Biology GK Questions Quiz-24

Biology GK Questions Quiz-24

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

    461. The pigment involved in photosynthetic activity is

    (1) anthocyanin
    (2) fucxanthin
    (3) carotenoid
    (4) chlorophyll
    Answer:
    461. (4) Chlorophyll is an extremely important bio-molecule, 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 chlorophyllcontaining tissues.

    462. Free-living nitrogen fixing microorganisms are

    (1) Rhizobia
    (2) Soil fungi
    (3) Vesicular arbuscular mycorrhiza
    (4) Blue green algae
    Answer:
    462. (1) Rhizobia are soil bacteria that fix nitrogen (diazotrophs) after becoming established inside root
    nodules of legumes. Rhizobia require a plant host; they cannot independently fix nitrogen. In general,
    they are Gram-negative, motile, non-sporulating rods.

    463. Vegetable oils are converted into solid fat (ghee) by

    (1) Hydrolysis
    (2) Addition of agar
    (3) Oxidation using air and a catalyst
    (4) Hydrogenation
    Answer:
    463. (4) Hydrogenation - to treat with hydrogen - is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst. The largest scale application of hydrogenation is for the processing of vegetable oils (fats to give margarine and related spreads and shortenings). Typical vegetable oils are derived from polyunsaturated fatty acids (containing more than one carbon-carbon double bonds).

    464. A drug which helps in controlling fever is

    (1) Ibuprofen
    (2) Penicillin
    (3) Paracetamol
    (4) Corticosteroid
    Answer:
    464. (3) Paracetamol is a widely used over-the-counter analgesic (pain reliever) and antipyretic (fever reducer). The World Health Organization (WHO) recommends that paracetamol only be used to treat fever in children if their temperature is greater than 38.5 °C.

    465. Identify the correct statement with respect to Biogas.

    (1) Mixture of gases from volcanoes
    (2) Gas produced from certain crude oil wells
    (3) Gas produced by incomplete combustion of biomass
    (4) Gas produced by fermentation of biomass
    Answer:
    465. (4) Biogas is produced by the anaerobic digestion or fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant material, and crops. Biogas comprises
    primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulphide
    (H2S), moisture and siloxanes.

    466. Aspartame is the name of a product used by diabetic patients as a sweetening agent. It belongs to the class of—

    (1) Carbohydrates
    (2) Peptides
    (3) Polyhydric alcohols
    (4) Alkaloids
    Answer:
    466. (2) Aspartame is an artificial, non-saccharide sweetener used as a sugar substitute in some foods
    and beverages. It is a methyl ester of the aspartic acid/phenylalanine dipeptide. Under strongly acidic
    or alkaline conditions, aspartame may generate methanol by hydrolysis. Under more severe conditions, the peptide bonds are also hydrolyzed, resulting in the free amino acids.

    467. Which one of the following four secretions, is different from the remaining three in regard to its mode of transport from the source gland to the site of action?

    (1) Saliva 
    (2) Sweat
    (3) Bile 
    (4) Epinephrine
    Answer:
    467. (3) Saliva: secreted by the salivary glands; Sweat: achieved by the water-rich secretion of the eccrine glands; Epinephrine: also known as adrenaline is a hormone and a neurotransmitter; and Bile: a bittertasting, dark green to yellowish brown fluid, produced by the liver that aids the process of digestion of lipids in the small intestine. Bile is the odd one among all four as it is secreted by liver, while others are secreted by glands.

    468. What is true about viruses without exception?

    (1) They contain a core of RNA
    (2) They can infect bacteria
    (3) They cannot produce antibodies
    (4) They can multiply only in host cells
    Answer:
    468. (4) Viruses do not contain enzymes for energy production or protein synthesis. For a virus to
    multiply, it must invade a host cell and direct the host’s metabolic machinery to produce viral enzymes,
    viral proteins, and copies of its nucleic acid, using the host cell's ATP to power the reactions.

    469. Haemoglobin is a

    (1) protein
    (2) carbohydrate
    (3) fat
    (4) vitamin
    Answer:
    469. (1) Hemoglobin is the iron-containing oxygen-transport metal-protein in the red blood cells of all vertebrates which carries oxygen from the respiratory organs (lungs or gills) to the rest of the body (i.e. the tissues) where it releases the oxygen to burn nutrients to provide energy to power the functions of the organism, and collects the resultant carbon dioxide to bring it back to the respiratory organs to be
    dispensed from the organism.

