A cross between true breeding purple beetles with thick wing

A cross between true breeding purple beetles with thick wing cover and true breeding blue beetles with thin wing cover produced all blue beetles with thick wing cover. If this cross were to represent a dihybrid with only dominant/recessive alleles present, then the expected F_2 should show the following phenotypic ratio: a) 1:1:1:1 b) 1:2:1 c) 1/2 blue, thin: 1/2 purple, thick d) 9/16 blue, thick: 3/16 blue, thin: 3/16 purple, thick: 1/16 purple, thin e) 3/4 blue, thick: 1/4 purple, thin Different chromosome types can be distinguished based on the position of the___. a) centromere b) centrosome c) center d) centriole e) arm Which of the following is true regarding a karyotype? a) it is an ordered display of the pairs of chromosomes from a cell b) it is usually prepared from a cell in metaphase c) chromosomes are ordered according to the size and type d) all of the above e) none of the above For a human with 47, XXY chromosomes, the expected number of Barr bodies is: A) 0 B) 1 C) 2 D) 3 E) 4 The inheritance illustrated in the pedigree is best explained by: a) autosomal dominant trait b) autosomal recessive trait c) X-linked dominant trait d) X-linked recessive trait In the ABO Wood types, a mother with type A and a father with type B can have the following offspring, except: a) type O blood b) type A blood c) type B blood d) type AB Wood e) all of the above Wood types are possible A human with 47, XX+18 chromosomes has a___. a) monosomy b) trisomy c) monoploidy d)triploidy c) none of the above A wild species with 2n=22 chromosomes is cultivated and it chromosome number is changed in the process to 3n=33 chromosomes. This is an example of a) monosomy b) trisomy c)aneuploidy d) euploidy e) none of the above The following illustrates a way in which___arises. a) an inversion b) an aversion c) deletion d) reciprocal translocation e) duplication Criss-cross pattern of inheritance suggests that the gene of interest is: a) autosomal dominant b) autosomal recessive c) X-linked dominant d) X-linked recessive e) none of the above Presence of only one copy of the X chromosome in males (XVI of some species produces a condition called___. a) haploidy b) monosomy c) hemizygosity d) haploinsufficiency e) none of the above, it is lethal A gene___ a) is a specific segment of DNA b) is a basic unit of biological information c) serves as a functional unit by encoding a particular RNA or protein d) a and c only e) a, b and c A mutation is___ a) a heritable alteration in DMA sequence b) source of new alleles c) a non-heritable change in the DNA structure d) a and b are true e) a and c are true A Drosophila recessive mutant allele called ruby (rb) causes ruby eye phenotype. In order to determine its localization a cross was set up between true breeding ruby female and wild type(red-eyed) male. If the mutation is X_linked, the expected F_2 offspring will show the following phenotypic ratio: a) 1 ruby female: 1 wild type female: 1 ruby male: 1 wild type male b) 3 ruby females: 1 wild type male c) 1 ruby female: 1 wild type male d) all females and males wild type e) 1 wild type female: 1 ruby male When working with Drosophila crosses, the P_1 should be transferred to a new vial before the F_1 emerge. a) true b) false

Solution

22. The Answer is option d.

According to Mendel\'s theory of dihybrid cross with only dominant/recessive allele present F2 phenotype ratio is 9:3:3:1. Out of 16 possible, 9 combinations produce offspring with both dominant phenotypes. Here it is blue color withthick wings.

23. The Answer is option a.

Different chromosome types (metacentric, submetacentric, acrocentric and telocentric) can be distinguished based on the position of centromere.

24. The Answer is option e. - none of the above

Karyotype is the number and appearance of chromosomes in the nucleus of eukaryotic cells. The term is also used for complete set of chromosomes of the species.

25. The Answer is option b.

XXY represents klinefelter syndrome. Men with Klinefelter syndrome have a single Barr body.

27. The Answer is option e.

The posibility of A,O allele in mother and B, O allele in father is there. The combination for progeny can result into any type of blood group. Type A, Type AB, Type O and Type B. Therefore the option all of the above blood types are possible is correct.

28. The Answer is option b.

The condition with 47,XX+18 is called Edwards syndrome, also known as trisomy 18.