Biology GK Questions Quiz-17

Biology GK Questions Quiz-17

Biology Multiple Choice Questions (MCQs) Quiz for State and UPSC Civil Services Examinations. Objective Questions on Biology for competitive examinations.

    321. Amoebic dysentery is caused by

    (1) Entamoeba histolytica
    (2) Salmonella typhi
    (3) E. coli
    (4) Streptococcus pyogenes
    Answer:
    321. (1) Amoebic dysentery (or amebic dysentery) is a type of dysentery caused primarily by the amoeba Entamoeba histolytica. Amoebic dysentery is transmitted through contaminated food and water.
    Amoebae spread by forming infective cysts which can be found in stools, and spread if whoever touches them does not sanitize their hands. There are also free amoebae, or trophozoites, that do not form cysts, however trophozoites do not survive long outside of the human gastrointestinal tract, and are a purely diagnostic observation. Trophozoites are the agent responsible for symptoms.

    322. DNA test was developed by

    (1) Dr. Alec Jeffreys
    (2) Dr. V.K. Kashyap
    (3) Watson and Crick
    (4) Gregor Mendel
    Answer:
    322. (3) A genealogical DNA test looks at a person’s genetic code at specific locations. Results give information about genealogy or personal ancestry. James D. Watson and Francis Crick are the two scientists who discovered the structure of DNA in 1953.

    323. An ECG shows the functioning of the

    (1) brain 
    (2) heart
    (3) lungs 
    (4) kidneys
    Answer:
    323. (2) The electrocardiogram (ECG or EKG) is a diagnostic tool that is routinely used to assess the electrical and muscular functions of the heart. The heart is a two stage electrical pump and the heart’s electrical activity can be measured by electrodes placed on the skin. The electrocardiogram can measure the rate and rhythm of the heartbeat, as well as provide indirect evidence of blood flow to the heart muscle.

    324. Which of the following is incorrect?

    (1) AIDS is retroviral disease
    (2) AIDS is transmitted by homo and hetero-sexual contact
    (3) AIDS was first recognised in USA in 1981
    (4) AIDS causes ano-genital warts
    Answer:
    324. (4) Warts are benign proliferations of skin and mucosa caused by the human papillomavirus (HPV). Currently, more than 100 types of HPV have been identified. Certain HPV types tend to infect skin at particular anatomic sites; however, warts of any HPV type may occur at any site. The primary clinical manifestations of HPV infection include common warts, genital warts, flat warts, and deep palmoplantar warts (myrmecia). Less common manifestations of HPV infection include focal epithelial hyperplasia (Heck disease), epidermodysplasia verruciformis, and plantar cysts. Warts are transmitted by direct or indirect contact, and predisposing factors include disruption to the normal epithelial barrier.

    325. If the radius of blood vessels of a person decreases his/her blood pressure will

    (1) increase 
    (2) decrease
    (3) remain unaffected
    (4) increase for males and decrease for females
    Answer:
    325. (1) An obese person has a greatly increased number of blood vessels because of the amount of adipose tissue that must be serviced. As a result, the total length of his or her vascular tree is greatly increased and this person tends to have a higher blood pressure because of the greater resistance to blood flow. Resistance is inversely proportional to the fourth power of the radius of the blood vessel. In other words, the smaller the diameter of the vessel, the greater the resistance it offers to blood flow. If the radius of a blood vessel decreases by ½, its resistance to blood flow increases 16 times (½ x ½ x ½ x ½= 1/16).

    326. Cell or tissue death within a living body is called as

    (1) Neutrophilia
    (2) Nephrosis
    (3) Necrosis
    (4) Neoplasia
    Answer:
    326. (3) Necrosis is death of body tissue. It occurs when there is not enough blood flowing to the tissue,
    whether from injury, radiation, or chemicals. Necrosis is not reversible. When substantial areas of tissue
    die due to a lack of blood supply, the condition is called gangrene. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma that result unregulated digestion of cell components.

