61.

Which one of the following is an example of polygenic inheritance?

• Flower colour in Mirabilis jalapa

• Production of male honey bee

• Pod shape in garden pea

• Pod shape in garden pea

Sertoli cells are regulated by the pituitary hormone known as

• FSH

• GH

• Prolactin

• Prolactin

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 x rryy?

• Only round seeds with green cotyledons

• Only wrinkled seeds with yellow cotyledons

• Only wrinkled seeds with green cotyledons

• Only wrinkled seeds with green cotyledons

One gene – one enzyme hypothesis was postulated by

• R. Franklin

• Hershey and Chase

• A. Garrod

• A. Garrod

One turn of the helix in a B-form DNA is approximately

• 20 nm

• 0.34 nm

• 3.4 nm

• 3.4 nm

Test cross involves

• crossing between two genotypes with recessive trait

• crossing between two F₁ hybrids

• crossing the F₁ hybrid with a double recessive genotype

• crossing the F₁ hybrid with a double recessive genotype

Antiparallel strands of a DNA molecule means that

• one strand turns anti-clockwise

• the phosphate groups of two DNA strands, at their ends, share the same position

• the phosphate groups at thestart of two DNA strands are in opposite position (pole)

• the phosphate groups at thestart of two DNA strands are in opposite position (pole)

Mast cells secrete

• hippurin

• myoglobin

• histamine

• histamine

If a colourblind woman marries a normal visioned man, their sons will be

• all normal visioned

• one-half colourblind and one-half normal

• three-fourths colourbling and one-fourth normal

• three-fourths colourbling and one-fourth normal

Restriction endonuclease

• cuts the DNA molecule randomly

• cuts the DNA molecule at specific sites

• restricts the synthesis of DNA inside the nucleus

• restricts the synthesis of DNA inside the nucleus