Following statements are regarding to the mechanism of migration of pollen tube.

A. The embryo sac is the product of three mitotic divisions of the diploid megaspore; it comprises seven cells and eight haploid nuclei.

B. The two polar nuclei in the central cell will fuse with the second sperm nucleus and produce the endosperm that will nourish the egg. The other six cells, including the egg, contain one haploid nucleus each.

C. After compatible pollen germinates, the pollen tube grows toward the micropyle.

D. The three cells from the pollen are connected to one another at the tip of the tube, and waves of sodium ions play a key role in the growth of the tube.

Which of the following combinations are correct?

#Question id: 5351

#Unit 8. Inheritance Biology

Consider the accompanying pedigree of a rare autosomal recessive disease, PKU. (Assume individual coming from outside that is homozygous for normal allele) What is the probability of child showing trait of A and B individuals?

#Question id: 5350

#Unit 8. Inheritance Biology

Which of the following most probable mode of genetic disorder?

#Question id: 5349

#Unit 8. Inheritance Biology

The following is the inheritance pattern of a trait under observation:

(i) The trait often follow cris cross inheritance 

(iii) Unaffected father born to affected daughter

The trait is likely to be

#Question id: 5348

#Unit 8. Inheritance Biology

Miniature wings (Xm) in Drosophila result from an X-linked allele that is recessive to the allele for long wings (XL). Following different cross with resulting progeny were possible

Which of the following above offspring is not possible to carry miniature wings?

#Question id: 5239

#Unit 8. Inheritance Biology

Which of the following statements is not true for Hfr strains of E. coli ?

#Question id: 5240

#Unit 8. Inheritance Biology

If bacteria grow in the presence of a large amount of DNase, which of the following recombination process completely inhibited?