18020.If two pea plants having red (dominant) coloured flowers with unknown genotypes are crossed, 75% of the flowers are red and 25% are white. The genotypic constitution of the parents having red coloured flowers will be
Both heterozygous
One homozygous and other heterozygous
Both homozygous
Both hemizygous
18021.In a given plant, red colour (R) of fruits is dominant over white fruit (r); and tallness (T) is dominant over dwarfness (t). If a plant with genotype RrTt is crossed with a plant of genotype rrtt, what will be the percentage of tall plants with red fruits in the next generation?
20%
40%
50%
60%
18022.In Mendel's experiments with garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy). What are the expected phenotypes in the F2 generation of the cross RRYY × rryy?
Only wrinkled seeds with green cotyledons
Only wrinkled seeds with yellow cotyledons
Only round seeds with green cotyledons
Round seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons
18023.Which of the following pair of features is a good example of polygenic inheritance?
Hair pigment of mouse and tongue rolling in humans
ABO blood group in humans and flower colour of Mirabilis jalapa
Human height and skin colour
Human eye colour and sickle cell anaemia
18024.The Genetic deficiency of ADH-receptor leads to
Diabetes Insipidus
Glycosuria
Diabetes mellitus
Nephrogenic Diabetes
18025.Genes for cytoplasmic male sterility in plants are generally located in:
Nuclear-genome
Mitochondrial genome
Chloroplast genome
Cytosol
18026.Sickle cell anemia is
Characterized by elongated sickle like RBCs with a nucleus
An autosomal linked dominant trait
Caused by substitution of valine by glutamic acid in the β globin chain of haemoglobin
Caused by a change in a single base pair of DNA
18027.Which one of the following conditions correctly describes the manner of determining the sex in the given example?
Homozygous sex chromosomes (XX) produce male in Drosophila
Homozygous sex chromosomes (ZZ) determine female sex in birds
XO type of sex chromosomes determine male sex in grasshopper
XO condition in humans as found in Turner Syndrome, determines female sex
18028.Two genes R and Y are located very close on the chromosomal linkage map of maize plant. When RRYY and rryy genotypes are hybridized, the F2 segregation will show:
Higher number of the parental types
Higher number of the recombinant types
Segregation in the expected 9 : 3 : 3 : 1 ratio
Segregation in 3 : 1 ratio
18029.Two pea plants were subjected cross pollination. Of the 183 plants produced in the next generation, 94 plants were found to be tall and 89 plants were found to be dwarf. The genotypes of the two parental plants are likely to be
TT and tt
Tt and Tt
Tt and tt
TT and TT