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وراثت اور خلیاتی تقسیم

10 سوالات: ایم ڈی کیٹ حیاتیات، جوابات اور وضاحت کے ساتھ۔

تمام سوالات جوابات کے ساتھ
  1. In which phase of mitosis do the chromosomes line up at the equator of the cell?

    • 1 Prophase
    • 2 Metaphase
    • 3 Anaphase
    • 4 Telophase
    جواب دیکھیں

    درست جواب: Metaphase

    In metaphase the chromosomes line up on the metaphase plate. In anaphase the sister chromatids separate.

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  2. Crossing over takes place during:

    • 1 Prophase I of meiosis
    • 2 Metaphase of mitosis
    • 3 Anaphase II of meiosis
    • 4 Interphase
    جواب دیکھیں

    درست جواب: Prophase I of meiosis

    Homologous chromosomes pair up in prophase I and exchange segments. This produces new combinations of alleles.

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  3. How many chromosomes are present in a normal human gamete?

    • 1 46
    • 2 23
    • 3 44
    • 4 92
    جواب دیکھیں

    درست جواب: 23

    Human body cells have 46 chromosomes. Meiosis halves this, so each gamete has 23.

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  4. A cross between two heterozygous tall plants (Tt x Tt) gives tall and short offspring in the ratio:

    • 1 1 : 1
    • 2 1 : 3
    • 3 3 : 1
    • 4 9 : 3
    جواب دیکھیں

    درست جواب: 3 : 1

    The offspring are TT, Tt, Tt and tt in the ratio 1:2:1. TT and Tt are tall, so tall to short is 3:1.

    غلطی کی اطلاع دیں

  5. Which base pairs with adenine in DNA?

    • 1 Guanine
    • 2 Cytosine
    • 3 Uracil
    • 4 Thymine
    جواب دیکھیں

    درست جواب: Thymine

    In DNA, adenine pairs with thymine by two hydrogen bonds, and guanine pairs with cytosine by three. Uracil replaces thymine in RNA.

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  6. A test cross is used to find the genotype of an individual by crossing it with:

    • 1 A homozygous dominant individual
    • 2 A homozygous recessive individual
    • 3 A heterozygous individual
    • 4 Any unrelated individual
    جواب دیکھیں

    درست جواب: A homozygous recessive individual

    Crossing with a homozygous recessive shows the unknown parent's alleles in the offspring. Any recessive offspring means the parent carries a recessive allele.

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  7. Down syndrome is caused by:

    • 1 Monosomy of chromosome 21
    • 2 Trisomy of chromosome 21
    • 3 Loss of the Y chromosome
    • 4 A missing X chromosome
    جواب دیکھیں

    درست جواب: Trisomy of chromosome 21

    Down syndrome results from three copies of chromosome 21, usually through non-disjunction in meiosis.

    غلطی کی اطلاع دیں

  8. Which experiment demonstrated that DNA replication is semi-conservative?

    • 1 Griffith's experiment
    • 2 Hershey and Chase
    • 3 Meselson and Stahl
    • 4 Mendel's pea crosses
    جواب دیکھیں

    درست جواب: Meselson and Stahl

    Meselson and Stahl used heavy nitrogen to show that each new DNA molecule keeps one old strand and gets one new strand.

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  9. Haemophilia is inherited as:

    • 1 An autosomal dominant trait
    • 2 An X-linked recessive trait
    • 3 A Y-linked trait
    • 4 An autosomal recessive trait
    جواب دیکھیں

    درست جواب: An X-linked recessive trait

    The gene is on the X chromosome. Males have one X, so one recessive allele is enough to show the disease, which is why it is more common in males.

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  10. The offspring of AaBb x AaBb (independent assortment, complete dominance) show a phenotypic ratio of:

    • 1 9 : 3 : 3 : 1
    • 2 3 : 1
    • 3 1 : 2 : 1
    • 4 1 : 1 : 1 : 1
    جواب دیکھیں

    درست جواب: 9 : 3 : 3 : 1

    This is Mendel's dihybrid cross. The four phenotypes appear in the ratio 9:3:3:1.

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