    327. Insufficient blood supply in human body is referred as

    (1) Ischemia
    (2) Hyperemia
    (3) Hemostasia
    (4) Hemorrhage
    Answer:
    327. (1) In medicine, ischemia denotes a restriction or thinning or to make or grow thin/lean, haema blood) is a restriction in blood supply to tissues, causing a shortage of oxygen and glucose needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue. It also means local anemia in a given part of a body sometimes resulting from congestion (such as vasoconstriction, thrombosis or embolism).

    328. Deep fried food materials are carcinogenic because they are rich in

    (1) Fats
    (2) Hydrocarbons
    (3) Cooking oil
    (4) Nicotine
    Answer:
    328. (2) If foods are overheated or burnt, a group of carcinogenic substances called polycyclic aromatic
    hydrocarbons (PAHs) are produced. PAHs represent a very large group of compounds. Chemically, they
    consist of fused aromatic rings made up of carbon and hydrogen atoms. After being ingested, PAHs can
    be absorbed in the intestine and distributed to other organs through blood circulation. Besides cancercausing, PAH exposure is also associated with many adverse effects in laboratory animals, including reproductive toxicity, cardiovascular toxicity, bone marrow toxicity, immune system suppression, and liver toxicity.

    329. The toxicity of which of the following heavy metals leads to liver cirrbosis?

    (1) Copper 
    (2) Lead
    (3) Mercury 
    (4) Zinc
    Answer:
    329. (1) Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules (lumps that occur as a result of a process in which damaged tissue is regenerated), leading to loss of liver function. Cirrhosis is most commonly caused by alcoholism, hepatitis B and hepatitis C, and fatty liver disease. Some inherited diseases that can cause cirrhosis include Wilson’s disease (which causes an accumulation of copper in the body), alpha-1
    antitrypsin deficiency (a genetic disorder caused by defective production of a particular enzyme), and
    glycogen storage diseases (a group of disorders that cause abnormal amounts of glycogen to be stored in the liver).

    330. Typhoid is caused by

    (1) Pseudomonas sp.
    (2) Staphylococcus
    (3) Bacillus
    (4) Salmonella typhi
    Answer:
    330. (4) Typhoid fever, also known as typhoid, is a common worldwide bacterial disease, transmitted by the ingestion of food or water contaminated with the feces of an infected person, which contain the bacterium Salmonella typhi, serotype Typhi. Salmonella enterica enterica is a subspecies of Salmonella enterica, the rod shaped, flagellated, aerobic, Gram-negative bacterium. It is a member of the genus Salmonella.

    331. BCG immunization is for

    (1) Measles
    (2) Tuberculosis
    (3) Diphtheria
    (4) Leprosy
    Answer:
    331. (2) Bacillus Calmette–Guérin (BCG) is a vaccine against tuberculosis that is prepared from a strain of the attenuated (weakened) live bovine tuberculosis bacillus, Mycobacterium bovis, that has lost its
    virulence in humans by being specially subcultured in an artificial medium for 13 years, and also prepared from Mycobacterium tuberculosis. The bacilli have retained enough strong antigenicity to become a somewhat effective vaccine for the prevention of human tuberculosis. At best, the BCG vaccine is 80% effective in preventing tuberculosis for a duration of 15 years; however, its protective effect appears to vary according to geography.

    332. Besides carbohydrates, a major source of energy in our food is constituted by

    (1) Proteins 
    (2) Fats
    (3) Minerals 
    (4) Vitamins
    Answer:
    332. (2) Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats provide a source of concentrated energy as well as the fat-soluble vitamins A, D, E and K. Fat transports these vital nutrients around the body. Fats or lipids are broken down in the body by enzymes called lipases produced in the pancreas. Examples of edible animal fats are lard, fish oil, butter/ghee and whale blubber.

    333. The limb bones of children become bent if there is deficiency of vitamin

    (1) A 
    (2) B1
    (3) D 
    (4) E
    Answer:
    333. (3) Rickets is weakness and deformity of the bones that occurs from lack of vitamin D. Vitamin D occurs in whole milk, butter, egg yolks, animal fats, and liver, especially fish liver oil. The body also makes its own vitamin D when sunlight shines on the skin. Children who do not eat enough foods with vitamin D, and who do not get enough sunlight, gradually develop signs of rickets. Rickets is fairly common in some countries, especially in cool mountain areas of Asia and Latin America where babies are kept inside and wrapped up. Rickets is also increasing in crowded cities where children are seldom taken into the sunlight.