    470. Natural organic fertilizers are found to be better then chemical fertilizers because

    (1) chemical fertilizers are less productive
    (2) organic fertilizers are more productive
    (3) organic fertilizers sustain soil productivity
    (4) chemical fertilizers are toxic
    Answer:
    470. (3) Organic fertilizers like compost are either soil conditioners or growth enhancers. They sustain crop yields and soil productivity in intensive cropping systems which leave low organic residues on the soil.

    471. Which of the following groups of organisms digest their food before it actually enters the organism?

    (1) Bacteria and Protozoa
    (2) Bacteria and Fungi
    (3) Fungi and Protozoa
    (4) Mucor and Rhizopus
    Answer:
    471. (2) Decay is an essential life process, which helps to digest food and recycle materials. Bacteria and fungi are the main groups of decomposer. They release enzymes to break down compounds, so that they can absorb the nutrients. Organisms that feed on dead material in this way are called saprophytes.

    472. The average heartbeat rate per minute in a normal person is

    (1) 82 
    (2) 92
    (3) 72 
    (4) 98
    Answer:
    472. (3) The average heart rate for adult humans is about 70 to 75 beats per minute in a normal relaxed mode. The "normal" heart beat rate is taken to be "72 beats per minute.”

    473. Metabolism is referred to as

    (1) synthesis of biomolecules
    (2) breaking-down of biomolecules
    (3) synthesis and breaking down of biomolecules
    (4) recycling of biomolecules
    Answer:
    473. (3) Metabolism is the sum total of chemical reactions occurring in cells. It includes both anabolism, the synthesis of the biomolecules (e.g., protein synthesis, DNA replication, glucose synthesis in plants) and catabolism, the degradation of molecules usually for the production of energy (e.g., glycolysis, Krebs Cycle). Metabolism is carried out by specific enzymes which catalyze each step of a long series of reactions.

    474. The enzymes are basically

    (1) carbohydrates
    (2) lipids 
    (3) proteins
    (4) amino acids
    Answer:
    474. (3) Enzymes are in general globular proteins and range from just 62 amino acid residues in size, for the monomer of 4-oxalocrotonate tautomerase, to over 2,500 residues in the animal fatty acid synthase. The activities of enzymes are determined by their three-dimensional structure.

    475. Why death of fish is more common during summer than in winter? It is because of

    (1) shortage of food
    (2) concentration of toxins
    (3) depletion of oxygen
    (4) spread of diseases
    Answer:
    475. (3) Fish die more in summer due to oxygen depletion which refers to low levels of dissolved oxygen (DO) in water. Warm water is much less capable of holding oxygen gas in solution than cool water. For example, water that is 90° F can only hold 7.4 mg/L DO at saturation, whereas water that is 45° F can hold 11.9 mg/L DO at saturation. This physical phenomenon puts the fish in double jeopardy because at high water temperatures their metabolic rates increase, hence their physiologic demand for oxygen increases.

    476. Which of the following groups of organisms reproduce faster?

    (1) Algae 
    (2) Fungi
    (3) Bacteria 
    (4) Protozoa
    Answer:
    476. (3) Unlike in multi-cellular organisms, increases in cell size (cell growth and reproduction by cell division) are tightly linked in unicellular organisms. Bacteria grow to a fixed size and then reproduce through binary fission, a form of asexual reproduction. Under optimal conditions, bacteria can grow and divide extremely rapidly, and bacterial populations can double as quickly as every 9.8 minutes.

    477. Which one of the following foodstuffs of the same quantity possesses the highest calorific value?

    (1) Butter 
    (2) Apple
    (3) Cheese 
    (4) Sugar
    Answer:
    477. (1) Calorific value refers to calories or thermal units contained in one unit of a substance and released when the substance is burned. Fats have higher calorific value than other food items. The calorific value of different food items (per 100 gram) are: Butter: 740; Cheese: 310; Sugar: 405; and Apple: 45.

    478. EEG is a technique to record the activity of

    (1) heart 
    (2) lungs
    (3) brain 
    (4) muscles
    Answer:
    478. (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.

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

    (1) xanthophyll 
    (2) riboflavin
    (3) ribulose 
    (4) carotin
    Answer:
    479. (4) 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.

    480. Which one of these is a communicable disease?

    (1) Diabetes 
    (2) Diphtheria
    (3) Arthritis 
    (4) Cancer
    Answer:
    480. (2) Diphtheria is an acute an upper respiratory tract illness and infectious disease caused by the bacteria Corynebacterium diphtheriae. It is spread by direct physical contact or breathing the aerosolized secretions of infected individuals.

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