A few Questions for BSc 5th Sem , from 2012 ,Botany Honours, TU

1. Answer in brief :.                  1 mark each

(a) What do you understand by map unit ?

(b)Define pseudoalleles.

(c)What is incomplete linkage ?

(d) What are Okazaki framents?

(e) Define frameshift mutation .

(f)What is synthetic cross ?

(g)What is meant by somatic embryo ?

(h)Differentiate between continuous and discontinuous variable .

(i) What is restorer gene ?

(2) What is equational division ? Why is meiotic division -l called reductional division ? If reduction occurs in 1st division of meiosis, why is there necessity for 2nd division to complete process of meiosis? Why is meiotic division-l not considered as true reduction division when crossing over occurs at prophase -l ? What is MPF ? Illustrate the role of p 34 protein kinase in progression of mitotic cell cycle.

2+2+2+2+2+5=15

(3) Define polysome . Mention the types of RNA and their occurrences that are found  in 80S & 70 S ribosomes . Describe the 'Fluid Mosaic ' model of the plasma membrane .2+(3+3)+7=15

(4) Why is incomplete dominance called blending inheritance ? What is epistasis ? Explain the dominant epistasis with suitable example .Differentiate between supplementary and comlementary factor. 2+2+7+4=15

(5) Define linkage .What is the significance of three-point test cross ? In maize ,A,B and D are three linked genes , with a, b and  d being recessive alleles of these three genes respectively .A homozyous normal strain was crossed to a triple homozygous recessive strain. The resulting F1 progeny were crossed to the triple recessive again ; the resulting progeny phenotypes were 

a B d----120

a b d----297

A B d----66

A b D----72

A B D ----301

a b D----131

a B D----13

which genotype  class is found missing ? Show the correct order of the genes A, B and  D .Construt a map showing the distances between the genes and calculate coefficient of coincidence .

2+3+(1+3+3+3)=15.

(6) Define genetic code . With suitable evidences, prove that genetic code is (i) in triplet and (ii) universal in nature .What is transcription bubble ? Mention the role sigma subunit of prokaryotic RNA polymerase. 2+(5+3)+3+2=15

(7) Define mutation at molecular level . Distinguish between transition and transversion .Show that nitrous acid induces transition in both <-->GC directions .What are missense and nonsense mutations ? 1+3+(4+4)+3=15

(8) What is heterosis ? Explain the genetical basis of heterosis with suitable examples. Distinguish between primary trisomic and secondary trisomoc .What is Triticale ? 2+7+3+3=15

(9)What is chi-square test ? When Yatescorrection is used in chi-square test ? In the primrose pure red flowered plants are crossed with white flowered plants, F1 are all pinked coloured.Inbreed F1 plants produced 113 red, 242 pink and 129 white.Analyse the result with suitable statistical test (x² value at 0.05 for 2 d.f. is 5.99).Write the classical definition of probability .Mention its limitations .A bag contains 5 blue balls and 10 red balls. What is the probability of drawing a blue ball ?(2+2+5)+(2+2+2)=15

(10) What is totipotency ? Why are all cells not totipotent in culture? What is callus tissue ? Describe the protocol of callus culture. Explain the genetic basis of chromosome variation in callus tissue.2+2+1+6+4=15

(11) Characterise the different types of restriction endonuclease. What is C-DNA? Discuss how C-DNA libraries are constructed.Mention its importance.4+2+7+2=15