Question

DNA has a strong attraction to nucleosomes because: Question 5 Not yet answered Points out of 2.50 P Flag question Select one: O a. DNA is positively charged and nucleosomal histones are negatively charged O b. DNA and nucleosomal histones are both positively charged and associate together O c. DNA and nucleosomal histones are both neutral and associate togethe о d. DNA and nucleosomal histones are both negatively charged and associate together о e. DNA is negatively charged and nucleosomal histones are positively charged

Answer 1

5) DNA is negatively charged, histone proteins are rich in positively charged amino acids arginine and lysine, so histone proteins are positively charged.

Nucleosome is the DNA wrapped around histone octamer.

so the answer is e) DNA is negatively charged and nucleosomal histones are positively charged.

7) Ab/aB is crossed with ab/ab ( test cross)

the parental type gametes produced by Ab/aB are Ab and aB, recombinant type gametes are AB and ab.

Ab/aB *ab/ab

	AB	Ab	aB	ab
ab	AB/ab	Ab/ab	aB/ab	ab/ab

recombinant progenies are formed from the recombinant gametes, ab is recombinant gamete, so ab/ab progeny is recombinant progeny.

recombination frequency is the percentage of recombinant progenies.

recombination frequency= (number of recombinant progenies/total number)$\times$100

distance between genes is 32 map units, so recombination frequency between genes is 32%.

recombination frequency in percentage is the distance between genes in map units.

so here percentage of ab/ab progeny + percentage of AB/ab progeny=32%

percentage of ab/ab progeny = percentage of AB/ab progeny=32/2=16%

( both recombinant progenies are expected in equal proportion)

expected number of ab/ab progenies among 100 progenies= 100$\times$16/100=16

so the answer is 16