cardiovascular illness, thalassemia may confer a degree of protection against malaria, which is or was prevalent in the regions where the trait is common.

Q21. Which of the following represents a foodchain involving a producer, a vegetarian and a nonvegetarian ?

(a) Grass – Insect – Elephant
(b) Plant – Rabbit – Tiger
(c) Fish – Insect – Whale
(d) Tiger – Rabbit – Owl
Ans: (b) A food chain is a linear sequence of links in a food web starting from a trophic species that eats no other species in the web and ends at a trophic species that is eaten by no other species in the web. Plant, rabbit and tiger form a food chain where plant represents producer, rabbits represent a vegetarian, while tiger represents a non-vegetarian.

Q22. Which of the following makes the skin layer impervious to water ?

(a) Collagen (b) Melanin
(c) Keratin (d) Chitin
Ans: (c) Keratin is a family of fibrous structural proteins. Keratin is the key structural material making up the outer layer of human skin. It is also the key structural component of hair and nails. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and insoluble and form strong unmineralized tissues found in reptiles, birds, amphibians, and mammals. Cells in the epidermis contain a structural matrix of keratin, which makes this outermost layer of the skin almost waterproof, and along with collagen and elastin, gives skin its strength.

Q23. Two richest known sources of edible protein are

(a) meat and eggs
(b) milk and vegetables
(c) soyabean and groundnut
(d) some type of algae and other micro-organisms
Ans: (c) The richest sources of protein are animal foods such as chicken, meat, fish, cheese and eggs. However, plant proteins are believed to be healthier because of their lower fat content. Plant protein is found (e.g.) in beans (esp. soy beans), lentils, nuts, quorn and seeds. Fish and seafood are some of the richest sources of protein. One-half of a typical fillet of halibut or salmon provides approximately 41g of protein. Soybeans are legumes that provide a valuable protein-rich food option for vegetarians and nonvegetarians alike. One cup of boiled soybeans provides over 28g of protein.

Q24. Which of the following weeds has been found useful to check water pollution caused by industrial affluents ?

(a) Parthenium
(b) Elephant grass
(c) Water hyacinth
(d) Both (a) and (b) above
Ans: (c) Around the world, there is an increasing trend in areas of land, surface waters and groundwater affected by contamination from industrial, military and agricultural activities due to either ignorance, lack of vision, or carelessness. In the last three decades a special interest in the world is aroused by the potential of using the biological methods in the waste water treatment. Water hyacinth (Eichhornia crassipes) constitutes an important part of an aquatic ecosystem. Water hyacinth as a very promising plant with tremendous application in wastewater treatment is already proved. Water hyacinth is used to treat waste water from dairies, tanneries, sugar factories, pulp and paper industries, palm oil mills, distilleries, etc.

Q25. Which of the following is correlated with blood pressure ?

(a) Liver (b) Testis
(c) Pancreas (d) Adrenal
Ans: (d) Blood pressure is an important indicator of adrenal health and function. Mild adrenal weakness is usually accompanied by normal to high blood pressure. As Adrenal Fatigue advances, low blood pressure, at rest or related to posture becomes more prevalent.

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