Genetics And Plant Breeding - Study Mode

[#886] The theory of organic solutes moving from 'the source to the sink' was proposed by
Correct Answer

(A) Munch

Explanation

Solution: The theory of organic solutes moving from 'the source to the sink' was proposed by Munch. It also known as the Pressure flow hypothesis or mass flow hypothesis, is the best-supported theory to explain the movement of sap through the phloem. It was proposed by Ernst Munch, a German plant physiologist in 1930. The gradient of sugar from source to sink causes pressure to flow through the sieve tube toward the sink. The pressure gradient is established as a consequence of the entry of sugars in sieve elements at the source and the removal of sucrose at the sink.

[#887] Which of the following is Autotriploid?
Correct Answer

(A) Cynodon dactylon

Explanation

Solution: Cynodon dactylon is Autotriploid. An autotriploid would have three copies of the basic chromosomal set. One way to produce an autotriploid is by mating a diploid with a haploid (n) gamete and a tetraploid with a 2n gamete. The offspring would have unbalanced gametes and therefore possibly be sterile. Autotriploids have three chromosome sets derived from a single taxon, and cyanadon has the same.

[#888] In the DNA double helix G / A is equal to
Correct Answer

(D) C / T

Explanation

Solution: In the DNA double helix, G / A is equal to C / T . Chargaff's rules state that in the DNA of any species and any organism, the amount of guanine should be equal to the amount of cytosine and the amount of adenine should be equal to the amount of thymine. This pattern is found in both strands of the DNA. They were discovered by Austrian-born chemist Erwin Chargaff, in the late 1940s.

[#889] According to Dosage compensation in Drosophila
Correct Answer

(D) Paternal chromosomes are hyperactivated

Explanation

Solution: According to Dosage compensation in Drosophila, Paternal chromosomes are hyperactivated. Dosage compensation in Drosophila increases the transcription of genes on the single X chromosome in males to equal that of both X chromosomes in females. In Drosophila, the Y chromosome has lost most of its genetic content and is retained in the karyotype only because of its specific genetic function in spermatogenesis.

[#890] The contrasting pairs of factors in Mendelian crosses are called
Correct Answer

(C) Allelomorphs

Explanation

Solution: The contrasting pairs of factors in Mendelian crosses are called Allelomorphs. Allelomorph is (genetics) one of several alternative forms of the same gene occupying a given position on a chromosome. An allele also termed an allelomorph that is any one of two or more genes that may occur alternatively at a given site (locus) on a chromosome. Alleles may occur in pairs, or there may be multiple alleles affecting the expression (phenotype) of a particular trait.