NEET-XII-Biology

P1 year:2019

with Solutions - page 3
 
  • Qstn #120
    Due to increasing air-borne allergens and
    pollutants, many people in urban areas are
    suffering from respiratory disorder causing
    wheezing due to
    (1) benign growth on mucous lining of nasal cavity
    (2) inflammation of bronchi and bronchioles
    (3) proliferation of fibrous tissues and
    damage of the alveolar walls
    (4) reduction in the secretion of surfactants
    by pneumocytes.
    digAnsr:   2
    Ans : ( 2 )
    Sol. Asthma is a difficulty in breathing causing
    wheezing due to inflammation of bronchi and
    bronchioles. It can be due to increasing air
    born allergens and pollutants. Asthma is an
    allergic condition. Many people in urban areas
    are suffering from this respiratory disorder.27
  • Qstn #121
    Select the incorrect statement.
    (1) Male fruit fly is heterogametic
    (2) In male grasshoppers 50% of sperms have
    no sex-chromosome
    (3) In domesticated fowls, sex of progeny
    depends on the type of sperm rather than
    egg
    (4) Human males have one of their sex-
    chromosome much shorter than the other
    digAnsr:   3
    Ans : ( 3 )
    Sol. In birds female heterogamety is found thus sex
    of progeny depends on the types of egg rather
    than the type of sperm.
    Birds
    (fowls)
     sperm = A + Z type (100%)
     eggs A + Z (50%)
    A + W (50%)
    eg.
  • Qstn #122
    DNA precipitation out of a mixture of
    biomolecules can be achieved by treatment
    with
    (1) Isopropanol
    (2) Chilled ethanol
    (3) Methanol at room temperature
    (4) Chilled chloroform
    digAnsr:   2
    Ans : ( 2 )
    Sol. During the isolation of desired gene, chilled
    ethanol is used for the precipitation of DNA.
  • Qstn #123
    Select the correct group of biocontrol
    agents.
    (1) Bacillus thuringiensis, Tobacco mosaic
    virus, Aphids
    (2) Trichoderma, Baculovirus, Bacillus
    thuringiensis
    (3) Oscillatoria, Rhizobium, Trichoderma
    (4) Nostoc, Azospirillium, Nucleopolyhedrovirus
    digAnsr:   2
    Ans : ( 2 )
    Sol. Fungs Trichoderma, Baculoviruses (NPV) and
    Bacillus thuringiensis are used as biocontrol
    agents.
    Rhizobium, Nostoc, Azospirillum and
    Oscillatoria are used as biofertilisers,
    whereas TMV is a pathogen and aphids are
    pests that harm crop plants.
  • Qstn #124
    Select the incorrect statement.
    (1) Inbreeding increases homozygosity
    (2) Inbreeding is essential to evolve purelines
    in any animal.
    (3) Inbreeding selects harmful recessive
    genes that reduce fertility and productivity
    (4) Inbreeding helps in accumulation of
    superior genes and elimination of
    undesirable genes
    digAnsr:   3
    Ans : ( 3 )
    Sol. Inbreeding exposes harmful recessive genes
    that are eliminated by selection. It also helps
    in accumulation of superior genes and
    elimination of less desirable genes. Therefore
    this is selection at each step, increase the
    productivity of inbred population. Close and
    continued inbreeding usually reduces fertility
    and even productivity.
  • Qstn #125
    Match the following organisms with the
    products they produce
    (a ) Lactobacillus (i) Cheese
    (b) Saccharomyces (ii) Curd cerevisiae
    (c) Aspergillus niger (iii) Citric Acid
    (d) Acetobacter aceti (iv) Bread
    (v) Acetic Acid
    Select the correct option.
    (a ) (b) (c) (d)
    (1) (ii) (iv) (v) (iii)
    (2) (ii) (iv) (iii) (v)
    (3) (iii) (iv) (v) (i)
    (4) (ii) (i) (iii) (v)
    digAnsr:   2
    Ans : ( 2 )
    Sol. Microbes are used in production of several
    household and industrial products -
    Lactobacillus - Production of curd
    Saccharomyces cerevisiae - Bread making
    Aspergillus niger - Citric acid production
    Acetobacter aceti - Acetic acid
  • Qstn #126
    What is the direction of movement of sugars
    in phloem?
    (1) Non-multidirectional
    (2) Upward
    (3) Downward
    (4) Bi-directional
    digAnsr:   4
    Ans : ( 4 )
    Sol. The direction of movement of sugar in phloem
    is bi-directional as it depends on source-sink
