Answer: Option [A]The term 'gene' was first used by Johannsen. Danish botanist Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity. He also made the distinction between the outward appearance of an individual (phenotype) and its genetic traits (genotype).
Answer: Option [B]Wilkins X-ray diffraction showed the diameter of the DNA helix as 20A. Wilkins X -ray diffraction showed the diameter of the DNA helix is around 20A. According to Maurice Wilkins, the structure of DNA of all species comprises two helical chains each coiled round the same axis, and each with a pitch of 34 angstroms and a radius of 10 angstroms. According to another study, when measured in a particular solution, the DNA chain measured 20 to 26 angstroms wide, and one nucleotide unit measured 3.3 long. Although each individual repeating unit is very small, DNA polymers can be very large molecules containing millions of nucleotides.
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Answer: Option [A]The number of autosomes in man is 22 pairs. Humans have 46 chromosomes out of which 22 pairs or 44 chromosomes are called autosomes and one pair of chromosomes, i.e. XX in female and XY in male are called heterosomes or sex chromosomes
Answer: Option [A]A normal metaphase chromosome with a midial centromere is metacentric. In metacentric chromosome centromere is present in the middle so, these chromosomes are isobrachial. In anaphase the chromosome appear V shaped.
Answer: Option [C]Lampbrush chromosomes are found inside Oocytes of frog. Lampbrush chromosomes are present in the nuclei of oocyte of vertebrates such as pisces, amphibians, reptiles and birds. They are absent in mammals. These are the largest chromosomes characterized by the presence of loops having a brushy appearance. These chromosomes are involved in DNA and yolk material synthesis.
