Which disease results from the genetic inability to synthesize a single enzyme ?

A. Diabetes

B. Phenylketonuria

C. Colour-blindness

D. Down's syndrome

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  1. If an individual does not breed true for its characters, it is called
  2. A codon is a sequence of 3 nucleolides on
  3. Crossing over in meiosis occurs in
  4.  A chemical mutagen is
  5. In humans, an example of sex-linked trait is
  6. In the Operon concept, the regulator gene regulates chemical reactions in the cell by
  7. Lethal genes are those which
  8. Base substitutions from base analogues I are called
  9. Mutations which are not dominant are not lost by a gene pooL This is known as
  10. The term 'meiosis' was coined bv
  11. A pure tall pea plant was reared in a soil poor in nutrition and reached the size of a pure dwarf pea…
  12. The crossing of a homozygous tall plant with a dwarf would yield plants in the ratio of
  13. DNA duplication occurs in
  14. The condition in which only one allele of a pair is present is known as
  15. In a monohybrid cross the Fi ratio of a backcross is
  16. Down's syndrome is an example of
  17. The scientists who rediscovered the Mendel's laws are
  18. An offspring of two homozygous parents different from one another by alleles at only one gene locus…
  19. Linked genes may be separated by the process of
  20. Some people experience PTC paper on tongue as bitter, others as tasteless. This character is hereditary…
  21. A giant chromosome having many chromo-nemata lying side by side all along their length is called
  22. A colour-blind man marries the daughter of a colour-blind person. In their progeny
  23. Dyad is
  24. Chromosomes exhibit minimum coiling during
  25.  A person meets with an accident and great loss of blood has occurred. There is no time to analyse…
  26. Exhibition of superiority by a hybrid over both of its parents is called
  27. The possibilities of hereditary and evolutionary changes are greatest in species that reproduce by
  28. How many meiosis will be required to produce 102 pollen-grains ?
  29. A child is bom with an extra chromosome in each of its cells. This is usually the result of
  30. Transfer of a gene or genes through a virus is called