    relationship which is variable in plants.
  • Qstn #127
    In some plants, the female gamete develops
    into embryo without fertilization. This
    phenomenon is known as
    (1) Autogamy
    (2) Parthenocarpy
    (3) Syngamy
    (4) Parthenogenesis
    digAnsr:   4
    Ans : ( 4 )
    Sol. The phenomenon in which female gamete
    develops into embryo without getting fused
    with male gamete (fertilisation) is called
    parthenogenesis.
  • Qstn #128
    Persistent nucellus in the seed is known as
    (1) Chalaza
    (2) Perisperm
    (3) Hilum
    (4) Tegmen
    digAnsr:   2
    Ans : ( 2 )
    Sol. Persistent Nucellus is called Perisperm
    e.g.: Black pepper, Beet
  • Qstn #129
    What map unit (Centimorgan) is adopted in the
    construction of genetic maps?
    (1) A unit of distance between two expressed
    genes representing 10% cross over.
    (2) A unit of distance between two expressed
    genes representing 100% cross over.
    (3) A unit of distance between genes on
    chromosomes, representing 1% cross
    over.
    (4) A unit of distance between genes on
    chromosomes, representing 50% cross
    over.
    digAnsr:   3
    Ans : ( 3 )
    Sol. 1 map unit represent 1 % cross over.
    Map unit is used to measure genetic distance.
    This genetic distance is based on average
    number of cross over frequency.
  • Qstn #130
    What would be the heart rate of a person if
    the cardiac output is 5 L, blood volume in the
    ventricles at the end of diastole is 100 mL and
    at the end of ventricular systole is 50 mL?
    (1) 50 beats per minute
    (2) 75 beats per minute
    (3) 100 beats per minute
    (4) 125 beats per minute
    digAnsr:   3
    Ans : (3)
    Sol. Cardiac output = stroke volume × Heart rate
    &implies; Cardiac output = 5L or 5000 ml
    &implies; Blood volume in ventricles at the end of
    diastole = 100 ml
    &implies; Blood volume in ventricles at the end of
    systole = 50 ml
    Stroke volume = 100 - 50
    = 50 ml.
    So,
    5000 ml = 50 ml × Heart rate
    So, Heart rate = 100 beats per minute.
  • Qstn #131
    Thiobacillus is a group of bacteria helpful in
    carrying out
    (1) Nitrogen fixation
    (2) Chemoautotrophic fixation
    (3) Nitrification
    (4) Denitrification
    digAnsr:   4
    Ans : ( 4 )
    Sol. Thiobacillus denitrificans cause denitrification
    i.e., conversion of oxides of nitrogen to free
    N
    2
    .
  • Qstn #132
    Which of the following factors is responsible
    for the formation of concentrated urine?
    (1) Low levels of antidiuretic hormone
    (2) Maintaining hyperosmolarity towards
    inner medullary interstitium in the kidneys.
    (3) Secretion of erythropoietin by
    Juxtaglomerular complex
    (4) Hydrostatic pressure during glomerular
    filtration
    digAnsr:   2
    Ans : (2)
    Sol. The proximity between loop of henle and vasa
    recta as well as counter current in them help
    in maintaining an increasing osmolalrity
    towards the inner medullary interstitium. This
    mechanism help to maintain a concentration
    gradient in medullary interstitium so human
    urine is nearly four times concentrated than
    initial filtrate formed.
  • Qstn #133
    Which of the following statements regarding
    mitochondria is incorrect?
    (1) Outer membrane is permeable to
    monomers of carbohydrates, fats and
    proteins.
    (2) Enzymes of electron transport are
    embedded in outer membrane.
    (3) Inner membrane is convoluted with
    infoldings.
    (4) Mitochondrial matrix contains single
    circular DNA molecule and ribosomes.
    digAnsr:   2
    Ans : (2)
    Sol. In mitochondria, enzymes for electron
    transport are present in the inner membrane.
  • Qstn #134
    Xylem translocates.
    (1) Water only
    (2) Water and mineral salts only
    (3) Water, mineral salts and some organic
    nitrogen only
    (4) Water, mineral salts, some organic
    nitrogen and hormones
    digAnsr:   4
    Ans : (4)
    Sol. Xylem is associated with tanslocation of
    mainly water, mineral salts, some organic
    nitrogen and hormones.