Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?

  • Two X - chromosomes 

  • Only one Y- chromosomes

  • Only one X - chromosome

  • Only one X - chromosome


A.

Two X - chromosomes 

The sex determining mechanism in case of humans is XY type. Sperms are of two types, one containing X -chromosome and another containing Y- chromosome.

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Which one of the following is a wrong matching of a microbe and its industrial product, while the remaining three are correct? 

  • Yeast - statins

  • Acetobacter aceti - acid

  • Clostridium Butulicum - lactic acid

  • Clostridium Butulicum - lactic acid


C.

Clostridium Butulicum - lactic acid

Clostridium butulicum forms butyric acid

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Sweet potato is homologous to 

  • potato

  • colocasia

  • ginger

  • ginger


D.

ginger

Sweet potato (Ipomoea batatas) and turnip (Brassica rapa)both are roots. However, sweet potato is tuberous adventitious root while turnip is napiform tap -root.

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The genotype of plant showing the dominant phenotype can be determined by 

  • test cross

  • dihybrid cross

  • pedigree analysis

  • pedigree analysis


A.

test cross

In Genetics, a test cross, first introduced by Gregor Mendel, is used to determine if an individual exhibiting a dominant trait is homozygous or heterozygous for that trait. More simply, test cross determines the genotype of an individual with a dominant phenotype. In some sources, the test cross is defined as being a type of back cross between the recessive homozygote and F1 generation

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Which one of the following cannot be explained on the basis of Mendel's Law of Dominance? 

  • the discrete unit controlling a particular character is called a factor

  • Out of one pair of factors, one is dominant and the other recessive

  • Alleles do not show any blending and both the characters recover as such in F2 generation

  • Alleles do not show any blending and both the characters recover as such in F2 generation


C.

Alleles do not show any blending and both the characters recover as such in F2 generation

The law of dominance does not occur universally. After Mendel, several cases were recorded by scientists, where a clear deviation from the law of dominance was seen. Such a deviation may be seen in the form of Incomplete dominance or Blending inheritance Co-dominance. 

Where F1 hybrids exhibited a mixture of blending or character of two parents, the case is considered as that of incomplete dominance blending inheritance. It simply means that two genes of an allelomorphic pair are not related as dominant or recessive, but each of them expresses itself partially. In the case of 4 o' clock plant, when plants with red flowers are crossed with plants having white flowers are crossed with plants having a white flower, the F1 hybrids bear a pink flower. When these pink flowers are self-pollinated, they develop red, pink and white flowers in the ratio of 1: 2:1 respectively.

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