    334. A medicine which promotes the secretion of urine is called

    (1) Adrenaline
    (2) Monouretic
    (3) Diuretic
    (4) Triuretic
    Answer:
    334. (3) A diuretic provides a means of forced diuresis which elevates the rate of urination. In medicine, diuretics are used to treat heart failure, liver cirrhosis, hypertension and certain kidney diseases. Some diuretics, such as acetazolamide, help to make the urine more alkaline and are helpful in increasing excretion of substances such as aspirin in cases of overdose or poisoning. Diuretics are often abused by sufferers of eating disorders, especially bulimics, in attempts at weight loss.

    335. The chemicals released by one species of animals in order to attract the other members of the same species are

    (1) Hormones
    (2) Nucleic acids
    (3) Pheromones
    (4) Steroids
    Answer:
    335. (3) A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology. Their use among insects has been particularly well documented. In addition, some vertebrates and plants communicate by using pheromones.

    336. Jaundice is caused due to the infection of

    (1) Brain 
    (2) Liver
    (3) Kidney 
    (4) Spleen
    Answer:
    336. (2) Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae (whites of the eyes), and other mucous membranes caused by hyperbilirubinemia (increased levels of bilirubin in the blood). This hyperbilirubinemia subse-quently causes increased levels of bilirubin in the extracellular fluid. Jaundice is often seen in liver disease such as hepatitis or liver cancer. Jaundice can occur if: too many red blood cells are dying or breaking down and going to the liver; the liver is overloaded or damaged; or the bilirubin from the liver is unable to move through the digestive tract properly.

    337. The average heart beat rate per minute in a normal person is

    (1) 82 
    (2) 92
    (3) 72 
    (4) 98
    Answer:
    337. (3) The average heart rate for adult humans is about 70 to 75 beats per minute in a normal relaxed mode. While we tend to think of the “normal” heart beat rate as being “72 beats per minute”, in actuality the heart beat rate is not and should not be constant. In fact, the contemporary understanding is that the degree to which the heart beat varies is a key indicator of health and well being. Conversely, the
    degree to which it does not vary is a key indicator of health risk. The “72 beats per minute” that we are
    familiar with is the normal average heart beat rate.

    338. EEG records the activity of

    (1) heart 
    (2) lungs
    (3) brain 
    (4) muscles
    Answer:
    338. (3) Electroencephalography (EEG) is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain. In clinical contexts, EEG refers to the recording of the brain’s spontaneous electrical activity over a short period of time, usually 20–40 minutes, as recorded from multiple electrodes placed on the scalp. Diagnostic applications generally focus on the spectral content of EEG, that is, the type of neural oscillations that can be observed in EEG signals. In neurology, the main diagnostic application of EEG is in the case of epilepsy.

    339. The colour of cow’s milk is slightly yellow due to the presence of

    (1) Xanthophyll
    (2) Riboflavin
    (3) Ribulose
    (4) Carotene
    Answer:
    339. (4) Yellow milk is commonly related to the diet that that cow is on. Grass is the most common diet that will turn milk (and fat) yellow, due to a compound in the grass that makes it green called Carotene.
    Carotene is a kind of plant-steriod that makes plants the vibrant colours they are, and this carries through the body of the grazer that eats these plants. Carotene mostly affects the colour of fat. Since milk is comprised of around 3.5% milk fat, a dairy cow that is grass-fed tends to produce yellow milk, over a dairy cow that is not grass-fed and fed primarily a mix of hay, silage and grain.

    340. Which one of these is a communicable disease ?

    (1) Diabetes 
    (2) Diphtheria
    (3) Arthritis 
    (4) Cancer
    Answer:
    340. (2) Diphtheria is an upper respiratory tract illness caused by Corynebacterium diphtheriae, a facultative anaerobic, Gram-positive bacterium. Diphtheria is a contagious disease spread by direct physical contact or breathing the aerosolized secretions of infected individuals. Diphtheria toxin is produced by C. diphtheriae only when infected with a bacteriophage that integrates the toxin-encoding genetic elements into the bacteria.

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